[R-390] 5 khz difference?

[David Wise]

Ahem.  8MHz and above does not use the 17MHz oscillator,
so your frequency counter observation completely accounts
for the discrepancy.  Maybe someone else can say whether
5kHz is small enough to be correctable and big enough to bother.

73,
Dave

> -----Original Message-----
> From: r-390-bounces at mailman.qth.net
> [mailto:r-390-bounces at mailman.qth.net]On Behalf Of Masters Andy
> Sent: Tuesday, February 28, 2006 2:55 PM
> To: r-390 at mailman.qth.net
> Subject: [R-390] 5 khz difference?
> 
> 
> Good evening.  I have an EAC-67 series R-390A that I
> am working through and learning about R-390A's in the
> process. 
> 
> Using a recently cal'd counter, I was able to set my
> BFO for top dead center on 455khz and it tracks +/- 3
> khz nicely as indicated by the ticks on the panel. I
> also adjusted the crystal calibrator by counting it on
> frequency at 200 khz.  It stays put rather nicely as
> well.
> 
> Having done this, I then went through all the bands to
> have a look at dial calibration and have discovered
> that .5-8.0 mhz, the dial reads 5 khz low on each band
> but on the higher bands it is relatively dead on. (or
> it might be said it can be set dead on using the Zero
> Adjust for the lower freqs and is actually 5khz high
> on the higher ones).  In any event, what gives here
> and why the disparity? I first thought it might be my
> 17 Mhz oscillator.  When I count the 17 mhz oscillator
> it indicates it is 4.790 khz low on all bands .5
> through 8 mhz.  After 8 mhz, it changes, but I can't
> get an accurate read on its error.  I don't see a way
> to "warp" the 17 mhz crystal on but I am not convinced
> that is the problem or that there is only one problem.
>  Any suggestions?
> 
> Thanks, 
> 
> Dutch Masters NU5O
> 
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