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Re: [CQ-Contest] Can Reverse Beacon Network skimmers get overloaded?

To: cq-contest@contesting.com
Subject: Re: [CQ-Contest] Can Reverse Beacon Network skimmers get overloaded?
From: Pete Smith N4ZR <n4zr@contesting.com>
Date: Tue, 28 May 2013 07:43:12 -0400
List-post: <cq-contest@contesting.com">mailto:cq-contest@contesting.com>
Hi Hank - to the best of my knowledge there is no such "desensing" phenomenon with CW Skimmer or Skimmer Server. During the contest, there were both a large number of six-band-at-once Skimmers (using QS1Rs, mostly) and a large number of one-band-at-a-time Skimmers using everything from Softrocks to QS1Rs to Perseus receivers. The single-banders consume relatively little computer power, as you can imagine, while the multi-banders use much more. In theory, if a Skimmer has too many decoders working at once, so that its CPU utilization hits 100 percent, it will not decode them all until the rush subsides. It is also possible that something as yet undiscovered may have caused not all spots to be passed on to the RBN's Telnet servers, but we have had no indication of this, and the sheer volume of spots that *were* forwarded suggests this is unlikely.

There are a couple of other possible explanations for why you were not successful in triggering more spots. You *must* use either "CQ" or "TEST" in your CQs, with no more than one other word between the keyword and your call, or else Skimmer doesn't know if you are CQing. QRM could have reduced the number of spots, simply because stations that you couldn't hear at your QTH were QRMing you in places like Europe, where there is the greatest concentration of RBN Skimmers. Or possibly, the times when you were trying to run were ones where you did not have propagation to large numbers of Skimmers.

I'm sorry, I know probably none of these answers is satisfactory. I'd love to hear other possible explanations, if anyone has them.

73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.

On 5/27/2013 11:21 PM, Hank Greeb wrote:
I had a terrible time trying to make a "run" when I tried now and then during the recent CQ WPX contest. I'd call CQ for as long as 10 minutes, and only once did I get more than one or two contacts in a row from trying to "run." I figured that propagation was weird, but couldn't figure out what the deal was.

After the fact I searched for my call in the past 24 hours, and found that I had rarely been heard calling CQ by any of the skimmers on the Reverse Beacon Network, and even more rarely was I more than 10 dB above ambient noise. I've had considerably better results in other recent contest efforts. On a typical day, if no contest is in progress, I can call CQ two or three times in a minute, and I'd be heard by numerous skimmers, with my poorer home location.

I figured that the skimmers must have been overloaded, or the fact that thousands of folks were calling CQ was overloading their capacity to dig down for the weaker stations.

In comparing my results, hour over hour compared to last year, I made "about" the same number of Q's per hour - >99.44% of the S&P, so it would appear that, even with lousy ionospheric conditions, I was able to S&P with similar effectiveness. Last year, at home, with just a low wire antenna, I didn't even try "running" so I don't know if I was being heard by the skimmers.

Is it possible that the sheer number of signals on the air make the skimmers less sensitive? Or is my thinking all wrong?

72/73 de n8xx Hg
QRP >99.44% of the time
Operated WQ8RP during CQ WPX 2013
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