Re: [Elecraft] ARRL book on receiving antennas
On 9/10/2018 1:25 PM, GWK wrote: We call it a "ground plane" antenna. No, it's quite different. 73, Jim K9YC __ 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] ARRL book on receiving antennas
Folks, lets end this OT tread for now. It is well past our short term postings limit. Also, do not leave all of the prior thread emails in your reply. Delete most of the prior posts and only keep the absolute minimum needed in your reply to maintain context. That really helps reduce clutter and overload for our digest readers and als for those on slower connections. 73, Eric Mooderator elecraft.com _..._ > On Sep 10, 2018, at 1:43 PM, Fred Jensen wrote: > > KFBK's are actually two, phased for day-night directional service. Been > awhile __ 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] ARRL book on receiving antennas
KFBK's are actually two, phased for day-night directional service. Been awhile since I saw them but the bottom insulators were maybe 10 ft above ground level [I'm 6'2" and it was just above my reach] so the feedpoint is a tiny bit higher than 1/4 wave. 1/2 wave at 1530 KHz is just over 300 ft and the feed system at 50 KW is mechanically complex and pretty heavy. I think [not sure where I read it but it was moderately recently] that KFBK's Franklin is the last AM broadcast one in NA. NIST photos of WWV HF antennas show about the same height more or less. WWVH uses 2-element phased elements to put a cardioid null at the CONUS to reduce interference. I would think that getting anything [including ground] farther out in the near field would reduce losses. The choice is an engineering cost-benefit trade off of course. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County On 9/10/2018 11:41 AM, Jim Brown wrote: On 9/9/2018 7:02 PM, Wes Stewart wrote: The WWV antennas are center-fed vertical dipoles. Thanks for the reminder about this -- I vaguely remember reading about their antennas years ago. Question -- from the description, is the feedpoint higher than a quarter wave above ground? A few years ago, I did an NEC modeling study of HF verticals that showed that doing that improved the vertical pattern and seemed to suggest that it reduced ground losses. Your thoughts? The study is here. http://k9yc.com/VerticalHeight.pdf 73, Jim K9YC __ 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 k6...@foothill.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
Re: [Elecraft] ARRL book on receiving antennas
We call it a "ground plane" antenna. W3HBM On 9/10/2018 2:48 PM, Walter Underwood wrote: From the official WWV site, the bottom element is a sloping skirt that also serves as guy wires. Sort of like a discone with the disc replaced by a vertical element, I guess. "The top half of each antenna is a quarter-wavelength radiating element. The bottom half of each antenna consists of nine quarter-wavelength wires that connect to the center of the tower and slope downwards to the ground at a 45 degree angle. This sloping skirt functions as the lower half of the radiating system and also guys the antenna." https://www.nist.gov/pml/time-and-frequency-division/radio-stations/wwv wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) On Sep 10, 2018, at 11:41 AM, Jim Brown wrote: On 9/9/2018 7:02 PM, Wes Stewart wrote: The WWV antennas are center-fed vertical dipoles. Thanks for the reminder about this -- I vaguely remember reading about their antennas years ago. Question -- from the description, is the feedpoint higher than a quarter wave above ground? A few years ago, I did an NEC modeling study of HF verticals that showed that doing that improved the vertical pattern and seemed to suggest that it reduced ground losses. Your thoughts? The study is here. http://k9yc.com/VerticalHeight.pdf 73, Jim K9YC __ 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 wun...@wunderwood.org __ 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 gkid...@ilstu.edu __ 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] ARRL book on receiving antennas
>From the official WWV site, the bottom element is a sloping skirt that also >serves as guy wires. Sort of like a discone with the disc replaced by a >vertical element, I guess. "The top half of each antenna is a quarter-wavelength radiating element. The bottom half of each antenna consists of nine quarter-wavelength wires that connect to the center of the tower and slope downwards to the ground at a 45 degree angle. This sloping skirt functions as the lower half of the radiating system and also guys the antenna." https://www.nist.gov/pml/time-and-frequency-division/radio-stations/wwv wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) > On Sep 10, 2018, at 11:41 AM, Jim Brown wrote: > > On 9/9/2018 7:02 PM, Wes Stewart wrote: >> The WWV antennas are center-fed vertical dipoles. > > Thanks for the reminder about this -- I vaguely remember reading about their > antennas years ago. Question -- from the description, is the feedpoint > higher than a quarter wave above ground? A few years ago, I did an NEC > modeling study of HF verticals that showed that doing that improved the > vertical pattern and seemed to suggest that it reduced ground losses. Your > thoughts? > > The study is here. http://k9yc.com/VerticalHeight.pdf > > 73, Jim K9YC > > > __ > 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 wun...@wunderwood.org __ 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] ARRL book on receiving antennas
On 9/9/2018 7:02 PM, Wes Stewart wrote: The WWV antennas are center-fed vertical dipoles. Thanks for the reminder about this -- I vaguely remember reading about their antennas years ago. Question -- from the description, is the feedpoint higher than a quarter wave above ground? A few years ago, I did an NEC modeling study of HF verticals that showed that doing that improved the vertical pattern and seemed to suggest that it reduced ground losses. Your thoughts? The study is here. http://k9yc.com/VerticalHeight.pdf 73, Jim K9YC __ 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] ARRL book on receiving antennas
On 9/9/2018 8:02 PM, Wes Stewart wrote: The WWV antennas are center-fed vertical dipoles. "The WWV antennas are half-wave vertical antennas that radiate omnidirectional patterns. ... And WWVH on Kauai, HI has two-element arrays of half-wave verticals on 5, 10, and 15 MHz. The arrays have cardioid patterns with deep nulls toward the mainland to minimize interference with WWV in Ft. Collins, CO. https://tf.nist.gov/images/radiostations/wwvh-large/wwvh5.jpg Gus Hansen, KB0YH __ 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] ARRL book on receiving antennas
The WWV antennas are center-fed vertical dipoles. "The WWV antennas are half-wave vertical antennas that radiate omnidirectional patterns. There are antennas at the station site for each frequency. Each antenna is connected to a single transmitter using a rigid coaxial line, and the site is designed so that no two coaxial lines cross. Each antenna is mounted on a tower that is approximately one half-wavelength tall. The tallest tower, for 2.5 MHz, is about 60 m tall. The shortest tower, for 20 MHz, is about 7.5 m tall. The top half of each antenna is a quarter-wavelength radiating element. The bottom half of each antenna consists of nine quarter-wavelength wires that connect to the center of the tower and slope downwards to the ground at a 45 degree angle. This sloping skirt functions as the lower half of the radiating system and also guys the antenna." Wes N7WS On 9/9/2018 3:48 PM, Fred Jensen wrote: It may be the only Franklin left in NA. __ 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] ARRL book on receiving antennas
Thanks Fred. I'm familiar with measuring broadcast fields for both directional and non directional systems. The variances over the seasons with varying moisture levels in the ground and the difference with and without vegetation is clearly measurable and predictable. But still the efficiency of the radiator was not clearly defined. As to hams, I suppose we individually evaluate a given antenna under the conditions we have available. From that we can say that given antenna ZZ is more or less efficient than antenna XX. What ever that XX antenna happens to be. While others may say that their XYZ is the best antenna they have ever had, this may be true, that is until one may find another antenna to be better. What ever "better" is defined. And again, each of us will have objectives in terms of what our antenna and station must attain. As Rob Sherwood said when asked "what is the best receiver", his answer; "what ever satisfies your needs and you feel as comfortable to operate and can afford". I suppose antennas are much in the same vein of characterization. Yes, at VHF and UHF there are means and facilities to accurately measure antenna efficiency. Usually we find those to be in the 60% to 80% range. Unfortunately some of the applied power is converted to heat, the result of IR loss, and thus is lost in terms of electromagnetic radiation. Again the means and the equipment required, as Jim K9YC stated, generally is well above and beyond the means of most hams. Some years ago I was fortunate to have supervised access to the antenna test range at the Motorola facility in Florida and also at the anechoic chamber owned by IBM in S. FL. These supported my graduate studies. No further answers required on my part. I've launched into a "reading" project to further educate myself on the topic. 73 Bob, K4TAX On 9/9/2018 5:48 PM, Fred Jensen wrote: Yes, very straightforward theory. Just gather all the watts actually radiated by the antenna and divide it by the watts you put into Rr. Unfortunately, I did not really address Bob's question ... "How do you sweep up all those watts?" :-) That is a nearly intractable problem at HF unless you'll tolerate significant inaccuracies and assumptions. It's much easier at UHF and uWaves. An alternative is to measure/compute the losses. Did something similar on a 10 KW FM broadcast TX, calculating the power it took to heat the exhaust air on the premise that the rest went up the coax to the antenna and I knew what the PA input power was. KFBK in Sacramento CA [1530 KHz] eliminated a lot of the unmeasurable variables by employing a Franklin antenna [center-fed half-wave vertical] over the rice fields of the southern Sacramento Valley [nearly always standing water, and always wet]. The center-fed vertical exhibits far less ground losses than bottom-fed monopoles ... at 50 KW, it's colloquially known as the "Flame Thrower of Sacramento." It may be the only Franklin left in NA. KFBK is also famous as the birthplace of the RCA Ampliphase transmitters and the radio birthplace of Rush Limbaugh. NEC models coupled with terrain models can be used to establish upper and lower bounds on antenna efficiency with pretty good fidelity to reality. But Bob still posed a good question. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County On 9/9/2018 2:01 PM, Don Wilhelm wrote: Skip, That is a great formula for theory - I vaguely remember it from my electromagnetic fields course. But how you measure it? With practical measurement equipment, it is difficult to isolate to a single plane. That may be do-able with fully characterized equipment in a controlled antenna field space or in an EMC lab, but it certainly is not practical in a typical ham antenna installation - and even the radiation resistance is not easily measured. Antenna modeling done properly will provide a much more easily produced result. Comparative results between different antennas can be obtained from a reference pickup antenna, but that can only show the relative performance, we still have to guess at the efficiency. 73, Don W3FPR __ 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
Re: [Elecraft] ARRL book on receiving antennas
On 09/09/2018 01:01 PM, Jim Brown wrote: On 9/9/2018 12:39 PM, Bob McGraw K4TAX wrote: How does one measure transmit antenna efficiency? Not easily. :) B... AND -- propagation reporting systems like WSPR and the Reverse Beacon Network (RBN) can provide very good comparisons between antennas IF a LOT of reports from a LOT of stations is averaged over a LOT of time. Back in the late 1970s, when I worked at W1AW, a new 90-foot tower with stacked monobanders for 20 meters was installed. We wanted to compare the new antenna against the big rhombic that had been used for many years for the 20 meter bulletin and code practice transmissions. So, for a week or two, we did test transmissions after each scheduled transmitting session. We would switch between antenna "A" and antenna "B", send long dashes, and ask listeners to send in QSL reports. (Which antenna was "A" and which was "B" varied randomly for each test.) I collected the reports and plotted them on a map of the US. We found that the rhombic was a little better directly on its boresight to the west (toward southern California from Connecticut) but the stacked Yagis had a much wider beamwidth so were better over the country as a whole. By the way, you don't have to transmit to compare two antennas if your receiver has an accurate S meter. Just switch between the antennas and compare S meter readings. Alan N1AL __ 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] ARRL book on receiving antennas
Yes, very straightforward theory. Just gather all the watts actually radiated by the antenna and divide it by the watts you put into Rr. Unfortunately, I did not really address Bob's question ... "How do you sweep up all those watts?" :-) That is a nearly intractable problem at HF unless you'll tolerate significant inaccuracies and assumptions. It's much easier at UHF and uWaves. An alternative is to measure/compute the losses. Did something similar on a 10 KW FM broadcast TX, calculating the power it took to heat the exhaust air on the premise that the rest went up the coax to the antenna and I knew what the PA input power was. KFBK in Sacramento CA [1530 KHz] eliminated a lot of the unmeasurable variables by employing a Franklin antenna [center-fed half-wave vertical] over the rice fields of the southern Sacramento Valley [nearly always standing water, and always wet]. The center-fed vertical exhibits far less ground losses than bottom-fed monopoles ... at 50 KW, it's colloquially known as the "Flame Thrower of Sacramento." It may be the only Franklin left in NA. KFBK is also famous as the birthplace of the RCA Ampliphase transmitters and the radio birthplace of Rush Limbaugh. NEC models coupled with terrain models can be used to establish upper and lower bounds on antenna efficiency with pretty good fidelity to reality. But Bob still posed a good question. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County On 9/9/2018 2:01 PM, Don Wilhelm wrote: Skip, That is a great formula for theory - I vaguely remember it from my electromagnetic fields course. But how you measure it? With practical measurement equipment, it is difficult to isolate to a single plane. That may be do-able with fully characterized equipment in a controlled antenna field space or in an EMC lab, but it certainly is not practical in a typical ham antenna installation - and even the radiation resistance is not easily measured. Antenna modeling done properly will provide a much more easily produced result. Comparative results between different antennas can be obtained from a reference pickup antenna, but that can only show the relative performance, we still have to guess at the efficiency. 73, Don W3FPR __ 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] ARRL book on receiving antennas
Skip, That is a great formula for theory - I vaguely remember it from my electromagnetic fields course. But how you measure it? With practical measurement equipment, it is difficult to isolate to a single plane. That may be do-able with fully characterized equipment in a controlled antenna field space or in an EMC lab, but it certainly is not practical in a typical ham antenna installation - and even the radiation resistance is not easily measured. Antenna modeling done properly will provide a much more easily produced result. Comparative results between different antennas can be obtained from a reference pickup antenna, but that can only show the relative performance, we still have to guess at the efficiency. 73, Don W3FPR On 9/9/2018 4:26 PM, Fred Jensen wrote: It's the double integral of the power [watts] over all elevation angles 0 to Pi and all azimuths 0 to 2Pi divided by the power [watts] dissipated in the radiation resistance at the feed point. This of course assumes the antenna is over a flat, horizontal plane. ;-) 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County On 9/9/2018 12:39 PM, Bob McGraw K4TAX wrote: How does one measure transmit antenna efficiency? 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] ARRL book on receiving antennas
That's one of the reasons I asked the question. Normally antenna efficiency is measured in an RF anechoic chamber. I'm not aware of one suitable in size for HF antennas. Bob, K4TAX Sent from my iPhone > On Sep 9, 2018, at 3:52 PM, Jim Brown wrote: > >> On 9/9/2018 1:03 PM, Mel Farrer via Elecraft wrote: >> VERY CAREFULLY on an antenna range for that purpose. You can model it and >> get an idea of what it should be, but it is installation specific. > > AND the test ranges required for HF and MF antennas occupy a lot of land with > well defined and consistent soil quality. We're talking tens and hundreds of > square miles, the ability to make calibrated measurements in three > dimensions, and military budgets. > > I'm aware of several excellent antenna engineers who have done some great > work with drones to measure antenna DIRECTIVITY. but efficiency is another > BIG step up in both complexity and cost. > > 73, Jim K9YC > > __ > 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
Re: [Elecraft] ARRL book on receiving antennas
On 9/9/2018 1:03 PM, Mel Farrer via Elecraft wrote: VERY CAREFULLY on an antenna range for that purpose. You can model it and get an idea of what it should be, but it is installation specific. AND the test ranges required for HF and MF antennas occupy a lot of land with well defined and consistent soil quality. We're talking tens and hundreds of square miles, the ability to make calibrated measurements in three dimensions, and military budgets. I'm aware of several excellent antenna engineers who have done some great work with drones to measure antenna DIRECTIVITY. but efficiency is another BIG step up in both complexity and cost. 73, Jim K9YC __ 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] ARRL book on receiving antennas
It's the double integral of the power [watts] over all elevation angles 0 to Pi and all azimuths 0 to 2Pi divided by the power [watts] dissipated in the radiation resistance at the feed point. This of course assumes the antenna is over a flat, horizontal plane. ;-) 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County On 9/9/2018 12:39 PM, Bob McGraw K4TAX wrote: How does one measure transmit antenna efficiency? Bob, K4TAX Sent from my iPhone On Sep 9, 2018, at 2:36 PM, Mel Farrer via Elecraft wrote: Great Don, You and I grew up in the same time era.. Now, I am wiser and have more CRS,Anyway, Here is my take on antennas in general. I have MANY that I can chose from at any time, HOWEVER, Some antennas "hear" better even if they are not as efficient as my transmitting antenna. The crazy thing is the good receiving antenna, when things get tough, are not the most efficient on transmit. Does that make sense? I hope so. Mel, K6KBE From: Don Roberts via Elecraft To: "Elecraft@mailman.qth.net" Sent: Sunday, September 9, 2018 12:27 PM Subject: [Elecraft] ARRL book on receiving antennas Having been a ham since 1956, I also agree from my experience, that I along with every ham I knew, used the same antenna to receive and transmit. From my first home brew one tube, through my first Globe Chief kit, through Globe Scout, NCX3, and Globe GTX 550, all in the 50/s and into the 60/s, and all had the same antenna for receive and transmit. I too, went from the dpdt knife switch, to the Dow Key relay. My QSL collection confirms this for the stations worked during that period. 73, Don W4CBS Sent from Yahoo Mail on Android __ 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 farrerfo...@yahoo.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 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 k6...@foothill.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
Re: [Elecraft] ARRL book on receiving antennas
You said it Jim, but in to many words, It is installation specific, period. Mel, K6KBE From: Jim Brown To: elecraft@mailman.qth.net Sent: Sunday, September 9, 2018 1:03 PM Subject: Re: [Elecraft] ARRL book on receiving antennas On 9/9/2018 12:39 PM, Bob McGraw K4TAX wrote: > How does one measure transmit antenna efficiency? Not easily. :) But NEC provides quite good predictions IF the antenna is completely and accurately described in the model. For verticals, that includes ground quality. For all antennas it includes height above ground, counterpoise, radial systems, and transmission lines. AND -- propagation reporting systems like WSPR and the Reverse Beacon Network (RBN) can provide very good comparisons between antennas IF a LOT of reports from a LOT of stations is averaged over a LOT of time. 73, Jim K9YC __ 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 farrerfo...@yahoo.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] ARRL book on receiving antennas
VERY CAREFULLY on an antenna range for that purpose. You can model it and get an idea of what it should be, but it is installation specific. Mel, K6KBE From: Bob McGraw K4TAX To: Mel Farrer Cc: "don_roberts2...@yahoo.com" ; "Elecraft@mailman.qth.net" Sent: Sunday, September 9, 2018 12:39 PM Subject: Re: [Elecraft] ARRL book on receiving antennas How does one measure transmit antenna efficiency? Bob, K4TAX Sent from my iPhone > On Sep 9, 2018, at 2:36 PM, Mel Farrer via Elecraft > wrote: > > Great Don, > You and I grew up in the same time era.. > Now, I am wiser and have more CRS, Anyway, Here is my take on antennas > in general. I have MANY that I can chose from at any time, HOWEVER, Some > antennas "hear" better even if they are not as efficient as my transmitting > antenna. The crazy thing is the good receiving antenna, when things get > tough, are not the most efficient on transmit. Does that make sense? I hope > so. > Mel, K6KBE > > From: Don Roberts via Elecraft > To: "Elecraft@mailman.qth.net" > Sent: Sunday, September 9, 2018 12:27 PM > Subject: [Elecraft] ARRL book on receiving antennas > > Having been a ham since 1956, I also agree from my experience, that I along > with every ham I knew, used the same antenna to receive and transmit. From my > first home brew one tube, through my first Globe Chief kit, through Globe > Scout, NCX3, and Globe GTX 550, all in the 50/s and into the 60/s, and all > had the same antenna for receive and transmit. I too, went from the dpdt > knife switch, to the Dow Key relay. My QSL collection confirms this for the > stations worked during that period. > 73, Don W4CBS > Sent from Yahoo Mail on Android > __ > 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 farrerfo...@yahoo.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 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
Re: [Elecraft] ARRL book on receiving antennas
On 9/9/2018 12:39 PM, Bob McGraw K4TAX wrote: How does one measure transmit antenna efficiency? Not easily. :) But NEC provides quite good predictions IF the antenna is completely and accurately described in the model. For verticals, that includes ground quality. For all antennas it includes height above ground, counterpoise, radial systems, and transmission lines. AND -- propagation reporting systems like WSPR and the Reverse Beacon Network (RBN) can provide very good comparisons between antennas IF a LOT of reports from a LOT of stations is averaged over a LOT of time. 73, Jim K9YC __ 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] ARRL book on receiving antennas
"The proof of the pudding is in the eating thereof." 73 - W3HBM On 9/9/2018 3:39 PM, Bob McGraw K4TAX wrote: How does one measure transmit antenna efficiency? Bob, K4TAX Sent from my iPhone On Sep 9, 2018, at 2:36 PM, Mel Farrer via Elecraft wrote: Great Don, You and I grew up in the same time era.. Now, I am wiser and have more CRS,Anyway, Here is my take on antennas in general. I have MANY that I can chose from at any time, HOWEVER, Some antennas "hear" better even if they are not as efficient as my transmitting antenna. The crazy thing is the good receiving antenna, when things get tough, are not the most efficient on transmit. Does that make sense? I hope so. Mel, K6KBE From: Don Roberts via Elecraft To: "Elecraft@mailman.qth.net" Sent: Sunday, September 9, 2018 12:27 PM Subject: [Elecraft] ARRL book on receiving antennas Having been a ham since 1956, I also agree from my experience, that I along with every ham I knew, used the same antenna to receive and transmit. From my first home brew one tube, through my first Globe Chief kit, through Globe Scout, NCX3, and Globe GTX 550, all in the 50/s and into the 60/s, and all had the same antenna for receive and transmit. I too, went from the dpdt knife switch, to the Dow Key relay. My QSL collection confirms this for the stations worked during that period. 73, Don W4CBS Sent from Yahoo Mail on Android __ 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 farrerfo...@yahoo.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 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 gkid...@ilstu.edu __ 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] ARRL book on receiving antennas
How does one measure transmit antenna efficiency? Bob, K4TAX Sent from my iPhone > On Sep 9, 2018, at 2:36 PM, Mel Farrer via Elecraft > wrote: > > Great Don, > You and I grew up in the same time era.. > Now, I am wiser and have more CRS,Anyway, Here is my take on antennas > in general. I have MANY that I can chose from at any time, HOWEVER, Some > antennas "hear" better even if they are not as efficient as my transmitting > antenna. The crazy thing is the good receiving antenna, when things get > tough, are not the most efficient on transmit. Does that make sense? I hope > so. > Mel, K6KBE > > From: Don Roberts via Elecraft > To: "Elecraft@mailman.qth.net" > Sent: Sunday, September 9, 2018 12:27 PM > Subject: [Elecraft] ARRL book on receiving antennas > > Having been a ham since 1956, I also agree from my experience, that I along > with every ham I knew, used the same antenna to receive and transmit. From my > first home brew one tube, through my first Globe Chief kit, through Globe > Scout, NCX3, and Globe GTX 550, all in the 50/s and into the 60/s, and all > had the same antenna for receive and transmit. I too, went from the dpdt > knife switch, to the Dow Key relay. My QSL collection confirms this for the > stations worked during that period. > 73, Don W4CBS > Sent from Yahoo Mail on Android > __ > 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 farrerfo...@yahoo.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 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
Re: [Elecraft] ARRL book on receiving antennas
Great Don, You and I grew up in the same time era.. Now, I am wiser and have more CRS, Anyway, Here is my take on antennas in general. I have MANY that I can chose from at any time, HOWEVER, Some antennas "hear" better even if they are not as efficient as my transmitting antenna. The crazy thing is the good receiving antenna, when things get tough, are not the most efficient on transmit. Does that make sense? I hope so. Mel, K6KBE From: Don Roberts via Elecraft To: "Elecraft@mailman.qth.net" Sent: Sunday, September 9, 2018 12:27 PM Subject: [Elecraft] ARRL book on receiving antennas Having been a ham since 1956, I also agree from my experience, that I along with every ham I knew, used the same antenna to receive and transmit. From my first home brew one tube, through my first Globe Chief kit, through Globe Scout, NCX3, and Globe GTX 550, all in the 50/s and into the 60/s, and all had the same antenna for receive and transmit. I too, went from the dpdt knife switch, to the Dow Key relay. My QSL collection confirms this for the stations worked during that period. 73, Don W4CBS Sent from Yahoo Mail on Android __ 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 farrerfo...@yahoo.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
