SB-102 weak modulation

[Diane Swynar]

Hi Gerry,

Therin lies the rub---you have NO assurance that it'll be any better, if
it's purchased USED. I've seen some that have hardly moved in frequency at
all, & others at the opposite end of the scale! It's all a matter of luck,
it seems...

Try this trick to assure yourself that you really need a new crystal in the
first place: with a WELL CALIBRATED general coverage receiver nearby
(something digital), remove its antenna & replace it with a short piece of
coax, long enough to reach the suspect crystal on the chassis. Attach a
short length of wire to the centre conductor at the end of this coax, &
place it close to the crystal, or the oscillator tube. Put the
transmitter/transceiver in the suspect mode, key the mic/key, & tune for
zero beat on the adjacent general coverage receiver.

You're listening to the actual crystal frequency in that circuit. A
frequency meter works just as well, if you have one. In any event, if the
displayed frequency is way off the frequency stamped on the crystal case,
start shopping.

If you don't trust RFE used rocks, contact JAN Crystals in Fort Myers,
Florida---I think you can get a brand new, custom cut replacement from them
for about $10.00 - $15.00, dependednt upon what tolerance you specify...

The beauty of a defect like this is that it CAN be fixed relatvely easily,
& you don't particularly need to cannibalize an older rig to repair
yours...GOOD LUCK!

~73~ Eddy VE3CUI - VE3XZ






>
> ----- Original Message -----
> From: "Eddy Swynar" <gswynar at DURHAM.NET>
>>
>> Those old Heath HC-6U crystals are rather notorious for
> changing frequency
>> over time. My former SB-400, after a long off-the-air
> absence, developed
>> weak, tinny-sounding audio on LSB---turns out that the
> LSB generator crystal
>> had, indeed, changed with age. A replacement crystal
> brought it back to life
>> in that mode...
>
> My HW-101 has developed a problem where it looks like I'm
> working "split" in CW mode.  This could very likely be due
> to the CW crystal changing frequency.  (I have no means
> for measuring its frequency.)  (The USB crystal seems to
> be OK, at least relative to the LSB crystal.)
>
> If I obtained a replacement, what assurance is there that
> the replacement is on frequency, if they're notorious for
> changing frequency?
>
> 73 de W2GERry

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