[hpsdr] Warbling audio on Tx.

[Chris Smith]

Hi

I paused briefly in my toil with my PA yesterday to try a brief contact on 40M. Before sending in anger I had tried transmitting into a dummy load and listening to the audio in MON mode. All had sounded OK so I answered a CQ but was told, by the other station, that my audio was almost unintelligible because of a warble. I ended the contact and said 73 which the other station said was the only part he had been able to hear properly.

I did a few more tests into the dummy load including the 2-tone test at full o/p of Pennywhistle. I noticed that during this test my power meter showed that the o/p power dropped momentarily several times during the 10 seconds that I continued the test - sometimes 3-4 times per second. At the same time as these drops in o/p power occurred the current drawn by the rig also fell.

I haven't tried the same test without Pennywhistle in the path so I don't know if the problem lies with PW or elsewhere.

I'm at a loss to understand what is happening. The average CPU usage varies between (approx) 16% & upper 30s% and I very occasionally (rarely) get  a momentary drop out of audio on Rx but nothing like the frequency of power drop on Tx. I'm using an Intel Atom board (1.6GHz) to run PSDR but have a much more powerful set-up available if that should prove necessary (Core 2 Quad at 2.4GHz (Q6600)).

Set up:

Metis @ 1.5
Pennylane @ 1.5
Mercury @ 3.0
Pennywhistle
Alex
PowerSDR KD5TFD 2feb2011b 1.10.4+
WinXP SP2

Any ideas gratefully received.

Cheers & 73

Chris G4NUX
 1317196659.0