[hpsdr] Warbling audio on Tx.

[Chris Smith]

Hi Paul

Thanks for your response. In Tune I see a steady o/p. Odd.

I've just repeated the 2-tone test without Pennywhistle in the path and I'm seeing a similar power drop from the 500mW o/p at similar frequency. So the problem is upstream of PW.

73 Chris G4NUX


On 28 Sep 2011, at 10:23, Paul Fletcher wrote:

> I have noticed something similar in tune - if I hit tune in a CW mode the power out is rock steady. If I do the same in other modes power out fluctuates quite rapidly. I've been too busy to look into this in detail. That being said I have used the rig on 40M SSB and got very good audio reports so I just put it down to the carrier generation in tune mode. I was also using Pennywhistle.
> 
> That was using v1.19.3.5 of PowerSDR and the V2.9/V1.4 firmware combination.
> 
> Regards,
> Paul M1PAF
> 
> ----- Original Message ----- From: "Chris Smith" <chris at vspl.co.uk>
> To: "HPSDR list" <hpsdr at lists.openhpsdr.org>
> Sent: Wednesday, September 28, 2011 8:57 AM
> Subject: [hpsdr] Warbling audio on Tx.
> 
> 
>> ***** High Performance Software Defined Radio Discussion List *****
>> 
>> 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
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