[CQ-Contest] Implementing a Dynamic error free RBN-Skimmer network

[Pete Smith N4ZR]

The RBN team was delighted to get an advance copy of this message 
yesterday. |We've barely begun to explore Jose's VBA-enabled 
spreadsheet, but it's obvious that he's drawn on his experience as a 
world-class contester to design his algorithms, and we are thinking hard 
about how best to incorporate them into the RBN.  One consideration has 
to be speed - with expected *average* spot rates of over 30 per second 
during the upcoming CQWW (that may be on the low side, actually), we 
need to be sure that whatever we do can handle |the flow without 
introducing delays.

One class of bad spots that Jose identified is the "Good call - wrong 
frequency?" type.  A quick review suggests that many of these resulted 
from what we call the "I/Q image" problem, in which an image is copied 
as far above the receiver's center frequency as the real signal is below 
it.  for example, if a receiver's center frequency is 7040 KHz and a 
station is at 7010, a much weaker image may appear at 7070 and be 
spotted along with the real one.  During the IARU contest last weekend, 
we tested beta versions of an Aggregator with an I/Q image filter at 
several prolific RBN stations.  It seems to work quite well, though 
there is still work to be done.

Ultimately, our goal is to roll the CT1BOH algorithms and our I/Q image 
filtering into a single routine to operate against the queue of spots 
coming into the RBN server.  Stay tuned!

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 7/15/2013 6:23 PM, José Nunes CT1BOH wrote:
> The purpose of this post is to present a way to implement a dynamic error
> free Skimmer-RBN/Packet network that automatically:
>
> 1. Flags and eliminates “Busted Spots” from the network
> 2. Flags  and eliminates “wrong frequency” spots from the network
> 3. Prevents inaccurate Skimmer-Spotters from feeding incorrect spots to the
> network
> 4. Eventually allow the Skimmer-RBN users to customize reception of spots
>