[Boatanchors] 17 M xtal for KWM-1

[AI2Q]

Bill, the PTO in the KWM-1 spans only 100-kHz. The heterodyne xtals 
therefore provide coverage in 100-kHz "chunks" of a band.

Yes, there is a small amount of range at both ends of the PTO travel, so I 
can operate a bit (about 5 to 8 kHz) out of each band coverage beyond the 
basic 100-kHz.

Vy 73, AI2Q, Alex

----- Original Message ----- 
From: "Bill Cromwell" <wrcromwell at gmail.com>
To: <boatanchors at mailman.qth.net>
Sent: Wednesday, June 08, 2011 6:03 PM
Subject: Re: [Boatanchors] 17 M xtal for KWM-1


> Alex AI2Q wrote:
>
> To determine the xtal frequency you need to look at the rig's
> conversion
> scheme, and have your calculator in hand.
>
> To put my KWM-1 on 17 meters I determined that an 11.034 Mc rock would
> be
> doubled to 22.068 Mc. Then, subtracting 4 Mc would yield tuning at
> 18.068
> Mc. Subtracting 3.9 Mc would yield 18.168 Mc.
>
> Wishing to use what I had on hand (namely a KWM-2A military xtal pack),
> I
> deployed a KWM-2A's 11.0775 Mc crystal. That delivers coverage in my
> KWM-1
> from 18.14 through 18.168 Mc. The dial reads from 085 to 013. The dial
> at
> 0.0 corresponds to 18.153 Mc.
>
> Vy 73, AI2Q, Alex
>
> Hi Alex,
>
> I "think" that radio is one that covers it's chunk of spectrum in 200 kc
> 'bands'. From the math you presented it has a 4 mc I.F. and the crystal
> oscillator is doubled to be 4 mc higher than the incoming frequency. Is
> that correct? In the next part of your info I come up with something
> different for your coverage from the 11.0775 rock.
>
> So a KWM-1 owner can determine from your math where the xtal they just
> happen to have will fall on the KWM-1 coverage. If I have the info about
> the I.F. and oscillator doubling then a 11.0 mc xtal will give coverage
> of the 17 meter band with the dial zero at 18.000 mc and the beginning
> of the 17 meter band starting at .068 on the dial. So if an owner has to
> buy a crystal that's what would be ordered. (It's what I would do)
>
> Trying it two different ways I come up with coverage on your rig
> starting at 18.155 (Dial = zero). What did I overlook? Maybe the 11.0775
> crystal is a bit "off" in the KWM-1? I am also guessing your dial goes
> down past zero to yield 18.140 at the very end. I have found that
> crystals vary by that much from transmitter to transmitter and unless
> you have a way to net them you live with it wherever it lands.
>
> 73,
>
> Bill  KU8H
>
>
>
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