[Top] [All Lists]

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

To: José Nunes CT1BOH <ct1boh@gmail.com>
Subject: Re: [CQ-Contest] Implementing a Dynamic error free RBN-Skimmer network
From: Pete Smith N4ZR <n4zr@contesting.com>
Date: Tue, 16 Jul 2013 09:58:28 -0400
List-post: <cq-contest@contesting.com">mailto:cq-contest@contesting.com>
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
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
4. Eventually allow the Skimmer-RBN users to customize reception of spots

CQ-Contest mailing list

<Prev in Thread] Current Thread [Next in Thread>