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Half of my spectrum is constanly +30 dbz in the red!

Posted: Tue Dec 13, 2016 10:48 am
by bubblegumpi
amwtrap15mhz.jpg
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Re: Half of my spectrum is constanly +30 dbz in the red!

Posted: Tue Dec 13, 2016 10:52 am
by bubblegumpi
OOPs here the rest of my post:

This has a longwire>homebuilt AM trap to balun.But even without the trap (its new) the left halfof the waterfall is always filed with noise?

I'll post more on the trap but this doesn't seem to be related. When you scroll up or down the spectrum always looks the same with signal popping out on the right but then they get lost in the noise as you scroll up in frequency. I have had little phantom peaks stick around on the left side of the spectrum that don't "move" left as you tune up but this is half the spectrum. I even set my spectrum to 1MHz because I know this computer has its memory tied up,

Re: Half of my spectrum is constanly +30 dbz in the red!

Posted: Tue Dec 13, 2016 12:31 pm
by 13dka
Your LO offset is around 500kHz in all 3 screenshots, but you say you selected a bandwidth of 1MHz, so you're tuned to the right edge of the spectrum all the time. Get LO and tuner frequency closer together.

Re: Half of my spectrum is constanly +30 dbz in the red!

Posted: Tue Dec 13, 2016 8:44 pm
by PG3
Try UN-zooming all the way out. It looks like you might be zoomed in on the end of your IF passband.

Re: Half of my spectrum is constanly +30 dbz in the red!

Posted: Wed Dec 14, 2016 6:47 pm
by Devotech
I have had this happen also (SDRuno 1.11 & RSP2). I had tried restarting SDRuno, changing bands, tuning to random areas, etc. The only thing that worked was changing the selected bandwidth on the Main panel. Once I did that everything returned to normal and I was able to return back to my original bandwidth and all was again receiving as normal.

Tom

Re: Half of my spectrum is constanly +30 dbz in the red!

Posted: Thu Dec 15, 2016 8:25 pm
by bubblegumpi
13dka wrote:Your LO offset is around 500kHz in all 3 screenshots, but you say you selected a bandwidth of 1MHz, so you're tuned to the right edge of the spectrum all the time. Get LO and tuner frequency closer together.
So how do I change the LO offset? What does that do? Is it something you can play around with?

Re: Half of my spectrum is constanly +30 dbz in the red!

Posted: Fri Dec 16, 2016 12:46 am
by bubblegumpi
Devotech wrote:I have had this happen also (SDRuno 1.11 & RSP2). I had tried restarting SDRuno, changing bands, tuning to random areas, etc. The only thing that worked was changing the selected bandwidth on the Main panel. Once I did that everything returned to normal and I was able to return back to my original bandwidth and all was again receiving as normal.

Tom
This did work, I set it from 1 to 2 . But that changed the LO. So how do I actually set the LO? The SDRCook book doesn't really tell you what this stuff does or why its important. Also its heavy on the acronyms which can really slow down a beginner. I do know a little bit about electronics and RF so its a matter of matching up my knowledge. Once I know the why I can usually figure out stuff on my own.

Re: Half of my spectrum is constanly +30 dbz in the red!

Posted: Tue Dec 20, 2016 10:50 pm
by 13dka
bubblegumpi wrote:
13dka wrote:Your LO offset is around 500kHz in all 3 screenshots, but you say you selected a bandwidth of 1MHz, so you're tuned to the right edge of the spectrum all the time. Get LO and tuner frequency closer together.
So how do I change the LO offset? What does that do? Is it something you can play around with?
Just click into the spectrum until the numbers (receiving frequency and LO frequency) shown to the right of the spectrum roughly match.