SB-102 weak modulation

[Hallidy, Dave]

Gerry-
The CW Carrier Oscillator crystal may well be off frequency.  It's only used
in CW xmit- in receive, the radio uses the USB Carrier Oscillator.  I just
went through this with my SB-101, and I had to adjust the crystal
frequencies of the LSB and CW Carrier Oscillators.  If the crystal isn't
"miles" off, you can probably bring it back on frequency.  There is a very
good article in February, 2003 QST on optimizing the performance of
HW-100/101's, SB-100/101/102's and one of the many things they talk about is
netting the Carrier Oscillator crystals on frequency.  It's fairly simple
but does require a halfway decent frequency counter.  A small capacitor in
series or parallel with the crystal (depending on whether it needs to move
up or down in frequency) is all it takes.  I moved my LSB crystal over a kHz
to get it back on and it works fine, the CW crystal was closer, but still
several hundred Hz off, and it also came back just fine.
I highly recommend the article in QST- it's got a lot of good, relatively
non-invasive tips for making these radios better- I did 'em all and am quite
pleased- the radio sounds as good as my 30 year newer Kenwood.
Good luck!
Dave K2DH

-----Original Message-----
From: CyberGeezer [mailto:cybergeezer74 at HOTMAIL.COM]
Sent: Friday, February 21, 2003 11:17 AM
To: HEATH at LISTSERV.TEMPE.GOV
Subject: Re: SB-102 weak modulation


----- 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

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.asp?list=HEATH
To post - HEATH at LISTSERV.TEMPE.GOV
Archives - http://interactive.tempe.gov/archives/HEATH.html

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.asp?list=HEATH
To post - HEATH at LISTSERV.TEMPE.GOV
Archives - http://interactive.tempe.gov/archives/HEATH.html