Article 58614 of sci.geo.satellite-nav:
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From: reinhard.zwirner@t-online.de (Reinhard Zwirner)
Newsgroups: sci.geo.satellite-nav
Subject: RF Emissions of GARMIN 12 XL
Date: 21 Feb 1998 00:16:04 GMT
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Hi all,

Today, I "measured " the rf emission of my 12 XL (v. 2.01, equipped
with fresh alkaline batteries) with a TAKEDA RIKEN spectrum analyzer
[SA ;-)]. I connected a rod antenna (of 30 cm/12 inches length) to the
input of the SA and held the 12 XL as near as possible to it.

1. 12 XL (still)"off", full 2000 MHz SPAN, 10 kHz RBW, 10 kHz VBW,
   100 sec SWEEP, 0 dB ATT, -10dB REF LEVEL:
   Some spurious signals well below -80 dBm.

2. Same as 1. except 12 XL now switched "on", no reception of SV 
   signals:
   A lot of signal peaks in the frequency range up to 700 MHz, above
   700 MHz no measurable signals (noise floor at about -90 dBm).

3. Same as 2. except 700 MHz SPAN, 18 sec SWEEP:
   Significant signals in the frequency range from 67 to 700 MHz; peak
   level (-52.5 dB) at 165.2 MHz; four signals (132/148.4/182/197.4 MHz)
   at -56.4 to -64.6 dBm; a lot of smaller (below -70 dBm) signals in
   frequency steps of about 16 MHz.

I do know that my method of measurement isn't too meaningful, but I
think it could be of some help in judging if a 12 XL could possibly
cause significant rf interference with aircraft equipment.

CU, Reinhard