From: ulki@hpbbrd.bbn.hp.com (Heinz-Peter Arndt)
Date: Tue, 21 Sep 1993 08:17:38 GMT
Subject: Re: WANTED: mods on ICOM W21AT
Organization: HP Mechanical Design Division
Newsgroups: rec.radio.amateur.equipment
X-Newsreader: TIN [version 1.1.8 PL6]
Lines: 84

Rafael Perez Rosales (rafperez@sevaxu.cica.es) wrote:
: 	Hello!. I am a recent owner of ICOM's HT W21AT. Of course I got
: the user book with my handie, but I'm interested about possible mods on
: this pretty ICOM's thing. Has someone got any information about?.

Ok, here's what I got:


SPECIAL THANKS: Icom Inc. Japan, ICOM AMERICA, USA.

NOTICE: Icom can not guarantee specifications when expand frqcy.

Receive only expansion:
------------------------
1) Turn radio off
2) Press [B]+[#] switch and turn ON radio.
   Depress [B] and [#] only when the display shows all functions and 
   the radio emits a beep.
3) Go to SET mode and a new function will appear after TONE selection.The
   new function is designed by PL. Set PL to "1"for 1 MHz frqcy. enter,
   to 10 for 10 MHz frqcy. enter and to 100 for 100 MHz frqcy. enter 
   resolution.

Note1: This modification does not reset information saved on the CPU.
Note2: Frequency range is 50,0-107,995 MHz FM
                         108,0-135,995 MHz AM (aviation band)
                         136,0-299,900 MHz FM 
                             for the VHF portion;
                         300,0-999,900 MHz FM for the UHF portion.

REMEMBER: It is illegal to listen cellular fones conversations!
          Some frequencies are not allowed for listenning. Those
          restriction varies from sate to state.

TRANSMIT EXPANSION:
-------------------
1) Call Icom Parts Dept. and order one diode MA132WK (D.23) for IC-W21AT,
   Symbol: MU;
2) Open radio and localize the logic unit;
   The logic unit is the half portion of the radio that contains the CPU,
   display, keyboard, etc...;
3) Localize some orange colour components in the lowset right part of the
   portion, below the CPU shield plate.
   Localize the smallest orange colour component. Note a empty place for a
   surface mount diode (3 dots) near this orange component (see draw below);

   ------\   :  .  <---- Empty place for surface mount diode MA132WK
   |oran- \                                   -----------| | DIAL button
   | ge   /  :<>.  <---- Surface mount diode  |    CPU   | |
   ----- /                   mounted          |  Shield  | | U vol button
     ^                                        |   Plate  . |
     |                                        .          . | V vol button
     |Smallest orange colour component  ------|------------|
                                               ---PTT,F,Moni..

4) Add D23 MA132WK diode in the empty place.
   Do use very fine soldering iron and temperature controlated gear.
   The circuit is very fragile and may burn if excecive heat is applied.
   Take care for static damage also; If you can, use professional gear
   for this purpose or find technical assistance of your choice.

Note1: It is illegal to transmit out of band without an appropriated 
license for MARS/CAP.
Note2: Icom does not guarantee the mod nor the specifications;
       Icom and the author don't take any responsability if any damage 
       occur while performing the mods.
       
-FULL CROSS BAND REPEATER OPERATION-
This feature enables HT to receive on one band and retransmit the content to
the other band. You can even choose tone squelsh selections, repeater offsets
and many other features available during normal operation.
1)Select frequencies on VHF&UHF and options (tones, DUP,...);
2)Set "key lock" by pushing [F]+[C] keys. Then turn radio off;
3)Push [F]+[MONI]+[RPT-M] keys and while holding them pressed, turn radio
on. You will get flashing "L", telling you cross band rpt. is enable.
4)Press [F]+[C] ("key lock" release) and you will clear the cross band rpt. 
mode.

-------------------------------------------------------------------------------
  Ulrich Kienzle   (ulki@hpbbn.bbn.hp.com or dl1sbl@db0sao)
  Hewlett-Packard Mechanical Design Division R&D, Boeblingen, Germany
  Phone: +49 7031 14 2893   FAX: +49 7031 14 2049
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