[Skimmertalk] Brief experiment with Skimmer and 40 Meter SoftRock at Field Day

kd4d at comcast.net kd4d at comcast.net
Mon Jun 30 11:19:46 EDT 2008

Hi Pete:

I had a bandpass filter in front of the SoftRock.  I do think that an attenuator would
have helped - I'm wondering if there is a better way to set it than fiddle with it and
see what happens in the waterfall display...does anyone have any suggestions?

Unfortunately, if we're transmitting on 40 with two or three or even four stations 
at Field Day for instance), a band-pass filter doesn't help.  :-)

Thanks, Pete.



 -------------- Original message ----------------------
From: Pete Smith <n4zr at contesting.com>
> The bandpass filters on the front end of the SoftRock are extremely broad, 
> so I'm not surprised.  On the other hand, if you had a set of W3LPL RX 
> bandpass filters in front of it, results might have been different.  I've 
> noticed that with my all-band Softrock I tend to demodulate SW broadcast 
> signals around the local oscillator frequency, which tells you something 
> about how broad it is.
> One possible option - I think N3HVQ is working with it - is the SDR-IQ 
> (www.rfspace.com).  I would still expect to need bandpass filtering in 
> front of it, in a multi-transmitter environment, but at least it has a 10db 
> attenuator and variable RF gain.  It also receives from 500Hz (that's 
> right, Hz) to 30 MHz, so it could be useful for a lot of other things, 
> including spectrum analysis, LOWFERing, and SWLing.  Best of all, it's 
> USB-powered and doesn't need a sound card!
> 73, Pete
> At 10:03 AM 6/30/2008, KD4D wrote:
> >Good day, everyone:
> >
> >I hooked a skimmer up to a 40 meter dipole at our Field Day just to play 
> >with it.  The
> >$12 SoftRock kit was, not surprisingly, completely overwhelmed by the RF 
> >environment
> >and mostly decoded every possible variant of W3AO at almost every 
> >frequency in the
> >band.  And, we were only running 100 watts.
> >
> >If this is going to be useful in a large multi-op scenario, a better 
> >receiver is going
> >to be required.  Has anyone had experience with some of the other SDR's in a
> >multi-op environment, especially one running high power.
> >
> >I expect even the SoftRock to work much better monitoring a band where there
> >isn't a local tranmitter active!
> >
> >73,
> >
> >Mark, KD4D
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