BFO low freq too high -- a problem or not?

[Rob Locher W7GH]

When I did Alignment and Test Part II the first time, my BFO low frequency  
was slightly too high: 4912.85 kHz, which is not <= 4912.7 kHz (the  
official specification).  After having done Assembly Part III and having  
checked the calibration of the master oscillator using WWV, I know that  
the calibration of the master oscillator is not the fault.

I carefully calibrated my filters using Tom NØSS's Spectrogram procedure.  
According to my filter calibration table, the lowest frequency required of  
the BFO is 4913.20 kHz, which is still 0.35 kHz higher than my BFO's  
minimum frequency.  Is my slightly-out-of-spec BFO really a problem?

73,
- Rob W7GH

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[Don Wilhelm-3]

Rob,

It might be a problem with the alignment of the SSB filter, especially if
you choose to install the capacitors for the 2.6 kHz filter width.  It could
also be a problem if you activate the RTTY filters - but the real answer
depends on your particular crystal set and the filter width you choose as
well as the audio spectrum that you wish to demodulate.

You are correct that things will work fine since your lowest BFO setting is
above your minimum.  So you could just make a note of it and leave it as-is
until it becomes a problem with the addition of either the SSB wide filter
or the RTTY filter activation.  The choice to correct it now or perhaps have
a need to correct it later is entirely up to you.

73,
Don W3FPR

> -----Original Message-----
>
> When I did Alignment and Test Part II the first time, my BFO low
> frequency
> was slightly too high: 4912.85 kHz, which is not <= 4912.7 kHz (the
> official specification).  After having done Assembly Part III and having
> checked the calibration of the master oscillator using WWV, I know that
> the calibration of the master oscillator is not the fault.
>
> I carefully calibrated my filters using Tom NØSS's Spectrogram
> procedure.
> According to my filter calibration table, the lowest frequency
> required of
> the BFO is 4913.20 kHz, which is still 0.35 kHz higher than my BFO's
> minimum frequency.  Is my slightly-out-of-spec BFO really a problem?
>
> 73,
> - Rob W7GH

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[Leigh L. Klotz Jr WA5ZNU]

Here is a point of experience for this situation: I operated FB like
this, using the Rev F filter width.   Below 15m RTTY worked fine because
of the default sideband placement, and on all bands in other modes it
also worked fine.  I saw no other effects.  I fixed only when I decided
I needed 15M RTTY mode for PSK.
Leigh/WA5ZNU
On Tue, 31 Jan 2006 10:31 am, Don Wilhelm wrote:
> Rob,
> It might be a problem with the alignment of the SSB filter, especially
> if you choose to install the capacitors for the 2.6 kHz filter width.  
> It could
> also be a problem if you activate the RTTY filters
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