Ed,
You have some sort of problem there.
I have two 205CAs, two 155CAs, and two 105CAs. Some of these started life
as BAs,
but all were installed here as CAs using the dimensions in the HyGain XXX CA
manuals.
All these antennas played without further adjustments and all exhibit
measured and practical performance
per the specs in the CA manuals.
I'd suggest you double-check that you used a good quality aluminum "grease",
like NOAlox, in your installation and that you sanded the portion of the
elements that are electrically connected to other elements (the parts that
slide together). It sounds to me like you have a less than perfect
electrical connection throughout your antenna. Also, and this is not
necessary - but I did it - I riveted all of the element connections using
1/8 inch stainless steel pop rivets. I used two per swaged joint, at 90DEG
offset and 1 inch offset from each other.
My two 205 CAs are stacks at 100/50 feet and are electrically identical when
measured with a TDR, SWR meter, or on-air performance. In fact, I took
great care to make sure that each antenna was constructed identically
because they would be used in a stack. I used the stock dimensions in the
CA manual for CW (I could care les about phone - It's easier to use an
antenna that's too long than it is to use one that's too short!).
So, I'd look for what I say above.
BTW, the person who suggested pointing your antenna straight up is correct.
If you can use a line ("rope") off your tower to support the antenna and a
tag line to keep it off the tower by 20 feet or so, elevate the bottom 4
feet off the ground and it'll have the same SWR as at 80 feet (within
negligible error). Keeping it on the ground is "OK" also - within a bit
more error, but not much. I've performed this measurement on my first 205CA
and it performs as I describe in this paragraph. I didn't do it to the 2nd
one since I built them to be identical.
If all of the above doesn't seem to be your problem, check that your
feedpoint connections are "good". Then check your BALUN. It could be bad.
If you aren't using a BALUN - *Get one* and use one!!
let us know what happens.
Visit my website and take a look at the antennas: www.erols.com/n3rr
73,
Bill, N3RR
----- Original Message -----
From: "Edwin Koch" <ejkoch@input-incl.com>
To: <towertalk@contesting.com>
Sent: Wednesday, March 20, 2002 7:46 PM
Subject: [Towertalk] hygain 205ca
> thanks for reading this. i have a 205ca that is driving me crazy. i set
the
> antenna for low phone, 14.150 mhz. on the ground with the antenna on saw
> horses, the mfj 259 showed the resonant freq to be 13.650mhz.
> with the antenna at the top of the tower 80ft the resonant freq never
> changed, only the swr got much better. i have checked and rechecked all
> measurements at least six times. the only way to get the resonant freq
where
> it belongs is to shorten the driven element up to where it is shorter than
> the first director. i read on e-ham where a guy put one together but
couldnt
> get it up the tower in time for a contest, so left on the saw horses and
> worked a hundred contacts. i recently redone a 40 meter beam and set it to
> 7.050 . on the saw horses the resonant freq was correct just the swr high.
i
> pulled up on the tram about 35 ft and the swr dropped to 1.5. this is the
> way i expected the 20 meter beam to work. i have tried a different balun,
no
> balun and a new pig tail. even checked the mfj 259 to make sure it was on
> freq. any ideas???
>
> thanks in advance,
>
> ed n4ek
>
>
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