Re: [Elecraft] Subject: The G5RV trivia
I just looked in some of my old ARRL Handbooks. The earliest I find the chart described as “Practical arrangement of a shortened antenna” is in the 1948 edition of the handbook. The 1944 edition has a very similar chart talking about multi band antennas but the description is somewhat different. 73, Chuck, AA3CS -- “It's still magic even if you know how it's done.” -- Terry Pratchett > On 23 Mar 2020, at 21:53, Bob McGraw K4TAX wrote: > > The same antenna, although not named the G5RV, is described in the 1956 ARRL > Handbook, Chapter 14, page 343. Fig 14-19 "Practical arrangement of a > shortened antenna."It may have been described in an earlier publication, > however the 1956 Handbook is the earliest I have for reference. > > The description shows "A" as the length of 1/2 of a dipole where "2A" is the > dipole total length and with the total length being less than 1/2 wavelength > as shown in table 14-1. The open wire feed line "B" is then 1/2 of "A". > Therefore A + A + B + B becomes the length of the standard 1/2 wave antenna. > When the length of A + A is is greater than a 1/4 wavelength the > effectiveness of the antenna is not changed. > > Table 14-1 shows the length of the antenna to be 135 ft with a feeder length > of 42 ft. covering 3.5 - 28 MHz which uses parallel feed for 3.5 - 21 MHz and > series feed for 28 MHz. A shortened version shows the antenna length to > be 67 ft with 42.5 ft feedline. In this case 3.5 MHz is series fed and 7 - > 28 MHz is parallel fed. > > Regarding connecting a balanced feed line to the transmitter, Fig 14-21 (B) > reference is made to do so using a pair of "balun" coils. This would imply > a proper balun would contain two separate coils existing on two separate > cores. The discussions by W8JI and DJ0IP would imply a single core will not > be the correct design although it may contain 4 windings existing on a signal > core. The original Heathkit balun, being two separate air wound dual > winding coils would satisfy the requirement. > > Yes, more interesting trivia. > > 73 > > Bob, K4TAX > > > On 3/23/2020 8:18 PM, Jan wrote: >> I first learned of the G5RV Antenna back in early 1963 in Malaya ~ as the >> Editor for the *M*alayan *A*mateur *R*adio *T*ransmitter *S*ociety's >> /NewsLetter/ . Jim, 9M2DQ (a rubber estate manager) sent me a copy of Mr. >> Varney's article; a simple wire antenna that covered 80-40-20-15-10 Meters. >> >> It became a popular antenna in South-East Asia ~ with many using it for >> chatting on 14.320 MHz ~ which became the SEA-NET in 1963 and beyond. I >> have fond memories of using it at 9M2JJ for two and a half years at the >> Secondary Trade School; where I taught as a Peace Corps Volunteer. >> >> Cheers, Jan K1ND >> >> >> >> >> __ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to rmcg...@blomand.net > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to aa...@me.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Subject: The G5RV trivia
I was also 16 in 1956, and do remember trying a few antennas. I had a 3 half waves in phase antenna for 40 meters, and it did the job nicely, but my first antenna was a 40 meter dipole fed with 75 ohm parallel feedline. It worked fine with my homebrew 75 watt 6146 transmitter with a Pi-Network output. The Pi-Network had a sufficient range to match it. I did not have an SWR meter at the time, so that is all I can say. The 3 half-waves in phase was fed in the center with true ladder line and the Pi-Network matched it too. Since modern transceivers want to see a 50 ohm load, the ATU takes the brunt of matching to the antenna and the task of achieving a good match is no longer by tuning to resonance (plate dip) and then loading for the desired amount of plate current. Those old days are gone. We could get radiation out in those old days just by looking at our meters and know that we had tuned up correctly. Such is not true anymore - there is just no proper comparison. You must tune the antenna/feedline to produce a 50 ohm load by use of antenna/feedline lengths and/or relying on a good ATU to bring the antenna load to near a 50 ohm match. An antenna analyzer is a great tool to use when working with antennas. A good link coupled antenna tuning unit can cover a large range (Johnson Matchbox is one example), and has many benefits that can be used today, but few know how to use it to advantage. 73, Don W3FPR On 3/23/2020 10:18 PM, Fred Jensen wrote: Bob: My memory from 1956 is a bit thin, I was 16 then, but I don't remember RF inductors wound on "cores", unless you count a plastic coil form with a 5-pin base to be a "core." Not sure ferrite had been invented. [:-) The Pi-network was a big deal then, those of us who couldn't afford the two capacitors used parallel resonant tanks with one capacitor with link coupling. Interestingly, it did harmonic suppression and also matched whatever impedance was at the shack end of the feedline to the plate impedance of the PA. I don't recall anyone talking about SWR. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Subject: The G5RV trivia
Bob: My memory from 1956 is a bit thin, I was 16 then, but I don't remember RF inductors wound on "cores", unless you count a plastic coil form with a 5-pin base to be a "core." Not sure ferrite had been invented. [:-) The Pi-network was a big deal then, those of us who couldn't afford the two capacitors used parallel resonant tanks with one capacitor with link coupling. Interestingly, it did harmonic suppression and also matched whatever impedance was at the shack end of the feedline to the plate impedance of the PA. I don't recall anyone talking about SWR. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County On 3/23/2020 6:53 PM, Bob McGraw K4TAX wrote: Regarding connecting a balanced feed line to the transmitter, Fig 14-21 (B) reference is made to do so using a pair of "balun" coils. This would imply a proper balun would contain two separate coils existing on two separate cores. Yes, more interesting trivia. 73 Bob, K4TAX __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Subject: The G5RV trivia
The same antenna, although not named the G5RV, is described in the 1956 ARRL Handbook, Chapter 14, page 343. Fig 14-19 "Practical arrangement of a shortened antenna." It may have been described in an earlier publication, however the 1956 Handbook is the earliest I have for reference. The description shows "A" as the length of 1/2 of a dipole where "2A" is the dipole total length and with the total length being less than 1/2 wavelength as shown in table 14-1. The open wire feed line "B" is then 1/2 of "A". Therefore A + A + B + B becomes the length of the standard 1/2 wave antenna. When the length of A + A is is greater than a 1/4 wavelength the effectiveness of the antenna is not changed. Table 14-1 shows the length of the antenna to be 135 ft with a feeder length of 42 ft. covering 3.5 - 28 MHz which uses parallel feed for 3.5 - 21 MHz and series feed for 28 MHz. A shortened version shows the antenna length to be 67 ft with 42.5 ft feedline. In this case 3.5 MHz is series fed and 7 - 28 MHz is parallel fed. Regarding connecting a balanced feed line to the transmitter, Fig 14-21 (B) reference is made to do so using a pair of "balun" coils. This would imply a proper balun would contain two separate coils existing on two separate cores. The discussions by W8JI and DJ0IP would imply a single core will not be the correct design although it may contain 4 windings existing on a signal core. The original Heathkit balun, being two separate air wound dual winding coils would satisfy the requirement. Yes, more interesting trivia. 73 Bob, K4TAX On 3/23/2020 8:18 PM, Jan wrote: I first learned of the G5RV Antenna back in early 1963 in Malaya ~ as the Editor for the *M*alayan *A*mateur *R*adio *T*ransmitter *S*ociety's /NewsLetter/ . Jim, 9M2DQ (a rubber estate manager) sent me a copy of Mr. Varney's article; a simple wire antenna that covered 80-40-20-15-10 Meters. It became a popular antenna in South-East Asia ~ with many using it for chatting on 14.320 MHz ~ which became the SEA-NET in 1963 and beyond. I have fond memories of using it at 9M2JJ for two and a half years at the Secondary Trade School; where I taught as a Peace Corps Volunteer. Cheers, Jan K1ND __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rmcg...@blomand.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] Subject: The G5RV trivia
I first learned of the G5RV Antenna back in early 1963 in Malaya ~ as the Editor for the *M*alayan *A*mateur *R*adio *T*ransmitter *S*ociety's /NewsLetter/ . Jim, 9M2DQ (a rubber estate manager) sent me a copy of Mr. Varney's article; a simple wire antenna that covered 80-40-20-15-10 Meters. It became a popular antenna in South-East Asia ~ with many using it for chatting on 14.320 MHz ~ which became the SEA-NET in 1963 and beyond. I have fond memories of using it at 9M2JJ for two and a half years at the Secondary Trade School; where I taught as a Peace Corps Volunteer. Cheers, Jan K1ND __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
