"Now to get the W9XT to work with the ICOM electret microphony input so I
can use the memory to call CQ rather than my voice!"
Dan,
Actually, it's not that hard - but it does require certain stuff. The
+8VDC voltage used to power ICOM electret mics which appears on the ICOM
mic input has to be blocked. A capacitor in series with the mic lead will
do the job, and this is shown in the W9XT documentation. The value is not
critical - you want enough capacitance to not effect the frequency response
of the mic audio, but yet you need a physically small part. Its been my
experience that 0.47 uF works well, but I've also used very small
electrolytic caps (1 uF or so) as well.
The trick is where to put it. I've stuffed the capacitor into the 8-pin
mic connector, but there's more room in the DB-25 which connects to the
W9XT card.
The ICOM adapters available from Heil already have the blocking capacitor
in them. At K8CC, where we have radios from all of the "big three"
manufacturers, and W9XT cards in all of the primary band computers, I'm
standardizing the cable coming out of the W9XT card to mate up with Heil
adapters. In this way, I can move radios around without having to swap
cables, or make new ones.
73,
Dave/K8CC
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