CCD antennas..how do I scale them (dowm!) ???
Richard Hulse
was presented in, i think, 73 magazine. It utilised sections of wire
broken with equal spaced, equal value capacitors and had to be build for
a full wave on the lowest frequency of interest. Mine was 80m long!
Does anyone know how to scale these antennas to be a more manageable
size.?
Thanks.
Richard Hulse
ZL2AJC
Bob Bruhns
shorten the leg length. You would start with a desired length, then
figure how much reactance has to be added to resonate, and distribute
that reactance. I read a suggestion that the reactances should be
distributed so that the capacitor reactances would be about 50 ohms at
the design frequency. (I have no design parameters for the wire lengths,
though.) I found this in an article by Harold Wheeler on HF antennas
designed to be mounted UNDERGROUND!
(This per the CCD antenna inventors.) There's supposed to be some magic
about the full wave antenna length. At this length, the reactance of the
series caps equals the inductive reactance of the wire lengths between
them. If the full wave length wire is too long to fit the lot, it is
reported to work quite well folded up all over the place.
My friend WB2CAU in Dix Hills, LI uses a CCD on 75 meters with
excellent results. I built an experimental CCD, but I found that cheap
non-zero-TC ceramic caps are no-go. Some day I will buy a bunch of 1100
pF 1000V 5% dipped micas and rebuild the thing, and try again.
Bob Bruhns, WA3WDR, bbr...@li.net
Richard Hulse
I had already built and 80 m version of the CCD which worked very well at
my last place. It was folded back on itself and ran very close to a large
tree and part of the roof. Unfortunately the houses next to where I now
live are very close together....a CCD folded back on itself 4 times would
no doubt upset the neighbours. Having just writen that I wonder if the
antenna could be folded _on_top_ of itself to reduce the length?
> I found this in an article by Harold Wheeler on HF antennas
>designed to be mounted UNDERGROUND!
Could you let me know where this was?
> Some day I will buy a bunch of 1100
>pF 1000V 5% dipped micas and rebuild the thing, and try again.
The problems is they are so time consuming to make! I took a week off
work to make my 80m one about ten years ago. If the performance hadn't
been so good I wouldn't be contemplating doing it again. Perhaps I should
wait until my kids grow up a bit more and get them to help!
Regards
Richard Hulse
ZL2AJC
John Hill
Richard Hulse <rhu...@radionz.co.nz> wrote:
>Thanks Bob...
>
>I had already built and 80 m version of the CCD which worked very
well at
-snip-
>> Some day I will buy a bunch of 1100
>>pF 1000V 5% dipped micas and rebuild the thing, and try again.
-snip-
If the performance hadn't
>been so good I wouldn't be contemplating doing it again.
I thought I had heard of just about every kind of antenna,
but this one eludes me. Could you post some reference
articles from magazine info, or textbook titles on it?
Thanks...John, NJ0M.
Bob Bruhns
Harold A. Wheeler, "Useful Radiation From An Underground Antenna",
Journal of Research of the National Bureau of Standards - Department of
Radio Propagation, Volume 65D, Number 1, January-February, 1961, Pg. 89.
(Presented at Conference on the Propagation of ELF Radio Waves, Boulder,
CO, January 26, 1960.)
Harry A. Mills, W4FD, and Gene Brizendine, W4ATE, "Antenna Design:
Something New!", Pg. 282 (???), 73 Magazine, October, 1978. (I think).
Harry A. Mills, W4FD, and Gene Brizendine, W4ATE, "The CCD Antenna -
Another Look", 73 Magazine, July, 1981, Pg. 50.
Harry Longerich, W4ANL, "The CCD Antenna Revisited", 73 Magazine, May,
1982, Pg. 40.
David Atkins, W6VX, "the high-performance, capacitively loaded diploe",
ham radio, May 1984, Pg. 33.
James E. Taylor, W2OZH, "The RASER", 73 Amateur Radio Today, September,
1992, Pg. 8.
James E. Taylor, W2OZH, "The RASER Revisited", 73 Amateur Radio Today,
October, 1993, Pg. 29.
Also see:
F. E. Terman, Radio Engineers Handbook, McGraw-Hill, New York, 1943,
Pg. 773.
Bob Bruhns, WA3WDR, bbr...@li.net
Robert Smits
John, here's an old post re ccds...
Newsgroups: rec.radio.amateur.antenna
References: <4eh2m9$p...@st-james.comp.vuw.ac.nz>
Subject: Re: (no subject)
Date: Mon, 29 Jan 1996 18:34:00 PST
Message-ID: <0129961834...@ham.island.net>
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Reply-To: r...@ham.island.net
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Richard Hulse <rhu...@radionz.co.nz> writes:
>Some years ago an antenna called the CCD (Constant Current Distribution)
>was presented in, i think, 73 magazine. It utilised sections of wire
>broken with equal spaced, equal value capacitors and had to be build for
>a full wave on the lowest frequency of interest. Mine was 80m long!
>
>I've mislaid the original article in a house shift so two questions..
>
>1. Where were the original articles published (so I can get new copies)?
>
The following articles are about the CCD:
H.A. Mills and G Brizendine, "Antenna Design: Something New!", 73, October
1978, pp 282-289
D. Atkins, "The High Performance, Capacitively Loaded Dipole", Ham Radio,
May 1984, pp 33-35
The material is also revisited in the ARRL Antenna Compendium, Volume 2,
which includes a Basic program to calculate CCD Dipoles, and the ARRL
Antenna Comendium, Volume 3 has an article analyzing its performance.
>and
>
>2. Does anyone know how to scale these antenna to be a more manageable
>size.?
The program askes for what frequency you'd like to make the antenna. I
don't know how well it scales from personal experience, though.
Bob, VE7HS
--
Sometimes you're the windshield, and sometimes you're the bug.
Mark Knopfler
Charles Hoffman
antennas similar to the one you call CCD. It is possible to reduce
the physical length required for the antenna.
You should be able to form the length into something of a compressed
square wave design or a sine wave design without difficulty. A 40m
amateur version may be reduced to lengths ten to twelve feet long and
spaced two or three feet apart. Do this with each half of the dipole
configeration so that all long lengths are parallel. DO NOT FORM THE
LENGTH INTO A COIL. This arrangement may be placed directly on the
ground or on the non metallic rooftop without difficulty. While the
antenna sensitivity is of course reduced, you will be able to use it
for many general amateur radio purposes.
Even better results may be expected with this configuration if
suspended inside four poles at about ten feet of height, and construct
a poultry netting wire counterpoise on the ground under it. You may
attach the counterpoise to the rig with a half wave long piece of
insulated wire sucessfully.
I have built dozens of various antenna designs using magnetic wave
component phasing with remarkable sucess on frequencies from 1 mHz to
over 800 mHz. You have a good project there. Just persue with a
specific mission and you will be much happier with the result.
You willl have some fun and just remember, if this project makes you
sick, I am not a real doctor.
73 Ric K5SBU
Richard Hulse <rhu...@radionz.co.nz> wrote:
>Thanks Bob...
>I had already built and 80 m version of the CCD which worked very well at
>my last place. It was folded back on itself and ran very close to a large
>tree and part of the roof. Unfortunately the houses next to where I now
>live are very close together....a CCD folded back on itself 4 times would
>no doubt upset the neighbours. Having just writen that I wonder if the
>antenna could be folded _on_top_ of itself to reduce the length?
>> I found this in an article by Harold Wheeler on HF antennas
>>designed to be mounted UNDERGROUND!
>Could you let me know where this was?
>> Some day I will buy a bunch of 1100
>>pF 1000V 5% dipped micas and rebuild the thing, and try again.
>The problems is they are so time consuming to make! I took a week off
Richard Hulse
> You should be able to form the length into something of a compressed
> square wave design or a sine wave design without difficulty. A 40m
> amateur version may be reduced to lengths ten to twelve feet long and
> spaced two or three feet apart. Do this with each half of the dipole
> configeration so that all long lengths are parallel. DO NOT FORM THE
> LENGTH INTO A COIL.
fortunately I suspected this may not be a good idea although was never quite sure why.
Surely the absence of high current points would reduce heating factors. Or is it that
the spreading of current increases heat problems?
> This arrangement may be placed directly on the
> ground or on the non metallic rooftop without difficulty. While the
> antenna sensitivity is of course reduced, you will be able to use it
> for many general amateur radio purposes.and:
>You have a good project there. Just persue with a
> specific mission and you will be much happier with the result.
I was already happy with the on-air result but the neighbours, I think, were not so
keen on the IN-AIR result !!
>
> You willl have some fun and just remember, if this project makes you
> sick, I am not a real doctor.
>
> 73 Ric K5SBU
Thanks Ric,
I will try out what you suggest (with tylanol on hand) as soon as I get some time.
73 Richard Hulse, ZL2AJC