[CQ-Contest] Understanding the dynamic error free RBN algorithm

Marijan Miletic', S56A s56a at bit.si
Sun Jul 21 00:24:29 EDT 2013

Real life 0IF RX could achieve 60 dB unavoidable image rejection and this is 
not enough in contests.  Our ham freqs are NOT channelized although one 
knows where the image is!

Direct HF sampling ADC RX like QS1R or Perseus with 16 bits has dynamic 
range over 100 dB with a single, clean XO and no inherent images.  This is 
several orders of magnitude better then single bit QSD.

We are dealing with low error rates and further processing would reduce 
insertion mistakes while increasing omissions.  I like to catch erronious 
ones - HI.

73 de Mario, S56A, N1YU

----- Original Message ----- 
From: "Brett Graham" <vr2bg at harts.org.hk>
To: <cq-contest at contesting.com>
Cc: <s56a at bit.si>; <ct1boh at gmail.com>
Sent: Sunday, July 21, 2013 3:19 AM
Subject: Re: [CQ-Contest] Understanding the dynamic error free RBN algorithm

> S56A said:
>> One of my posts was censored so I repeat again - the main problem of RBN 
>> are
>> cheap QSD 0IF RX with I/Q images due to sampling in the middle of CW 
>> bands.
>> Just make QS1R requirement for RBN connection and live happily ever 
>> since!
> Not true - that the cause of wrong-frequency RBN spots can be attributed 
> to I/Q gain/phase unbalance of QSD SDRs.
> There are a number of mechanisms involved, depending on the SDR used. 
> Parroting that it is all due to just one mechanism & only with one 
> particular receiver architecture will not change this.
> QS1R is unique in that it is not QSD, yet it has the problem of spurious 
> responses that look like the one mechanism that keeps getting blamed - a 
> mechanism that shouldn't be seen with that particular receiver's 
> architecture.
> And don't forget, we have already been told that wrong-freq RBN spots are 
> all due to fecal signals.
> Everything is what you are told it is & what you are allowed to say 
> yourself is decided for you!
> -ex-VR2BG/p.

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