[hpsdr] External disable of Penelope RF output?

[n3evl]

Hi Helmut,

Thanks for the information.  I'll review my existing bias switching 
arrangement and figure out a way to interrupt on high SWR.  I was 
concerned if there was a problem with still supplying RF to the AMP in 
this mode and certainly don't want to get into issues with hot-switching 
relays in the RF input circuit.

I'm already using the PTT out pin and also using the open collectors for 
band selection on the associated LPF.

Pete

On 1/3/2017 7:21 AM, Helmut wrote:
>
> Pete, SWR protection is always a good idea to extend life time of your 
> amp, hi. As drive reduction doesn’t solve a mismatch problem of the 
> antenna, it’s better and safer to stop your amp by interrupting the 
> amp’s bias. An analogue ALC is not provided on any HPSDR exciter 
> board, because PowerSDR prevents any form of override of the board’s 
> RF signal.
>
> Pin1 (PTT-input) switches the Penelope to TX mode, when grounded. At 
> pin 13 (PTT out) you’ll have access to the drain of a buffer FET to 
> control  e.g. an external relay for accessories like amps, XVTRs etc. 
> Please see schematics.
>
> 73, Helmut, DC6NY
>
> *Von:*Hpsdr [mailto:hpsdr-bounces at lists.openhpsdr.org] *Im Auftrag von 
> *n3evl
> *Gesendet:* Dienstag, 3. Januar 2017 00:18
> *An:* HPSDR
> *Betreff:* [hpsdr] External disable of Penelope RF output?
>
> I'm contemplating some kind of high swr detection circuit in an 
> external homebrew amp. I've seen some designs that detect hi swr and 
> block RF from the driving rig by using the ALC line.  Since Penelope 
> does not have an ALC line, is there some way an external device can 
> tell Penelope to cease generating RF?Â
>
> I see Penelope has pin 1 on the DB25 connector labeled as "PTT Input - 
> active when connected to ground" - but I'm not sure if this is 
> relevant to this issue or how this pin is used.
>
> Thanks,
>
> Pete, N3EVL
>
>
>
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