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Subject: Re[2]: TWL: Iridium antennas
From: Peter Bennett (peterbb@XXX.XXX)
Date: Sun Dec 01 2002 - 20:11:54 EST
Saturday, November 30, 2002, 5:35:29 PM, Steven wrote:
> At 04:44 PM 11/30/2002 -0800, you wrote:
>>Since the Iridium phone must transmit as well as receive, you would
>>need a _passive_ GPS antenna. Many remote GPS antennas are "active"
>>(they include a preamplifier to overcome cable loss) - the preamp
>>would block transmitted signals, and would likely be destroyed,
>>rendering the antenna useless for either Iridium or GPS.
> Hi Peter:
> Thanks. I had not thought of that. Is there any way of telling whether an
> antenna is active or passive?
> Steve
I would check the resistance of the antenna with an ohmmeter. A
passive antenna should be either open circuit, or nearly a short
circuit. An active antenna would (I expect) show an intermediate
resistance, and would probably show different resistance depending on
the meter polarity. (I may be able to check an active antenna on
Monday.)
-- Peter Bennett, VE7CEI Vancouver, B.C., Canada GPS and NMEA info: http://vancouver-webpages.com/peter Vancouver Power Squadron: http://vancouver-webpages.com/van-ps _______________________________________________ http://lists.samurai.com/mailman/listinfo/trawler-world-list
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