-----Original Message-----
From: Larry Molitor <w7iuv@axtek.com>
To: amps@contesting.com <amps@contesting.com>
To: <amps@contesting.com>
Date: Wednesday, June 23, 1999 7:24 PM
Subject: Re: [AMPS] YC156 Photos
>
>At 11:39 AM 6/23/99 -0500, you wrote:
>>
>>Make sure you have an RF choke accross the output
>>of the amp because is is just a matter of time until
>>those "TV" type doorknobs are going to smoke. They
>>are not RF rated for 1500 watts.
>>
>>(((73)))
>>Phil, K5PC
>
>Sorry Phil, you are completly off base here. I have never seen a cap with a
>"power rating".
Not off base, just another way of saying TV doorknobs were not designed
to handle a great amount of RF.
RF rated caps are rated in amps of RF at selected frequencies.
TV doorknobs have no such rating.
>
>In anode DC block use, with 4 in parallel, the RF current in each of them
>is on the order of 200 to 300 milliamps. Even a crummy ceramic cap can
>handle that.
That depends on several factors. You are painting with a very broad brush
here.
The current in Cblock is dependent on frequency, Ip, Ep, and the output
capacitance
of the tube(s). As frequency is increased and the tube(s) output
capacitance
constitutes a significant portion of the total tank capacitance, a
significant portion
of circulating tank current flows through the blocking capacitor. A cap that
would
get by on 160 meters may crispy critter on 10 meters.
>You are more than welcome to give the surplus bandits your money, but for
>me, I'll use the free stuff whenever I can.
Not me! I buy my RF rated doorknobs by the pound at the local radio factory
junk yard.
(((73)))
Phil, K5PC
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