The Motorola MT500 Series Index Page

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Back to Home The Motorola MT500 / PT500 Series of Hand-held and Portable radios
compiled by Mike Morris WA6ILQ
Maintained by Robert Meister WA1MIK

An eight frequency PL model.
The PL/Carrier switch is in the lower right corner
An eight frequency PL and scan model.
The Scan/PL/Carrier switch is in the lower right corner

Does anyone have an original brochure or catalog sheet for the MT500 or the PT500?

The MT500 was the follow-on radio to the HT220 handheld, was first introduced in February of 1977 and used many of the existing accessories. The MT500 series was produced for only a few years before the MX series was introduced. The MX was the primary handheld radio during the period that saw the end of the crystal controlled radios and the introdution of the synthesized radios.

Like the HT220 the MT500 came in two versions - Slim-Line (sometimes called "Basic") and Omni (sometimes called "Universal"). The Omni / Universal models are thicker, allow larger (higher capacity) batteries and have a speaker-mic connector on the side, while the Slim-Line / Basic models has the jacks for speaker/earpiece and antenna on the (crowded) top of the radio. The additional thickness allows for a second layer of circuit board(s) for optional features - additional frequencies, higher power PAs, or even a multichannel scanner.

Speaking of antennas, here's a cross-reference list (7kb PDF) that lists and identifies the various units.

An additional difference is that the both the Basic and Universal radios came in two different heights of cases - short and tall cases. The additional 5/8 of an inch was used for smaller options like PL.

Since the PT500 is a MT500 in a "lunchbox" case with a big pack of "D" flashlight cells ora rechargeable battery (very popular with railroads, pipline crews, road crews, etc) those folks working on the PT500 radios will find the handheld manuals useful. Click here for an oblique view photo of an 8-channel PT500. Click here for a top view photo of an 8-channel PT500.

There used to be a web site at www.mt500.com that had a great deal of information on these radios but it went away in mid-2003. Also, there used to be a web page that gave information on the channel elements at http://users.leading.net/~radiotr/MT500 but it's gone also. If anyone knows who ran those web pages we'd be happy to talk to them about rehosting their information.

Like other Motorola radios of that era the MT500 RF section comes in multiple frequency ranges or splits for each frequency band. Unfortunately the split is not encoded in the model number.
For low band, the published splits are 30-36, 36-42 and 42-50 MHz. The manuals don't mention a 25-30 Mhz range but I've seen one on 26.62 MHz (a media remote pickup channel) and several folks that I trust have told me that they were available in a 25-30 MHz split.
Supposedly there were mid band MT500 radios for Europe. If so, they would probably be in two splits, 66-77 and 77-88 MHz.
For high band there are three splits, 136-150.8, 150.8-162, and 162-174 MHz. I've seen several MT500s on US Navy Shore Patrol channels in the 140-141 MHz.
For UHF there are four splits, 406-420, 450-470, 470-490, 490-512 MHz. There were some SP radios on 512-524 MHz during the 1984 Olympics here in Los Angeles.

Where the prior models (the HT200 and HT220) used crystals the VHF and UHF models of this radio use small "Channel Element" in the receiver and transmitter, the low band MT500s continued to use crystals. A channel element is a plug-in module containing the crystal and a complete temperature compensated oscillator followed by a tripler-buffer. The multiplier chain following the channel element multipies up to what the exciter or receiver mixer needs. BTW, the transmit elements (either a KXN1083A or a KXN1042A) have five pins and the receive elements (KXN1075A) have only three pins. The crystals themselves are in a HC-49/X package.

Like all crystal controlled radios the MT500 radio is power miser, especially in receive. The average draw is about 11 milliamps squelched and 70 milliamps at a loud volume. In transmit the low power MT500 radios draw about 450 mills, and the high power radios draw just about an amp. Synthesized radios draw much, much more power. The 11 ma idle drain was a big selling point to the US Forest service for their firetower radios that ran on storage batteries.

The serial tag on the back of the radio

The MT500 Model Number:

Numbers that are in [brackets] refer to notes at the bottom of the tables.

Sample model number: H34BBU-3184AN

H 3 4 BB U

Radio Type Transmit
Power Frequency
Range Series Feature Set

H
Hand-
held

or

Z
Special
Product [8] 3
66-88 MHz:
?

146-174 MHz:
2 W

403-470 MHz:
1.5 W 1
30-50 MHz BB
MT500 B
Slim Line / Basic
(Thin Case)

4
25-50MHz:
6 W [1]

66-88 MHz:
?

136-174 MHz:
5 W

403-512 MHz:
4 W 2
68-88 MHz
[2] U
Omni / Universal
(Thick Case)

3
136-174 MHz

4
403-512 MHz

Sample model number: H34BBU-3184AN

3 1 8 4 A N SPnn

Squelch Bandwidth [4] Channels Variation [5] Revision [6] Shipping Package [7] Special [8]

1
Carrier
Squelch 0
Wide Band
(15 Khz
Deviation
Very Rare!) 1
Single channel 0 A (blank)
a warranty replacement radio,
shipped bare (no battery, antenna, etc.) SPnn

2
2-tone
paging
decoder [3] 1
Narrow Band
(5 Khz) 2
2 Channels 4 B A
Shipped with Alkaline battery and antenna

3
PL
squelch 4
4 Channels C N
Shipped with Nicad battery and antenna

6
6 Channels D ?
There was an option to ship with a Mercury battery and antenna. I don't know what that code was.

8
8 Channels E

Notes:
[1]: There was no low power low band radio that I know of. The 41 series radio produced 3 watts on a 12.7 volt Mercury battery or 6 watts on a 15 volt NiCD batery.
[2]: I've never seen a mid band (66-88 MHz) MT500 or the book for one.
[3]: I've been inside a 2-tone radio to change the reeds. It was a -2110CN and the radio was not an SP radio.
[4]: This is the 1960s-1980s definition of narrowband. These days it's considered wideband.
[5]: I have no info on the translation of this column. I've seen radios with "0" and "4".
[6]: Think of this as the hardware version. You need a "C" radio or later to run DPL.
[7]: This column was dropped on some serial tags (like the one shown above).
[8]: a -SP suffix specifies that the radio was a Special Production (or Special Product, or Special Purpose, take your pick...)... If a radio model number ends in SP followed by any number or numbers then it was a special factory modification. It could be as simple as a yellow or orange case for a railroad or it could be a special IF frequency, or a special channel count or dual PL or... You would need the exact manual (or manual supplement) to know what is going on with any but the most obvious SP radio.
If the first letter of the model number was a "Z" then the radio was part of a special production run, not a modification of a relatively small number of radios.
And some were shipped with "-SPnn" suffixes and some with "SPnn" (with out the "-") like shown above.

The MT500 Manual Library:

We have a number of MT500 manuals courtesy of Brian Alesio, Skip Clark, Eric Lemmon plus a few that are anonymous....
Click here to go to the list...

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This page originally posted on Monday 30-Sept-2011

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.