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RTL-SDR / SDR Sharp - AM blasts over SSB

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#1
Hi Forum Geniuses,

I'm hoping you can point me in the right direction, If recently got a RTL-SDR USB and I'm using SDR Sharp with it. I'm using it with a range of antenna's ... Homebrew Carolina Windom 80 at 20m, 10m/11m bobtail curtain at 10m and a tunable 2m dipole at roof height.

I've managed to set my offest correctly and I get wickedly strong signals from AM stations, but these stations seem to repeat up the spectrum and they are blasting over the Amateur bands SSB and FM stations. Is there anything that I can do to filter out these mega-signals, so that I could hear the amateur bands more clearly ?

p.s. I've checked my signals against the my Grundig Sat 750 and the AM signals are there, but the radio seems to be able to tune them out, in favour of the SSB / FM stations.

Any help would be gratefully received ... Thanks Colin (M6ONK)
 
Joined
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Corbin, KY
#2
Hi Forum Geniuses,

I'm hoping you can point me in the right direction, If recently got a RTL-SDR USB and I'm using SDR Sharp with it. I'm using it with a range of antenna's ... Homebrew Carolina Windom 80 at 20m, 10m/11m bobtail curtain at 10m and a tunable 2m dipole at roof height.

I've managed to set my offest correctly and I get wickedly strong signals from AM stations, but these stations seem to repeat up the spectrum and they are blasting over the Amateur bands SSB and FM stations. Is there anything that I can do to filter out these mega-signals, so that I could hear the amateur bands more clearly ?

p.s. I've checked my signals against the my Grundig Sat 750 and the AM signals are there, but the radio seems to be able to tune them out, in favour of the SSB / FM stations.

Any help would be gratefully received ... Thanks Colin (M6ONK)
Get a high pass filter to filter/reduce the AM band.

The reason this is happening is the front end of those sticks are pretty weak. The filter would help.
 

rbm

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Jan 25, 2005
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Upstate New York
#4
If you have the two SDR# AGC boxes checked, try unchecking them and adjust the dongle RF Gain slider manually.

You 'may' be seeing some RF overload.

Rich

The image below shows two identical dongles running simultaneously while sharing the very same antenna.
I don't use a converter so I couldn't demonstrate on SSB

The top instance of SDR# has the gain set higher than it needs to be.
The bottom instance has a very clean signal.

If I select both AGC boxes in the bottom instance, it will look just like the top one.

 
Joined
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Messages
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#5
Brilliant ! Many thanks for all your help.

Many thanks to everyone for your help. As soon as you said it ... my brain went DOH !

Of course, why did I think that it wouldn't need some form of incoming attenuation, when everything else I listen on does :)

I've had a quick play with RF Gain and it is much better. I will finer tune it up later and definitely look into a high pass filter to help clean up my signal. I must admit to just leaving the settings to default ... again DOH !

Many thanks to everyone.

Have a good day :)

Col (M6ONK)
 
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