[amsat-bb] RTL-SDR downlink

Jim Jerzycke kq6ea at verizon.net
Thu Jun 16 21:15:14 UTC 2016

I did some experimentation with the $20 dongle vs the FunCube dongle for 
receiving weather satellites.

If you live in an RF dense area, like here in Southern California, they 
BOTH benefit from having some front-end filtering added.

Other wise you have to turn the RF gain down quite a bit on both of them 
to prevent 'break through' from strong signals that can be may MHz away 
from your band of interest.

In my case, I used an SSB Electronik 2 Meter preamp with an old M2 2 
Meter Eggbeater antenna. I could get reasonable copy above 10*~15* 
elevation with just the dongle and antenna, but suffered from strong 
signal break through. If I turned the RF gain down to where the 
interfering signals no longer broke through, it cut my reception down to 
maybe 25*~30* elevation.

With the SSB preamp and it's built-in helical filter, even operating at 
137 MHz, the difference was staggering, and I could get good copy down 
to 5* or so.

The only other SDR I played with for a while was the HackRF, which I 
found to be unsuitable for what I was looking for. Despite the hype 
behind it, it's still an 8-bit unit with limited dynamic range.


73, Jim  KQ6EA

On 06/16/2016 08:33 PM, Peter Laws wrote:
> On Thu, Jun 16, 2016 at 3:22 PM, Patrick STODDARD (WD9EWK/VA7EWK)
> <amsat-bb at wd9ewk.net> wrote:
>> Unfortunately there isn't anything in the middle ground between these
>> dongles and devices like the
> The $20 versions are well worth the effort if you've never played with
> an SDR of any sort before.  For satellite downlinks?  Dunno, never
> tried.  Surely as you describe!
> Has anyone done any kind of "shoot out" comparing the cheapos to the
> real ones or even between the real ones (FCD, SDRPlay)?  Before I
> plunk down $200, I'd like to see what I'm getting ...  over and above
> what my $20 dongle can do, of course.  :-)  I read what you typed, but
> I'd like to see numbers.

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