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.
[email protected]
73
Dave, ZL3FJ
----- Original Message -----
From: "Mike Dennison" <[email protected]>
To: <[email protected]>
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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