Marcus,

    

    Absolutely correct on the hardware side of things, I write DSP
    software and I'm doing a deep-dive on the physical setup. 
    Thanks for all your help.  As I am assembling all of this over
    the next month or so, no doubt I will pick your brains.

    

    Right now, I have a noise issue.  I am using the WBX board.  All
    throughout the sub-1GHz band, I find the following noise pattern
    with limited gaps of 20MHz or so now and again.  They are
    narrow-band AM signals that are ever-so-slightly FM modulated. 
    See this image:

    

    http://i.imgur.com/OSVhxp8.jpg

    

    My area should be RF quiet and by that I mean absolutely dead
    unless cows can broadcast.

    

    I went to the 2-meter band and I found this:

    

    http://i.imgur.com/0tbZt3x.jpg

    

    Any idea what this is???  Or better yet, how to get rid of it?

    

    Regards,

    

    Mark McCarron

Hard to tell from just looking at a the spectra.  My guess, would be
digital noise from your own equipment.



RF noise even "out with the cows" can be a real problem if you're
observing near the noise floor.   Particularly as noise figures of
LNAs

  continue to plummet, stuff that 20 years ago your receiver
wouldn't have noticed, now sticks out like a sore thumb.







-- 

Marcus, I powered down everything in the house and switched to a laptop. There was no change. Have a look: http://i.imgur.com/JIiUHwL.jpg I added a little gain to that signal on 2 meters...: http://i.imgur.com/jEPgyyM.jpg I pulled the antenna from the USRP and it appears to be internal. Is this normal? It looks like this board or box may be defective. I'll contact Ettus Research and find out. Regards, Mark McCarron Date: Tue, 7 May 2013 22:13:07 -0400 From: mleech@ripnet.com To: usrp-users@lists.ettus.com Subject: Re: [USRP-users] USRP B100 Tuning Issue Marcus, Absolutely correct on the hardware side of things, I write DSP software and I'm doing a deep-dive on the physical setup. Thanks for all your help. As I am assembling all of this over the next month or so, no doubt I will pick your brains. Right now, I have a noise issue. I am using the WBX board. All throughout the sub-1GHz band, I find the following noise pattern with limited gaps of 20MHz or so now and again. They are narrow-band AM signals that are ever-so-slightly FM modulated. See this image: http://i.imgur.com/OSVhxp8.jpg My area should be RF quiet and by that I mean absolutely dead unless cows can broadcast. I went to the 2-meter band and I found this: http://i.imgur.com/0tbZt3x.jpg Any idea what this is??? Or better yet, how to get rid of it? Regards, Mark McCarron Hard to tell from just looking at a the spectra. My guess, would be digital noise from your own equipment. RF noise even "out with the cows" can be a real problem if you're observing near the noise floor. Particularly as noise figures of LNAs continue to plummet, stuff that 20 years ago your receiver wouldn't have noticed, now sticks out like a sore thumb. -- Marcus Leech Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org _______________________________________________ USRP-users mailing list USRP-users@lists.ettus.com http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com