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#1
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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. |
#2
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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 |
#3
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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. |
#4
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![]() "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. |
#5
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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. |
#6
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![]() "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. |
#7
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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 |
#8
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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 |
#9
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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 |
#10
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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 |
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