[Amps] rf choke on output

[m.ford]

    Thank you Peter and Guillermo. I think you just solved a long standing
quirk that I have had with one of my NCL amps.

    When the plate switch is turned off and the bleeders are doing there job
as indicated on the voltmeter, there comes a point when I hear a faint "tic".
It occurs when the voltage has dropped to about 100 from 3kv. A quick
check of the schematic shows that if the choke is open,  there is no discharge
path for the pi network. The filter caps discharge through the bleeders just fine.

    I gotta check that choke.

Mike  k1ern



----- Original Message ----- 
From: "GGLL" <nagato at arnet.com.ar>
To: "Amplificadores Lineales" <amps at contesting.com>
Sent: Tuesday, March 28, 2006 5:36 AM
Subject: Re: [Amps] rf choke on output


That happened to a friend's 813 linear amplifier!. There was a barely notable
"Tic...Tic..." every a few seconds. Because we had no choke at hand, it was
temporarily solved  with a 68 K 2W resistor in parallel with Load capacitor.

Best regards
Guillermo- LU8EYW.

Peter Chadwick escribió:
> One function is to stop the pi tank components floating up towards the
> HV supply if there is no dc connection to ground. If you put two
> capacitors in series, then applying DC will lead to the junction
> floating to a voltage determined by the capacitance ratio. This can give
> problems if the antenna has no DC connection e.g. a dipole: you could
> get flashover in the loading capacitor.
>
> 73
>
> Peter G3RZP
>