Hello Gary,
I have seen a similar problem before, but not sure if it is the same as
yours.
This is going to take some explaining so read on..
I have two Alpha 99's, I have one mostly on 20M and the other on 80M.
My antennas are a Cushcraft A4S for 10-15-20, and a Sloper for 40-80-160.
I noticed this problem when I got my first Alpha99 after replacing an old
Ameritron AL1500. I talked to the Glenn at Alpha
and they asked me what kind of rig I was using and I told them it
was a 756 Pro. He asked if I had another rig, and I told him yes
I have a Kenwood 870. He said just for the heck of it without
telling me where he was going with this to try the other radio.
It work fine on the Kenwood.. ???? What the hell ????
Glenn explained to me that some of the Transceivers on the market
when first keyed, produce a large output spike.
That was very true and I had seen this before on my watt meters..
Both my 756Pro and Icom706MKIIg did it..
So I reduced the exciter output on my 756 Pro, and the trip problem
went away. I was not happy about this, but excepted it.. for a while..
A few months later my 2nd Alpha99 I had on order came in.
They are about 3 months apart in age.
I said to myself OK... lets see if this new one does the same thing.
"Trip" ! It did it again. Wow this is driving me nuts.
So I reduced power, and kept using it with reduced output.
Like a few 100 watts are going to make a difference anyway..
So one day during a contest I switched from 80 to 40, and later
back to 80, and noticed my problem was gone.
It was the ATR-30 Tuner.... Maybe?
I observed that on the 80M band, my inductance
setting on the Tuner was not what I had written down in my notes.
This particular day, I decided to tune manually for some reason.
I pulled out the ATR-30 Doc and it says to tune the tuner for
min inductance, and then adjust trans and ant.
I typically tune for minimum SWR, and write down the settings
and use my notes when changing bands.
So what I did.. I put the settings back to what I had written
down, and "Trip" the problem was back again.
Now this goes further..
I happen to have another ATR-30, and swapped it with this one.
It did the same thing !
So I am not sure if this helps you.
You can see in my case it took me about 6 months before I figured out the
problem,
but reducing the 756Pro output solved the problem quickly when working
with Glenn/Molly at Alpha.
My conclusion:
It looks like I possibly had some increase voltages
inside the tuner that was feeding back to either the 756Pro or
the Amplifier due to the fact I was not tuning it correctly?
Since I made the change above, I have also changed
my coax to the Cable Experts 9913 double shielded
cables between radio, tuner, and amplifier.
Also, I isolated the grounds of the radio and the tuner/amplifier.
So.. yes I made a bunch of changes gradually until it was
fixed.. and I am a happy camper now.
So that's my story.. Have not had any problems ever since.
I had mention earlier on another post to this group that I have
been accumulating 4CX800 tubes. So I have a good stock
of them. I plan to have these amplifiers until I go SK !
You can go to my website, and click on the left where it says
"Marietta GA" and you can see pictures of how my equipment
is configured.
Hope this was a help, so you can experiment some more.
I ruled out the Alpha's being the problem when I had two
of them doing the same thing and they were one was about
3 months older then the newer one. It were not for my
second Alpha, I would have been blaming the Amplifier.
Molly and Glenn went out of there way to help me
and I am very appreciative.
Thanks,
Keith, K4KAL
http://www.qsl.net/wd5bjq
----- Original Message -----
From: "Gary D Elliott" <k7ox@pipeline.com>
To: <amps@contesting.com>
Sent: Wednesday, March 05, 2003 12:50 AM
Subject: [Amps] Alpha 99
> I have a Alpha 99 with a rather strange problem in that on 15 meters only
> after tuning up it will trip off or fault as soon as it is key on RTTY,
SSB
> or CW. It will not reset and can't use it on 15 meters. Other bands
> operation is normal and no problems this happens with both my ICOM 761 and
> 756. Anybody out there with a Alpha 99 have a problem like this ?
>
> 73 Gary
>
>
>
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