IC901.1

Date: 09 Oct 92 23:56:28 EDT (Fri)
From: wa2ise@kb7uv.#nli.ny.usa (BOB)
Subject: IC901 mod file

Subject: IC-901A Frequency Ranges

Here are the frequency coverage ranges for the various band modules and the
modifications to the control head diodes to get these extended ranges:

Band     Range (MHz)      RX diode       TX diode

10m       28-40            24 out         21 in
6m        40-54            28 out         26 in
2m        138-174          no change      18 in
220       216-236          no change      12 in
440       400-479          25 out         23 in
1200     1240-1300         no change      no change

To modify, remove the back of the control head and add or remove diodes from
the marked pads as described in the above table.

notes:  coverages are for RX.  TX may not work over entire range, but will come
close.  RX sensitivity is front-end tuning dependant.  10m, 6m, 2m and 1200
modules will have OK RX sensitivity over most of their range.  220 RX sensivity
is unknown over its range.  440 RX sensitivity will cover about 25 MHz with
good sensitivity, tuning out of the box is from about 438-463.

Other '901A tricks:

Memory and microprocessor reset - turn power on while holding down check and
memory write buttons.

Crossband repeat - turn power on while holding down check and lock buttons.  If
crossband repeat has been engaged, the "lock" display will flash.  PL can not
be selected in either band for crossband repeat to work. If you need PL to
operate the repeater you are linked to, generate it on the radio you are using
to talk to the 901.  The PL will pass through the 901 just fine to access the
linked system.  Since the radio is in the locked mode, you can't change
frequencies or bands during crossband repeat.  To disengage crossband repeat,
turn off power or press lock button.  If there is no audio during crossband
repeat, open up the front of the dual-band unit by removing the plastic cover
behind where the control head would plug in if the 901 is not used in the
remote-control head configuration and look for a slide switch mounted on the
edge of one of the vertical circuit boards and slide it the other way.  The
switch does not seem to come in any pre-determined configuration from ICOM, so
some radios work OK for crossband repeat right out of the box, and some require
the switch to be in the opposite position.

                      Chuck Adams,  WB5WRR   (The Chuckster)
                       Internet:  chuck_adams@qmail.ssc.gov
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Note: I haven't tried or verified this, proceed at your own risk.  WA2ISE
And do not transmit outside of legal bands!