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