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Question on bi-conical antenna
The May 2005 issue of QST had an interesting antenna article on page 33... basically discussing broadband dipoles. I am particularly interested in the biconical (fan) dipole discussed. It is basically two dipoles common at the feed point, with a slight divergence out to the ends. I believe they discussed a spread of 6 feet at the ends for an 80 meter version. This antenna may be just what I was looking for to put up on 75M. Do you antenna experts here on this list have any opionions on this? I prefer "resonant" antennas fed with coax as opposed to open wire feedline with tuners, but I would like to be able to operate over the entire 75M band with my IC746Pro.. Comments? Ed |
Aside from a few errors in the article, (ie: 4*2.8 does not equal 10.2) If
your going to use open wire feed, make the antenna 135 feet. See Cecils site, Cover all bands and save a bunch of wire. I have used a number of methods over the years to cover 75/80 with a single antenna. A 12" diameter cage works well at low heights. I used sections of 12 " sewer pipe cut 3/8" thick and 6 wires coming to a cone at the end. Reg has a program that shows bandwidth vs. Cage diameter. My practical results achieved greater band width than predicted by the program. Then again It was at 30 feet. Some things that do not work, "the bazooka", dual wires spread less than 15 feet, and any of the antennas that are terminated folded dipoles. "Ed" wrote in message . 93.175... The May 2005 issue of QST had an interesting antenna article on page 33... basically discussing broadband dipoles. I am particularly interested in the biconical (fan) dipole discussed. It is basically two dipoles common at the feed point, with a slight divergence out to the ends. I believe they discussed a spread of 6 feet at the ends for an 80 meter version. This antenna may be just what I was looking for to put up on 75M. Do you antenna experts here on this list have any opionions on this? I prefer "resonant" antennas fed with coax as opposed to open wire feedline with tuners, but I would like to be able to operate over the entire 75M band with my IC746Pro.. Comments? Ed |
Some things that do not work, "the bazooka", dual wires spread less than 15 feet, and any of the antennas that are terminated folded dipoles. Fred, I appreciate your comments on my questions. Could you elaborate on your statement (above) that "dual wires spread less than 15 feet" do not work? The QST article, Table 1, seems to indicate they do work, with a spread of only 6 feet, or even 3 feet, for 75M dipoles. Ed K7AAT |
Reg has a program that shows bandwidth vs. Cage diameter. My
practical results achieved greater band width than predicted by the program. Then again It was at 30 feet. ================================= My program, DIPCAGE2, is concerned with the bandwidth of a cage dipole in isolation. But the type and length, in wavelengths, of the feedline has a considerable effect on the bandwidth of the radiating SYSTEM as a whole. And a tuner, if used, also plays a part. It is not surprising that practical measurements made from the shack randomly indicate somewhat different bandwidths. But neverthless the bandwidth of the antenna itself, as predicted by the program, plays the principal part. In general, the bandwidth of an antenna does not increase in proportion to its efective diameter so much as is often fondly expected. But it is not a critical performance characteristic. ---- Reg, G4FGQ |
Reg, I was not impuning your program. I used it as a guide and found that it
followed my actual findings once I scaled the results for my particular location. My point was that at the heights most of us "mere mortal" hams are able to achieve, one can cover 75 meters with a 12" diameter cage. "Reg Edwards" wrote in message ... Reg has a program that shows bandwidth vs. Cage diameter. My practical results achieved greater band width than predicted by the program. Then again It was at 30 feet. ================================= My program, DIPCAGE2, is concerned with the bandwidth of a cage dipole in isolation. But the type and length, in wavelengths, of the feedline has a considerable effect on the bandwidth of the radiating SYSTEM as a whole. And a tuner, if used, also plays a part. It is not surprising that practical measurements made from the shack randomly indicate somewhat different bandwidths. But neverthless the bandwidth of the antenna itself, as predicted by the program, plays the principal part. In general, the bandwidth of an antenna does not increase in proportion to its efective diameter so much as is often fondly expected. But it is not a critical performance characteristic. ---- Reg, G4FGQ |
Maybe I misunderstood the point below, but it looked to me, from examining
the empirical data presented in the article, that a spread of 6 feet did a decent job of broadening the swr curve of a 75/80 m dipole. If 6' worked so well in the article, why are you saying "dual wires spread less than 15'" as something that "doesn't work" ? Are you discussing something else? ....hasan, N0AN "Fred W4JLE" wrote in message ... Some things that do not work, "the bazooka", dual wires spread less than 15 feet, and any of the antennas that are terminated folded dipoles. |
Ed, this comes from years of practical experience in trying to achieve a
broad antenna. With all due respect to the various "NEC" programs as well as Reg's program, they are great for comparing antennas. In the real world environment of most hams, results do not agree with the predicted on 75. Why?, because few of us can get a 75 meter antenna any where near a half wave length high and in the clear. While one may be able to model the real antenna environment, I am not smart enough. I would suggest that you model your particular 75 meter antenna, and then measure actual results as a fun exercise. Now to the original question, in spite of the data in QST, I have found spreads of less than 15 feet in a practical environment will not achieve your goal. YMMV. We have got to the point in ham radio, we are measuring with a micrometer, marking with a crayola, and cutting with an axe. I doubt that anyone in the history of the world has calculated a 75 meter dipole, put it up, and made no adjustments unless they mis-measured. Heck for years we have used 468/F to cut our antennas and that is incorrect as well! Don't rob yourself of the fun of trying something based on a program. Last night, for example, I had an enjoyable ragchew with a fellow in England, running my barefoot Icom 706 MKIIG on 75. My antenna is 40 feet up at it's highest point. Anecdotal evidence for sure, but the QSO was fun anyway! Sorry to get so long winded... Good luck on your broad antenna experiments, the journey is the fun part. 73 Fred W4JLE "Ed" wrote in message . 93.175... Some things that do not work, "the bazooka", dual wires spread less than 15 feet, and any of the antennas that are terminated folded dipoles. Fred, I appreciate your comments on my questions. Could you elaborate on your statement (above) that "dual wires spread less than 15 feet" do not work? The QST article, Table 1, seems to indicate they do work, with a spread of only 6 feet, or even 3 feet, for 75M dipoles. Ed K7AAT |
Dear W4JLE:
Please expand on the paragraph shown below. Sewer pipe is most often, hereabout, made of cast iron. What is your pipe made of? How thick is it? (I assume that the 3/8" mentioned is the height of pieces of pipe that were used as wire spacers.) How many short sections of pipe did you use? Thanks, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: "Fred W4JLE" wrote in message ... snip I have used a number of methods over the years to cover 75/80 with a single antenna. A 12" diameter cage works well at low heights. I used sections of 12 " sewer pipe cut 3/8" thick and 6 wires coming to a cone at the end. snip |
Just information gained from experiments to achieve a broad 75 meter antenna
in my particular antenna environment. "hasan schiers" wrote in message ... Maybe I misunderstood the point below, but it looked to me, from examining the empirical data presented in the article, that a spread of 6 feet did a decent job of broadening the swr curve of a 75/80 m dipole. If 6' worked so well in the article, why are you saying "dual wires spread less than 15'" as something that "doesn't work" ? Are you discussing something else? ...hasan, N0AN "Fred W4JLE" wrote in message ... Some things that do not work, "the bazooka", dual wires spread less than 15 feet, and any of the antennas that are terminated folded dipoles. |
They make a 12" PVC pipe. I got some scrap sections from the guy who put in
sewer lines in my town. The pipe is cut in such a way that you have rings 12" in diameter and 3/8" wide. Holes are drilled every 60 degrees. I use 5 rings on each end (10 total). The wires are tied together at the center and end insulators. I normally tie a wire between a tree and the hitch on my pickup with the 5 rings pre strung. Then add the other 5 wires. Once the whole mess is put together slide the rings an equal distance apart. The ones at the ends should be 18 inches from each insulator. Use 6 inch pieces of wire to anchor the rings. Wrap a couple of inches around the wire, over the top of the ring and continue wrapping on the wire. 3 per ring works well. Being cheap and as this antenna uses a LOT of wire I make mine out of electric fence wire (1/4 mile for $7.00). Get some help holding the ends as you raise it. If not you will end up with the worlds biggest "slinky". "J. Mc Laughlin" wrote in message ... Dear W4JLE: Please expand on the paragraph shown below. Sewer pipe is most often, hereabout, made of cast iron. What is your pipe made of? How thick is it? (I assume that the 3/8" mentioned is the height of pieces of pipe that were used as wire spacers.) How many short sections of pipe did you use? Thanks, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: "Fred W4JLE" wrote in message ... snip I have used a number of methods over the years to cover 75/80 with a single antenna. A 12" diameter cage works well at low heights. I used sections of 12 " sewer pipe cut 3/8" thick and 6 wires coming to a cone at the end. snip |
Ed, this comes from years of practical experience in trying to achieve a
broad antenna. With all due respect to the various "NEC" programs as well as Reg's program, they are great for comparing antennas. In the real world environment of most hams, results do not agree with the predicted on 75. Why?, because few of us can get a 75 meter antenna any where near a half wave length high and in the clear. While one may be able to model the real antenna environment, I am not smart enough. I would suggest that you model your particular 75 meter antenna, and then measure actual results as a fun exercise. Now to the original question, in spite of the data in QST, I have found spreads of less than 15 feet in a practical environment will not achieve your goal. YMMV. We have got to the point in ham radio, we are measuring with a micrometer, marking with a crayola, and cutting with an axe. I doubt that anyone in the history of the world has calculated a 75 meter dipole, put it up, and made no adjustments unless they mis-measured. Heck for years we have used 468/F to cut our antennas and that is incorrect as well! Don't rob yourself of the fun of trying something based on a program. Last night, for example, I had an enjoyable ragchew with a fellow in England, running my barefoot Icom 706 MKIIG on 75. My antenna is 40 feet up at it's highest point. Anecdotal evidence for sure, but the QSO was fun anyway! Sorry to get so long winded... Good luck on your broad antenna experiments, the journey is the fun part. 73 Fred W4JLE "Ed" wrote in message . 93.175... Some things that do not work, "the bazooka", dual wires spread less than 15 feet, and any of the antennas that are terminated folded dipoles. Fred, I appreciate your comments on my questions. Could you elaborate on your statement (above) that "dual wires spread less than 15 feet" do not work? The QST article, Table 1, seems to indicate they do work, with a spread of only 6 feet, or even 3 feet, for 75M dipoles. Ed K7AAT |
Ed wrote:
The May 2005 issue of QST had an interesting antenna article ... Interesting choice of verb tense, Ed, to describe May 2005. :-) -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
Proves the old saying "Even a blind hog finds an acorn sometime."
"Bart Bailey" wrote in message ... In posted on Sun, 17 Apr 2005 09:24:23 -0400, Fred W4JLE wrote: Begin I doubt that anyone in the history of the world has calculated a 75 meter dipole, put it up, and made no adjustments unless they mis-measured. I must be the exception that proves a rule, but back when living in rural Alabama I measured, cut, and hung mine from pine trees and didn't have to make any adjustments... When it blew down during hurricane Fredrick in '79, the replacement, identical length, never quite matched the original, of course I had to use different trees, maybe there's a botanical (resin) factor involved? -- Bart |
Fred W4JLE wrote:
I doubt that anyone in the history of the world has calculated a 75 meter dipole, put it up, and made no adjustments unless they mis-measured. I'm one of the hams who calculated a 75 meter dipole, fed it with ladder-line, and had to make no adjustments. :-) -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Nah! Cecil you mis-measured, you can't even get the impedance right. Next
you will be telling me that you change the length of your feed line and don't need a tuner. :) "Cecil Moore" wrote in message ... Fred W4JLE wrote: I doubt that anyone in the history of the world has calculated a 75 meter dipole, put it up, and made no adjustments unless they mis-measured. I'm one of the hams who calculated a 75 meter dipole, fed it with ladder-line, and had to make no adjustments. :-) -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Fred W4JLE wrote:
Nah! Cecil you mis-measured, you can't even get the impedance right. With a ~50 ohm antenna and ~450 ohm ladder-line, a match is impossible so why fret about it? :-) Patient: Doc, it hurts when I do this. Doc: Then don't do that. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
The May 2005 issue of QST had an interesting antenna article ... Interesting choice of verb tense, Ed, to describe May 2005. :-) Don't blame me; blame ARRL for coming out so darned early with it! :^) Ed |
I think that the reference is to "had" as compared to "has."
73 Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: "Ed" wrote in message . 93.175... The May 2005 issue of QST had an interesting antenna article ... Interesting choice of verb tense, Ed, to describe May 2005. :-) Don't blame me; blame ARRL for coming out so darned early with it! :^) Ed |
I never used clamps, simply put the 6 wires through the eye of an insulator
and wrap it back on it's self. The pvc is plenty strong enough, I think the last ones I made the pipe was almost 1/2" thick outside to inside. I have used a number of different type wires, one made from enameled copper wire #18 was neat. You almost could not see the wires at certain times of day and had the illusion of the rings floating in the air. At another time of day the sun hit it just right and appeared to be a solid copper pipe hanging in the air. I have used both Au and galvanized wire and for all practical purposes they operated the same. The fence wire is #16. For the connection I normally use brass contacts salvaged from an old electrical panel. They seem to work well and last a long time.Let me define my long time, I rarely have an antenna up more than 2 years as I am always trying something new. "J. Mc Laughlin" wrote in message ... Dear Fred (W4JLE): Oh my. I never thought of PVC 12" sewer pipe. Thank you for that, and the other, details. I will be on the lookout for such pipe and measure its thickness. Apparently, the pipe is strong enough that the end supports do not buckle. I would have expected to need supplemental braces on the end supports. Presumably, the electric fence wire is solid aluminum. If so, you must use a pair of substantial clamps at the feed point and some sort of Al to Cu transition. Thanks. 73 Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: "Fred W4JLE" wrote in message ... They make a 12" PVC pipe. I got some scrap sections from the guy who put in sewer lines in my town. The pipe is cut in such a way that you have rings 12" in diameter and 3/8" wide. Holes are drilled every 60 degrees. I use 5 rings on each end (10 total). The wires are tied together at the center and end insulators. I normally tie a wire between a tree and the hitch on my pickup with the 5 rings pre strung. Then add the other 5 wires. Once the whole mess is put together slide the rings an equal distance apart. The ones at the ends should be 18 inches from each insulator. Use 6 inch pieces of wire to anchor the rings. Wrap a couple of inches around the wire, over the top of the ring and continue wrapping on the wire. 3 per ring works well. Being cheap and as this antenna uses a LOT of wire I make mine out of electric fence wire (1/4 mile for $7.00). Get some help holding the ends as you raise it. If not you will end up with the worlds biggest "slinky". "J. Mc Laughlin" wrote in message ... Dear W4JLE: Please expand on the paragraph shown below. Sewer pipe is most often, hereabout, made of cast iron. What is your pipe made of? How thick is it? (I assume that the 3/8" mentioned is the height of pieces of pipe that were used as wire spacers.) How many short sections of pipe did you use? Thanks, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: "Fred W4JLE" wrote in message ... snip I have used a number of methods over the years to cover 75/80 with a single antenna. A 12" diameter cage works well at low heights. I used sections of 12 " sewer pipe cut 3/8" thick and 6 wires coming to a cone at the end. snip |
Ed wrote:
"This antenna may be just what I was looking for to put up on 75M." ON4UN says on page 10-13 of "Low-Band DXing" that: "By using one of the above mentioned loading methods and a switching arrangement, a loop can be made that covers the entire 80-m band with an SWR below 2:1." Best regards, Richard Harrison, KB5WZI |
the search for the broad band antenna continues.
It appears putting more wire in the air is the preferred solution, but more wire means more weight more weight make the antenna droop - and can break a tree limb. a dipole fed with ladder line is lightweight. it doesn't droop it doesn't break limbs it works I like Cecil's antenna at his web site. A few 4pdt ice-cube relays @ 7.50 each and the sockets @ 2.50 each can switch different lengths of ladder line in and out. Put the line and relays in the attic. I think you could also make use of an old TV tuner switch (The old clunker channel changers) I considered using a PLC to switch the relays. "Fred W4JLE" wrote in message ... Aside from a few errors in the article, (ie: 4*2.8 does not equal 10.2) If your going to use open wire feed, make the antenna 135 feet. See Cecils site, Cover all bands and save a bunch of wire. I have used a number of methods over the years to cover 75/80 with a single antenna. A 12" diameter cage works well at low heights. I used sections of 12 " sewer pipe cut 3/8" thick and 6 wires coming to a cone at the end. Reg has a program that shows bandwidth vs. Cage diameter. My practical results achieved greater band width than predicted by the program. Then again It was at 30 feet. Some things that do not work, "the bazooka", dual wires spread less than 15 feet, and any of the antennas that are terminated folded dipoles. "Ed" wrote in message . 93.175... The May 2005 issue of QST had an interesting antenna article on page 33... basically discussing broadband dipoles. I am particularly interested in the biconical (fan) dipole discussed. It is basically two dipoles common at the feed point, with a slight divergence out to the ends. I believe they discussed a spread of 6 feet at the ends for an 80 meter version. This antenna may be just what I was looking for to put up on 75M. Do you antenna experts here on this list have any opionions on this? I prefer "resonant" antennas fed with coax as opposed to open wire feedline with tuners, but I would like to be able to operate over the entire 75M band with my IC746Pro.. Comments? Ed |
Now to the original question, in spite of the data in QST, I have found spreads of less than 15 feet in a practical environment will not achieve your goal. YMMV. Again, thanks for the comments. For clarification, though, could you describe what you mean by the 15 feet spread for a 75M antenna? The QST author is describing a biconical antenna with two dipoles tied common at the feedpoint, but spreading out a couple degrees to the ends.... his figures indicating 6 feet at the ends working, but 15 feet the spread if using the recommended 2.8 degree angle from the apex. Is this what you mean, or are you describing two dipoles separated their full length by 15 feet? Ed |
Hal Rosser wrote:
I like Cecil's antenna at his web site. A few 4pdt ice-cube relays @ 7.50 each and the sockets @ 2.50 each can switch different lengths of ladder line in and out. I got my relays for $2.50 at surplus stores in Silicon Valley. I finally settled on knife switches mounted on Plexiglas in my hamshack window. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Ed, spread 15 feet at the ends.Nothing critical once your beyond the 15
feet. I have varied the lengths of the legs, where one is longer than the other. For example think of two dipoles one cut for 3.6 and the other cut for 3.8. I have also played with 4 wires spread 2 vertical and 2 horizontal. The biconal has been around for ever and was widely used in the old TV antennas to broadband the response. If there is any interest, I could dig out my old notebooks and post the SWR tables of a bunch of designs. "Ed" wrote in message . 92.175... Now to the original question, in spite of the data in QST, I have found spreads of less than 15 feet in a practical environment will not achieve your goal. YMMV. Again, thanks for the comments. For clarification, though, could you describe what you mean by the 15 feet spread for a 75M antenna? The QST author is describing a biconical antenna with two dipoles tied common at the feedpoint, but spreading out a couple degrees to the ends.... his figures indicating 6 feet at the ends working, but 15 feet the spread if using the recommended 2.8 degree angle from the apex. Is this what you mean, or are you describing two dipoles separated their full length by 15 feet? Ed |
I got a bit slicker with mine, I have an updown binary counter with an
updown switch. It feeds the relay driver circuit and a 2 digit decimal display . One of these days I plan to have the box driven automatically from the rig. "Cecil Moore" wrote in message ... Hal Rosser wrote: I like Cecil's antenna at his web site. A few 4pdt ice-cube relays @ 7.50 each and the sockets @ 2.50 each can switch different lengths of ladder line in and out. I got my relays for $2.50 at surplus stores in Silicon Valley. I finally settled on knife switches mounted on Plexiglas in my hamshack window. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Ed wrote:
"I prefer "resonant" antennas fed with coax as opposed to open wire feedline with tuners,---" Bamdwidth of a resonant antenna depends on its antenna Q. A high-Q antenna can cover a wide band by retuning for the frequency to be used. Biconical antennas are used for their feedpoint impedance of about 72 ohms and for their low-Q (wide bandwidth). A high-Q loop antenna can be efficient and smaqll but must be tuned for the frequency of use. An interesting example appears in the July 1968 QST. It`s the cover story. The loop is a rectangle 8 feet long and 4 feet wide made of copper-plated aluminum rain downspout. It is tuned and loaded with dual-section 500-pf variable capacitors such as pmight be used in a TRF set. With additional switched-in fixed capacitors, it matches 50 ohms from 2.8 MHz to 7.3 MHz, and from 14 to 22 MHz. It also works to 30MHz with an SWR under 3:1. This mobile antenna was mounted on a car roof. Some YL`s may not appreciate its beauty. Best regards, Richard Harrison, KB5WZI |
Ed, spread 15 feet at the ends.Nothing critical once your beyond the 15 feet. I have varied the lengths of the legs, where one is longer than the other. For example think of two dipoles one cut for 3.6 and the other cut for 3.8. I have also played with 4 wires spread 2 vertical and 2 horizontal. Fred, again, thanks for these comments. A 75M broadband biconical antenna is apparently just what fits my needs and "tree configuration". Question for you: The QST article does not address whether or not the two dipoles are cut to different frequencies, as you suggested for your personal situation you had. Do you think two exact length dipole lengths are what the QST article author was talking about, or are two different lengths necessary? All I am trying to accomplish is put a a full size 75M dipole between two tall trees (will be about 50' or 60' high dipole) and to have an SWR across the band that does not exceed about 3:1 . Ed K7AAT |
A biconal has all the legs the same length. I varied the lengths to see if I
could get by with less than 15 feet. It was not successful. A biconal cage however gets really wide. Less than 2:1 from 3.5 to 4. As an aside, anecdotally the cage and biconal are both quieter than a dipole. "Ed" wrote in message . 93.175... Ed, spread 15 feet at the ends.Nothing critical once your beyond the 15 feet. I have varied the lengths of the legs, where one is longer than the other. For example think of two dipoles one cut for 3.6 and the other cut for 3.8. I have also played with 4 wires spread 2 vertical and 2 horizontal. Fred, again, thanks for these comments. A 75M broadband biconical antenna is apparently just what fits my needs and "tree configuration". Question for you: The QST article does not address whether or not the two dipoles are cut to different frequencies, as you suggested for your personal situation you had. Do you think two exact length dipole lengths are what the QST article author was talking about, or are two different lengths necessary? All I am trying to accomplish is put a a full size 75M dipole between two tall trees (will be about 50' or 60' high dipole) and to have an SWR across the band that does not exceed about 3:1 . Ed K7AAT |
:
A biconal has all the legs the same length. I varied the lengths to see if I could get by with less than 15 feet. It was not successful. A biconal cage however gets really wide. Less than 2:1 from 3.5 to 4. Given the wind potential here, along with loading on my antenna support lines, I probably should go with the biconical dipole over a cage. I do have plenty of room to do a 15' end spacing, though. As an aside, anecdotally the cage and biconal are both quieter than a dipole. I hadn't seen any reference to noise benefits from a biconical, so that's nice to hear! Thanks for the info. Ed K7AAT |
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