[Hackrf-dev] Signal at IF

[James Brown]

I have two HackRF that both exhibit a set of signals in the center of the IF across all bands and all frequencies. I have posted screen grabs on my web site here:
http://www.seti.net/engineering/engineering.php
Initially I thought it was an I/Q imbalance problem with the software I was using, SDR Console V3, but now I’m not sure. 
These grabs were with the HackRF running at 2 mHz bandwidth but it’s the same at all other bandwidth settings.
The signals remain but change in amplitude with all settings of  LNA , VGA settings, and external amp. They remain the same with all receive modes (AM, USB, etc).
The receivers are running with no antenna, no clock input and antenna input terminated with a 50 ohm load.
Windows 10 64 bit.
One of the other users of SDR Console suggested that a change in IF frequency might move the signals off to the side but SDR Console does not provide control over that.

I am running the following firmware revisions on the two HackRf:

USB descriptor string: 000000000000000040a465c83826294b
Board ID Number: 2 (HackRF One)
Firmware Version: 2015.07.2
Part ID Number: 0xa000cb3c 0x006a4f5f
Serial Number: 0x00000000 0x00000000 0x40a465c8 0x3826294bFound HackRF board 0:


Board ID Number: 2 (HackRF One)
Firmware Version: git-44df9d1
Part ID Number: 0xa000cb3c 0x00674744
Serial Number: 0x00000000 0x00000000 0x457863c8 0x2337151f

Has anyone else run into this?
Suggestions?


 
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