Very good advice! However, I doubt that the fixed output caps are actually
doorknobs. Probably disc ceramics as the schematic calls for one to be 430
pf @ 2KV and the other being 330 pf @ 2KV. It appears that the output
loading variable is 800 pf. I haven't looked inside my amp in years. It
just keeps on putting out lotsa' RF when called upon to do so.
73
Bob, K4TAX
----- Original Message -----
From: "Ken Brown" <ken.d.brown@verizon.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Monday, June 20, 2005 11:05 PM
Subject: Re: [TenTec] Centurion loading
> Hi Mike,
>
>> Highest output
>>is still obtained with the Load control on 10.
>>
> Most amplifiers do not have enough capacitance in their variable loading
> capacitor to operate much lower than on about 14 MHz. Fixed capacitors
> are switched in parallel for the lower bands. An air variable of high
> enough capacity to work on 160 or 80 meters, without paralleling some
> fixed capacitors, would be huge, and the amplifier cabinet would have to
> be much larger to accomodate it. My guess is that in your amplifier one
> of the fixed capacitors that should be paralleled with the variable
> loading capacitor has failed, become disconnected, or changed value, so
> that when you're on 80 meters, your pi-net really does not have enough
> loading capacitance. Could be a burned contact in the band switch or a
> loose screw terminal on a doorknob capacitor.
>
> Disconnect all power and short the HV to ground before checking it out.
>
> DE N6KB
>
>
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