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@amsat.org] On Behalf Of Charles Reiche Sent: Thursday, June 28, 2018 3:16 PM To: Amsat-bb@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 _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb