Drifting "birdie"

[kd7mw]

I'm generally loving my RSP1A. One issue I'm having: When I start the RSP1A, I get a raspy, digital sounding "birdie" that starts at about 7060 kHz, and slowly drifts down to about 6900-6920 kHz over about 15 minutes. This makes 40m CW very difficult to listen to for the first few minutes of operation. See attached screen clip files for examples of the interference both while drifting, and when it's settled down. It occurs even if I disconnect the antenna from the RSP1A, so it isn't coming from over the air. It seems It occurs whether I'm running SDRUno or HDSDR, and with no other software running on my Windows 7 x64 computer.

If I "STOP" SDRUno, wait a minute, then "START" it again, the interference has moved up in frequency, and begins to drift back down as the software runs. So I don't think it is neighborhood RFI hash, because I can affect it by starting and stopping the software.

I'm not sure if the interference is coming from the RSP1A or from the computer, perhaps through the USB cable. I am using a cable with ferrite chokes on each end, but I have no way of knowing how good the shielding is. Can anyone recommend a USB cable brand that will not pick up RFI from the computer or various devices in the shack?

Thanks!
--Peter

[DK7OB]

That's a known issue with the RSP1A. See this thread:
viewtopic.php?f=5&t=2727

[Tech_Support]

Try to use the highest level of RF gain setting (lowest level of gain reduction) that you can get away with without overload and it will help minimise the impact of this spur.

Sincerely

SDRplay Tech_Support