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Message-ID: <014a01c68adc$b9e998d0$7900a8c0@athlon1200>
From: "Dave Brown" <tractorb@ihug.co.nz>
To: <rsgb_lf_group@blacksheep.org>
Cc: "bob vernall" <vernall@xtra.co.nz>
References: <4487EB8A.27171.B415B8@localhost>
Date: Thu, 8 Jun 2006 21:20:04 +1200
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Subject: Re: LF: BBC 198kHz
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Mike
Don't think Bob ZL2CA has resubbbed to the list yet but he has a TS850 
and would no doubt be able to shed some light on this. He has measured 
DDS errors at less than a few tens of mHz I think, but easily seen 
with Argo at high resolution and fairly sure they are both positive 
and negative. Bob would be able to confirm this.

However this is much worse - it looks like the reference is off 
frequency but if the percentage error was the same at higher 
frequencies (~ +90 Hz at 15MHz, based on your measurements) I'm sure 
you would have noticed it by now. Must be something more subtle. Don't 
know the architecture of the 850 so sorry can't comment further.  Try 
emailing Bob direct.

vernall@xtra.co.nz

73
Dave, ZL3FJ


----- Original Message ----- 
From: "Mike Dennison" <mike.dennison@ntlworld.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Thursday, June 08, 2006 8:19 PM
Subject: Re: LF: BBC 198kHz


> Thanks to all those who responded to my query about the apparent
> errors seen on frequency standards.
>
> I am now convinced my problem is caused by frequency error in my TS-
> 850. Looking at several standards, the errors are as follows
> (relative to an arbitrary zero):
> 60.0kHz:  -1.0Hz
> 75.0kHz: -0.8Hz
> 77.5kHz: -0.7Hz
> 162kHz: -0.1Hz
> 198kHz: +0.1Hz
> 490kHz (using my LF Tx DDS) +3.0Hz
> Plotting this on a graph shows approximately a straight line. This
> indicates a progressive error as frequency increases.
>
> As a quick fix, I can now use the graph to determine the readings at
> 198 and 60kHz that will give me a zero offset at 136kHz. However, is
> there a more permanent way of overcoming this problem?
>
> Mike, G3XDV
> ==========
>
>
>
>> Nothing unusual seen here - checked against my Rb standard.
>> Walter G3JKV.
>
>
>
>
> -- 
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> 6/06/2006
>
> 


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