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From: mcg@joevax.UUCP (Mark Germain)
Newsgroups: net.ham-radio
Subject: The Efficacy of ICOM HF Transceivers for Mobile Operation
Message-ID: <102@joevax.UUCP>
Date: Mon, 28-Oct-85 15:50:36 EST
Article-I.D.: joevax.102
Posted: Mon Oct 28 15:50:36 1985
Date-Received: Mon, 28-Oct-85 23:25:42 EST
Distribution: na
Organization: Bell Communications Research Inc., Morristown, NJ
Lines: 16

For the past four years I have used a dedicated IC-720A in a mobile
environment and while it's reliability has been excellent, severe
design problems with the noise blanker significantly degrades the
receiver performance under conditions of crowded bands, presence
of moderately strong carriers. The problem is apparently due to
back-biasing if the noise detection diode, related to time constants
which are too long in the presence of strong signals in the wide passband of
first IF. For example, in the presence of strong broadcast carriers on 
forty meters, even 500 KHz away, ignition pulses to pass through the
noise blanker almost completely intact. 
I am currently looking for another transceiver more suitible for mobile
applications, one with a significantly better-designed noise blanker.
Does anyone have experience with the more recent ICOM's or the Kenwood
line, eg. IC-751, IC-735, 430S ?

                     Mark, KB2IF