[hpsdr] K5OOR SDR Preamp

[Daniel Quigley]

Hi Cliff,
 
I've been waiting until I can empirically test audio performance before I complete my post.  Right now I'm having trouble (as reported by others) with noise when using the Penelope microphone input.   
 
I can confirm that interfacing the amp is straight forward and unmodulated output looks good. I measured output of a tad over 10W depending on drive from Penelope.  As expected, you will need to filter the output (or the next stage if you are using this board as a driver) as there are unwanted harmonics.  I recommend switching the amp on with a tx keying circuit (Pin 13 on Penny's 25pin) rather than relying on the the SDR preamp's RF detection circuit as that will produce a more reliable way to vary output power.
 
73,
Dan (N7HQ)



From: boatguy1964 at gmail.comTo: hpsdr at hpsdr.orgCC: dquigley at msn.comSubject: K5OOR SDR PreampDate: Mon, 26 Jan 2009 13:44:34 -0600



Dan, 
 
I just ordered one of Virgil’s K5OOR SDR preamps from HF Projects and look forward to getting it built. I saw the notes that you made regarding the buildup, and haven’t seen anything about it, since then. I was wondering if you might give any impressions that you have, now that you have gotten it (I assume) integrated, and are using it.
 
73,
 
Cliff-KE5FJV 
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