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HF Discones

(VY1JA) on September 24, 2008
View comments about this article!

About 35 years ago, and northwest of Detroit, I built a full sized 40-meter discone, which worked fairly well for DX on 40 meters. I did not take the scientific approach of a true experimenter, so I did not compare it with any other antennas or keep reasonable records.

One thing I did notice was that the antenna worked DX and even cross the continent to Japan on 80 meter CW from MI with about 140 watts of RF going into it through a tuner. That was 1/2 of design frequency.

Now, many years later, I look back at that antenna and wonder if any amateur has performed and recorded experiments on HF and what they have found. What have experiments on VHF and UHF shown besides high SWR on frequencies below the "design cutoff"? What angles of radiation was I likely getting on 1/2 and 1/4 of design low end?

I have an HF tower with a tribander at 110 feet. The tower and guyline system could easily house a full sized 80-meter wire discone. Would I be better off to build that 80-meter discone, or a set of the directional antennas from the ON4UN book? Would the raised current point of the discone and resulting reduced ground losses be worth experimenting with? Will the wave elevation angles be too low to be useful from an 80-meter discone. What are chances of having a repeat of good luck at 1/2 frequency operation this time on 160?

I have spent time with the ARRL 16th and other antenna books I have here, but they seem focused on the discone's low SWR frequency spectrum and show no experiments from below that. The Internet has not revealed secrets which I am sure can be found if I type in the right question.

One writer on the Internet mentioned good results with a tuner similar to mine, but again only anecdotal information and no measured or repeatable experimental results.

Does any experimental data exist? In lieu of such information how many others have tried discones at 1/2 or 1/4 of design? Anyone ever build a bug catcher for 80?

If you have solid information or just wish to say, "Hello" send to vy1ja at ARRL dot net.

Thanks, J.

Member Comments:
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HF Discones  
by K1CJS on September 24, 2008 Mail this to a friend!
There is a full size HF discone--I believe it is an 80 meter size--at the Titan Missile Museum in Arizona.

www.titanmissilemuseum.org
 
RE: HF Discones  
by KF7CG on September 24, 2008 Mail this to a friend!
I don't have a discone. After considering all the alternatives, I think a discone is the nearest relative of the vertical that I use. It has a moderately large counterpoise (about 8.5 feet on a side) at the top and the elements, 1 per band project downard from there. The longer wavelengths use inductively loaded shortened elements.

Comparing this antenna to a dipole and a ground mounted vertical show it to have better low angle radiation factors than either. (subjective measurements at best)

I would guess that a full size discone on any band would make a nice low angle radiator for that band.

I think that the strange look of this antenna discouraged its use.

KF7CG
 
RE: HF Discones  
by N2KFC on September 24, 2008 Mail this to a friend!
Hello,

Yes,years ago I did a lot of testing useing Vector Network Analyzer on Discone HF for 20-30MHz range...very low SWR in this range.I do not operate below 15mtrs ,but this antenna has much wider usefull SWR range.
On the Air testing done under YB1AQV was very positive,very good antenna for cross-band operation!!!

73!John
SP2GGZ,N2KFC,YB1AQV,
 
RE: HF Discones  
by K0BG on September 24, 2008 Mail this to a friend!
I'm not going to try, but whomever decides to model one of these is in for a formidable task.

Alan, KBG
www.k0bg.com
 
HF Discones  
by WW5AA on September 24, 2008 Mail this to a friend!
Here is a good read on the discone antenna:

http://www.radio-electronics.com/info/antennas/wideband/discone.php

I played with one for 15 meters in the 70's when there was a lot of experimenting going on with this type of antenna. The complexity of adjusting proper angles and maintenance did not make it a viable antenna in my situation. It was marginally better on receive, sometimes than my 15 meter ground plane, and although broad band it was about the same on transmit.

73 de Lindy
 
HF Discones  
by N4OGW on September 24, 2008 Mail this to a friend!
I once used one when I operated the Sweepstakes CW contest from Los Alamos National Lab. I didn't feel that it was any better than a 1/4 wave vertical. Unless you need the wideband characteristics of the discone (which they needed at the Lab), I wouldn't bother.

Tor
N4OGW
 
HF Discones  
by WW5AA on September 24, 2008 Mail this to a friend!
Here is a good read on the discone antenna:

http://www.radio-electronics.com/info/antennas/wideband/discone.php

I played with one for 15 meters in the 70's when there was a lot of experimenting going on with this type of antenna. The complexity of adjusting proper angles and maintenance did not make it a viable antenna in my situation. It was marginally better on receive, sometimes than my 15 meter ground plane, and although broad band it was about the same on transmit.

73 de Lindy
 
RE: HF Discones  
by KB9CRY on September 24, 2008 Mail this to a friend!
One thing I did notice was that the antenna worked DX and even cross the continent to Japan on 80 meter CW from MI with about 140 watts of RF going into it through a tuner.


This statement tells nothing about the efficiency or performance of any antenna, unless you also did A/B comparisons at the same time. The contacts may have been due to propagation or the other stations' excellent antennas.



Now, many years later, I look back at that antenna and wonder if any amateur has performed and recorded experiments on HF and what they have found.

Probably not since they are close to a vertical which is easier to install. And most likely hands below any antenna that has gain and/or front to back & side.
 
RE: HF Discones  
by KC5HMC on September 24, 2008 Mail this to a friend!
I think it would be fun, but they take up more room than I have.
 
RE: HF Discones  
by W9OY on September 24, 2008 Mail this to a friend!
You can make a 4 square using ropes off the tower in 4 directions and then drop a wire down from the rope at the proper spacing. You will need a radial field of 20-30 radials at each vertical Its pretty hard to beat the performance of a 4 square on 80M

73 W9OY
 
RE: HF Discones  
by AB7E on September 24, 2008 Mail this to a friend!
W9OY: "You can make a 4 square using ropes off the tower in 4 directions and then drop a wire down from the rope at the proper spacing. You will need a radial field of 20-30 radials at each vertical Its pretty hard to beat the performance of a 4 square on 80M "


That would be my choice as well, but with a 110 feet of tower to work with it should also be possible to hang four 80m vertical dipoles from it, with the feedpoints pulled out away from the tower, to avoid the need for radials. Either way, four phased vertical elements in almost any configuration would beat the pants off any discone.

By the way, nobody answered VY1JA's question about feeding a 40m discone on 80m. The feedpoint impedance would be very ugly, thereby defeating the only real advantage of a discone (SWR curves used to be in the Handbook), and even if you used a good matching network to get power to it I doubt it would be any more effective signal-wise than a 40m vertical fed on 80m would be.

There is nothing special about a discone other than it's broad bandwidth, and they have two major disadvantages for HF:

a. All those wires in the skirt have a significant visual impact, cost, and footprint.

b. The horizontal top hat is structurally complex for something that puts out no better signal than a single vertical wire would.

73,
Dave AB7E
 
RE: HF Discones  
by KE5BXY on September 24, 2008 Mail this to a friend!
Here is a related study http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA262098&Location=U2&doc=GetTRDoc.pdf
 
RE: HF Discones  
by K5UJ on September 24, 2008 Mail this to a friend!
I've seen articles in magazines (probably QST and CQ) here and there on building discones for HF. The authors always seem to write that they have gotten good results (on the other hand, have there ever been any antenna construction articles where the author concluded that the antenna was lousy?). It's worth noting that the ARRL has at last put up pdf files for most QST articles from the beginning through 2004 on their website with a searchable index. I'd try searching that with "discone" as a keyword and see if you can find any reports. N.B. you have to be an ARRL member to see the articles I think.

You don't hear much about these antennas on HF, not because they are no good but (in my case at least) because for 7 MHz and below, they require some space and are pretty involved projects for the wire cone, not to mention the disk. Nevertheless, there was a small company selling HF cone antennas a few years ago through a website, coneantenna.com or something like that.

One thing about these antennas that would give me pause is that if the VHF versions are anything to go by, you give up gain in favor of broadbandedness.
The problem with that is that you have to be really sure you have a clean signal with sufficiently attenuated harmonics etc. because a discone will take anything above the operating frequency and let it go.
 
HF Discones  
by AE6YB on September 24, 2008 Mail this to a friend!
KH6BB, from the USS Missouri in Honolulu, uses one. Here's a link. http://kh6bb.org/photos2.html

Will
 
RE: HF Discones  
by AD5TD on September 24, 2008 Mail this to a friend!
I had the privilege of a QSO with the "Mighty MO" a couple of years ago on 40M. I was in the radio room of the USS Lexington in Corpus Christi. Big signal.
 
RE: HF Discones  
by KC9GJC on September 24, 2008 Mail this to a friend!
Quote: K0BG
>I'm not going to try, but whomever decides to model one of these is in for a formidable task.
---------------
Cebik has indeed done some modeling of an HF discone, if only for 20 to 10 meters (although he does scale his design up for 160 meters at the end, he only really goes into describing the SWR curve in any detail). I would think that one could extrapolate from at least some of his findings for the lower bands.

Quote: K5UJ
>I've seen articles in magazines (probably QST and CQ) here and there on building discones for HF. The authors always seem to write that they have gotten good results (on the other hand, have there ever been any antenna construction articles where the author concluded that the antenna was lousy?). It's worth noting that the ARRL has at last put up pdf files for most QST articles from the beginning through 2004 on their website with a searchable index. I'd try searching that with "discone" as a keyword and see if you can find any reports. N.B. you have to be an ARRL member to see the articles I think.
----------
Even better, my copy of the 16th Ed. (2nd printing, 1992) of the ARRL Antenna Handbook has a reprint from the July 1975 QST article detailing an HF discone (7-17ff); the article does talk mainly about a 40 to 10 meter discone, but at the beginning they write, "Thus, it should be possible to cover the 3.5- to 29.7-MHz spectrum with a single antenna... However, this would require a 75-foot vertical structure and a clear circular area 65 feet in diameter on the ground." You have the height, in the tower, and I assume you'd have the yard space (because you'd need that much just for the guy wires). Again, it shouldn't be too difficult to extrapolate their findings and design your own discone.

Cebik also references an article written by Krupp, W8WNF, in Vol. 5 of the ARRL Antenna Compendium, which also appears with some editing in The ARRL Antenna Handbook 21st Ed. in Chapter 7. (I don't own either of these books so I can't comment on this article.) I hope this helps.
 
RE: HF Discones  
by AE6YB on September 24, 2008 Mail this to a friend!
"I had the privilege of a QSO with the "Mighty MO" a couple of years ago on 40M. I was in the radio room of the USS Lexington in Corpus Christi. Big signal."

I will have the opportunity to operate from the USS Missouri, in two weeks. Fri., Oct. 10 from 01:00 to 03:00z. Probably on 20 meters. Sorry this is off topic.
 
RE: HF Discones  
by K4JSR on September 24, 2008 Mail this to a friend!
K0BG said, "I'm not going to try, but whomever decides to model one of these is in for a formidable task."

I agree, Alan. They would be Scattering Parameters everywhere!

73, Cal K4JSR

 
USS MISSOURI BOW  
by G3SEA on September 24, 2008 Mail this to a friend!

There is an effective one on the bow of the USS Missouri anchored in Pearl Harbour.

Visiting hams can sign up to use the radio shack onboard.

Look up KH6BB

KH6/G3SEA
 
RE: HF Discones  
by W5WSS on September 24, 2008 Mail this to a friend!
Lb Cebik has done extensive modeling of the discone and his findings are positive
 
HF Discones  
by AC0IV on September 24, 2008 Mail this to a friend!
For the last 4 years I worked at Thule Air Base in Greenland and had two large discone antennas at my disposal. I was able to use them from 80 meter through 6 meter all with a very low SWR. They were military antennas about 60 feet high and about 150 feet across. The whole getup looked like an inverted discone with the top (now bottom) being radial that were about 100 feet in lenth and there were too many to actually count. They were all tied together on the perimeter. Great antenna. Could easily work Japan from Greenland with it.
 
RE: HF Discones  
by NA0AA on September 24, 2008 Mail this to a friend!
I operated the Discone at the Titan Missile site about a year or so ago. I don't know if it was a big signal, but I sure generated a bit of interest on 20 meters with it.

In spite of comments regarding 'no gain', it's hard for me to believe you can put that much wire up and not get a bit of something from it. so be it if I cannot prove it!

If I had the space to hang one and the fabrication capacity, I would be tempted just because they look so darn cool - string it with lights and you have a nice Chauunaka Bush....

 
HF Discones  
by AC0GR on September 24, 2008 Mail this to a friend!
On a related topic. Does anyone know about any design specs for inverted discones? For the low bands, it would seem much easier to build than trying to design/support a massive top-hat.

 
HF Discones  
by K8WV on September 24, 2008 Mail this to a friend!
The USAF HF discones installed at Minuteman Launch Facilities did not operate well on 75/80, and an emergency tech order was distributed warning against trying.

Whether these were the same antennas used at the Titan facilities I don't know, but I expect they were.

 
HF Discones  
by K1DA on September 24, 2008 Mail this to a friend!
The Navy had a transmitter site on the south end of the island I live on. There were at least 6 inverted discones, including a tiny one only about ten feet high. After the Navy left (leaving all the antennas including the rotating logs behind) we tried a few. The LF discones had an extensive radial system and were located in an area where the ground water rose to the surface. they were broadband and low angle - not good for much during the day below 20. The important thing to remember is the military isn't looking to win any techno gain contests -- what they want is broadband, stay up all forever designs because they are not power limited. The Navy had a receiver site located about 10 miles away -- the receive ability of the discone was not even an issue. Most of their receiving was done with long wires.
 
HF Discones  
by KC7MF on September 25, 2008 Mail this to a friend!
I am about 3 minutes from the Titan Missile Museum Discone antenna and have used it several times. It is a fine antenna. I have worked 20 40 and 80 meters with it usually with a small tuner. It is a 1960's vintage Collins antenna.

The antenna really gets out. I have had good luck with it. We used it for field day this year and held our own at 75 watts. It only let me down once when the Collins club was having their event. I thought they would like to hear from this venerable old antenna but though I could hear them.....

If someone is interested in hearing from this great old antenna I can fire it up on Sunday. Just let me know when and where. Maybe try it across its advertized 6-30 meters.
 
HF Discones  
by W8ZNX on September 25, 2008 Mail this to a friend!
HF discones are big and expensive

only one reason the military
used discones

they are broad banded

THAT IT
the only reason to put up and use a discone

they are simply big wide band antennas

a few simple 1/4 wave verticals
with good ground and phasing lines
will leave a discone in the dust
 
RE: HF Discones  
by G8JNJ on September 25, 2008 Mail this to a friend!
Hi All,

I think a conventional discone is not practicable for HF use.

I have played with them extensively for VHF and UHF and they have an inherent problem in that the angle of radiation increases with frequency.

The lower cut off frequency is also very abrupt.

However I think an 'Inverted' discone could make a good simple broadband antenna.

Perhaps a skeleton of three or more sloping wires (or fishing poles) of 1/4 wavelength at the lowest operating frequency, fed from a centre point above a series of radial wires (or wire mesh) would be worth investigating. Especially as the radials would be shorter than 1/4 wavelength long (at the lowest operating frequency).

Regards,

Martin - G8JNJ

www.g8jnj.webs.com
 
RE: HF Discones  
by N3OX on September 25, 2008 Mail this to a friend!
"only one reason the military
used discones

they are broad banded

THAT IT
the only reason to put up and use a discone

they are simply big wide band antennas
"

I agree with Mac.

If they weren't also unwieldy it would probably make a good backup antenna for HF, but it seems like they're too hard to build for the payoff.

73,
Dan
 
HF Discones  
by KC2BHE on September 25, 2008 Mail this to a friend!
The 21st edition of the ARRL Antenna Book contains an article on HF discone antennas. The material in the article was adapted from an article in The ARRL Antenna Compendium Vol.5 by W8NWF Danial A Krupp.
It is an interesting read, with the usual charts, pictures and diagrams. If one has a lot of room, money, time and several friends to help construct one of these behemoths it could be a very interesting antenna. One thing for sure my XYL would want me to string colored lights on it at Christmas time.
Have fun, 73
Russ (KC2BHE)
 
HF Discones  
by AD4U on September 25, 2008 Mail this to a friend!
Unless I am missing something, about the ONLY advantage of a discone antenna over just about any other full size, single element antenna is bandwidth. A discone certainly does not have any "gain" over even a simple half wave dipole.

Considering all the grief gettting this monster to work, I have to ask "why"?

Dick AD4U
 
RE: HF Discones  
by WB4LFC on September 26, 2008 Mail this to a friend!
The only advantage I can see in the discone that it is so broadbanded.They are unity gain and the feed point is 50 ohm.The Navy and Coast Guard have used them on all types of ships.
The "cone skirt" is 1/4wave of the lowest frequency used so it would take a lot of material to construct one.Who ever built one would certainly be talked about.
A 40 meter sloper and a 80 meter sloper off the side of a tower would work better and be alot cheaper to construct.
 
RE: HF Discones  
by N0EQ on September 26, 2008 Mail this to a friend!
Here's my trip to the giant discone
south of Tucson at the Titan Missle Museum -

http://www.digitalcartography.com/n0eq/discone.htm


Craig 'Lumpy' Lemke

www.n0eq.com
 
HF Discones a passing novelty for most  
by AI2IA on September 26, 2008 Mail this to a friend!
Discones are great antennas for scanners and for some receivers. If they were great for anything else, you would see them everywhere.

Are you an average ham? Try a wire dipole, or a vertical antenna. Want more directivity? Go for a yagi and maybe a rotator. Don't mind some drawbacks and like to experiment? Try loops, rhombics, and other transmit/receive antennas.

Putting a lot of time into discones is not going to get you very far or make you very happy.
 
RE: HF Discones  
by WB4LFC on September 26, 2008 Mail this to a friend!
Here are some good examples on the USS Missouri.
www.kh6bb.org/photos2.html
73's
 
RE: HF Discones  
by N2KFC on September 27, 2008 Mail this to a friend!
Hello,
Discones Antennas are very easy and cheap to make...Just few bamboo sticks and a spool of wire...at total cost abt 10$!!!

73!
John,sp2ggz,n2kfc,yb1aqv,
 
RE: HF Discones  
by N6HPX on September 27, 2008 Mail this to a friend!
Seen some on Guam but rather big and about 50 ft tall. Might be that type as they were hard to get near and no one wasd around to tell me what they were but sure looked like a HF Discone from a distance. Or maybe a Directional dipole type.

Larry, n6hpx/mm
 
RE: USS MISSOURI BOW  
by NS5M on September 29, 2008 Mail this to a friend!
"There is an effective one on the bow of the USS Missouri anchored in Pearl Harbour.

Visiting hams can sign up to use the radio shack onboard.

Look up KH6BB

KH6/G3SEA "

Likewise USS New Jersey (NJ2BB). I've had the privilege of working as guest op aboard both on 20m with reasonable success (600W from Mighty Mo, 100W from Big J).

Staying off-topic for a moment, both clubs are extraordinarily kind and accomodating to guest ops and the opportunity shouldn't be missed if at all possible.

Contact KH6BB or NJ2BB for info.

Jim N5VT
 
RE: HF Discones  
by W6RMK on September 30, 2008 Mail this to a friend!
As to why a HF discone? Back before microprocessors made fast tuning antenna matching networks possible, this was a good solution to needing a wideband HF antenna. As others have pointed out, as a radiator, they're no better than a vertical of comparable size. These days, you'd solve the broadband problem with a autotuner, unless you need wide instantaneous bandwidth (e.g. for a frequency hopper), in which case, other strategies might be useful.
 
RE: HF Discones  
by N2KFC on September 30, 2008 Mail this to a friend!
You need Wideband Antenna for modern,state of art Wideband SDR RX/Station...

John,sp2ggz,n2kfc,yb1aqv,
 
RE: HF Discones  
by W6RMK on September 30, 2008 Mail this to a friend!
re n2kfc:You need Wideband Antenna for modern,state of art Wideband SDR RX/Station

Sure.. but for receive, on HF, an untuned whip or loop would probably work just as well. Particularly on lower HF frequencies, the atmospheric noise will greatly outweigh receiver front end noise, so having a physically small antenna isn't as big a deal.
 
RE: HF Discones  
by N2KFC on October 1, 2008 Mail this to a friend!
W6RMK Wrote:"Sure.. but for receive, on HF, an untuned whip or loop would probably work just as well. Particularly on lower HF frequencies, the atmospheric noise will greatly outweigh receiver front end noise, so having a physically small antenna isn't as big a deal. "

It is not a problem at all.Modern SDR RX has very high dynamic range and with Channelized Preselector and proper level of Attenuation in Channels is working very well!!!

John,N2KFC
 
HF Discones  
by K7TLX on October 6, 2008 Mail this to a friend!
There is an article in January 1966 CQ magazine about a very similar antenna. The conical monopole. It is a great construction article and has dimensions for four different antennas covering 1.8 Mhz to 56 mhz. Several pictures are showen in the article as well. I am in the process of building the 14 Mhz to 56 Mhz version and I will post the results in a week or two. 73 to all. K7TLX
 
RE: HF Discones  
by KQ6Q on October 8, 2008 Mail this to a friend!
The military discones at the Titan II sites had two feedpoints, selectable at the Deputy's console - top feedpoint as a discone for 6-30 mhz, and feedpoint at the bottom that treated the cone and wire from the outer ring to the base as a folded cage monopole fromn 3-6 mhz. It was gangbusters on 80 meters when I operated from a hillside site across the valley from the Titan Museum. The museum hookup for guests, as far as I know, only connects you to the top feedpoint, so it won't work well on 80m. If the Green Valley club puts out a second connection for the Folded Cage Monopole connection, you'll love it on 80m

Fred Wagner, KQ6Q
(W7HSS when I was MCCC of crew R-152)
 
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