[hpsdr] Mercury and 28Mhz receive

[Mike Stevenson]

I have been spending quite a lot of time operating on  
10m now is open again.
There has always been a higher level of spurious signals on this band than any other even with Mercury input terminated directly in 50 ohms.

What I am now seeing  using Doug's, W5WC software with zero frequency IF is between about 28.300 and 28.650 a spurious signal at 0Hz in the receive pass band.
Also I am hearing what sounds like intermod produced by other signals in the display pass band producing an audible output. I have see the effect produce by signal of only S7. Also at the same time I see the 0Hz spurious being modulated by the off frequency S7 signal.
The above applies to Doug's software 1.19.3.4, 1.19.3.5 and 2.2.3.

Using Bill's KD5TFD software with 9Khz IF I see much the same spurious on the spectrum display but 0Hz spurious is offset by 9Khz and so far have not detected any unwanted products in the audio output.

Current cards
Mercury  V2.9
Pennylane  V1.4
Metis   V1.4
Excalibur
Alex

Has anyone else seen this or do I have a one off problem.

Mike G8ALS
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/attachments/20110926/2da6c4e3/attachment-0003.htm>