OT:. G5RV's
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Alan,
I do understand the situation for those with limited antenna space and restrictions. What I do not understand is the "magical" qualities that have been attributed to many antennas. They are compromise antennas, and I want everyone to understand that they are a compromise. If a ham wants to operate on multiple bands and can have only one antenna, that compromise may be necessary, but for those who can install no-compromise antennas such as a fan dipole, it will provide better performance than the G5RV or the 'Carolina windom'. A fan dipole can be operated on multiple bands without a tuner. Of course, LB Cebik advocated the 44 foot dipole for 40 thru 10 meters (88 foot for 80 thru 20) because it has no sidelobes. It works well, but must be fed with low loss parallel feedline which requires a good antenna tuner at the shack end of that feedline. What I am trying to communicate is that the user of a compromise antenna should understand its properties and limitations. Despite what advertising and 'ham lore' would say, there is no 'magic' in any particular antenna. They all have their limitations. 73, Don W3FPR On 8/5/2016 8:34 AM, G4GNX wrote: > Don, > > With respect for your wisdom and your good advice, in the UK in > particular (home of the G5RV) the 'ordinary' ham has real-estate > issues, big time! > > Louis Varney's garden/back yard was of average British size, which is > actually quite small when compared to 'average' gardens that I've seen > in the USA. That was his prime reason for designing a compact wire > antenna. > > We have other issues with planning regulations and erecting a mast or > tower over 40ft in height would probably meet with a brick-wall > attitude from the local planning authorities. Attitudes towards > structures in the UK are very different to the USA and there are many > snobs who claim offense when they see something that appears above the > roof line of an average house. > > My back yard is even smaller than Louis's and I just don't have space > for lengthy wires or even slopers. Even erecting tall supports is > difficult as there's limited ground to dig holes to fill with concrete > supports. > > Maybe in the USA, the use of G5RV antennas doesn't make too much > sense, but to us Brits, compact antennas are often the only thing we > can use. > > > 73, > > Alan. G4GNX > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Wes Stewart-2
Alas, the poor G5RV. Now that its been flogged to
death, maybe we need a new target -- say the Windom? Phil W7OX On 8/4/16 10:22 PM, Wes Stewart wrote: > The tuner loss also depends on how it is > adjusted. For example the very popular high-pass > Tee with three adjustable elements has an > infinite number of possible combinations that > will effect a match on the same load Z. One of > them is the lowest loss solution, all of the > others aren't. > > As I said earlier, in a letter to Dean Straw > dated February 2, 1994 I offered an example > where the SPC tuner, then current in the > handbooks, could be used to match an impedance > of 4.34 +j46 to 50 ohm. (I forget where this > came from but it was a real possibility) I > assumed Qc = 1000 and Ql = 300 (generous). I > used Touchstone to calculate the minimum loss > and maximum loss solutions The best case was 1.6 > dB and the worst case was 7.8 dB. > > With lower Q components, Qc = 500, Ql =200, the > losses were 2.4 to 9.5 dB! > > Wes N7WS > > > On 8/4/2016 2:00 PM, Alan Bloom wrote: >> > It's a pity that too many newcomers, as well >> as many oldsters, are >> > enamored by this piece of wire. >> >> The G4RV is definitely a compromise antenna. >> However its advantage is that is has low-enough >> SWR to be easily matched by most tuners on a >> number of bands. >> >> > ... the horrific losses that could be >> incurred even >> > with high quality tuners, >> >> It's true that tuner losses are the >> manufacturers' dirty little secret. Loss is >> rarely specified, partly because it can be >> pretty bad, and partly because it is hard to >> measure, but also because it is not constant - >> it depends on the particular impedance being >> matched. >> >> One exception is the old Drake tuners. Their >> Pi-L topology makes the loss almost independent >> of the load impedance. If you can get it to >> match, you know that almost all the power is >> going into the feed line. For example, the >> MN-2700 that I designed when I was at Drake was >> specified at 0.5 dB maximum insertion loss and >> I did a lot of testing and tweaking to achieve >> that on all bands. >> >> Alan N1AL ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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And you now dear list users, i have a G5RV and i really love it it works allways, and give’s me good results :-))
Just have to say that. Regards William PE1BSB > On 05 Aug 2016, at 16:58, Phil Wheeler <[hidden email]> wrote: > > Alas, the poor G5RV. Now that its been flogged to death, maybe we need a new target -- say the Windom? > > Phil W7OX > > On 8/4/16 10:22 PM, Wes Stewart wrote: >> The tuner loss also depends on how it is adjusted. For example the very popular high-pass Tee with three adjustable elements has an infinite number of possible combinations that will effect a match on the same load Z. One of them is the lowest loss solution, all of the others aren't. >> >> As I said earlier, in a letter to Dean Straw dated February 2, 1994 I offered an example where the SPC tuner, then current in the handbooks, could be used to match an impedance of 4.34 +j46 to 50 ohm. (I forget where this came from but it was a real possibility) I assumed Qc = 1000 and Ql = 300 (generous). I used Touchstone to calculate the minimum loss and maximum loss solutions The best case was 1.6 dB and the worst case was 7.8 dB. >> >> With lower Q components, Qc = 500, Ql =200, the losses were 2.4 to 9.5 dB! >> >> Wes N7WS >> >> >> On 8/4/2016 2:00 PM, Alan Bloom wrote: >>> > It's a pity that too many newcomers, as well as many oldsters, are >>> > enamored by this piece of wire. >>> >>> The G4RV is definitely a compromise antenna. However its advantage is that is has low-enough SWR to be easily matched by most tuners on a number of bands. >>> >>> > ... the horrific losses that could be incurred even >>> > with high quality tuners, >>> >>> It's true that tuner losses are the manufacturers' dirty little secret. Loss is rarely specified, partly because it can be pretty bad, and partly because it is hard to measure, but also because it is not constant - it depends on the particular impedance being matched. >>> >>> One exception is the old Drake tuners. Their Pi-L topology makes the loss almost independent of the load impedance. If you can get it to match, you know that almost all the power is going into the feed line. For example, the MN-2700 that I designed when I was at Drake was specified at 0.5 dB maximum insertion loss and I did a lot of testing and tweaking to achieve that on all bands. >>> >>> Alan N1AL > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Don Wilhelm
The problem with every one of these antenna discussions is that some of
us are looking for a reasonable set of compromises, and that discussion tends to get lost in the "this antenna ain't perfect!" discussion that invariably results. When I bought this house, I knew the lot size, and I saw the power lines running along the back property line. Someone said that rotating dipoles would outperform most of the alternatives. That means a good mast, a rotor, and I'd have to make damn sure the mast couldn't fall across power lines. I guess the bottom line is that perfect is the enemy of good enough. -- Lynn On 8/5/2016 6:37 AM, Don Wilhelm wrote: > What I am trying to communicate is that the user of a compromise > antenna should understand its properties and limitations. Despite > what advertising and 'ham lore' would say, there is no 'magic' in any > particular antenna. They all have their limitations. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by William Lagerberg
When I started in the hobby, I worked 150 countries before I found out a G5RV didn't work. Took it down and haven't used it since.
Sent from my iPhone > On Aug 5, 2016, at 11:21 AM, William Lagerberg <[hidden email]> wrote: > > And you now dear list users, i have a G5RV and i really love it it works allways, and give’s me good results :-)) > > Just have to say that. > > Regards William PE1BSB > > > >> On 05 Aug 2016, at 16:58, Phil Wheeler <[hidden email]> wrote: >> >> Alas, the poor G5RV. Now that its been flogged to death, maybe we need a new target -- say the Windom? >> >> Phil W7OX >> >>> On 8/4/16 10:22 PM, Wes Stewart wrote: >>> The tuner loss also depends on how it is adjusted. For example the very popular high-pass Tee with three adjustable elements has an infinite number of possible combinations that will effect a match on the same load Z. One of them is the lowest loss solution, all of the others aren't. >>> >>> As I said earlier, in a letter to Dean Straw dated February 2, 1994 I offered an example where the SPC tuner, then current in the handbooks, could be used to match an impedance of 4.34 +j46 to 50 ohm. (I forget where this came from but it was a real possibility) I assumed Qc = 1000 and Ql = 300 (generous). I used Touchstone to calculate the minimum loss and maximum loss solutions The best case was 1.6 dB and the worst case was 7.8 dB. >>> >>> With lower Q components, Qc = 500, Ql =200, the losses were 2.4 to 9.5 dB! >>> >>> Wes N7WS >>> >>> >>> On 8/4/2016 2:00 PM, Alan Bloom wrote: >>>>> It's a pity that too many newcomers, as well as many oldsters, are >>>>> enamored by this piece of wire. >>>> >>>> The G4RV is definitely a compromise antenna. However its advantage is that is has low-enough SWR to be easily matched by most tuners on a number of bands. >>>> >>>>> ... the horrific losses that could be incurred even >>>>> with high quality tuners, >>>> >>>> It's true that tuner losses are the manufacturers' dirty little secret. Loss is rarely specified, partly because it can be pretty bad, and partly because it is hard to measure, but also because it is not constant - it depends on the particular impedance being matched. >>>> >>>> One exception is the old Drake tuners. Their Pi-L topology makes the loss almost independent of the load impedance. If you can get it to match, you know that almost all the power is going into the feed line. For example, the MN-2700 that I designed when I was at Drake was specified at 0.5 dB maximum insertion loss and I did a lot of testing and tweaking to achieve that on all bands. >>>> >>>> Alan N1AL >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Alan Bloom
On 8/4/2016 4:00 PM, Alan Bloom wrote: > It's true that tuner losses are the manufacturers' dirty little > secret. Loss is rarely specified, partly because it can be pretty bad, > and partly because it is hard to measure, but also because it is not > constant - it depends on the particular impedance being matched. I read about tuner losses often, and I've seen figures posted, but whenever I try to determine it, I can't. The only way I can determine tuner loss is by signal reports. While participating in round tables on 80 meters, I go down in power as low as the K3 will go, and the participants in state, and in an adjacent state or two, still hear me as evidenced by carrying on a discussion. I use open wire feedline with a loop cut for the bottom of 80 meters. I know this is not an accurate way to measure tuner loss, but the loss doesn't seem to be a problem. ??? Dick, n0ce -- ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Alan. G4GNX
The UK does not have a monopoly on such folk, Alan. Just ask Tom,
K5RC/W7RN. 10 acres on a hilltop in an extremely rural area ... 3 1/2 years of legal battles with distant neighbors and the County government. Tom prevailed, finally, and I operate his station remotely from time to time. Our homeowners' association is pretty benign and benevolent here, and I've learned over the years that I can be a pretty adaptable ham, still satisfy my urge to radiate RF, and get along with my neighbors. 73, Fred K6DGW Sparks NV Washoe County DM09dn On 8/5/2016 5:34 AM, G4GNX wrote: > Attitudes towards structures in the > UK are very different to the USA and there are many snobs who claim > offense when they see something that appears above the roof line of an > average house. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Richard Fjeld-2
Eric closed the G5RV thread, so I will change this subject as it is not
related to the G5RV. On 8/5/2016 11:57 AM, Richard Fjeld wrote: > > On 8/4/2016 4:00 PM, Alan Bloom wrote: >> It's true that tuner losses are the manufacturers' dirty little >> secret. Loss is rarely specified, partly because it can be pretty >> bad, and partly because it is hard to measure, but also because it is >> not constant - it depends on the particular impedance being matched. > > I read about tuner losses often, and I've seen figures posted, but > whenever I try to determine it, I can't. The only way I can determine > tuner loss is by signal reports. While participating in round tables > on 80 meters, I go down in power as low as the K3 will go, and the > participants in state, and in an adjacent state or two, still hear me > as evidenced by carrying on a discussion. I use open wire feedline > with a loop cut for the bottom of 80 meters. > > I know this is not an accurate way to measure tuner loss, but the loss > doesn't seem to be a problem. ??? > > Dick, n0ce > -- ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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