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Does anybody here use an antenna tuner?
I've read and heard both sides of the argument about
antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". |
"Sanjaya" wrote
I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". Sanjaya, I doubt that anyone else's opinion about a tuner selling new for $15 is worth much to you. Go ahead and try the thing for Pete's sake! Expect to get $15 worth of product. Or, spend 5 times that much for MFJ equipment that adds a noise-feed which a tuner can then be adjusted to null the noise, and the tuner is then configured to make your antenna resonant for the given frequency. That will definitely improve reception. So will a preselector, and so will a step-attenuator, once you learn to use it. But for $15, what have you got to lose? It might work, you can let us know if you try it. Best regards, Jack |
"Jack Painter" wrote in message news:k5m3d.44727$Ka6.18669@okepread03... "Sanjaya" wrote I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". Sanjaya, I doubt that anyone else's opinion about a tuner selling new for $15 is worth much to you. Go ahead and try the thing for Pete's sake! Expect to get $15 worth of product. Or, spend 5 times that much for MFJ equipment that adds a noise-feed which a tuner can then be adjusted to null the noise, and the tuner is then configured to make your antenna resonant for the given frequency. That will definitely improve reception. So will a preselector, and so will a step-attenuator, once you learn to use it. But for $15, what have you got to lose? It might work, you can let us know if you try it. Best regards, Jack Thanks Jack. But I think you looked at the price of the power supply, which is $14.95 The tuner is $89.95 |
"Mark S. Holden" wrote in message ... Sanjaya wrote: I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". I've tried a variety of antenna tuners and preselectors. If you're looking for more knobs to twiddle, they're great. But I prefer impedance matching transformers. No knobs to twiddle, no need for batteries or an AC adapter, and they seem to work at least as well with my radios and antennas. Thanks Mark : ) |
Sanjaya wrote: I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". I use an old Grove MiniTun3. It has all of 2 knobs one to select a frequency range the other to tune for best signal. It woorks well from 500 kHz to 30 mHz. I find it most usefull on lower frequencies in particular below 4 mHz. It use it with my 135 foot longwire that goes to my ICOM and Drake receivers. It is not a cure all but helps -- 73 and Best of DX Shawn Axelrod VE4DX1SMA Visit the AMANDX DX site with info for the new or experienced listener: http://www.angelfire.com/mb/amandx/index.html REMEMBER ON A CLEAR DAY YOU CAN HEAR FOREVER |
Mark...Can you be specific on what type and/or impeadance of the
transformer you are using? Also what antennas are you using it on? "Mark S. Holden" wrote in message ... Sanjaya wrote: I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". I've tried a variety of antenna tuners and preselectors. If you're looking for more knobs to twiddle, they're great. But I prefer impedance matching transformers. No knobs to twiddle, no need for batteries or an AC adapter, and they seem to work at least as well with my radios and antennas. |
"Sanjaya" wrote in message ink.net... I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. IMHO..... for receive only I would not bother with one. If you want the maximum signal transfer then a tuner will make the receiver see the proper impedence... therefore more signal. Also more noise. Signal/noise ratio is what matters for a receiver. I very rarely run my receivers without the RF gain reduced 25-40% depending on noise. In the last ARRL 160 meter CW contest I operated in....2001... I did not have a beverage or any "special receive" antenna. Turns out a 5 element Force12 Yagi for the 10 meter band @ 50 feet was the best.....lowest signal/noise ratio....for most of the 1100 or so stations I worked. What was the impedence mismatch? Beats me.... but it worked . 73 es DX Ken KG4BIG |
Hi hi, maybe so Sanjaya, sorry if that's the case. For $89 maybe you need
some coaching, lol. I will add that I use a few MFJ products and have been very happy with them. Not everyone is, as eidenced by the eHam rviews. Seems some folks have bad experiences. But my tuners by MFJ work very well. best regards, Jack "Sanjaya" wrote in message ink.net... "Jack Painter" wrote in message news:k5m3d.44727$Ka6.18669@okepread03... "Sanjaya" wrote I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". Sanjaya, I doubt that anyone else's opinion about a tuner selling new for $15 is worth much to you. Go ahead and try the thing for Pete's sake! Expect to get $15 worth of product. Or, spend 5 times that much for MFJ equipment that adds a noise-feed which a tuner can then be adjusted to null the noise, and the tuner is then configured to make your antenna resonant for the given frequency. That will definitely improve reception. So will a preselector, and so will a step-attenuator, once you learn to use it. But for $15, what have you got to lose? It might work, you can let us know if you try it. Best regards, Jack Thanks Jack. But I think you looked at the price of the power supply, which is $14.95 The tuner is $89.95 |
In article . net,
"Sanjaya" wrote: I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". A tuner solves a specific problem. If you don't have that problem it's not going to help much. The problem is selectivity. If your radio has enough for your listening situation then the tuner will not do much for you other than boost the signal a little that you are trying to hear. The tuner will reduce the other signals above and below where it is tuned to your radio. There are various types of tuners that behave somewhat differently but this is the GENERIC explanation for them. You can the maximum benefit from a tuner if it is used to resonate an ordinarily non-resonant antenna like a random wire Marconi type antenna. For this to work well the wire is directly connected to the tuner and then the tuner is connected by coax to the radio. The tuner changes the ELECTRICAL LENGTH of the wire so it resonates at some frequency. The boost from using the tuner to resonate the wire can make the difference between hearing a very weak signal or helping to make it more legible if it is next to a much stronger station on a nearby channel. It is basically a DX'ing tool used to tweak the antenna situation in order to get the weakest of stations. -- Telamon Ventura, California |
Antenna tuners for receive have not been very useful in my experience, nor have
preamps. The exception is trying to work full duplex on marine radios, then you need a good preselector so that your xmtr does not totally overwhelm the rcvr that is tuned to a nearby freq. It is easy to be fooled by preamps, they make things louder, but they normally amplify noise as much as signal so you are not gaining in S/N ratio. Similarly, antenna tuners give you a peak and you get excited, but compare it to an untuned longwire and you wont hear any difference in most cases. In the case of poorly designed rcvrs, a tuner or tuned preamp might help make up for poor front end design, but with a good rcvr, they just dont do much in my experience. Read a good communications electronics book about noise floor and what it really means. You'll see that there is no magic bullet for reducing random incoherent noise. DSP can work wonders in removing non random noise (hetrodynes, spectral notches, etc). Digital modulation can also work wonders in giving noise free comms. But, when all is said and done noise is random and random stuff is hard to remove. Its all about entropy and electrons. Directional antennas... now there is a way to improve SN, big time in some cases. |
Sanjaya wrote:
I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". If you're using a portable receiver with a fairly long external antenna, a passive preselector would be the most useful device between the antenna and receiver. It would help to eliminate the symptoms of signal overloading caused by insufficient dynamic range in the receiver. I used a preselector with the Sony-2010, connected to an inverted-L antenna. It made a big difference with reducing intermod's. Quality table-top receivers like the Drake-R8, Icom-R75, AOR-7030 and many others, don't need a pre-selector or antenna tuner to enhance reception. They work very well when connected directly to a well designed external antenna. My R8B uses an inverted-L with a good 'RF' grounding system to reduce the noise from domestic sources like televisions and computers. Keeping the noise down is more important than getting the last bit of energy from the antenna with a tuner. BTW- The MFJ-959C is "for receive only" because it's componants can't handle the power from a transmitter. Universal is not trying to give their opinion on whether you should or should not use an antenna tuner for receiving. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
"The Axelrods" wrote in message ... Sanjaya wrote: I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". I use an old Grove MiniTun3. It has all of 2 knobs one to select a frequency range the other to tune for best signal. It woorks well from 500 kHz to 30 mHz. I find it most usefull on lower frequencies in particular below 4 mHz. It use it with my 135 foot longwire that goes to my ICOM and Drake receivers. It is not a cure all but helps -- 73 and Best of DX Shawn Axelrod VE4DX1SMA Thanks Shawn. |
"Ken Wilson" wrote in message ... "Sanjaya" wrote in message ink.net... I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. IMHO..... for receive only I would not bother with one. If you want the maximum signal transfer then a tuner will make the receiver see the proper impedence... therefore more signal. Also more noise. Signal/noise ratio is what matters for a receiver. I very rarely run my receivers without the RF gain reduced 25-40% depending on noise. In the last ARRL 160 meter CW contest I operated in....2001... I did not have a beverage or any "special receive" antenna. Turns out a 5 element Force12 Yagi for the 10 meter band @ 50 feet was the best.....lowest signal/noise ratio....for most of the 1100 or so stations I worked. What was the impedence mismatch? Beats me.... but it worked . 73 es DX Ken KG4BIG Thank you Ken. |
"Telamon" wrote in message ... In article . net, "Sanjaya" wrote: I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". A tuner solves a specific problem. If you don't have that problem it's not going to help much. The problem is selectivity. If your radio has enough for your listening situation then the tuner will not do much for you other than boost the signal a little that you are trying to hear. The tuner will reduce the other signals above and below where it is tuned to your radio. There are various types of tuners that behave somewhat differently but this is the GENERIC explanation for them. You can the maximum benefit from a tuner if it is used to resonate an ordinarily non-resonant antenna like a random wire Marconi type antenna. For this to work well the wire is directly connected to the tuner and then the tuner is connected by coax to the radio. The tuner changes the ELECTRICAL LENGTH of the wire so it resonates at some frequency. The boost from using the tuner to resonate the wire can make the difference between hearing a very weak signal or helping to make it more legible if it is next to a much stronger station on a nearby channel. It is basically a DX'ing tool used to tweak the antenna situation in order to get the weakest of stations. -- Telamon Ventura, California Thanks Telamon. |
"starman" wrote in message ... Sanjaya wrote: I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". If you're using a portable receiver with a fairly long external antenna, a passive preselector would be the most useful device between the antenna and receiver. It would help to eliminate the symptoms of signal overloading caused by insufficient dynamic range in the receiver. I used a preselector with the Sony-2010, connected to an inverted-L antenna. It made a big difference with reducing intermod's. Quality table-top receivers like the Drake-R8, Icom-R75, AOR-7030 and many others, don't need a pre-selector or antenna tuner to enhance reception. They work very well when connected directly to a well designed external antenna. My R8B uses an inverted-L with a good 'RF' grounding system to reduce the noise from domestic sources like televisions and computers. Keeping the noise down is more important than getting the last bit of energy from the antenna with a tuner. BTW- The MFJ-959C is "for receive only" because it's componants can't handle the power from a transmitter. Universal is not trying to give their opinion on whether you should or should not use an antenna tuner for receiving. Thanks for clearing that up Starman. |
= = = "Sanjaya" wrote in message
= = = link.net... I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". SANJAYA, The Age Old SWL'ers Question: Do I Need a Antenna Tuner ? -or- a Pre-Selector ? The MFJ-959 is OK for what it does. The one feature that would interest me would be the ability to use it with Two (2) Radios and Two (2) Antennas. Switch between the Radios and Antennas. The built-in Amplifier can be helpful for hearing weak signals. If you are using a simply Random Wire Antenna or any Antenna with a 'direct' Coax Cable Feed-in-Line. The MFJ-959 should help in 'matching' you Antenna to the Radio's Input and improving your signal transfer. HOWEVER - If you are using an Improved SWL Random Wire Antenna that uses a 9:1 Matching Transformer (Balun / MLB) then you may not see any real 'improvement' in your receive signal. This is the so called "Low Noise" SWL Antenna. [ Please READ These Three Links ] http://www.anarc.org/naswa/badx/ante...e_antenna.html http://www.anarc.org/naswa/badx/ante..._longwire.html http://www.anarc.org/naswa/badx/antennas/grounding.html ABOUT THE "LOW NOISE" ANTENNA 'DESIGN CONCEPTS': A Random Wire Antenna Element coupled via a 9:1 Matching Transformer at the Near-End of the Antenna with a Ground Rod and Coax Cable Feed-in-Line to the Receiver. This is the basic SWL Antenna that uses the "Low Noise Antenna" 'design concepts' that were popularized by John Doty. You may also wish to consider these two other MFJ Products: * MFJ-1045C SWL Receiver Pre-Selector with built-in Amplifier which covers the Shortwave Bands from 1.8 to 54 MHz. http://www.universal-radio.com/catal...amps/0807.html * MFJ-1020C Indoor Active Antenna which covers 300 kHz to 40 MHz (LW, AM/MW and SW Bands) in five bands; and when used with an External (OutSide) Antenna, the MFJ-1020C functions as a Pre-Selector. http://www.universal-radio.com/catalog/sw_ant/1413.html FWIW: I use a Low Noise SWL Antenna with a Grove Mini-Tuner "TUN 3" which is very much like the MFJ-956 MFJ-956 Long Wave, Medium Wave and Shortwave Pre-Selector Tuner. http://www.universal-radio.com/catal...amps/2964.html - Most times I simply use it in the ByPass Mode. - Sometimes I will switch it over ti Fine-Tune a Signal. - The major reason I use it is to Switch-Out "Ground-Out" the Antenna when I am not using the Radio for Safety. READ: John Wagner's Shortwave Tips & Tricks http://www.dxing.com/tips.htm - Section: Antennas for Portable Receivers - Point # (7) The Wagner Active Preseletor Antenna READ: Antenna Tuner, radio preselector, what is the difference? http://groups.yahoo.com/group/Shortw...a/message/1119 - Five "Do-It-Yourself" Antenna Turners with Schematics - Impedance Matching Unit VS. Pre-Selector/ATU - Pre-Selectors = So Many Choices . . . - Antenna Tuner / Pre-Selector = The 'little' Box that May Help ! iane ~ RHF .. Some Say: On A Clear Day You Can See Forever. http://groups.yahoo.com/group/Shortw...na/message/502 I BELIEVE: On A Clear Night... You Can Hear Forever and Beyond, The Beyond ! .. .. |
Radio Man wrote:
Mark...Can you be specific on what type and/or impeadance of the transformer you are using? Also what antennas are you using it on? I mostly use 9:1 impedance matching transformers I wound myself according to the directions on CW's web site. http://www.kc7nod.20m.com/new_page_1.htm On antennas: #1 is out at the moment because of a lightning strike a few weeks ago and I've been too busy to get it replaced - but it was a 65' random wire made with #14 wire that's 225 feet away from my house (and farther from the neighbors) The coax is underground. It gets practically no RFI. I'm sure it would work almost as well if it was 60-70 feet away from the house, but I don't have tall sturdy trees there. Here's a web site with a discussion of this type of antenna. http://www.anarc.org/naswa/badx/antennas/low-noise_antenna.html #2 is a triangular horizontal loop antenna that's partially over the house. It was made with about 150 feet of #14 wire. Loops are low noise designs, but my house is filled with gizmos that cause rfi, so it's not my favorite. It has a 4:1 impedance matching transformer. #3 was my first antenna at the house - it's 40 feet of wire stapled to the rafters in my attic. It's closer to the RFI and I haven't used it in years. 9:1 transformer. #4 is my current camping and vacation antenna. It's a 3 meter folding whip originally intended for a PRC-25 or PRC-77 with a 9:1 impedance matching transformer that mounts onto a photographic tripod. It works quite well. #5 is an Electro-Metrics ALR-25 Loop. I still need to create a control box to switch bands on it electrically, but ultimately, this may become the "portable" antenna for places I can drive to where I need to use an indoor antenna. This has it's own impedance matching circuitry built in. I have some extra #43 ferrite's on hand that are a little smaller than the one CW's design calls for. They work well. If you'd like one, you can have it for the price of a small padded mailing bag and a couple of stamps. Contact me directly for details. |
"RHF" wrote in message om... = = = "Sanjaya" wrote in message = = = link.net... I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". SANJAYA, The Age Old SWL'ers Question: Do I Need a Antenna Tuner ? -or- a Pre-Selector ? The MFJ-959 is OK for what it does. The one feature that would interest me would be the ability to use it with Two (2) Radios and Two (2) Antennas. Switch between the Radios and Antennas. The built-in Amplifier can be helpful for hearing weak signals. If you are using a simply Random Wire Antenna or any Antenna with a 'direct' Coax Cable Feed-in-Line. The MFJ-959 should help in 'matching' you Antenna to the Radio's Input and improving your signal transfer. HOWEVER - If you are using an Improved SWL Random Wire Antenna that uses a 9:1 Matching Transformer (Balun / MLB) then you may not see any real 'improvement' in your receive signal. This is the so called "Low Noise" SWL Antenna. [ Please READ These Three Links ] http://www.anarc.org/naswa/badx/ante...e_antenna.html http://www.anarc.org/naswa/badx/ante..._longwire.html http://www.anarc.org/naswa/badx/antennas/grounding.html ABOUT THE "LOW NOISE" ANTENNA 'DESIGN CONCEPTS': A Random Wire Antenna Element coupled via a 9:1 Matching Transformer at the Near-End of the Antenna with a Ground Rod and Coax Cable Feed-in-Line to the Receiver. This is the basic SWL Antenna that uses the "Low Noise Antenna" 'design concepts' that were popularized by John Doty. You may also wish to consider these two other MFJ Products: * MFJ-1045C SWL Receiver Pre-Selector with built-in Amplifier which covers the Shortwave Bands from 1.8 to 54 MHz. http://www.universal-radio.com/catal...amps/0807.html * MFJ-1020C Indoor Active Antenna which covers 300 kHz to 40 MHz (LW, AM/MW and SW Bands) in five bands; and when used with an External (OutSide) Antenna, the MFJ-1020C functions as a Pre-Selector. http://www.universal-radio.com/catalog/sw_ant/1413.html FWIW: I use a Low Noise SWL Antenna with a Grove Mini-Tuner "TUN 3" which is very much like the MFJ-956 MFJ-956 Long Wave, Medium Wave and Shortwave Pre-Selector Tuner. http://www.universal-radio.com/catal...amps/2964.html - Most times I simply use it in the ByPass Mode. - Sometimes I will switch it over ti Fine-Tune a Signal. - The major reason I use it is to Switch-Out "Ground-Out" the Antenna when I am not using the Radio for Safety. READ: John Wagner's Shortwave Tips & Tricks http://www.dxing.com/tips.htm - Section: Antennas for Portable Receivers - Point # (7) The Wagner Active Preseletor Antenna READ: Antenna Tuner, radio preselector, what is the difference? http://groups.yahoo.com/group/Shortw...a/message/1119 - Five "Do-It-Yourself" Antenna Turners with Schematics - Impedance Matching Unit VS. Pre-Selector/ATU - Pre-Selectors = So Many Choices . . . - Antenna Tuner / Pre-Selector = The 'little' Box that May Help ! iane ~ RHF . Some Say: On A Clear Day You Can See Forever. http://groups.yahoo.com/group/Shortw...na/message/502 I BELIEVE: On A Clear Night... You Can Hear Forever and Beyond, The Beyond ! . . Thanks RHF. Checking your links. |
We use an antenna tuner to feed our W8JK antenna for use for shortwave
reception for two reasons: 1. The 8JK has a high impedence input so it is fed with 300 ohm ladder line; thus the use of the tuner (in this case) acts as a balanced transformer. 2. The 8JK was "cut" for 20 meters. For use on other frequencies, the tuner acts (with adjustment) as a conjugate match that provides a 50 ohm input to the receiver. Results of the tuner appears to peak signal strength as the impedence of the receiving antenna is transformed by the matching provided by the tuner. Tuners are passive in nature; that is, they require no amplifier electronics and associated power. They may be unbalanced input to balanced output (or vice versa) or unbalanced to unbalanced input/output. Preselectors on the other hand are active devices. They vary in design and may provide matching as well as gain. The selection of the device you choose will depend on the type on antenna system you employ. In any case, good luck! John Sanjaya wrote: I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". |
In article . net,
"Sanjaya" wrote: "Telamon" wrote in message .. . In article . net, "Sanjaya" wrote: I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". A tuner solves a specific problem. If you don't have that problem it's not going to help much. The problem is selectivity. If your radio has enough for your listening situation then the tuner will not do much for you other than boost the signal a little that you are trying to hear. The tuner will reduce the other signals above and below where it is tuned to your radio. There are various types of tuners that behave somewhat differently but this is the GENERIC explanation for them. You can the maximum benefit from a tuner if it is used to resonate an ordinarily non-resonant antenna like a random wire Marconi type antenna. For this to work well the wire is directly connected to the tuner and then the tuner is connected by coax to the radio. The tuner changes the ELECTRICAL LENGTH of the wire so it resonates at some frequency. The boost from using the tuner to resonate the wire can make the difference between hearing a very weak signal or helping to make it more legible if it is next to a much stronger station on a nearby channel. It is basically a DX'ing tool used to tweak the antenna situation in order to get the weakest of stations. Thanks Telamon. Your welcome and I meant to say above "You can get the maximum benefit" at the start of the second paragraph up. -- Telamon Ventura, California |
That site is still up? I haven't updated it in years. I too have used a
tuner. On short antennas, it can make a good deal of difference. On longer ones, it doesn't seem to matter much. The transformer is the way to go. Easy, works well and you don't have to mess with it. "Mark S. Holden" wrote in message ... Radio Man wrote: Mark...Can you be specific on what type and/or impeadance of the transformer you are using? Also what antennas are you using it on? I mostly use 9:1 impedance matching transformers I wound myself according to the directions on CW's web site. http://www.kc7nod.20m.com/new_page_1.htm On antennas: #1 is out at the moment because of a lightning strike a few weeks ago and I've been too busy to get it replaced - but it was a 65' random wire made with #14 wire that's 225 feet away from my house (and farther from the neighbors) The coax is underground. It gets practically no RFI. I'm sure it would work almost as well if it was 60-70 feet away from the house, but I don't have tall sturdy trees there. Here's a web site with a discussion of this type of antenna. http://www.anarc.org/naswa/badx/antennas/low-noise_antenna.html #2 is a triangular horizontal loop antenna that's partially over the house. It was made with about 150 feet of #14 wire. Loops are low noise designs, but my house is filled with gizmos that cause rfi, so it's not my favorite. It has a 4:1 impedance matching transformer. #3 was my first antenna at the house - it's 40 feet of wire stapled to the rafters in my attic. It's closer to the RFI and I haven't used it in years. 9:1 transformer. #4 is my current camping and vacation antenna. It's a 3 meter folding whip originally intended for a PRC-25 or PRC-77 with a 9:1 impedance matching transformer that mounts onto a photographic tripod. It works quite well. #5 is an Electro-Metrics ALR-25 Loop. I still need to create a control box to switch bands on it electrically, but ultimately, this may become the "portable" antenna for places I can drive to where I need to use an indoor antenna. This has it's own impedance matching circuitry built in. I have some extra #43 ferrite's on hand that are a little smaller than the one CW's design calls for. They work well. If you'd like one, you can have it for the price of a small padded mailing bag and a couple of stamps. Contact me directly for details. |
On Tue, 21 Sep 2004 01:15:42 GMT, John Steffes
wrote: We use an antenna tuner to feed our W8JK antenna for use for shortwave reception for two reasons: 1. The 8JK has a high impedence input so it is fed with 300 ohm ladder line; thus the use of the tuner (in this case) acts as a balanced transformer. 2. The 8JK was "cut" for 20 meters. For use on other frequencies, the tuner acts (with adjustment) as a conjugate match that provides a 50 ohm input to the receiver. Results of the tuner appears to peak signal strength as the impedence of the receiving antenna is transformed by the matching provided by the tuner. Tuners are passive in nature; that is, they require no amplifier electronics and associated power. They may be unbalanced input to balanced output (or vice versa) or unbalanced to unbalanced input/output. Preselectors on the other hand are active devices. They vary in design and may provide matching as well as gain. The selection of the device you choose will depend on the type on antenna system you employ. In any case, good luck! John John, I'm not sure I understand why you feel a preselector is an "active device"? From everything I've learned, active devices are such things as transistors, IC's, hybrids etc or a reference to a circuit that requires power to operate. The preselectors I've seen are 'passive' in that there are no semiconductors and no power required - excluding models that also have a built in pre-amp. Rather they are basically a 'tank' circuit that with a combination of inductance and capacitance create a 'bandpass' so only frequencies in a given range easily pass through the preselector to the receiver. Am I missing something in either your explanation or my understanding of a preselector? Howard |
"John Steffes" wrote in message ... We use an antenna tuner to feed our W8JK antenna for use for shortwave reception for two reasons: 1. The 8JK has a high impedence input so it is fed with 300 ohm ladder line; thus the use of the tuner (in this case) acts as a balanced transformer. 2. The 8JK was "cut" for 20 meters. For use on other frequencies, the tuner acts (with adjustment) as a conjugate match that provides a 50 ohm input to the receiver. Results of the tuner appears to peak signal strength as the impedence of the receiving antenna is transformed by the matching provided by the tuner. Tuners are passive in nature; that is, they require no amplifier electronics and associated power. They may be unbalanced input to balanced output (or vice versa) or unbalanced to unbalanced input/output. Preselectors on the other hand are active devices. They vary in design and may provide matching as well as gain. The selection of the device you choose will depend on the type on antenna system you employ. In any case, good luck! John Thanks John. Very informative post. |
Howard,
The preselectors we have dealt with have been , in general, active. They have used positive feedback to increase the "Q" of the resonant tank circuit providing greater selectivity. It is reasonable to accomplish this using no positive feedback (bandpass design) as you suggested. John Howard wrote: On Tue, 21 Sep 2004 01:15:42 GMT, John Steffes wrote: We use an antenna tuner to feed our W8JK antenna for use for shortwave reception for two reasons: 1. The 8JK has a high impedence input so it is fed with 300 ohm ladder line; thus the use of the tuner (in this case) acts as a balanced transformer. 2. The 8JK was "cut" for 20 meters. For use on other frequencies, the tuner acts (with adjustment) as a conjugate match that provides a 50 ohm input to the receiver. Results of the tuner appears to peak signal strength as the impedence of the receiving antenna is transformed by the matching provided by the tuner. Tuners are passive in nature; that is, they require no amplifier electronics and associated power. They may be unbalanced input to balanced output (or vice versa) or unbalanced to unbalanced input/output. Preselectors on the other hand are active devices. They vary in design and may provide matching as well as gain. The selection of the device you choose will depend on the type on antenna system you employ. In any case, good luck! John John, I'm not sure I understand why you feel a preselector is an "active device"? From everything I've learned, active devices are such things as transistors, IC's, hybrids etc or a reference to a circuit that requires power to operate. The preselectors I've seen are 'passive' in that there are no semiconductors and no power required - excluding models that also have a built in pre-amp. Rather they are basically a 'tank' circuit that with a combination of inductance and capacitance create a 'bandpass' so only frequencies in a given range easily pass through the preselector to the receiver. Am I missing something in either your explanation or my understanding of a preselector? Howard |
On Tue, 21 Sep 2004 09:22:41 GMT, John Steffes
wrote: Howard, The preselectors we have dealt with have been , in general, active. They have used positive feedback to increase the "Q" of the resonant tank circuit providing greater selectivity. It is reasonable to accomplish this using no positive feedback (bandpass design) as you suggested. John John, Thanks for the reply, nice to know I wasn't off-base in my thinking. Howard |
Howard wrote:
On Tue, 21 Sep 2004 09:22:41 GMT, John Steffes wrote: Howard, The preselectors we have dealt with have been , in general, active. They have used positive feedback to increase the "Q" of the resonant tank circuit providing greater selectivity. It is reasonable to accomplish this using no positive feedback (bandpass design) as you suggested. John John, Thanks for the reply, nice to know I wasn't off-base in my thinking. Howard A shortwave preselector can be either active or passive. The former usually has an amplification stage followed by an impedance matching output circuit in addition to the tuned circuit(s). The passive type has only the tuned circuits. Some preselectors can be both active or passive if the amp' circuit can be turned off (lowered to unity gain) or completely bypassed. The main advantage of any preselector is it's bandpass filtering (tuned circuit) which provides a means of removing signals outside the frequency range (band) that the user wants to hear. This is particularly useful for receivers (usually portables) that don't have a good antenna input circuit to accomplish this filtering process internally. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
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