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

To: <vr2bg@harts.org.hk>, <cq-contest@contesting.com>
Subject: Re: [CQ-Contest] Understanding the dynamic error free RBN algorithm
From: "Marijan Miletic', S56A" <s56a@bit.si>
Date: Sun, 21 Jul 2013 06:24:29 +0200
List-post: <cq-contest@contesting.com">mailto:cq-contest@contesting.com>
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@harts.org.hk>
To: <cq-contest@contesting.com>
Cc: <s56a@bit.si>; <ct1boh@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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