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Stacking Winegard HD-6065P antennas
I'm looking for a source for a second Winegard HD-6065P antenna that I can stack with my existing one to increase the FM gain. At the moment I can pull in most Mt Wilson stations in San Diego, but only in mono. I realize an amplifier would likely do the job easier, but I think this would be a cool thing to do.
Cheers! Paul Pomes, DVM |
Stacking Winegard HD-6065P antennas
On Tue, 1 Jan 2013 14:07:45 -0800 (PST), Paul Pomes
wrote: I'm looking for a source for a second Winegard HD-6065P antenna that I can stack with my existing one to increase the FM gain. At the moment I can pull in most Mt Wilson stations in San Diego, but only in mono. I realize an amplifier would likely do the job easier, but I think this would be a cool thing to do. Cheers! Paul Pomes, DVM If you have lots of lossy coax cable and a typically insensitive consumer grade receiver, an amplifier might give you 10dB of gain. A second stacked antenna will give you exactly 3dB gain. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Quote:
On 88 - 108 MHz there is not a lot of loss - hence there is not a lot to be gained by using a preamplifier. Winegard maintains a web site which can be accessed via internet - what you need is a antenna with better rejection and more forward gain. Because you did not post a physical address, there is no way for sure for me to give you accurate information - because my crystal ball is broken... Go to FM Fool.com and post your address and you will get a beam heading and distance to the transmitters. It will also show a graph with what is between the transmit and the receive antenna's... FM works on the principal of capture effect - hence it will receive the strongest signals and reject all others. Your problem might be that you have another station on the same frequency or close by that is stronger then the signal you desire... The Winegard 7694 - 7698P antenna's are a very good source for better reception. You might also want to incorporate a good antenna rotor... |
Stacking Winegard HD-6065P antennas
"only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one.
John K9RZZ |
Stacking Winegard HD-6065P antennas
On Tuesday, January 1, 2013 4:07:45 PM UTC-6, Paul Pomes wrote:
I'm looking for a source for a second Winegard HD-6065P antenna that I can stack with my existing one to increase the FM gain. At the moment I can pull in most Mt Wilson stations in San Diego, but only in mono. I realize an amplifier would likely do the job easier, but I think this would be a cool thing to do. Cheers! Paul Pomes, DVM Oh, he Dear John, Stacking 2 HD6065P antennas in the same direction for gain you would mount them 72" apart vertically from boom to boom. The phasing line will be 52" long each +/- 1/8" of each other in length. The phasing lines will feed a CC-7870 coupler to combine the signals. Your single output is now you signal. Cordially, Hans Rabong Tech. Service Manager. Winegard Company |
Stacking Winegard HD-6065P antennas
wrote in message ... Dear John, Stacking 2 HD6065P antennas in the same direction for gain you would mount them 72" apart vertically from boom to boom. The phasing line will be 52" long each +/- 1/8" of each other in length. The phasing lines will feed a CC-7870 coupler to combine the signals. Your single output is now you signal. Cordially, Hans Rabong Tech. Service Manager. Winegard Company Unless I am missing something, seems like a waste of antenna and money. I looked for the coupler and found this: "You have the CC-7870 hooked up properly. However this coupler is just like a 2-way splitter hooked up in reverse; in that it will reduce the signal from each antenna by about 30%. " If it is just a 2 way splitter in reverse, there is usually a 3 db loss and all you get with 2 antennas is a gain of 3 db, so you gain nothing over a single antenna with this coupler. To get close to 3 db of gain you need to have a combiner of near zero loss. This is often done by using an odd number of wavelenghts of feedline of a differant impedance and hooking them in parallel to keep the impedance the same. I doubt it would work very well over the while FM band,but may for a small portion of it. I don't know how big the antenna is, but you would be beter off with a single larger antenna, or possiably an amplifier. Maybe an even beter feedline. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com |
Stacking Winegard HD-6065P antennas
On Sat, 4 Jan 2014 11:14:23 -0500, "Ralph Mowery"
wrote: Unless I am missing something, seems like a waste of antenna and money. Nope. Stacking antennas works. Analysis of the HD-6066P antenna. http://www.ham-radio.com/k6sti/hd6065p.htm "You have the CC-7870 hooked up properly. However this coupler is just like a 2-way splitter hooked up in reverse; in that it will reduce the signal from each antenna by about 30%. " Since when do we measure signal levels in percent? Decibels would be nice. http://www.solidsignal.com/pview.asp?p=cc7870&d=winegard-cc-7870-2-way-tv-antenna-joiner-coupler-(cc7870) If it is just a 2 way splitter in reverse, there is usually a 3 db loss and all you get with 2 antennas is a gain of 3 db, so you gain nothing over a single antenna with this coupler. Nope. Let's pretend for a moment that there's no loss in the splitter/coupler. If you feed a signal into the common (output) port, the RF power is split equally between the other two (input) ports for a -3dB loss per port. However, if you feed a signal into either ONE of the two (input) ports, all of the signal will appear on the common (output) port. That's because there's about 20dB of isolation between the two (input) ports so that no RF is lost going out the other (input) port. If you have the same signal (in phase) going into both the two (input) ports, they add, producing a combined signal 3dB higher. However, reality requires that the combiner has some loss. Usually, that's about -0.5dB per (input) port for a total loss of 1dB. So, instead of 3dB gain with the stacking arrangement, you will see about 2dB gain. The -0.5dB loss varies across the band and tends to be higher at the extreme frequencies, and less in the middle. To get close to 3 db of gain you need to have a combiner of near zero loss. This is often done by using an odd number of wavelenghts of feedline of a differant impedance and hooking them in parallel to keep the impedance the same. I doubt it would work very well over the while FM band,but may for a small portion of it. Yep. That's the problem. The splitter/combiner is a broadband device, that will work over the entire TV band. 5-1000 MHz is common. Not so if you remove the splitter/combiner and simply parallel the phasing lines. That's a narrow band device that works over a narrow frequency range determined by the length of the phasing lines. That's not what you would want with a TV antenna. However, the HD-6065P is a FM band only Yagi, which might work without the splitter combiner, but as you mention, probably will not work over the entire FM band. I don't know how big the antenna is, but you would be beter off with a single larger antenna, or possiably an amplifier. Maybe an even beter feedline. If you use a Yagi antenna, you would need to approximately double the length of the boom in order to obtain an additional 3dB of gain. The boom on the HD-6065P is 128 inches long. I would hate to see a similar antenna with a boom twice as long. Yagi antennas also tend to be more narrow band than Gray Hoverman antennas for TV use. For FM band only, gain is more important, so a Yagi is probably best. For TV, I prefer a Gray Hoverman. Incidentally, for TV, you can compare the characteristics between both types for real antennas at: http://www.hdtvprimer.com/ANTENNAS/types.html http://www.hdtvprimer.com/ANTENNAS/comparing.html http://www.hdtvprimer.com/antennas/temporarypage.html -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Stacking Winegard HD-6065P antennas
In message , Ralph
Mowery writes wrote in message ... Dear John, Stacking 2 HD6065P antennas in the same direction for gain you would mount them 72" apart vertically from boom to boom. The phasing line will be 52" long each +/- 1/8" of each other in length. The phasing lines will feed a CC-7870 coupler to combine the signals. Your single output is now you signal. Cordially, Hans Rabong Tech. Service Manager. Winegard Company Unless I am missing something, seems like a waste of antenna and money. I looked for the coupler and found this: "You have the CC-7870 hooked up properly. However this coupler is just like a 2-way splitter hooked up in reverse; in that it will reduce the signal from each antenna by about 30%. " If it is just a 2 way splitter in reverse, there is usually a 3 db loss and all you get with 2 antennas is a gain of 3 db, so you gain nothing over a single antenna with this coupler. To get close to 3 db of gain you need to have a combiner of near zero loss. This is often done by using an odd number of wavelenghts of feedline of a differant impedance and hooking them in parallel to keep the impedance the same. I doubt it would work very well over the while FM band,but may for a small portion of it. I don't know how big the antenna is, but you would be beter off with a single larger antenna, or possiably an amplifier. Maybe an even beter feedline. Strange as it may seem, if you use (for example) a TV 2-way '3dB' splitter to combine two identical in-phase signals, you DON'T lose 3dB. Apart from the unavoidable slight inherent losses of the two transformers the circuit uses (a total of around 0.5dB at low VHF, increasing to 1dB at high UHF), the splitter is lossless. Ignoring the transformer loss, the 3dB loss occurs simply because the power at each output port is half of that at the input. You haven't actually lost anything. If the splitter is now turned around to become a combiner, it doesn't suddenly become more lossy. If you again ignore the transformer losses, the two identical in-phase signals you feed into the 'output' ports are added, and the result is a signal 3dB higher. An interesting experiment would be to cascade two splitters - the first used as a splitter, and the second used to combine the two split signals (via identical lengths of coax). The loss (because of the transformers) should be only 1dB (low VHF) to around 2dB (high UHF), and not 7 to 8dB. -- Ian |
Stacking Winegard HD-6065P antennas
"Jeff Liebermann" wrote in message ... On Sat, 4 Jan 2014 11:14:23 -0500, "Ralph Mowery" wrote: Unless I am missing something, seems like a waste of antenna and money. Nope. Stacking antennas works. Analysis of the HD-6066P antenna. http://www.ham-radio.com/k6sti/hd6065p.htm "You have the CC-7870 hooked up properly. However this coupler is just like a 2-way splitter hooked up in reverse; in that it will reduce the signal from each antenna by about 30%. " Since when do we measure signal levels in percent? Decibels would be nice. http://www.solidsignal.com/pview.asp?p=cc7870&d=winegard-cc-7870-2-way-tv-antenna-joiner-coupler-(cc7870) I agree that stacking antennas works, the problem I have is the type of combiner that is used. The 30% was from another web site and I assume it was from someone at the Winegard factory. Not sure why he would say 30% instead of db. Even so 30 % is nowhere near the 3.5 db listed in the ad. From the url you gave, the spec is for 3.5 db which is around what I would think it could be if simple resistors were used. That combiner seems to be made not for stacking antennas for more gain, but to combine several antennas either pointed at differant directions or so a single feedline could be used for a TV and FM antenna or where you hae seperate antennas on the same mast for UHF and VHF. As the specs is for a 3.5 db loss, I assume that is if you hook up two antennas to it, the antennas will have a gain of 3 db at the most, then you go to the combiner and loose 3.5 db for an overall loss of .5 db. That is where I don't see stacking two antennas and using that combiner for more signal strength. I do agree that to get 3 db of gain from the antenna it would need to be about twice as long. I did not look up to antenna to see that it was about 10 feet long already. A 20 foot long antenna would be large, but so would two antennas 10 feet long and seperated by around 5 feet. Maybe not too bad as I have several antennas on booms that are close to 15 feet long stacked about 5 feet apart. Not the best, but it was what I could do for what I had to work with. You can see them on my QRZ.com page under KU4PT. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com |
Stacking Winegard HD-6065P antennas
"Ian Jackson" wrote in message Strange as it may seem, if you use (for example) a TV 2-way '3dB' splitter to combine two identical in-phase signals, you DON'T lose 3dB. Apart from the unavoidable slight inherent losses of the two transformers the circuit uses (a total of around 0.5dB at low VHF, increasing to 1dB at high UHF), the splitter is lossless. Ignoring the transformer loss, the 3dB loss occurs simply because the power at each output port is half of that at the input. You haven't actually lost anything. If the splitter is now turned around to become a combiner, it doesn't suddenly become more lossy. If you again ignore the transformer losses, the two identical in-phase signals you feed into the 'output' ports are added, and the result is a signal 3dB higher. Jeff found a url with the specs for the combiner. http://www.solidsignal.com/pview.asp?p=cc7870&d=winegard-cc-7870-2-way-tv-antenna-joiner-coupler-(cc7870) It says 3.5 db of loss. I assume they use the simple resistor network instead of transformers. If so, then the net results not counting feedline loss would be a minus .5 db. That combiner does not seem to be made to add signals from idinitical antennas for more gain, but just to let you use one feedling for several differant antennas such as putting a FM antenna up and a TV antenna up, or a seperate UHF and VHF antenna up and using one feedline to the receiver. I have one for designed for my ham transceivers,and have measured less than .5 db of loss, but that is for differant frequency ranges and not to combind two antennas on the same band. Even if he does get the maximum of 3 db of gain, will that acutally get him anywhere ? Will that be enough gain for the FM broadcast band to be noticiable ? --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com |
Stacking Winegard HD-6065P antennas
In message , Ralph
Mowery writes "Ian Jackson" wrote in message Strange as it may seem, if you use (for example) a TV 2-way '3dB' splitter to combine two identical in-phase signals, you DON'T lose 3dB. Apart from the unavoidable slight inherent losses of the two transformers the circuit uses (a total of around 0.5dB at low VHF, increasing to 1dB at high UHF), the splitter is lossless. Ignoring the transformer loss, the 3dB loss occurs simply because the power at each output port is half of that at the input. You haven't actually lost anything. If the splitter is now turned around to become a combiner, it doesn't suddenly become more lossy. If you again ignore the transformer losses, the two identical in-phase signals you feed into the 'output' ports are added, and the result is a signal 3dB higher. Jeff found a url with the specs for the combiner. http://www.solidsignal.com/pview.asp...cc-7870-2-way- tv-antenna-joiner-coupler-(cc7870) $18.99? They're having a laff! $5 max. It says 3.5 db of loss. I assume they use the simple resistor network instead of transformers. If so, then the net results not counting feedline loss would be a minus .5 db. A typical TV 2-way equal splitter has 3dB splitting loss (because it splits the signal in two), plus a little loss in the two ferrite-cored RF transformers inside. The spec is usually something like 3.5dB at 50MHz, increasing to 4 or 4.5dB at 900MHz. A resistive 2-way star or delta splitter/combiner has a loss of 6dB (3 due to the splitting, and 3 in the resistors), However, whereas the 3dB transformer splitter theoretically has infinite isolation between the outputs (when the input is terminated) - and in practice it is 25 to 40dB - the 6dB resistive splitter/combiner has only 6dB (essentially, all three ports are interchangeable). That combiner does not seem to be made to add signals from idinitical antennas for more gain, but just to let you use one feedling for several differant antennas such as putting a FM antenna up and a TV antenna up, or a seperate UHF and VHF antenna up and using one feedline to the receiver. It is extremely bad practice to use a wideband combiner to connect two antennas pointing in different directions. For analogue signals, that's a sure recipe for multipath and ghosting - and it can't be good for digitals either. The combiner needs to be filtered (eg a diplexer), so that one antenna provides signals (on the appropriate frequencies) from one direction, and the other antenna provides signals (on the appropriate frequencies) from the other direction. I have one for designed for my ham transceivers,and have measured less than .5 db of loss, but that is for differant frequency ranges and not to combind two antennas on the same band. That sounds like a diplexer (frequency selective), and not a wideband splitter/combiner. These can indeed be low loss, as they consist of frequency-selective (or lowpass-highpass) filters connected to a common port, and there is no need for wideband combining/splitting. Even if he does get the maximum of 3 db of gain, will that acutally get him anywhere ? Will that be enough gain for the FM broadcast band to be noticiable ? Well, every little helps! -- Ian |
Stacking Winegard HD-6065P antennas
"Ian Jackson" wrote in message Strange as it may seem, if you use (for example) a TV 2-way '3dB' splitter to combine two identical in-phase signals, you DON'T lose 3dB. Apart from the unavoidable slight inherent losses of the two transformers the circuit uses (a total of around 0.5dB at low VHF, increasing to 1dB at high UHF), the splitter is lossless. Ignoring the transformer loss, the 3dB loss occurs simply because the power at each output port is half of that at the input. You haven't actually lost anything. If the splitter is now turned around to become a combiner, it doesn't suddenly become more lossy. If you again ignore the transformer losses, the two identical in-phase signals you feed into the 'output' ports are added, and the result is a signal 3dB higher. I don't have a TV splitter/combiner to play with. I do have a MiniCircuits combiner I have been playing with. http://www.minicircuits.com/pdfs/ZFSC-2-2.pdf I am not sure what is in the combiner but it must be transformers of some type as the resistance of the ports are near zero ohms. Their specs is for a 3 db loss and then an aditional loss of about .2 to 1.2 depending on the frequecy. Are you sure that is not the case where you are saying you do not loose the 3 db ? That is the ratings is for the extra ..5 or so not counting the already 3 db of loss. Maybe you can tell me if I am playing with the wrong type of combiner.. Here are some results of my tests. using a HP 8924C service monitor and another signal generator. With one input port of the combiner having a signal and the other port terminated with a 50 ohm load (the nominal impedance of all devices) there is a 3 db loss (small values not being included) not the low values you mention to the output port. When I hook up the other signal generator, I get from almost a total of 0 db to 6 db of loss. I asume the spectrum analizer going from 0 to 6 db is the phasing of the two generators. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com |
Stacking Winegard HD-6065P antennas
On 1/4/2014 5:40 PM, Ralph Mowery wrote:
snip As the specs is for a 3.5 db loss, I assume that is if you hook up two antennas to it, the antennas will have a gain of 3 db at the most, then you go to the combiner and loose 3.5 db for an overall loss of .5 db. That is where I don't see stacking two antennas and using that combiner for more signal strength. Jeff is correct. Your error is believing the combiner has 3.5db loss. When splitting a signal, you do have about a 3.5db loss per output, because the signal is halved plus a bit of additional loss. However, when combining the signals, the signal is NOT halved, so you don't have the 3db loss there. You only have about 0.5db loss (more or less, depending on the quality of the combiner and other factors). Let's take an example. Since a combiner is just a splitter turned around, we'll start with the splitter end. Let's feed 2mw to the input of the splitter. This means each output gets 1mw (3db loss) (we could use voltage also, but since power is E^2/R, it's not so straightforward). So now each leg has 1mw on it. Now let's turn the splitter around and make it a combiner and feed two signals, 1mw ea., same frequency, to the inputs to the combiner. Since this is a totally passive device, the effects are reversible. If the signals are 180 degrees out of phase, of course the output is 0. However, if the two signals are in phase with each other, the putout is 2mw. Note there is no 3db loss in the combiner. But of course this assumed a "perfect" combiner, with no losses. In reality, the combiner will have a bit of loss (typically 0.5db as noted above), so the output from the splitter will be slightly less than 1mw and the output from the combiner will be slightly less than 2mw. Does this help clarify things? And yes, phasing harnesses work the same way. The can be either splitters or combiners, depending on how they are used. The advantage is they have less loss; the disadvantage, as noted, is they have a much narrower effective bandwidth. -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
Stacking Winegard HD-6065P antennas
"Jerry Stuckle" wrote in message ... Jeff is correct. Your error is believing the combiner has 3.5db loss. When splitting a signal, you do have about a 3.5db loss per output, because the signal is halved plus a bit of additional loss. However, when combining the signals, the signal is NOT halved, so you don't have the 3db loss there. You only have about 0.5db loss (more or less, depending on the quality of the combiner and other factors). Let's take an example. Since a combiner is just a splitter turned around, we'll start with the splitter end. Let's feed 2mw to the input of the splitter. This means each output gets 1mw (3db loss) (we could use voltage also, but since power is E^2/R, it's not so straightforward). So now each leg has 1mw on it. Now let's turn the splitter around and make it a combiner and feed two signals, 1mw ea., same frequency, to the inputs to the combiner. Since this is a totally passive device, the effects are reversible. If the signals are 180 degrees out of phase, of course the output is 0. However, if the two signals are in phase with each other, the putout is 2mw. Note there is no 3db loss in the combiner. But of course this assumed a "perfect" combiner, with no losses. In reality, the combiner will have a bit of loss (typically 0.5db as noted above), so the output from the splitter will be slightly less than 1mw and the output from the combiner will be slightly less than 2mw. Does this help clarify things? And yes, phasing harnesses work the same way. The can be either splitters or combiners, depending on how they are used. The advantage is they have less loss; the disadvantage, as noted, is they have a much narrower effective bandwidth. What I am having trouble with is the 'perfect' combiner. The one by Wineguard specs 3.5 db loss and the MiniCircuits I have specs at 3 db plus slightly more depending on frequency. I had forgotten that I built one years ago out of the ARRL Handbook. They give it a spec of 6 db of loss per port. The one I built has that not counting minor errors and loss. Just checked it out. My problem is where are you going to find a combiner for a broad frequency that does not have any large (say over 1 db ) of loss ? Are the ones for the TV frequencies built differant ? For the splitters, I see the 3 db because the signal is going to two places (3 db equals half power as we all know). But then the problem I am having is the extra 3 db that is lossed in the combiner instead of just half of a db or so. Has anyone actually put one on accurate test equipment to see about the loss like I have been trying to do ? I understand phasing harnesses for antennas. They are almost loseless. Only a few feet of coax worth. I have used them on antennas before. They are not usually very broad banded unless the antennas are broad banded and made so the impedance is not the nominal 50 ohms. That is for comercial 4 or 8 dipole arays for VHF/UHF. Lots of 'tricks' used to do that. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com |
Stacking Winegard HD-6065P antennas
On 1/4/2014 9:23 PM, Ralph Mowery wrote:
"Jerry Stuckle" wrote in message ... Jeff is correct. Your error is believing the combiner has 3.5db loss. When splitting a signal, you do have about a 3.5db loss per output, because the signal is halved plus a bit of additional loss. However, when combining the signals, the signal is NOT halved, so you don't have the 3db loss there. You only have about 0.5db loss (more or less, depending on the quality of the combiner and other factors). Let's take an example. Since a combiner is just a splitter turned around, we'll start with the splitter end. Let's feed 2mw to the input of the splitter. This means each output gets 1mw (3db loss) (we could use voltage also, but since power is E^2/R, it's not so straightforward). So now each leg has 1mw on it. Now let's turn the splitter around and make it a combiner and feed two signals, 1mw ea., same frequency, to the inputs to the combiner. Since this is a totally passive device, the effects are reversible. If the signals are 180 degrees out of phase, of course the output is 0. However, if the two signals are in phase with each other, the putout is 2mw. Note there is no 3db loss in the combiner. But of course this assumed a "perfect" combiner, with no losses. In reality, the combiner will have a bit of loss (typically 0.5db as noted above), so the output from the splitter will be slightly less than 1mw and the output from the combiner will be slightly less than 2mw. Does this help clarify things? And yes, phasing harnesses work the same way. The can be either splitters or combiners, depending on how they are used. The advantage is they have less loss; the disadvantage, as noted, is they have a much narrower effective bandwidth. What I am having trouble with is the 'perfect' combiner. The one by Wineguard specs 3.5 db loss and the MiniCircuits I have specs at 3 db plus slightly more depending on frequency. I had forgotten that I built one years ago out of the ARRL Handbook. They give it a spec of 6 db of loss per port. The one I built has that not counting minor errors and loss. Just checked it out. A perfect combiner (like anything else "perfect") doesn't exist. But it is a very common (and handy) way of specifying how things work. It's used all over the place in EE degree programs, for instance. So you start with the perfect item, then add losses, phase shifts, etc. as they occur to get a "real" part. My problem is where are you going to find a combiner for a broad frequency that does not have any large (say over 1 db ) of loss ? Are the ones for the TV frequencies built differant ? There are good combiners and bad combiners. The commercial grade ones we use typically have 1db loss from 50Mhz to 2Ghz. Note that these are basically splitters which are reversed to form combiners, when necessary. For the splitters, I see the 3 db because the signal is going to two places (3 db equals half power as we all know). But then the problem I am having is the extra 3 db that is lossed in the combiner instead of just half of a db or so. In a good quality combiner, there is no extra 3db of loss. Has anyone actually put one on accurate test equipment to see about the loss like I have been trying to do ? I haven't actually measured it myself, but I do use commercial grade splitters/combiners (not as much any more because a lot of video has gone digital). Typical loss as a combiner is around 0.5 - 0.7 db from 50Mhz to 2Ghz. But you also won't find these at Radio Shack or Best Buy. And there are testing labs out there who do test these things; if any of the ratings were off, the manufacture would quickly lose credibility in commercial circles. I understand phasing harnesses for antennas. They are almost loseless. Only a few feet of coax worth. I have used them on antennas before. They are not usually very broad banded unless the antennas are broad banded and made so the impedance is not the nominal 50 ohms. That is for comercial 4 or 8 dipole arays for VHF/UHF. Lots of 'tricks' used to do that. Phasing harnesses are just another form of splitter/combiner. One way they combine; turn them around and they split. That's why they work for both transmitting and receiving. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
Stacking Winegard HD-6065P antennas
On Sat, 4 Jan 2014 17:40:20 -0500, "Ralph Mowery"
wrote: I agree that stacking antennas works, the problem I have is the type of combiner that is used. Well, one could always use an active combiner. For just the FM band, that's quite easy. The 30% was from another web site and I assume it was from someone at the Winegard factory. Not sure why he would say 30% instead of db. This may help explain the problem: http://www.journalistunits.com It doesn't include most electronic units of measure, but I think you see the problem. Even so 30 % is nowhere near the 3.5 db listed in the ad. From the url you gave, the spec is for 3.5 db which is around what I would think it could be if simple resistors were used. Nope. A resistive combiner/splitter is -6dB. http://www.microwaves101.com/encyclopedia/resistive_splitters.cfm "Resistive power dividers are easy to understand, can be made very compact, and are naturally wideband, working down to zero frequency (DC). Their down side is that a two-way resistive splitter suffers 10xlog(1/2) or 3.0103 dB of real resistive loss, as opposed to a lossless splitter like a hybrid. Accounting for 3.0103 dB real loss and 3.0103 dB power split, the net power transfer loss you will observe from input to one of two outputs is 6.0206 dB for a two-way resistive splitter, so they are often called 6 dB splitters. Dig?" That combiner seems to be made not for stacking antennas for more gain, but to combine several antennas either pointed at differant directions or so a single feedline could be used for a TV and FM antenna or where you hae seperate antennas on the same mast for UHF and VHF. When one combines two different band antennas, the usual method is a diplexer. Since the receiver only sees one antenna on each band, the impedance is constant. A low pass filter can also be made very low loss if you don't care much about rolloff and ripple. However, if we're down to the point where small fractions of a dB produce a noticeable difference, I suspect that additional gain (tower mounted pre-amp) or less loss (better coax cable) will be more important. Something like this: http://www.solidsignal.com/pview.asp?p=uvsj 0.5 dB insertion loss. Oh well. As the specs is for a 3.5 db loss, I assume that is if you hook up two antennas to it, the antennas will have a gain of 3 db at the most, then you go to the combiner and loose 3.5 db for an overall loss of .5 db. Please re-read what I wrote. From each of the (input) ports to the receiver port (output), there is only 0.5dB of loss. If two antennas provide an additional 3dB of gain, and each port gobbles 0.5dB, then the combined gain is 2dB. That is where I don't see stacking two antennas and using that combiner for more signal strength. Would you rather make the yagi twice as long? Once we get to very large antennas, 3dB of additional gain can easily become a mechanical challenge. I do agree that to get 3 db of gain from the antenna it would need to be about twice as long. I did not look up to antenna to see that it was about 10 feet long already. A 20 foot long antenna would be large, but so would two antennas 10 feet long and seperated by around 5 feet. Note that FM broadcast stations with directional antennas use various vertically mounted antennas, not Yagis. They're interested in survivability as well as gain and pattern. A 20ft long antenna is possible, but I don't think anyone wants to climb the tower and drop the antenna to fix a broken element. That's much easier with a side mounted barbeque grill type antenna, stacked dipoles, crossed dipoles, horizontal loops, etc. Maybe not too bad as I have several antennas on booms that are close to 15 feet long stacked about 5 feet apart. Not the best, but it was what I could do for what I had to work with. You can see them on my QRZ.com page under KU4PT. You probably don't have overweight birds sitting on your yagi elements. Yes, it can be made to work but it's so much easier and neater to do it with a combiner. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Stacking Winegard HD-6065P antennas
On Sat, 4 Jan 2014 21:23:14 -0500, "Ralph Mowery"
wrote: What I am having trouble with is the 'perfect' combiner. I feel your pain. Many years ago, I made a similar mistake on the NEC antenna modeling mailing list. I then processed to make a total fool of myself and had to be corrected by the experts. Even so, I still didn't believe it so I built a Wilkinson combiner and bench tested it for loss. I still have the combiner somewhere as a reminder of my mistake. Incidentally, a Wilkinson combiner might be a tolerable solution for combining two FM antenna. The loss is much less than a bifilar wound toroid. I'm not sure if it will work over the entire FM band. I can grind the numbers if anyone is interested. My problem is where are you going to find a combiner for a broad frequency that does not have any large (say over 1 db ) of loss ? Are the ones for the TV frequencies built differant ? There's only so much you can do with passive only designs. The next step up is an active combiner: http://www.rldrake.com/product-ac1686.php 0-3dB gain per port. 54 to 860 MHz. Has anyone actually put one on accurate test equipment to see about the loss like I have been trying to do ? Yep. I have. There's very little loss between the combiner input ports and the "sum" port. However, in the other direction, there's a bit over 3dB loss due to the power splitting. See the specs on the MCL splitter/combiner that you have and try it with a service monitor or generator. Since it works down to 10 MHz, you might be able to do the test with a function generator, a few dummy loads, some T connectors, and an oscilloscope. I understand phasing harnesses for antennas. They are almost loseless. Only a few feet of coax worth. I have used them on antennas before. They are not usually very broad banded unless the antennas are broad banded and made so the impedance is not the nominal 50 ohms. That is for comercial 4 or 8 dipole arays for VHF/UHF. Lots of 'tricks' used to do that. It's low, but the phasing harness loss for stacked vertical dipoles is not zero. I've never calculated or measured it, but this might help: http://www.kg4jjh.com/pdf/2-Meter%20Vertical%20Dipole%20Array.pdf "The phasing harness loss at 150 MHz is calculated to be 0.67 dB." Scaled for 100 Mhz, I would guess about 0.5 dB. Might as well use a combiner/splitter. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Stacking Winegard HD-6065P antennas
"Jeff Liebermann" wrote in message ... On Sat, 4 Jan 2014 21:23:14 -0500, "Ralph Mowery" wrote: What I am having trouble with is the 'perfect' combiner. I feel your pain. Many years ago, I made a similar mistake on the NEC antenna modeling mailing list. I then processed to make a total fool of myself and had to be corrected by the experts. Even so, I still didn't believe it so I built a Wilkinson combiner and bench tested it for loss. I still have the combiner somewhere as a reminder of my mistake. Incidentally, a Wilkinson combiner might be a tolerable solution for combining two FM antenna. The loss is much less than a bifilar wound toroid. I'm not sure if it will work over the entire FM band. I can grind the numbers if anyone is interested. My problem is where are you going to find a combiner for a broad frequency that does not have any large (say over 1 db ) of loss ? Are the ones for the TV frequencies built differant ? There's only so much you can do with passive only designs. The next step up is an active combiner: http://www.rldrake.com/product-ac1686.php 0-3dB gain per port. 54 to 860 MHz. Has anyone actually put one on accurate test equipment to see about the loss like I have been trying to do ? Yep. I have. There's very little loss between the combiner input ports and the "sum" port. However, in the other direction, there's a bit over 3dB loss due to the power splitting. See the specs on the MCL splitter/combiner that you have and try it with a service monitor or generator. Since it works down to 10 MHz, you might be able to do the test with a function generator, a few dummy loads, some T connectors, and an oscilloscope. I understand phasing harnesses for antennas. They are almost loseless. Only a few feet of coax worth. I have used them on antennas before. They are not usually very broad banded unless the antennas are broad banded and made so the impedance is not the nominal 50 ohms. That is for comercial 4 or 8 dipole arays for VHF/UHF. Lots of 'tricks' used to do that. It's low, but the phasing harness loss for stacked vertical dipoles is not zero. I've never calculated or measured it, but this might help: http://www.kg4jjh.com/pdf/2-Meter%20Vertical%20Dipole%20Array.pdf "The phasing harness loss at 150 MHz is calculated to be 0.67 dB." Scaled for 100 Mhz, I would guess about 0.5 dB. Might as well use a combiner/splitter. -- I understand the idea of using 'perfect' items in electronics, then going for more exect calculations if needed. As most electronic items are often a 5 to 10 percent variation anyway. Often you get a close calculation and build it and trim for the desired results. I did take 2 year course in electronics engineering about 40 years ago for an associates degree, so know about perfect vers real components. The Wilkinson combiner is possiable for relative narrow frequencies. Not sure if building one out of descrete components or full size transmission lines would be broad enough for the whole FM band either. Wild guess it would be about the same if just two pieces of transmission line of the correct impedance and length were used. Isn't the Wilkinson combiner just two pieces of transmission line (or simulated with components) with a resistor across two of the ports to absorbe the diffeance if the loads/sources are not ballanced ? I know what they are and have seen equipment with them in it,but never did much of a study on it. As the subject is combining, I have not looked into the losses of splitting, but it would be 6 db for the simple resistor designs not counting the minor losses. That would be 3 db for the ports and 3 db lost in the resistors. To combind signals you would get the loss of the resistors of 3 db and a fraction of other loss. I am using a HP 8924C for a test set. It has just about everything you can think of for a service monitor. Calibrated from 30 to 1000 MHz but usuable uncalibrated to about a half of a mhz. http://www.amtronix.com/hp8924c60.htm As mentioned the only combiner I have is a MiniCircuits and they spec it at 3 db plus small losses depending on the frequency. That is what I am measuring. The diplexer/combiner will have very low loss. I have checked out 2 of them in the past just to see and the losses were about half a db or so. However that is for frequencies seperated by a very large percentage. Usually one port is a low pass and the other is a high pass filter. Not suited for signals on the same frequency as the origional poster wanted to do. Yes, phasing harnesses on antennas are not totally loseless, but will be mainly whatever the loss of the coax is between the elements. If were the origional poster and there were not too many transmitters near me, I would try a good preamp first. Mast mounted if possiable as it is for receive only. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com |
Stacking Winegard HD-6065P antennas
"Jerry Stuckle" wrote in message ... A perfect combiner (like anything else "perfect") doesn't exist. But it is a very common (and handy) way of specifying how things work. It's used all over the place in EE degree programs, for instance. So you start with the perfect item, then add losses, phase shifts, etc. as they occur to get a "real" part. I am awear of that 'perfect' vers 'real world'. Took a 2 year asociate degree in electronics engineering about 40 years ago. Most things are calculated close and then trimmed to take care of the usual 5 to 10 percent differance in components. That is why I was not worried about anything under a DB, but just the parts close to 3 db. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com |
Stacking Winegard HD-6065P antennas
In message , Ralph
Mowery writes "Ian Jackson" wrote in message Strange as it may seem, if you use (for example) a TV 2-way '3dB' splitter to combine two identical in-phase signals, you DON'T lose 3dB. Apart from the unavoidable slight inherent losses of the two transformers the circuit uses (a total of around 0.5dB at low VHF, increasing to 1dB at high UHF), the splitter is lossless. Ignoring the transformer loss, the 3dB loss occurs simply because the power at each output port is half of that at the input. You haven't actually lost anything. If the splitter is now turned around to become a combiner, it doesn't suddenly become more lossy. If you again ignore the transformer losses, the two identical in-phase signals you feed into the 'output' ports are added, and the result is a signal 3dB higher. I don't have a TV splitter/combiner to play with. I do have a MiniCircuits combiner I have been playing with. http://www.minicircuits.com/pdfs/ZFSC-2-2.pdf The spec says "• low insertion loss, 0.4 dB typ." This is the real loss - the loss that will make the splitter get warm when you feed a signal into it. I am not sure what is in the combiner but it must be transformers of some type as the resistance of the ports are near zero ohms. The usual basic circuit is: Input port to ground - a 2:1 impedance ratio step-down ferrite-cored autotransformer T1 to ground. T1 tap is connected to the centre tap of a second 1:1 ratio ferrite-cored autotransformer T2. Each end of T2 of connected to each output port. A 100* ohm resistor R is connected between the ends of T2 (ie between the output ports). *R is 2 x Zo, so for a 75 ohm system, it will be 150 ohms. Note the purpose of T2 and R is to provide isolation between the outputs (for signals coming back into the output ports). Their specs is for a 3 db loss and then an aditional loss of about .2 to 1.2 depending on the frequecy. Are you sure that is not the case where you are saying you do not loose the 3 db ? That is the ratings is for the extra .5 or so not counting the already 3 db of loss. For forward-going signals, T2 and R play no part in the operation of the circuit. The signal current from T1 tap enters T2 at its centre tap, splits, and flows outwards in opposite directions to the ends of T2. The magnetic flux created by the currents cancels out, so T2 presents no impedance whatsoever. In effect, it isn't there, and the two outputs are connected in parallel. The impedance presented to the centre tap of T1 is therefore 25 ohms, which is exactly what T1 is there for - to match the 50 ohm input to 25 ohms of the two (effectively) parallel outputs. So you see that apart from the unavoidable losses in the transformers and in the copper wire, there are no losses in this circuit. However, because the power emerging from each output is half the power of the input, the loss measures 3dB (plus a bit). If you can devise a passive 2-way equal splitter with less than 3dB loss, you will make a fortune! Maybe you can tell me if I am playing with the wrong type of combiner.. Here are some results of my tests. using a HP 8924C service monitor and another signal generator. Theoretically, this type of circuit has no loss (whether used as a splitter of an in-phase combiner). It's only the 'extra' losses that will give you trouble. The same is true of any other type of combiner, so which one you use may depend on which will have the least extra loss. If you don't need high (or any) isolation between the 'output' ports ('input' if a combiner), you might do better with one of the transmission line alternatives. With one input port of the combiner having a signal and the other port terminated with a 50 ohm load (the nominal impedance of all devices) there is a 3 db loss (small values not being included) not the low values you mention to the output port. When I hook up the other signal generator, I get from almost a total of 0 db to 6 db of loss. I asume the spectrum analizer going from 0 to 6 db is the phasing of the two generators. Not quite sure what you're doing here. However, for this circuit to act as a lossless combiner, it relies on there being no voltage across the resistor R. This means that the two input signals must in phase and of equal amplitude. Typical measurements for this sort of device would be (with all three ports correctly terminated): In to Out: 3.5dB Out to Out: 30dB With one Out unterminated (o/c or s/c): In to Out: 3.5 to 4dB With In unterminated (o/c or s/c): Out to Out: 7dB -- Ian |
Stacking Winegard HD-6065P antennas
"Ian Jackson" The usual basic circuit is: Input port to ground - a 2:1 impedance ratio step-down ferrite-cored autotransformer T1 to ground. T1 tap is connected to the centre tap of a second 1:1 ratio ferrite-cored autotransformer T2. Each end of T2 of connected to each output port. A 100* ohm resistor R is connected between the ends of T2 (ie between the output ports). *R is 2 x Zo, so for a 75 ohm system, it will be 150 ohms. Note the purpose of T2 and R is to provide isolation between the outputs (for signals coming back into the output ports). Now we are getting somewhere. The circuit you describe is differant from any that I have seen in my very short search for combiners. With nothing but transformers in the circuit I can see where the losses would only be part of a DB or so. Much differant than the combiners that I saw using either resistors or combinations of resistors and a single core 'transformer'. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com |
Stacking Winegard HD-6065P antennas
In message , Ralph
Mowery writes "Ian Jackson" The usual basic circuit is: Input port to ground - a 2:1 impedance ratio step-down ferrite-cored autotransformer T1 to ground. T1 tap is connected to the centre tap of a second 1:1 ratio ferrite-cored autotransformer T2. Each end of T2 of connected to each output port. A 100* ohm resistor R is connected between the ends of T2 (ie between the output ports). *R is 2 x Zo, so for a 75 ohm system, it will be 150 ohms. Note the purpose of T2 and R is to provide isolation between the outputs (for signals coming back into the output ports). Now we are getting somewhere. The circuit you describe is differant from any that I have seen in my very short search for combiners. With nothing but transformers in the circuit I can see where the losses would only be part of a DB or so. Much differant than the combiners that I saw using either resistors or combinations of resistors and a single core 'transformer'. This circuit is used in 1001 makes of wideband FM/TV splitters (typically 5 to 900+MHz) and even in satellite IF splitters up to 2100MHz. It is also widely used for combining signals on different frequencies (where the loss is indeed 3-plus-some dB). However, while it CAN be used for combining co-phased antennas, it's more usual to use transmission lines (as have been described). Note that the small ferrite-cored transformers are completely suitable for putting any real RF power into, but transmission lines don't have this problem. -- Ian |
Stacking Winegard HD-6065P antennas
wrote:
"only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg |
Stacking Winegard HD-6065P antennas
On 1/6/2014 1:28 AM, gregz wrote:
wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. -- ================== Remove the "x" from my email address Jerry Stuckle JDS Computer Training Corp. ================== |
Stacking Winegard HD-6065P antennas
On Mon, 6 Jan 2014 06:28:11 +0000 (UTC), gregz
wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Nope. Power is by the square of the voltage: P = V^2 / R If you double the voltage, you get 4 times the power. A 1.414 times increase in voltage will produce twice the power. I tried to convert the antenna model of the HD-6066P antenna from the AO .ant format to .nec using 4NEC2 and failed. The plan was to model the stacked arrangement and see what happens: http://www.ham-radio.com/k6sti/hd6065p.htm The .ant file imported without error, the wire tables and images look correct, but the pattern is more like a point source than a gain antenna. I'll look at it later to see where I screwed up, but it would be nice if someone would look at the problem. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Stacking Winegard HD-6065P antennas
Jerry Stuckle wrote:
On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg |
Stacking Winegard HD-6065P antennas
On 1/6/2014 10:19 PM, gregz wrote:
Jerry Stuckle wrote: On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg No, 2 microvolts would be four times the signal. Remember that power equals the voltage SQUARED divided by resistance. When you double the voltage, you also double the amperage (assuming resistance stays the same). -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
Stacking Winegard HD-6065P antennas
On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz
wrote: Jerry Stuckle wrote: On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal voltage but only 1.414 times the signal power. That's why we have units of measure to avoid such ambiguities. Just to be difficult, working with antennas, the "signal" is the field strength measured in dBuV/M. If you define what you're measuring and specify your units of measure, you wouldn't be having such problems. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Stacking Winegard HD-6065P antennas
On 1/6/2014 11:04 PM, Jeff Liebermann wrote:
On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz wrote: Jerry Stuckle wrote: On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal voltage but only 1.414 times the signal power. That's why we have units of measure to avoid such ambiguities. Just to be difficult, working with antennas, the "signal" is the field strength measured in dBuV/M. If you define what you're measuring and specify your units of measure, you wouldn't be having such problems. You've got it backwards, Jeff. Twice the voltage is 4 times the power. 1.414 times the voltage would be twice the power. -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
Stacking Winegard HD-6065P antennas
On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle
wrote: On 1/6/2014 11:04 PM, Jeff Liebermann wrote: On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz wrote: Jerry Stuckle wrote: On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal voltage but only 1.414 times the signal power. That's why we have units of measure to avoid such ambiguities. Just to be difficult, working with antennas, the "signal" is the field strength measured in dBuV/M. If you define what you're measuring and specify your units of measure, you wouldn't be having such problems. You've got it backwards, Jeff. Twice the voltage is 4 times the power. 1.414 times the voltage would be twice the power. Very embarrassing. Temporary loss of IQ from working on my broken car with a cold or flu this afternoon. It should be: If you got 1 microvolt, 2 microvolts will be twice the signal voltage but 4 times the signal power. Thanks for the correction (grumble)... Maybe if I go to sleep early, when I wake up tomorrow, this didn't happen. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Stacking Winegard HD-6065P antennas
Jeff Liebermann wrote:
On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle wrote: On 1/6/2014 11:04 PM, Jeff Liebermann wrote: On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz wrote: Jerry Stuckle wrote: On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal voltage but only 1.414 times the signal power. That's why we have units of measure to avoid such ambiguities. Just to be difficult, working with antennas, the "signal" is the field strength measured in dBuV/M. If you define what you're measuring and specify your units of measure, you wouldn't be having such problems. You've got it backwards, Jeff. Twice the voltage is 4 times the power. 1.414 times the voltage would be twice the power. Very embarrassing. Temporary loss of IQ from working on my broken car with a cold or flu this afternoon. It should be: If you got 1 microvolt, 2 microvolts will be twice the signal voltage but 4 times the signal power. Thanks for the correction (grumble)... Maybe if I go to sleep early, when I wake up tomorrow, this didn't happen. I have not really been specifying units. I was just going over the situation in my mind, and I straightened out in rf terms. I got this going out terminology. IF, in audio, I got two speakers transmitting equal energy, with two amps or channels, and I receive that totally in phase, I got twice the signal or 6 dB power increase. I've measured it. It's true. Same thing would happen with two antennas with two transmitters. Two antennas, one transmitter, with one splitter would only give 3 dB power increase at the receiver. I'm just thinking out loud. I had to ease my mind. I think I'm ok now. Almost bedtime. Greg |
Stacking Winegard HD-6065P antennas
gregz wrote:
Jeff Liebermann wrote: On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle wrote: On 1/6/2014 11:04 PM, Jeff Liebermann wrote: On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz wrote: Jerry Stuckle wrote: On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal voltage but only 1.414 times the signal power. That's why we have units of measure to avoid such ambiguities. Just to be difficult, working with antennas, the "signal" is the field strength measured in dBuV/M. If you define what you're measuring and specify your units of measure, you wouldn't be having such problems. You've got it backwards, Jeff. Twice the voltage is 4 times the power. 1.414 times the voltage would be twice the power. Very embarrassing. Temporary loss of IQ from working on my broken car with a cold or flu this afternoon. It should be: If you got 1 microvolt, 2 microvolts will be twice the signal voltage but 4 times the signal power. Thanks for the correction (grumble)... Maybe if I go to sleep early, when I wake up tomorrow, this didn't happen. I have not really been specifying units. I was just going over the situation in my mind, and I straightened out in rf terms. I got this going out terminology. IF, in audio, I got two speakers transmitting equal energy, with two amps or channels, and I receive that totally in phase, I got twice the signal or 6 dB power increase. I've measured it. It's true. Same thing would happen with two antennas with two transmitters. Two antennas, one transmitter, with one splitter would only give 3 dB power increase at the receiver. I'm just thinking out loud. I had to ease my mind. I think I'm ok now. Almost bedtime. Greg Tomorrow I will think the reverse of the antenna reception combining. It does not work for me right now. Greg |
Stacking Winegard HD-6065P antennas
On 1/7/2014 2:29 AM, gregz wrote:
Jeff Liebermann wrote: On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle wrote: On 1/6/2014 11:04 PM, Jeff Liebermann wrote: On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz wrote: Jerry Stuckle wrote: On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal voltage but only 1.414 times the signal power. That's why we have units of measure to avoid such ambiguities. Just to be difficult, working with antennas, the "signal" is the field strength measured in dBuV/M. If you define what you're measuring and specify your units of measure, you wouldn't be having such problems. You've got it backwards, Jeff. Twice the voltage is 4 times the power. 1.414 times the voltage would be twice the power. Very embarrassing. Temporary loss of IQ from working on my broken car with a cold or flu this afternoon. It should be: If you got 1 microvolt, 2 microvolts will be twice the signal voltage but 4 times the signal power. Thanks for the correction (grumble)... Maybe if I go to sleep early, when I wake up tomorrow, this didn't happen. I have not really been specifying units. I was just going over the situation in my mind, and I straightened out in rf terms. I got this going out terminology. IF, in audio, I got two speakers transmitting equal energy, with two amps or channels, and I receive that totally in phase, I got twice the signal or 6 dB power increase. I've measured it. It's true. Same thing would happen with two antennas with two transmitters. Two antennas, one transmitter, with one splitter would only give 3 dB power increase at the receiver. I'm just thinking out loud. I had to ease my mind. I think I'm ok now. Almost bedtime. Greg No, two in-phase speakers provide 3db increase, not 6db. If you could double the signal and get 4x the power you could make gazillions! Of course, you'd be creating energy out of nothing, but who cares about the laws of physics? :) -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
Stacking Winegard HD-6065P antennas
In message , Jerry Stuckle
writes On 1/7/2014 2:29 AM, gregz wrote: Jeff Liebermann wrote: On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle wrote: On 1/6/2014 11:04 PM, Jeff Liebermann wrote: On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz wrote: Jerry Stuckle wrote: On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal voltage but only 1.414 times the signal power. That's why we have units of measure to avoid such ambiguities. Just to be difficult, working with antennas, the "signal" is the field strength measured in dBuV/M. If you define what you're measuring and specify your units of measure, you wouldn't be having such problems. You've got it backwards, Jeff. Twice the voltage is 4 times the power. 1.414 times the voltage would be twice the power. Very embarrassing. Temporary loss of IQ from working on my broken car with a cold or flu this afternoon. It should be: If you got 1 microvolt, 2 microvolts will be twice the signal voltage but 4 times the signal power. Thanks for the correction (grumble)... Maybe if I go to sleep early, when I wake up tomorrow, this didn't happen. I have not really been specifying units. I was just going over the situation in my mind, and I straightened out in rf terms. I got this going out terminology. IF, in audio, I got two speakers transmitting equal energy, with two amps or channels, and I receive that totally in phase, I got twice the signal or 6 dB power increase. I've measured it. It's true. Same thing would happen with two antennas with two transmitters. Two antennas, one transmitter, with one splitter would only give 3 dB power increase at the receiver. I'm just thinking out loud. I had to ease my mind. I think I'm ok now. Almost bedtime. Greg No, two in-phase speakers provide 3db increase, not 6db. If you could double the signal and get 4x the power you could make gazillions! Of course, you'd be creating energy out of nothing, but who cares about the laws of physics? :) Two identical receiving antennas would provide twice the signal voltage if their RF outputs were connected in series. One way of doing this would be for coax feed from each antenna to be connected to the primary of a 1:1 RF transformer, and the secondaries of the two transformers were connected in series. So if each antenna delivered 1V from a resistive source impedance (R) of 1 ohm into a matched resistive load of 1 ohm, the two secondaries in series would provide 2V. However, the output impedance of the two secondaries would be twice that of each antenna, ie 2R. To preserve matching, the load would also have to be 2R. However, the snag is..... The matched power from each antenna is 1V squared divided by 1 ohm (=1W), but the matched power from the combined antennas is 2V squared divided by 2 ohms (=2W) - which is an increase of 3dB (and not 6dB). Of course, if the receiver input was not matched, and its impedance was much higher than R or 2R, it might be possible to benefit from adding the two antenna signals in this way. Has anybody tried this? -- Ian |
Stacking Winegard HD-6065P antennas
No, two in-phase speakers provide 3db increase, not 6db. If you could double the signal and get 4x the power you could make gazillions! Of course, you'd be creating energy out of nothing, but who cares about the laws of physics? :) Two identical receiving antennas would provide twice the signal voltage if their RF outputs were connected in series. One way of doing this would be for coax feed from each antenna to be connected to the primary of a 1:1 RF transformer, and the secondaries of the two transformers were connected in series. So if each antenna delivered 1V from a resistive source impedance (R) of 1 ohm into a matched resistive load of 1 ohm, the two secondaries in series would provide 2V. However, the output impedance of the two secondaries would be twice that of each antenna, ie 2R. To preserve matching, the load would also have to be 2R. However, the snag is..... The matched power from each antenna is 1V squared divided by 1 ohm (=1W), but the matched power from the combined antennas is 2V squared divided by 2 ohms (=2W) - which is an increase of 3dB (and not 6dB). Of course, if the receiver input was not matched, and its impedance was much higher than R or 2R, it might be possible to benefit from adding the two antenna signals in this way. Has anybody tried this? I don't think anyone would try this because every television input is either 75 or 300 ohms or both. Hoping for an input of 1000 ohms would be a vain hope. |
Stacking Winegard HD-6065P antennas
In message , boomer
writes No, two in-phase speakers provide 3db increase, not 6db. If you could double the signal and get 4x the power you could make gazillions! Of course, you'd be creating energy out of nothing, but who cares about the laws of physics? :) Two identical receiving antennas would provide twice the signal voltage if their RF outputs were connected in series. One way of doing this would be for coax feed from each antenna to be connected to the primary of a 1:1 RF transformer, and the secondaries of the two transformers were connected in series. So if each antenna delivered 1V from a resistive source impedance (R) of 1 ohm into a matched resistive load of 1 ohm, the two secondaries in series would provide 2V. However, the output impedance of the two secondaries would be twice that of each antenna, ie 2R. To preserve matching, the load would also have to be 2R. However, the snag is..... The matched power from each antenna is 1V squared divided by 1 ohm (=1W), but the matched power from the combined antennas is 2V squared divided by 2 ohms (=2W) - which is an increase of 3dB (and not 6dB). Of course, if the receiver input was not matched, and its impedance was much higher than R or 2R, it might be possible to benefit from adding the two antenna signals in this way. Has anybody tried this? I don't think anyone would try this because every television input is either 75 or 300 ohms or both. I think you might be surprised at how unlike the supposed 75 or 300 ohms some TV sets might be. Hoping for an input of 1000 ohms would be a vain hope. Possibly a purpose-built preamp could be designed to have a distinctly higher input impedance. Of course, it would also have to have an appropriately low noise figure (certainly at least as good as the receiver). -- Ian |
Stacking Winegard HD-6065P antennas
On 1/7/2014 9:06 AM, Ian Jackson wrote:
In message , Jerry Stuckle writes On 1/7/2014 2:29 AM, gregz wrote: Jeff Liebermann wrote: On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle wrote: On 1/6/2014 11:04 PM, Jeff Liebermann wrote: On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz wrote: Jerry Stuckle wrote: On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal voltage but only 1.414 times the signal power. That's why we have units of measure to avoid such ambiguities. Just to be difficult, working with antennas, the "signal" is the field strength measured in dBuV/M. If you define what you're measuring and specify your units of measure, you wouldn't be having such problems. You've got it backwards, Jeff. Twice the voltage is 4 times the power. 1.414 times the voltage would be twice the power. Very embarrassing. Temporary loss of IQ from working on my broken car with a cold or flu this afternoon. It should be: If you got 1 microvolt, 2 microvolts will be twice the signal voltage but 4 times the signal power. Thanks for the correction (grumble)... Maybe if I go to sleep early, when I wake up tomorrow, this didn't happen. I have not really been specifying units. I was just going over the situation in my mind, and I straightened out in rf terms. I got this going out terminology. IF, in audio, I got two speakers transmitting equal energy, with two amps or channels, and I receive that totally in phase, I got twice the signal or 6 dB power increase. I've measured it. It's true. Same thing would happen with two antennas with two transmitters. Two antennas, one transmitter, with one splitter would only give 3 dB power increase at the receiver. I'm just thinking out loud. I had to ease my mind. I think I'm ok now. Almost bedtime. Greg No, two in-phase speakers provide 3db increase, not 6db. If you could double the signal and get 4x the power you could make gazillions! Of course, you'd be creating energy out of nothing, but who cares about the laws of physics? :) Two identical receiving antennas would provide twice the signal voltage if their RF outputs were connected in series. One way of doing this would be for coax feed from each antenna to be connected to the primary of a 1:1 RF transformer, and the secondaries of the two transformers were connected in series. So if each antenna delivered 1V from a resistive source impedance (R) of 1 ohm into a matched resistive load of 1 ohm, the two secondaries in series would provide 2V. However, the output impedance of the two secondaries would be twice that of each antenna, ie 2R. To preserve matching, the load would also have to be 2R. However, the snag is..... The matched power from each antenna is 1V squared divided by 1 ohm (=1W), but the matched power from the combined antennas is 2V squared divided by 2 ohms (=2W) - which is an increase of 3dB (and not 6dB). Of course, if the receiver input was not matched, and its impedance was much higher than R or 2R, it might be possible to benefit from adding the two antenna signals in this way. Has anybody tried this? But then I DID qualify my statement with "if the resistance (impedance in this case) stays the same". In your case, as you indicated, it is not the same. For the same impedance you would need a matching network. Assuming no loss in the matching network, the output would be 1.414V. -- ================== Remove the "x" from my email address Jerry Stuckle JDS Computer Training Corp. ================== |
Stacking Winegard HD-6065P antennas
On Sun, 5 Jan 2014 00:01:47 -0500, "Ralph Mowery"
wrote: I understand the idea of using 'perfect' items in electronics, then going for more exect calculations if needed. I like to design perfect antennas and circuits as a sanity check to see if it can be done. Then, I throw in the losses and see what happens. It's also a crude form of sensitivity analysis, which tells me which parameters are most important. The Wilkinson combiner is possiable for relative narrow frequencies. Not sure if building one out of descrete components or full size transmission lines would be broad enough for the whole FM band either. Wild guess it would be about the same if just two pieces of transmission line of the correct impedance and length were used. Good guess. Discrete or coaxial performance (loss, isolation, and bandwidth) are about the same. You're also correct that it wouldn't cover the entire FM band. I could do it with a single stage Wilkinson combiner by lowering the Q of the components. However, that will increase the losses, which is not a great idea. Much better is to use a multi-stage Wilkinson combiner: http://www.microwaves101.com/encyclopedia/wilkinson_multistage.cfm It's a common stripline technique. You probably recognize the general pattern: http://www.eee.bham.ac.uk/yatesac/Web%20PDF%27s/Test%20Gear/Wideband%20Wilkinson%20Coupler_1-2%20GHz_Layout.pdf http://www.eee.bham.ac.uk/yatesac/Web%20Pages/Wideband%20Wilkinson%20Splitter%20&%20Combiner.htm Isn't the Wilkinson combiner just two pieces of transmission line (or simulated with components) with a resistor across two of the ports to absorbe the diffeance if the loads/sources are not ballanced ? The resistor is NOT to provide a load in case of an imbalance. It's to provide an impedance match for a 180 degree out of phase path between input/output ports. A signal that tries to go between the two input/output ports has two paths along which it can go. One is down one 1/4 wave coax, and up the other 1/4 wave coax, resulting in a 180 degree phase shift. The other is through the resistor with a 0 degree phase shift. If everything is roughly impedance matched, the signals through the two paths cancel, resulting in very good isolation between ports. As the subject is combining, I have not looked into the losses of splitting, but it would be 6 db for the simple resistor designs not counting the minor losses. That would be 3 db for the ports and 3 db lost in the resistors. Yep, that's correct. http://www.microwaves101.com/encyclopedia/resistive_splitters.cfm To combind signals you would get the loss of the resistors of 3 db and a fraction of other loss. Yep, that's correct. I am using a HP 8924C for a test set. It has just about everything you can think of for a service monitor. Calibrated from 30 to 1000 MHz but usuable uncalibrated to about a half of a mhz. http://www.amtronix.com/hp8924c60.htm http://axfp.org/god-bless-the-hp-8924c-a-tale-and-tutorial-of-the-service-monitor/ Nice. I'm into opening a museum of antique test equipment: http://802.11junk.com/jeffl/pics/home/slides/test-equip-mess.html Yes, phasing harnesses on antennas are not totally loseless, but will be mainly whatever the loss of the coax is between the elements. Nope. A phasing harness is much like the Wilkinson combiner without the balancing resistor. Isolation between antennas would be nice, but kinda futile with the antennas that close. Like the Wilkinson combiner, the cables are odd multiples of 1/4 wave electrical. Like the Wilkinson, such phasing harnesses have a limited bandwidth, where losses increase the further away one gets from resonance. In other words, you can't supply a single number for the losses in a phasing harness. What's needed are numbers for the losses at resonance and at band edges. At this time, I still don't know if a Wilkinson combiner or phasing harness will have sufficient bandwidth to cover the FM broadcast band. That's 20 Mhz bandwidth at 100 Mhz or Q=5. I don't think that's possible. To make my life more difficult, it's not possible to easily model coax cables using NEC2. I've been using a mythical 50 ohm open wire line, which can be modeled. I would recommend either a messy multistage Wilkinson power splitter/combiner, or go the broadband route with a common CATV/FM power splitter/combiner. If were the origional poster and there were not too many transmitters near me, I would try a good preamp first. Mast mounted if possiable as it is for receive only. Preamps are a mixed blessing. With a good antenna, they can pickup signals at impressive distances. However, they can also overload miserably if there is a nearby transmitter on a nearby frequency. The directionality of a Yagi is a big help, but if the nearby transmitter is too close, the amplifier will overload, desensitize, belch intermod, or otherwise cause problems. At best, the tower mounted amp should be used only to compensate for coax losses. Any more gain than that reduces the dynamic range of the system. Therefore, if the coax cables is fairly short, and the cable is low loss, I wouldn't bother with an amplifier. If the coax cable run is long and/or the coax is junk, a tower mounted amp might be worth trying. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Stacking Winegard HD-6065P antennas
"Jeff Liebermann" wrote in message ... On Mon, 6 Jan 2014 06:28:11 +0000 (UTC), gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Nope. Power is by the square of the voltage: P = V^2 / R If you double the voltage, you get 4 times the power. A 1.414 times increase in voltage will produce twice the power. I tried to convert the antenna model of the HD-6066P antenna from the AO .ant format to .nec using 4NEC2 and failed. The plan was to model the stacked arrangement and see what happens: http://www.ham-radio.com/k6sti/hd6065p.htm The .ant file imported without error, the wire tables and images look correct, but the pattern is more like a point source than a gain antenna. I'll look at it later to see where I screwed up, but it would be nice if someone would look at the problem. I just set up an experiment. I connected my roof antenna to my signal level meter and read the signal strength of my Channel 10. It was 10 dBmV, the unit typically used for TV signal strength work. Next, I connected the same roof antenna to the inport port of one of a pair of passive splitters connected back-to-back with equal short lengths of the same 75-ohm cable. Finally, I connected the output port of this network to the signal level meter and observed a signal that was approximately 1.25 dBmV less. (A quarter of a dBmV is about as close as I can reliably read; individual whole number marks are only a few mm apart.) Thus, I conclude that the 1 dB nominal loss for a passive splitter -- either combining or splitting -- is confirmed. Combining two identical suignals does get you something more than one, alone. RELATED: When I used identical twin UHF antennas side-by-side, separated by a free-space half-wave distance to cancel interference from one side, it worked nicely and showed about the same loss figures as above. That is, my reading for two antennas combined was about 2 dBmV higher than for either of the twin antennas alone, thus reflecting the 1dB loss in the combiner. Combining antennas can be an uncertain business because the phase relationships change with wavelength; the arrangement that strengthens one channel may weaken another channel if the respective signals come from different directions and/or the cable lengths are not matched. It's a matter of reinforcement or cancellation, depending on phase relationships. "Sal" (KD6VKW) |
Stacking Winegard HD-6065P antennas
Jerry Stuckle wrote:
On 1/7/2014 2:29 AM, gregz wrote: Jeff Liebermann wrote: On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle wrote: On 1/6/2014 11:04 PM, Jeff Liebermann wrote: On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz wrote: Jerry Stuckle wrote: On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal voltage but only 1.414 times the signal power. That's why we have units of measure to avoid such ambiguities. Just to be difficult, working with antennas, the "signal" is the field strength measured in dBuV/M. If you define what you're measuring and specify your units of measure, you wouldn't be having such problems. You've got it backwards, Jeff. Twice the voltage is 4 times the power. 1.414 times the voltage would be twice the power. Very embarrassing. Temporary loss of IQ from working on my broken car with a cold or flu this afternoon. It should be: If you got 1 microvolt, 2 microvolts will be twice the signal voltage but 4 times the signal power. Thanks for the correction (grumble)... Maybe if I go to sleep early, when I wake up tomorrow, this didn't happen. I have not really been specifying units. I was just going over the situation in my mind, and I straightened out in rf terms. I got this going out terminology. IF, in audio, I got two speakers transmitting equal energy, with two amps or channels, and I receive that totally in phase, I got twice the signal or 6 dB power increase. I've measured it. It's true. Same thing would happen with two antennas with two transmitters. Two antennas, one transmitter, with one splitter would only give 3 dB power increase at the receiver. I'm just thinking out loud. I had to ease my mind. I think I'm ok now. Almost bedtime. Greg No, two in-phase speakers provide 3db increase, not 6db. If you could double the signal and get 4x the power you could make gazillions! Of course, you'd be creating energy out of nothing, but who cares about the laws of physics? :) The reason big speaker systems work in large places is efficiency gain using multiple arrays, must be in phase. As I was saying, it's a known fact, which I have measured. You can actually get near 10 dB gain using several speakers. It's why horn loudspeakers have gain, better impedance matching to air. I once believed two in phase speakers provided 3 dB increase also. I then read a speaker project by the now famous diAppolito configuration designer in Speaker Builder magazine 80's ?. I can try to find a reference. Greg |
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