[Hackrf-dev] Signal at IF

[Dominic Spill]

On 13 February 2017 at 09:23, James Brown <Jim at seti.net> wrote:
>
> 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.

Could you try using another piece of software, such as SDR#, to verify if
this is an issue with HackRF or the software?  We aren't familiar with SDR
Console and I'd like to verify that you see this across multiple pieces of
software.  You could also try booting a live OS image and running gqrx.

> 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.

Again, it may be helpful to test with some software that allows changing
the IF.

> I am running the following firmware revisions on the two HackRf:
>
> Board ID Number: 2 (HackRF One)
> Firmware Version: 2015.07.2
>
> Board ID Number: 2 (HackRF One)
> Firmware Version: git-44df9d1

This second firmware is rather old (July 2014), I would recommend upgrading
it.  While you're at it, I would also recommend upgrading both to the
2017.02.1 release, although I don't think that will affect your issue here.

Thanks,
  Dominic
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