[hpsdr] Penelope max pwr without final amp

[Graham / KE9H]

Joe:

I find that the maximum stable power output on my Penelope occurs
at a PA gain setting of 38.8 dB.  At settings between 38.0 and 38.7,
I see the AGC power control loop going unstable, and introducing some
kind of slow random AM modulation on the signal.  It might be variable
on a unit to unit basis, but based on my unit, I would not go below 38.8.

--- Graham / KE9H

==

Joe Martin K5SO wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> On closer examination, I see that Penelope puts out a very trashy 
> signal spectrally (any band)  if the PA setting is set for absolute 
> maximum power out (i.e., 38.0) even though the power level looks okay 
> on a power meter.  Here, at least, it appears that a "practical" 
> maximum PA setting is 38.4, instead in order to maintain a nice clean 
> signal.  At a slightly lower power output setting of 38.4 for the PA 
> setting value, the signal is clean once again on mine.   Bottom line, 
> I suppose, is to avoid using the absolute highest power output (lowest 
> PA setting value) settings in PowerSDSR with Penny!
>
> I suppose I've answered my own original question then.  Thanks anyway!
>
> Joe K5SO
>
>
> On Jan 17, 2009, at 8:24 AM, Joe Martin K5SO wrote:
>
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> Phil or anyone,
>>
>> I am using low power (mW) output from Penelope by removing JP2 and 
>> taking the rf output from pins 1 & 3 of JP2 to drive a high power 
>> amplifier system.
>>
>> I would like to run the PA settings in PowerSDR at maximum (38.0 = 
>> max pwr output setting for all bands).  Will Penny be alright running 
>> at maximum in this way?  I don't see any obvious problems with Penny 
>> at the moment but thought I'd ask to be sure.
>>
>> 73,  Joe K5SO


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