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

Bill Tippett btippett at alum.mit.edu
Mon Jun 30 11:32:13 EDT 2008


 >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.

         The Achilles heel of today's SDRs is relatively
poor BDR, which is exactly what's needed in a multi-op
environment.  For example, the Flex 5000, one of the
better SDRs, has BDR of 121 dB versus the K3 at 140 dB.
Of course this may change as 32-bit ADCs become available.

         BTW I did a little RX-only experiment myself.
My rules were to tune 7018-7042 kHz in 3 consecutive
15 minute intervals using the following methods:

1.  Using one VFO and my ears.
2.  Using one VFO, PowerSDR's waterfall and my ears.
3.  Using Skimmer.

The reason for the 24 kHz limitation is due to the way
Skimmer limits the Softrock-IF mode when using the K3.
If this limit were removed, then Skimmer should have
doubled its results over a 48 kHz swath (and even more
if 96 kHz were used).  I doubt a human would have
improved #1 or #2 much with wider bandwidths.

         Drumroll...and the results are:

1.  37 calls.
2.  47 calls.
3.  86 calls (7 obvious busts...possibly more).

         I could have improved #1 and #2 above by
leap-frogging two VFOs (which is what I normally do)
but I just wanted to see what could be done with one.
If anyone thinks Skimmer would not totally redefine
SOU they're kidding themselves.

         My other observation is that the CW skills
of many hams today are very poor.  Many busted calls,
poor sending skills, folks who cannot copy simple
questions like "SEC?", etc.  I wonder if Skimmer
would improve these skills or make the situation
even worse?  Time will tell...

                                         73,  Bill  W4ZV

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