[Skimmertalk] Monitoring Band Openings

David Gilbert xdavid at cis-broadband.com
Mon Jul 14 22:15:43 EDT 2008


What an impressive setup!  It sounds like if anyone is going to be able 
to explore the multiple possibilities for this technology, you will.  
I'm glad to hear that you also have an interest in propagation 
monitoring, and I'll be very interested to see how that works out.

When you add the QS1R, do you anticipate being able to cover most or all 
of the HF spectrum with just the one receiver, or will you have to 
software "bandswitch" it in some fashion in order to get decent 
decoding?  Multiple SDR-IQ receivers represent a fairly sizeable 
investment by themselves, but in addition not everyone is going to have 
the knowledge or resources to network them together on a server as you 
have done.  Having one wideband receiver would open up a lot of 
possibilities for experimentation.  My oldest son is a software engineer 
for a company that specializes in high performance SDR applications in 
the government/military field, and I have fantasies of coercing him into 
writing various software modules for particular amateur radio 
applications once I learn more about this stuff myself ;)

Thanks for the info!

Dave   AB7E

p.s.  Your antenna farm is also particularly impressive.  I have a 
single OB16-3 and an OB2-40 on an HD-70 tower, and you still make me 

Rick Walker wrote:
> Dave,
> I have invested pretty heavily in skimmer technology and have been using it
> extensively for several months.  I use six SDR-IQ receivers by RF Space in
> my skimmer cluster not Softrocks.  I'm hosting the skimmer cluster software
> on a server with dual quad-core 2.5 GHz Intel Xenon processors and a 5 TB
> RAID disk farm.  Alex actually recommended the QS1R receiver, unfortunately,
> support for that device was not available when I started my project.   I was
> in a hurry to get an initial capability up and running to evaluate the
> technology so I chose not to wait on support of the QS1R by Skimmer.
> I have done some after-action analysis of the data I collected with my
> skimmer cluster during the 2008 CQWW WPX.  In case anyone is interested,
> here are the overall WPX results:
> Recorded data:           430 GB in 48 hours
> Total Spots:             67,885 in 34 hours
> Unique Call Signs:       12,605 in 34 hours
> Unique Call Signs/Band:  17,162 in 34 hours
> 					Unique Call Signs (Band-by-Band)
> Totals								
> 10M	  	15M	  	20M	  	40M		80M
> 160M		 TOTAL
> 351		2,059		9,031		4,745		865
> 111		17,162
> Note:  The CQWW WPX data were collected using my main yagis configured for
> general geographical coverage and NO interference from local transmitting.
> If you do the math, the average aggregate spot rate was just under 2000
> spots per hour and on average my skimmer cluster found 370 unique callsigns
> per hour.  Obviously Skimmer has an inherent callsign detection error rate,
> but even if the error rate is 50% (it's actually more like 10-20%) that
> still represents a significant sample set of potential, valid contest
> contacts.
> Based on the performance from my skimmer cluster that I observed during
> Scott's IARU effort this past weekend, I think the spot numbers were much,
> much smaller than in the WPX.  The cluster was using only a small DX
> Engineering active RX vertical and Scott was, of course, transmitting the
> whole time.  I didn't collect any statistics during this contest because I
> didn't want to interfere in any way with Scott's effort.  However, my visual
> observation of the spot rates from the skimmer cluster data stream indicated
> to me that it was still producing at least as many spots as one generally
> sees from a packet node during a major contest. 
> Incidentally, I plan to add at least one QS1R into the configuration in the
> very near future to run Alex's Faros application once support for the QS1R
> receiver is available in Faros.  (I corresponded with Alex about adding
> support for the SDR-IQ in Faros, and he indicated his plan for Faros was to
> skip the SDR-IQ in favor of the QS1R).  I am interested in collecting
> propagation data from the beacon network, which Faros does very well.
> I read this prior to hitting the send button and realized my comments were
> all over the spectrum and not confined to monitoring band openings...
> Hopefully I didn't bore you too much with my ramblings...
> 73,
> Rick
> K4TD
> _______________________________________________
> Skimmertalk mailing list
> Skimmertalk at contesting.com
> http://dayton.contesting.com/mailman/listinfo/skimmertalk

More information about the Skimmertalk mailing list