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Re: LF: Eb/N0 values for amateur modes

To: [email protected]
Subject: Re: LF: Eb/N0 values for amateur modes
From: John Rabson <[email protected]>
Date: Sun, 11 Jan 2015 09:54:35 +0100
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Andy, G4JNT, had a piece in CREGJ in 2012 about assessing SNR for voice, CW and 
single tones. See http://bcra.org.uk/pub/cregj/index.html?j=78.

John F5LVF

> On 10 Jan 2015, at 23:13, Alan Melia <[email protected]> wrote:
> 
> Hi Pieter, Dave G3YXM and I did some quick and dirty estimations of QRSS 
> about 10 years ago on 136kHz I cant remember whether we did DFCW where the 
> main advantage is that it is faster, but the decode threshold is about the 
> same as QRSS  It is a little subjective but the results seemed reasonably 
> what we might suspect.
> 
> They may be on his web-site still  www.wireless.org  I think the we only 
> considered fully reading the ID and Dave reduced power until it was not 
> possible to decode. The results were in line with the FFT resolution used, 
> but we have no measured values.
> 
> I believe someone in the States also did some tests, John W1TAG could 
> probably help there. They may be on the LWCA web-site.
> 
> Best Wishes
> Alan
> G3NYK
> G3NYK
> 
> ----- Original Message ----- From: "Pieter-Tjerk de Boer" 
> <[email protected]>
> To: <[email protected]>
> Sent: Saturday, January 10, 2015 9:17 PM
> Subject: Re: LF: Eb/N0 values for amateur modes
> 
> 
>> 
>> On Fri, Jan 09, 2015 at 10:15:24AM +1100, edgar wrote:
>> 
>>> In your email, in which mode grouping would DFCW 180 fit?
>> 
>> Not in any, really. I'm not aware of any (published) experiments having
>> been done to establish decoding thresholds for it, which I could use
>> to put it in the table.
>> 
>> Compared to regular CW transmitted at the same (peak) power, DFCW has
>> about 3 dB more average power because the transmitter is on continuously,
>> so just because of that, it should give better performance at the same
>> _peak_ power level. However, whether the performance difference is more
>> or less than 3 dB, and thus whether it is better or worse than CW at the
>> same _average_ power (as normally used for Eb/N0 calculation), is harder
>> to predict.
>> 
>> Regards,
>> Pieter-Tjerk, PA3FWM
>> 
> 
> 

[email protected]

Researching history of RABSON, BLACKSHAW, GAUNTLETT, VERLANDER and ROBSONNE






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