[hpsdr] Penny PTT unkeying spike - T/R sequencing?

[Tom Cathey]

Hi Phil,

I trust you got the spike screen shot Gerd made via email. It bounced back
once, maybe cuz it was a large 2 meg .bmp. 

(On my rig) The spike is clear on carrier modes like AM or FM. However, the
spike seems  lost in the rubble or maybe not as prominent on ssb because
there is no steady state carrier energy to dump on unkey, I dunno. On ssb, I
can see the general KEY-UP energy more clearly and still some unkey energy
away from the main frequency.  On AM/FM, the spike generally has a long
base, meaning it spreads out maybe +- 10 khz at -50db down on my rig.
Generally, my spike peak is only down -30db from main carrier on AM or FM.
Though others see more attenuation. Gerd's picture shows maybe -30db too, as
a guess.

I don't have the equipment to independently see Penny's output other than a
standard o'scope and the Mercury panscope. I do hear the spike on a remote
receiver and it sounds like a fast beep, down -30db, up 2khz.

I can live with the spike, however, when I run a KW later, -30db down
becomes a one watt pop when I unkey and will be heard nearby. It also has
potential to cause problems in the station receivers.  


Thanks for the info on the Codan amps. I will check out the site.


****  New question:  Is there a simple way to monitor the output of an
EXTERNAL linear amplifier on the Mercury panadapter during normal Penny
transmit? It would mean disconnecting the internal Penny to Merc RF sampler
and inputting the external linear sample somehow, no?   Obviously, Penny's
clean output is meaningless if the external amplifier is not clean, thus the
motivation to monitor the last component in the RF chain.

Thanks.


73,
Tom, K1JJ



----------------
Hi Tom,

Looks like you are making good progress.

Can you please confirm that the spike,

1. Only appears when using AM or FM
2. Appears at the output of Penelope and not just on the bandscope screen.

Re the "Codan Flying Doctor Radio?". I gave an HPSDR presentation last year
to the Adelaide Hills Amateur Radio Society. A number of their members were
using this PA. I suggest you contact them via their web page

http://www.ahars.com.au/

73 Phil..VK6APH



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