[hpsdr] PennyWhistle driving an Ameritron AL-811

[Ken N9VV]

P*SDR software has three special timing delay selections to keep
RF from flowing during the T/R transition. Check it out in the SETUP
menu GENERAL ---> Options
[1] PTT Delay
[2] MOX Delay
[3] RF Delay

all the best,
73 de Ken N9VV

On 5/11/2013 10:48 AM, Tom McDermott wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
>
>
>  > Has anyone else tried driving an Ameritron AL-811 amplifier using the
>  > PennyWhistle amplifier? I have ruined 6 power MOS FETs trying to do this.
>  >
>  > It's weird because my SoftRock can drive my AL-811 to 30 Watts by itself
>  > without damage but as soon as I try the PennyWhistle I blow out its FETs.
>  >
>  > Has anyone else had this problem -- and if so what changes did you
> make to
>  > the AL-811 or PennyWhistle to stop this from happening?
>  >
>  > Mike N9MS
>
> Hi Mike - the schematic of the AL-811 shows that the input relay is
> open-circuited
> during the brief few-milliseconds time that it takes to switch from
> receive to transmit.
> If your Pennywhistle were putting out RF during those few milliseconds,
> it would be into an
> open circuit.
> I don't find any RF protection circuitry on the output of the
> Pennywhistle schematic;
> thus don't know whether it can or cannot handle operation into an open
> circuit without failure.
> -- Tom, N5EG
>
>
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