[Amps] RF Choke At Amp Output ??

[Bill, W6WRT]

ORIGINAL MESSAGE:

On Thu, 20 Aug 2009 01:37:32 +0000, RICHARD SOLOMON <w1ksz at q.com> wrote:

>Several HB Amp circuits I see have an RF Choke across the Output. Other than
>the obvious (protection against Plate Coupling Cap short), what are the other
>Pro's and Con's ?
>
>I was thinking I should use an Ohmite Z-50 on the output of my 6 Meter Amp.
>Comments ??

REPLY:

If your antenna is an open circuit for DC as many are, there would be a HV pulse
applied to the coax through the plate blocking cap. If the DC leakage on your
coax and antenna is very low, this pulse could take a long time to decay. This
pulse is equal to your HVDC and might be enough to arc the coax, the antenna
itself or any switches, etc, in the feedline. 

It's been about 50 years since I used a Z-50, but from what I remember it should
be ok.  :-)

73, Bill W6WRT