[UK-CONTEST] Voice keyers

[Cooper, Stewart]

The MFJ voice keyers do have a problem with RF getting into them. I
found that this is caused because (in the earlier 432 model at least)
the mic is not actually disconnected on 'transmit' (i.e. when the keyer
keys) and the RF gets in on the mic lead. I solved this by putting a
small relay into mine which disconnects the mic on TX. I also put
ferrite clamps on the input and output leads and some small ferrite
beads/rings on the internal wiring behind the front panel. I have heard
folk say that they got rid of the RF problem by using internal
betteries, but mine works fine with a small external supply.
I key mine using a connection to the DX Doubler/LPT1 line which fires
the keyer when I hit F1 on the keyboard and it works fine. F2, 3 and 4
don't work but I've given up on that one!!
However, I would recommend something a bit more heavy duty. I've used
the ZS4TX keyer. It works well and is RF tight. Also WinTest and
WriteLog use the sound card (other logging programs are available) which
saves a lot of hassle but I have little experience of that.
73
Stewart
GM4AFF

-----Original Message-----
From: uk-contest-bounces at contesting.com
[mailto:uk-contest-bounces at contesting.com] On Behalf Of Adrian Rees
(MW1LCR)
Sent: 27 May 2007 14:45
To: uk-contest at contesting.com
Subject: [UK-CONTEST] Voice keyers

Hi all

Anyone have any comments on the MFJ Voice Keyer ?
Cntemplating buying one.

Cheers

Adrian MW1LCR

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