Newsgroups: rec.radio.amateur.misc
From: wtm@uhura.neoucom.edu (Bill Mayhew)
Subject:  Here is MARS/CAP expansion for Std. C528A or Hth. HW-24-T
Message-ID: <1993Jul17.115415.14940@uhura.neoucom.edu>
Summary:  Opening radio / soldering NOT required.
Organization: Northeastern Ohio Universities College of Medicine
Date: Sat, 17 Jul 1993 11:54:15 GMT
Lines: 97


Here is a copy of the original sheet form Heathkit.  The ht-24-t is
abosolutely identical to the C528A.  Both are manufactured by
Marantz of Japan.

Note:  I did not need to press reset before entering the
modification sequence.  The memories I had programmed stayed
intact.

Note:  If you change UHF bands, the contents of whatever memory is
up when you change bands may be modified.  Be sure to change to VFO
mode before changing bands.  The radio transmits anywhere, excpet
for the 800-900 MHz region.

Note:  You need an apropriate license to transmit on the freqencies
enabled by the expansion process.  Unauthorized transmissions may
be lead to undesirable attention, emberassment and action by
unsympathetic government agencies.  In some locations, it may not
be lawful to montior and/or disclose content of trnasmissions in
the 800-900 MHz region.  Use discression.

Note:  Not responsible for scanning errors in text below.  This
came from the original Heath sheet and I've checked it carefully.
Use at your own risk.

Question:  Does anybody know if there is a function code on the
C528A that enables muting of the speaker on the opposite band when
transmitting? I am interested in using the radio on UHF/VHF split,
and want to avoid audio feedback.

73,
Bill

    ------------------- begin included text ------------------

               HEATH COMPANY TECHNICAL ASSISTANCE
                  BENTON HARBOR, MICHIGAN 49022
                          616-982-3296


             MARS and CAP modification for HW-24-T


Dear Customer:

In order  to  modify your Heath HW-24-T handheld  transceiver  to
transmit  out  of  band, please enter the code  below  from  your
keypad. After the code is entered you can use your transceiver to
transmit on the CAP and MARS frequencies.

Please  keep this modification procedure in a safe place. If  you
ever  reset  your transceiver, you will need to  enter  the  code
again.


-- Push RESET
-- Press FUNCTION (hold) and 0
-- Press FUNCTION (hold) and ENT
-- Press PTT (briefly)
-- Press UHF
-- Press FUNCTION (hold) and L (lamp)
-- Press FUNCTION (hold) and 0
-- Press FUNCTION (hold) and CODE
-- Press FUNCTION (hold) and L (lamp)
-- Press FUNCTION (hold) and 3
-- Press PTT (briefly)
-- Press VHF
-- Press FUNCTION (hold) and STEP
-- Select 12.5 KHz (with rotary selector knob)
-- Press PTT (briefly)
-- Press FUNCTION (hold) and 8
-- Press FUNCTION (hold) and 8
-- Press FUNCTION (hold) and 7
-- Press FUNCTION (hold) and 7
-- Press FUNCTION (hold) and MS.M
-- Select 144.9875 MHz. (with rotary selector knob)
-- Press FUNCTION (hold) and 0
-- Press FUNCTION (hold) and ENT
-- Press PTT (briefly)
-- Press FUNCTION (hold) and 0
-- Press FUNCTION (hold) and MS.M
-- Press PTT (briefly)

In addition to transmitting out of band, you can also receive the
frequencies  between 300 - 400 and 800 - 900 MHz. To do this  use
the code below.

-- Press UHF
-- Press FUNCTION (hold) and SET
-- Press FUNCTION (hold) and 3 (this will select bands)


---- end of included text ----
-- 
Bill Mayhew        NEOUCOM Computer Services Department
Rootstown, OH  44272-9995  USA      phone: 216-325-2511
wtm@uhura.neoucom.edu       amateur radio 146.58: N8WED