[amsat-bb] IC-910h preamp power and inline coax switch.

[George Henry]

Many antennas present a DC short, so the preamp power is current-limited,
and you will not damage it by using an antenna switch that shorts the
connection when switched.


73,
George, KA3HSW



-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces at amsat.org] On Behalf Of Charles
Reiche
Sent: Thursday, June 28, 2018 3:16 PM
To: Amsat-bb at amsat.org
Subject: [amsat-bb] IC-910h preamp power and inline coax switch.

I am getting up to speed on working NO-84 with my TH-D72a.  My primary
antenna system and radio is IC-910h with the Icom Preamp installed near the
antenna.  The 910 powers the preamp through the coax, and I tend to leave
the preamp on selection on the radio on all the time.

I want to put a MFJ1702C coax switch inline with the 2m side so I can
branch out the 2m antenna to my HT.  The non selected port of the coax
switch is grounded.  If you accidentally ground the IC-910's coax with the
preamp selected on, does it damage the preamp power circuit or is it
tolerant of a short? I could not find a definitive answer in the manual
other than the preamp may not activate properly.  I know it wont power up
the preamp.

Inevitably, if I have to rely on remembering to turn off the preamp before
I switch to the HT to work NO-84, I will forget. Just want to prevent
burning something up.

Thanks for any suggestions.

N3CRT
Charles Reiche
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