[PCR-1000] iCOM Servicing

[Bryce Ringwood]

Hi - and thanks to Craig for the feedback.

Some thoughts on aerials.

I think I finally figured out what made the set a bit deaf on UHF -
simply a matter of polarisation.  Most TV transmissions are horizontally
polarised, whilst the discone is a vertically polarised antenna.
Probably explains why the UHF TV signals dip and dive the whole time.

For HF, I use a long wire, but with a 4:1 RF transformer at one end,
then a long run of buried co-ax to the receiver. This gives you a short
to static, so there's a bit of protection. (And less chance of picking
up noise from the computer.) The other thing said to cause a blown
front-end is simply very strong signals.  Local AM stations can  put
several volts into the antenna, and I was told that using an active
antenna with some modern RXs can also cause blown FETs in the front-end.
(Old XYL's tale?).

For the transformer, you can experiment with a ferrite ring 10-15 cm
o/d with about 25 turns wire wrapping wire on the primary. (Or buy one)
Tap at the centre, or use a separate winding. Ground one end of the
primary and attach to the coax outer. The long wire goes to the other
end of the primary and the centre of the coax goes to the tap. Trim the
length of the long wire until the set stops overloading and you can
operate it without the "att"...8-)

Enjoy
>>> craig.woods@photographers.co.za 03/04/02 11:55AM >>>
Just to confirm Bryce's comments , I had a PCR-1000 that went deaf
because
of static buildup on a long wire. The local agents chief technician was
away
on a d-expedition but when he got back things moved. About six
components
had blown and were replaced. I gave them a copy of the EX2099 program
(written by IBM by the way) and the rig was realigned. Total cost just
under
R400 or about $35. I now use an Italian made discone that has quite a
high
bandwidth and is adequate for APRS etc. signals from satellites but
still
suffers from static build-up when we have an electrical storm in the
offing.
Talk PCR is the favoured software and I'm hoping there's an upgrade in
the
offing.
Craig ZR6ABU

----- Original Message -----
From: "Bryce Ringwood" <BRingwoo@csir.co.za>
To: "<" <pcr-1000@mailman.qth.net>
Sent: Monday, March 04, 2002 9:39 AM
Subject: [PCR-1000] iCOM Servicing

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