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replacing rg 213 with hardline
I would like some opinions as if anyone could notice replacing 100 feet of
rg-213 with 7/8 inch or larger hardline would be noticiable. One ham said when he did he could tell the differance. I just don't see that going from about .4 db or less of loss to .15 db of loss on 80 meters is going to be noticed. That is about like going from 100 watts of transmitted power to maybe 105 watts or less. In the past I have inserted some 1 and 3 db pads in line with a receiver to see if I could tell the differance and have a hard time telling that even the 3 db pad makes much differance in casual operation, especially below 20 MHz. Maybe some have more sensitive ears than I have. |
replacing rg 213 with hardline
El 27-06-14 17:15, Ralph Mowery escribió:
I would like some opinions as if anyone could notice replacing 100 feet of rg-213 with 7/8 inch or larger hardline would be noticiable. One ham said when he did he could tell the differance. I just don't see that going from about .4 db or less of loss to .15 db of loss on 80 meters is going to be noticed. That is about like going from 100 watts of transmitted power to maybe 105 watts or less. In the past I have inserted some 1 and 3 db pads in line with a receiver to see if I could tell the differance and have a hard time telling that even the 3 db pad makes much differance in casual operation, especially below 20 MHz. Maybe some have more sensitive ears than I have. What kind of difference did he notice? I am thinking of signal strength at target area, received signal strength, S/N ratio, change in antenna radiation pattern, etc. Some other thing to consider, what will be the VSWR in the line. If that is really high, hardline can make a difference like coaxial versus ladder line attenuation. -- Wim PA3DJS Please remove abc first in case of PM |
replacing rg 213 with hardline
Ralph Mowery wrote:
I would like some opinions as if anyone could notice replacing 100 feet of rg-213 with 7/8 inch or larger hardline would be noticiable. One ham said when he did he could tell the differance. I just don't see that going from about .4 db or less of loss to .15 db of loss on 80 meters is going to be noticed. But what when he was working on 70 centimeters instead of 80 meters? Then it would be a large difference. |
replacing rg 213 with hardline
"Rob" wrote in message ... One ham said when he did he could tell the differance. I just don't see that going from about .4 db or less of loss to .15 db of loss on 80 meters is going to be noticed. But what when he was working on 70 centimeters instead of 80 meters? Then it would be a large difference. I should have made it clear that this is for 80 meters only, no higher band. Also he did not say what kind of differance he noticed, just that he did. Most of my work is 2 meters and higher and good transmission there is a must. I just don't have the operating time on the low bands to know if that extra .2 db would make any diffreance there. That is 2/10 of a db. |
replacing rg 213 with hardline
Ralph Mowery wrote:
"Rob" wrote in message ... One ham said when he did he could tell the differance. I just don't see that going from about .4 db or less of loss to .15 db of loss on 80 meters is going to be noticed. But what when he was working on 70 centimeters instead of 80 meters? Then it would be a large difference. I should have made it clear that this is for 80 meters only, no higher band. Also he did not say what kind of differance he noticed, just that he did. Most of my work is 2 meters and higher and good transmission there is a must. I just don't have the operating time on the low bands to know if that extra .2 db would make any diffreance there. That is 2/10 of a db. On 70 centimeters that would not make any difference either, but on 70 the difference is more than that. On 80 meters you should use a 2x20m dipole with open line feeder. Coax is only good for driving an unbalanced 50 ohm load, which is practical on VHF and above but not on HF bands where you are going to use a tuner. |
replacing rg 213 with hardline
"Rob" wrote in message ... Most of my work is 2 meters and higher and good transmission there is a must. I just don't have the operating time on the low bands to know if that extra .2 db would make any diffreance there. That is 2/10 of a db. On 70 centimeters that would not make any difference either, but on 70 the difference is more than that. On 80 meters you should use a 2x20m dipole with open line feeder. Coax is only good for driving an unbalanced 50 ohm load, which is practical on VHF and above but not on HF bands where you are going to use a tuner. I don't think .2 db would be detected unless maybe moon bounce or very weak signals with special equipment. I am thinking more of the average ham station. Yes , the losses go up as you go higher in frequency. Don't recall without looking it up, but around 2 meters is is probalby slightly under 1 db for the hardline and around 3 db for the rg-213 which is getting into the noticable range. For myself, I am lucky have up antennas that are reasonable for my type of casual operation. I don't go at it hot and heavy, just like to chat on the low bands. I have a 3 element triband at 60 feet , and OCF (home built Carolina Windom about 125 feet long at 50 feet) for 80-10 and it will work the 18 and 24 mhz bands good enough for me with a tuner. Also a 80 meter dipole. All of this is fed with some Davis BuryFlex which is similar to LMR-400 with a stranded center conductor that is 100 feet long for each antenna. |
replacing rg 213 with hardline
Ralph Mowery wrote:
"Rob" wrote in message ... One ham said when he did he could tell the differance. I just don't see that going from about .4 db or less of loss to .15 db of loss on 80 meters is going to be noticed. But what when he was working on 70 centimeters instead of 80 meters? Then it would be a large difference. I should have made it clear that this is for 80 meters only, no higher band. Also he did not say what kind of differance he noticed, just that he did. If changing from RG213 to hardline made any real difference at 80M, then the RG213 was bad and needed replacing. Very few hams have anything in their shack that can detect differnces of a fraction of a db. The only advantage to hardline at HF that I can think of is that good hardline will likely outlive you and hence not require replacing in your lifetime. -- Jim Pennino |
replacing rg 213 with hardline
On Fri, 27 Jun 2014 17:42:38 +0200, Wimpie wrote:
El 27-06-14 17:15, Ralph Mowery escribió: I would like some opinions as if anyone could notice replacing 100 feet of rg-213 with 7/8 inch or larger hardline would be noticiable. One ham said when he did he could tell the differance. I just don't see that going from about .4 db or less of loss to .15 db of loss on 80 meters is going to be noticed. That is about like going from 100 watts of transmitted power to maybe 105 watts or less. In the past I have inserted some 1 and 3 db pads in line with a receiver to see if I could tell the differance and have a hard time telling that even the 3 db pad makes much differance in casual operation, especially below 20 MHz. Maybe some have more sensitive ears than I have. What kind of difference did he notice? I am thinking of signal strength at target area, received signal strength, S/N ratio, change in antenna radiation pattern, etc. Some other thing to consider, what will be the VSWR in the line. If that is really high, hardline can make a difference like coaxial versus ladder line attenuation. Other possibilities: He swapped out poor RF connectors for good ones. Or, the WX beaten - possibly water penetrated coax was replaced by better condition hardline. Not pertaining, but at a previous QTH I used 1/2" Cable TV hardline to feed a 6M beam, and 3/4" Cable TV hardline to feed a 2M beam. I had nothing to compare it with, but I was Very, Very Pleased with the results. All-in-all I believe the hardline will be more WX durable than the coax. 73 Jonesy -- Marvin L Jones | jonz | W3DHJ | linux 38.24N 104.55W | @ config.com | Jonesy | OS/2 * Killfiling google & XXXXbanter.com: jonz.net/ng.htm |
replacing rg 213 with hardline
El 27-06-14 18:30, Ralph Mowery escribió:
wrote in message ... One ham said when he did he could tell the differance. I just don't see that going from about .4 db or less of loss to .15 db of loss on 80 meters is going to be noticed. But what when he was working on 70 centimeters instead of 80 meters? Then it would be a large difference. I should have made it clear that this is for 80 meters only, no higher band. Also he did not say what kind of differance he noticed, just that he did. Most of my work is 2 meters and higher and good transmission there is a must. I just don't have the operating time on the low bands to know if that extra .2 db would make any diffreance there. That is 2/10 of a db. Variation in propagation conditions at HF are in the tens of dB's (depending on wave and particle radiation from our sun). So you will never notice 0.2 dB. Besides the VSWR issue, I can only think of special applications/situations where screening is of prime importance. For this case, screening is the only big difference between RG213 and hardline. -- Wim PA3DJS Please remove abc first in case of PM |
replacing rg 213 with hardline
El 27-06-14 19:45, Allodoxaphobia escribió:
On Fri, 27 Jun 2014 17:42:38 +0200, Wimpie wrote: El 27-06-14 17:15, Ralph Mowery escribió: I would like some opinions as if anyone could notice replacing 100 feet of rg-213 with 7/8 inch or larger hardline would be noticiable. One ham said when he did he could tell the differance. I just don't see that going from about .4 db or less of loss to .15 db of loss on 80 meters is going to be noticed. That is about like going from 100 watts of transmitted power to maybe 105 watts or less. In the past I have inserted some 1 and 3 db pads in line with a receiver to see if I could tell the differance and have a hard time telling that even the 3 db pad makes much differance in casual operation, especially below 20 MHz. Maybe some have more sensitive ears than I have. What kind of difference did he notice? I am thinking of signal strength at target area, received signal strength, S/N ratio, change in antenna radiation pattern, etc. Some other thing to consider, what will be the VSWR in the line. If that is really high, hardline can make a difference like coaxial versus ladder line attenuation. Other possibilities: He swapped out poor RF connectors for good ones. Or, the WX beaten - possibly water penetrated coax was replaced by better condition hardline. Not pertaining, but at a previous QTH I used 1/2" Cable TV hardline to feed a 6M beam, and 3/4" Cable TV hardline to feed a 2M beam. I had nothing to compare it with, but I was Very, Very Pleased with the results. All-in-all I believe the hardline will be more WX durable than the coax. 73 Jonesy You are right, damaged/aged HW (cables/connectors) versus good HW can make a difference. If so, in my opinion the "one ham" should have mentioned relevant additional info. -- Wim PA3DJS Please remove abc first in case of PM |
replacing rg 213 with hardline
On 6/27/2014 10:15 AM, Ralph Mowery wrote:
I would like some opinions as if anyone could notice replacing 100 feet of rg-213 with 7/8 inch or larger hardline would be noticiable. One ham said when he did he could tell the differance. I just don't see that going from about .4 db or less of loss to .15 db of loss on 80 meters is going to be noticed. That is about like going from 100 watts of transmitted power to maybe 105 watts or less. In the past I have inserted some 1 and 3 db pads in line with a receiver to see if I could tell the differance and have a hard time telling that even the 3 db pad makes much differance in casual operation, especially below 20 MHz. Maybe some have more sensitive ears than I have. It was better, caused by the placebo effect. It was better, caused by the extra dollars he spent. It was better, because he thought it should be better. Changing the coax made it 0.25db better, but he didn't hear it. Mikek |
replacing rg 213 with hardline
"Ralph Mowery" wrote in message m... "Rob" wrote in message ... One ham said when he did he could tell the differance. I just don't see that going from about .4 db or less of loss to .15 db of loss on 80 meters is going to be noticed. But what when he was working on 70 centimeters instead of 80 meters? Then it would be a large difference. I should have made it clear that this is for 80 meters only, no higher band. Also he did not say what kind of differance he noticed, just that he did. Most of my work is 2 meters and higher and good transmission there is a must. I just don't have the operating time on the low bands to know if that extra .2 db would make any diffreance there. That is 2/10 of a db. ================================================== ======== Yes. It takes 6dB to make a 1 S-unit change. Almost all the time at 80m, the atmospheric noise is much stronger than the receiver's thermal noise, so the ability of the other guy to deliver enough signal power to you to be louder than the atmospherics is the key. He controls that, not you. On transmit, I suppose every dB counts, considering you're competing with atmospherics for the other guy's ear. Sort of the inverse of the above. "Sal" |
replacing rg 213 with hardline
El 01-07-14 4:41, amdx escribió:
On 6/27/2014 10:15 AM, Ralph Mowery wrote: I would like some opinions as if anyone could notice replacing 100 feet of rg-213 with 7/8 inch or larger hardline would be noticiable. One ham said when he did he could tell the differance. I just don't see that going from about .4 db or less of loss to .15 db of loss on 80 meters is going to be noticed. That is about like going from 100 watts of transmitted power to maybe 105 watts or less. In the past I have inserted some 1 and 3 db pads in line with a receiver to see if I could tell the differance and have a hard time telling that even the 3 db pad makes much differance in casual operation, especially below 20 MHz. Maybe some have more sensitive ears than I have. It was better, caused by the placebo effect. It was better, caused by the extra dollars he spent. It was better, because he thought it should be better. Changing the coax made it 0.25db better, but he didn't hear it. Mikek Hello Mike, You did read my mind! -- Wim PA3DJS Please remove abc first in case of PM |
replacing rg 213 with hardline
On 6/30/2014 9:41 PM, amdx wrote:
On 6/27/2014 10:15 AM, Ralph Mowery wrote: I would like some opinions as if anyone could notice replacing 100 feet of rg-213 with 7/8 inch or larger hardline would be noticiable. One ham said when he did he could tell the differance. I just don't see that going from about .4 db or less of loss to .15 db of loss on 80 meters is going to be noticed. That is about like going from 100 watts of transmitted power to maybe 105 watts or less. In the past I have inserted some 1 and 3 db pads in line with a receiver to see if I could tell the differance and have a hard time telling that even the 3 db pad makes much differance in casual operation, especially below 20 MHz. Maybe some have more sensitive ears than I have. It was better, caused by the placebo effect. It was better, caused by the extra dollars he spent. It was better, because he thought it should be better. Changing the coax made it 0.25db better, but he didn't hear it. Mikek Very well said. I am afraid we are all guilty of that at times. I just bought a pixel magnetic loop receiving antenna. At first blush I thought it was great. Then I put together an A-B switch so that I can make a well thought out review for e-ham. The loop has some advantages, especially during electrical storm noise. However, it does not come close to equalling the performance of a horizontal loop cut for the right frequency. I had spent 500 dollars on this project, I wanted it to perform better and then saw it better in my own mind. Careful measurements dispelled my wild enthusiasm. I admit there are often times it is better at receiving on 20, 15, and 10 than my 75 meter loop. Michael |
replacing rg 213 with hardline
On Tuesday, July 1, 2014 1:51:23 PM UTC-5, FBMboomer wrote:
I am afraid we are all guilty of that at times. I just bought a pixel magnetic loop receiving antenna. At first blush I thought it was great. Then I put together an A-B switch so that I can make a well thought out review for e-ham. The loop has some advantages, especially during electrical storm noise. However, it does not come close to equalling the performance of a horizontal loop cut for the right frequency. What do you mean by performance? You will have trouble getting a decent null using a horizontal loop. And the easily steerable nulls are 90% of the reason to use a small loop. But I only use small loops on low frequencies.. IE: LW to about 2.5 mhz or so.. AM-BC more than anything, but I've used it on 160m at times. A small loop can make an offensive ground or space wave signal disappear. OK at night, but they are not near as effective nulling a sky wave signal as a ground wave. |
Quote:
Simple math tells us that as long as the op is only wanting to compare power in vs power out and signal in vs signal out that he should be using Belden 9913 F7 or LMR 400 coax. You wouldn't or couldn't use hardline for a dipole antenna, maybe for a beam antenna, if you were going to attach the hardline to the side of the tower or to a track. The Hardline would be too heavy to support with a rope. RG 213 is not a very good coax from my perspective - especially if you want to get maximum performance out of a piece of coax.. At higher frequencies you are throwing away a proportional amount of signal in the coax and a proportional amount of power loss between the transmitter and the antenna. If you were building a repeater, you would want hardline going up the tower to the antenna, regardless if it was 6 meters, 2 meters or 70 cm.. If you were trying to work rare DX on either of those bands, you would want to use the best possible coax with the lowest loss, and if you went to the expense to put up a tower and a stacked beam antenna array to work those bands, you would want hardline to feed those antenna's.. That is the purpose of hardline - not to feed a HF antenna! |
replacing rg 213 with hardline
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replacing rg 213 with hardline
On Thursday, July 3, 2014 4:20:56 PM UTC-5, FBMboomer wrote:
By performance, I mean the readability of a received signal. The signal to noise ratio. What I was trying to explain also was that my 75 meter horizontal full wave loop does not receive as well on 20, 15, and 10. Generally! It should be OK. But the pattern is going to change for each band, and having modeled that antenna, most of the higher bands don't really have a low angle pattern. But good enough for general use I guess. But then you also have to consider if any decoupling problems, and local shack noise being piped up and back down to the radio. Only the operator can judge what any issues might be. When I operate on 20, 15, and 10, I use the pixel loop for receive. I get a better signal to noise ration on these higher frequencies. I have no idea why. Like I say, could be any number of reasons, from antenna pattern, to excess shack noise due to decoupling issues. etc.. 40 meters is kind of a crap shoot. The 75 meter loop might work better for receive or the magnetic loop. That is one of the reason I made an AB switch. Handy to have.. I have several.. I usually keep one of those small ones in my trunk for portable use. I do not know, but I can surmise that my receive on 75 would be better on the magnetic loop if I was using a dipole for my antenna. I don't know what you mean by this. It's not going to change if you change the full size antenna. I had a dipole up at my lot a few years ago. The noise level in town was horrendous. It was locking me out of using 75 meters. So I am now comparing the pixel magnetic loop to a full size horizontal loop. This may be kind of an unfair comparison. Most people probably would be judging its improved performance over a dipole. I am currently unable to make that kind of AB comparison. I took my dipole down in favour of the full wave loop. The performance comparison between the dipole and loop was profound. (meaning at least 10 db better S/N. Normally there shouldn't be much difference between the dipole and horizontal loop. I've run both, and I never did see that much difference. If you had less local noise, it was probably sort of a fluke thing where the pattern of the loop just happened to be what you wanted for that direction and angle to the noise source. The sky wave patterns are pretty close overall. In fact, I found them so close in performance, I quit using the loops because they take more wire, and more of a hassle to string up and keep in the air. Also the dipole will give me max current at the apex, which on mine is always the highest point of the antenna. And yes, BC band performance is better than my 75 meter loop. That is what I mainly use mine for. I have a couple of them. One is a round circle 16 inch dia loop. The other is a diamond that is 48 inches on each side. It's PVC, and stands on the floor in a rotatable stand. My loops cost me very little.. This is the basic design I use for the PVC loops. http://home.comcast.net/~nm5k/loop5.jpg |
replacing rg 213 with hardline
I do not know, but I can surmise that my receive on 75 would be better on the magnetic loop if I was using a dipole for my antenna. I don't know what you mean by this. It's not going to change if you change the full size antenna. What I mean is that I once had a 120 foot dipole for 75 meters. It was pretty damn noisy. I think that if I had it again to compare to the pixel loop for receive, I am guessing that the pixel loop would have a better S/N than the dipole. Just a guess. |
replacing rg 213 with hardline
On Thursday, July 3, 2014 6:30:35 PM UTC-5, FBMboomer wrote:
What I mean is that I once had a 120 foot dipole for 75 meters. It was pretty damn noisy. I think that if I had it again to compare to the pixel loop for receive, I am guessing that the pixel loop would have a better S/N than the dipole. Just a guess. Sounds normal to me, unless you were picking up shack noise. Noise is RF the same as any other signal. It follows the same rules. Properly functioning antennas should pick up a lot of noise if the noise is there to be received. If they don't, they are not very good antennas. Or at least as far as atmospheric noise. If the noise is atmospheric, I suspect the s/n ratio of the small loop would not be that much better than the dipole or loop. You can't null general atmospheric noise, so the small loop has no real advantage in that case. |
replacing rg 213 with hardline
On Friday, June 27, 2014 11:15:56 AM UTC-4, Ralph Mowery wrote:
I would like some opinions as if anyone could notice replacing 100 feet of rg-213 with 7/8 inch or larger hardline would be noticiable. One ham said when he did he could tell the differance. I just don't see that going from about .4 db or less of loss to .15 db of loss on 80 meters is going to be noticed. That is about like going from 100 watts of transmitted power to maybe 105 watts or less. Just from the signal? Not at all likely. What could happen is that you might have less RFI. |
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