Hello Carl,
Thank you, and you are right about the photos! I'm really sorry about that.
I should delete the old photos before I answer anything else.
The plate choke (From a Gates 1 kW AM BCB transmitter) was like that when I
got it. Of course, that doesn't mean it's not the problem. I did check it
for resonances; it has a very slight resonance at about 2.9 MHz (forget the
details). I am currently only using it on 160.
The coupling capacitors are two ceramic .001/10kV (marked "102M") in
parallel. I didn't use that dinosaur coupling capacitor in the old photos.
The choke bypass is a .002/6kV disc ceramic. It's all I had.
Anyway, have work to do ri9ght now, but I appreciate all the advice!
73, Mike
www.w0btu.com
On Wed, Sep 11, 2013 at 11:00 AM, <amps-request@contesting.com> wrote:
>
> From: "Carl" <km1h@jeremy.mv.com>
> To: <amps@contesting.com>, <mikewate@gmail.com>
> Cc:
> Date: Wed, 11 Sep 2013 10:05:01 -0400
> Subject: Re: [Amps] Power output drop
>
> Tank circuit cap drifting should be mitigated by retuning and going open
> is very uncommon in US made caps.
>
> More likely a coupling cap, plate coke or its bypass.
>
> A .0047 is sufficient as coupling at 160 and should be made of 2-4 decent
> size ceramic caps that can handle the current. WW2 micas are prone to
> leakage and RF heating.
>
> And the plate choke looks like it got rather hot in the center. The
> Ameritron is a good replacement at $20.
>
> There is too much variation in the photos to figure out what caps are used
> and where/when.
>
> Carl
> KM1H
>
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