[CQ-Contest] Busted Reversed Beacon Network spots

Peter Voelpel dj7ww at t-online.de
Sun Jun 9 12:28:11 EDT 2013

All SDRs have good results with narrow spaced dynamic range, but that is

ON5KQ is also using the QSR1 with his skimmer.
It is totally useless without massive front end attenuation from the late
afternoon on.
It hears nothing then intermodulation and broadcast in the ham bands,
especially on 15m and 17m, without it.
At present he is working extensively on filters to get rid of that.


-----Original Message-----
From: CQ-Contest [mailto:cq-contest-bounces at contesting.com] On Behalf Of
Pete Smith N4ZR
Sent: Sonntag, 9. Juni 2013 16:04
To: CQ Contest
Subject: Re: [CQ-Contest] Busted Reversed Beacon Network spots

Interesting - I "admitted" what?  That there are a lot of Softrock-type
receivers on the RBN, some of which have inadequate I/Q image reduction?
Sure. That direct downconversion receivers like the QS1R occasionally throw
what look like I/Q spots, even though there is no simple explanation.  Sure.
I saw mine throw one of those just yesterday. Wish I knew why.

The RBN teamis actively working on a promising technological solution to get
rid of all of thisclass of busted spots.

Wrong-band spots are quite another creature.  I'm still waiting for data on
these, but think that either inadequate harmonic suppression and/or intermod
will be shown to be the source. If that's the case, then the receiver used
probably makes little difference.

Bret, before you attack SDR receiver performance indiscriminately, take a
look at Rob Sherwood's review of the KX3.

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 6/8/2013 11:37 PM, Brett Graham wrote:
> Eventual admission from N4ZR that a subset of just 
> wrong-freq-same-band spots were seen at a tad over one-per-minute 
> (during a contest) got me looking at this again, using non-weekend RBN 
> data for 2013-03-08 (also with all spots of DXpedition/special event 
> calls omitted, so hopefully missing majority of stations deliberately 
> QRV on >1 band or >1 frequency within same band simultaneously, or 
> deliberately transmitting a fecal signal as no contest that day).

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