[hpsdr] Penelope DUC and Spurious Output?

[Merv Thomas]

Hi,

Recently I have upgraded the firmware in Mercury to V3.4 and Penny to V1.8

I use Win 7 Home Premium 64 bit and OpenHPSDRmRX PS V3.2.10 (04.10.14). 
Viewing the output from Penny on my Spectrum Analyzer (Signal Hound) via a 
30dB pad I observed unwanted signals on 12 and 10m.

On all other bands hardly any harmonics are noticeable.  However, 
transmitting on 12 and 10m I get an unwanted signal at approximately -17dBc. 
On 12m, 24.9MHz, the undesired output is at 3.43557MHz and on 24.95MHz it is 
at 3.55729MHz. Transmitting on 10m, 28.5MHz,  the undesired output is at 
7.02083MHz.

Changing my fundamental frequencies on 12 and 10m also changes the 
frequencies of the unwanted signals but not Hz for Hz.

If I connect Penny into my recently constructed Munin PA followed by Alex TX 
and a 50R dummy load all signals are clean except on the 2 offending bands. 
The unwanted signals still show up with the same differential power as 
measured without the PA.

Using a Penelope-EU with V1.8 firmware the problems are exactly the same.

Where can I find a solution to this problem?

Thank you.

73 Merv....VK6BMT