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Back to Home 		  The Motorola® Spectra™
Mobile Radio Page
Including non-mobile Spectra-based products
By multiple authors
edited by Mike Morris WA6ILQ 		  Print this Page


The Spectra line was MD'd (Manufacture Discontinued) a few years ago, and depot maintenance was terminated recently. Many public safety agencies nationwide are being forced into new radios (if they stay with Motorola it's usually the MCS2000 series) and the Spectras are showing up in surplus in large quantities. Once you replace the "time bomb" capacitors (under US$10 in parts, see the article "Recapping the Spectra mobile" below) you can end up with an excellently performing mobile radio at a decent price (new they were $1500 to $2000 each, sometimes higher, depending on the options). And the intermod performance alone is many times better than any Japanese-built amateur grade radio.

The Spectra radios transmit and receive signals that are 5 kHz wide on VHF, UHF, and 800 MHz. On 900 MHz, the bandwidth is only 2.5 kHz. This can NOT be changed in software. There's no "switch" or any mode-specific setting. You might be able to increase the transmit modulation level by adjusting the radio and/or modifying it. The receiver's bandwidth is controlled by small bandpass filters that are not easily replaced.

The Astro Spectra was a follow-on design that used most of the cosmetic parts and accessories, but was very different inside. One of the differences was a much more powerful microprocessor that suported digital audio in multiple formats like VSLEP (Moto proprietary) and IMBE/P25 (the "Project 25" digital audio standard that is supported by several manufacturers). Be very careful when purchasing any surplus Astro product. A good percentage of the surplus stuff hitting the market is not IMBE but older (proprietary) VSELP modulation and some of the radios are flashed (i.e. contain firmware) for analog only (i.e. won't do digital at all). Since VSELP is not an open standard the popular opinion is it's not legal on the amateur bands much like GE / Ericsson / Ma-Com AEGIS and Pro-Voice. The only way to tell is check the flashcode, and once you have that you will need to find someone with the flashcode feature list. If the seller can't provide the flashcode just walk away from the deal... no point in buying something that may end up as useful as a paperweight.

If someone has that flashcode feature list, and it's legal to post, please send it in and we will put here in a new article. If you what to write that artice, even under the name of A. Nony Mous, that's fine too. He (or is it she?) has written a number of articles for this web site.

If someone wants to do a generic Astro writeup (i.e. Spectra, Saber, etc) we will be happy to add it to the Moto page. If they'd rather limit their contribution to the Astro Spectra alone we'll put it here as an article. If they'd rather limit their contribution to the Astro Saber then it will go on that web page.

When I get them, I'll insert photos (either individual or both in one photo) of an A2 and an A3 radio here. Anybody want to provide photos?


An A4 base station on top (the left knob is Mode, the right knob is Volume)


An A5 mobile


An A7 mobile
All of the above have 8 characters in the display.
And yes, the A4 and A5 also light up at night (that photo was taken in the daylight).


A DEK on top of a A9 head. These heads have 11 characters in the display.


An A7 Spectra desktop base station (without microphone)
These units have an internal power supply, and there are UHF repeater versions with two radio chassis and a mobile duplexer inside. However as a repeater they have the normal mobile limitations on transmit duty cycle. The photo of this particular one was taken with it sitting vertically on the back of the cabinet. The black dot under the "Power On" light is the secure keyloader (i.e. encryption) connector. The white square knockout to the right of center is for the clock option. Motorola also refers to sets with Astro radios as Consolettes. A similar version containing one or two MaxTracs would be called a DeskTrac. Internal photos of a similar unit show what looks like a PC power supply, a fan, an interface board (tone remote control or analog wire-line), and an Astro Spectra remote mount mobile radio. Click on the links below for more photos.
Top view     Rear view of the control panel     Rear of the radio showing the antenna jumper and the wireline control board
You should read the Spectra Desktop Station article at the end of this page for more detailed information.




An A7 Spectra tabletop base station - speaker-box-under-a-mobile type (with mobile microphone) These units use an external power supply that is larger than a red clay brick.
The Spectra desktop base tray is the HLN5309 and has a speaker in it, where the MaxTrac and GM300 use the HLN5292B tray - it's identical except that it is missing the speaker.
The Spectra version parts list is here.


The photo shows two 900 MHz radios. The joint between the heatsink and radio chassis is easily seen. The 30 watt heatsink is longer and the connectors are oriented on the top of the heatsink rather than on the back, as they are on the low power heatsink. The size (depth of the radio) difference really isn't more than 2 inches, if that. See the "Programming cable" article below for more information on the accessory jack. On the power connector the exposed pin is positive.


This photo shows a complete low-power / mid-power mobile radio kit, with control head, a mounting bracket, a coiled up control and power cable kit, microphone, speaker, and control head. This particular kit has an A7 head (the full keypad on the right side of the head).


This photo shows a complete high power remote mount mobile radio kit, with a control head, a head mounting bracket, coiled up control and power cables, mike and speaker. Not visible is the radio tray that is bolted to the vehicle. This particular kit has an A9 head.

   

A rather interesting Spectra. This is what is used in railroad locomotive cabs. There is no mobile microphone jack, the engineer uses a handset plugged into the rightmost connector on the rear. The SO-239 antenna connector is under the cover on the top left connector in the photo of the rear of the radio. The big red cap at the bottom left is the DC power input connector, and has multiple pins. Specific wiring of the mating connector selects 12, 36 or 72vDC, negative or positive ground operation... there is no voltage select switch to set improperly. Most modern locomotives are 72vDC, the 12vDC mode is used in trucks or on the repair bench. This particular radio is a MBR43KME1170AD. The leading MB indicates Canadian manufacture, the R in the R43KME indicates Railroad.


K6CCC's truck control group (looking down at the console from head height)... From the top is a MCS2000 on 900 MHz (the shop radio), a Syntor X9000 on 800 MHz (using a type 9 head), three Spectras on 482-512 MHz, 450-482 MHz (both with type 7 heads), and a 146-174 MHz on a type 5 head. To the right are a pair of Midland Syntechs on low band. The Syntor, Spectras and Midlands are used for state and local gov't, law enforcement and fire communications. Amateur radio communications utilize a few frequencies in the high band Spectra plus an overhead-mounted Kenwood 742 on 220 MHz, 440 MHz and 1200 MHz. The truck in the photo is a 1986 Toyota pickup that was recently retired after 300,000 miles. The radios are going into a new truck.


FAQs not answered / handled:
1) How to use the wrong head on a radio (i.e. using an A5 head on an A4 radio, or an A4 head on an A7 radio, etc). Also, how to straighten out a mismatch (This is a candidate for a bit banging article on how to change the control head type, from what I've been told it just requires changing the model number in the MLM and the Command board in two different memory locations and you're all set).
2)How to crack the model number / ID number... Full, current model number information doesn't seem to be available. There is a partial chart below that has been reverse engineered. Some spectras have both an "ID Number" and a new format "Model Number" in the format of "TA9KX-068W" and nobody seems ot have a breakdown chart on that format number.
3) There is an early Spectra and a later Spectra II; apparently the latter gives SmartZone capability for trunking systems and uses a different command board (E-series) which does NOT have a separate MLM (memory logic module).


Mike Blenderman K7IC has a very extensive web site on Spectras, and there is no point in duplicating his effort here at Repeater-Builder. This web page is only going to cover topics that are not covered at Mike's site. I really suggest that you go to Mike's site first (and bookmark it) as the topics there include:

From a ham's point of view, the A7 radio is probably the most desirable, as it's a (usually) 128 channel conventional radio (i.e. not trunked) and has the 12-button 8-character display control panel/control head. If you are going to use a remote mount radio (i.e. the radio chassis is in the trunk), and have the dash space, then the A9 control head may interest you as it has 3 more characters on the head display plus you can use a DEK. The type 7 and type 9 heads will generate 12-button DTMF, there never was a 16-button DTMF model made. If you need 16-button DTMF then use a Motorola touchtone microphone and modify it as per the Jim Reese WD5IYT article (on the Motorola index page), or use a Midland or Johnson 16-button microphone and modify it for the Motorola microphone circuitry (and with a Spectra microphone cable and plug).

Spectra Model Chart (partial)
Sample model number: D44ZXA5JC7AK
D 4 4 Z X A
Radio Type Power Level Band Split Unknown System Operation Supply Voltage
D Dash 1 <10 W 1 Low Band VHF F ? G Trunking A 12v [1]
L Consolette 2 15 W 2 Mid Band VHF K ? M Conventional  
M Motorcycle 3 30 W 3 High Band VHF V ? X SecureNet
T Trunk 4 45 W 4 UHF Z ?  
Z Special 6 75 W 5 800 MHz  
  7 100 W 7 900 MHz
8 110 W
If anyone has the breakdown of the fourth column ("Z" in the table above), we'd appreciate the information.

5 J C 7 A K
Operational Mode Model Specific Control Version Control Type Version Package
5 Trunking J Model Specific A Conventional 2 Limited A K [4]
7 Conventional   B Privacy Plus 3 HHCH [2] B  
  C SmartNet 4 Rotary C
D StarSite 5 Standard (3 Button) D
E Note [3] 7 Expanded (12 Button) E
  8 Expanded Control Station  
9 Systems 9000
[1] Positive or negative ground.
[2] HHCH = Hand Held Control Head.
[3] Enhanced or SmartZone, depending on which book you read.
[4] Shipped with the standard mobile installation kit.

The following table was extracted from the Feature Matrixes in the Spectra 900/9000 Basic Service Manual, 6880101W37-C, for 4, 12, and 30 watt, 900 MHz mobile radios. Entries in the table with no revision letter came from the matrixes in the front of the manual. Entries with a revision letter (A, B, C, D, or E) came from an appendix that has additional feature matrixes based on the 11th character of the radio's model number. The 12th (last) character is always 'K' in these charts.

In the table below:

Head Rev. Conv. Sys. Flt.
A5 # 128 0 0
A5 A, B, C 32 0 0
A7 # 128 0 0
A7 A, B, C 64 0 0
A9 # 128 0 0
B2 #, A, B 0 2 2
B5 # 10 10 10
B5 A, B 0 3 8
B5 C, D 1 6 8
B5 E 10 10 10
B5 F 128 10 10
B7 # 10 15 10
B7 A, B 0 8 8
B7 C, D 10 8 8
B7 E 10 15 10
B9 # 10 15 15
B9 A, B, C, D 10 8 8
B9 E 10 15 10
C2 #, A, B, C 10 8 8
C5 #, A, B, C 10 8 8
C7 # 10 15 16
C9 # 10 15 16

The 9th character specifies the trunking/coding style:

The 10th character specifies the type of control head. All of these control heads have rocker buttons for MODE and VOLUME and an 8-character 14-segment display unless otherwise noted:

An E7 radio was capable of 10 conventional modes and 15 systems of 16 sub-fleets each. After deleting all but the last trunking system and its modes, I was able to increase the number of conventional modes to 128, but I didn't try filling them all.

There's only so much codeplug space in the radio; each trunking system reserves space for all of its sub-fleets, whether they're utilized or not. You can increase the conventional mode space by giving up some trunking mode space, on those radios that support both.

Spectra and Astro Spectra compatible microphones:
The A9 / W9 / Series 9000 head, has its microphone jack on the rear of the control head. It's still a six-pin connector, but it is oriented vertically rather than horizontally. All of the Spectra microphones plug into either front or rear connectors. All of the mobile microphones are hand-size; there are no palm-size microphones (such as the HMN1056D that's common with MaxTracs; see the comparison photo in the Motorola section of this web site). A list of known Spectra-compatible mikes is shown below. If anybody knows of others or wants to contribute schematic scans, let Repeater-Builder know.

Spectra Mobile Power Consumption:
Model Series Standby Receive Transmit
D43 (High Band 25-50w) 0.5A 2.5A 13.0A
T83 (High Band 110w) 0.6A 3.6A 27A
D14 (UHF 4w) 0.5A 2.5A 3.5A
D34 (UHF 25w) 0.5A 2.5A 6.5A
D44 (UHF 45w) 0.5A 2.5A 12.5A
T84 (UHF 100w) 0.6A 3.6A 31A
D45 (800 MHz 35w) 0.5A 2.5A 13.5A
D17 (900 MHz 4w) 0.5A 2.5A 4.5A
D27 (900 MHz 12w) 0.5A 2.5A 7.0A
D37 (900 MHz 30w) 0.5A 2.5A 14.5A
NOTE: "Standby" implies receiver squelched. "Receive" is the power consumption at maximum volume setting and with white noise.
With the System 9000 control head, all the current drains increase by 0.2A due to the additional segments on the display and additional computer components.

Other Notes:

Programming

If RSS or the RIB is a new topic to you I suggest that you see the RSS and RIB pages at this web site.

Programming 2m and 440 MHz amateur frequencies is no problem as VHF range 1 covers 2m and UHF range 2 covers 440 MHz. However to program 900 MHz amateur frequencies into the radio you will have to hex-edit one file in the RSS package: "spectra1.exe". Instructions are available in an article below. If you have a remote mount / trunk mount radio the programming has to be done to the head and the radio separately. Also the VCO might need to be modified slightly (definitely necessary for 900 MHz radios - see article below).

If you plug a programming cable into a Spectra, and the RIB is attached but not powered up, the radio will do all sorts of strange things, like turn on and off and display some error codes, when you turn it on. You'll think you have some bad connections. The RIB loads down the BUSY and BUS lines and confuses the radio. The solution is to apply power to the RIB before attaching it to the radio. The Spectra has a switched +12v pin in the accessory / programming connector that (among other things) was intended for powering the real Motorola RIB (RLN4008 series) through the programming cable (the DB25F connector on the RIB).

Mounting Bracket
The Moto part number HLN5015 is the dash-mount mobile mounting kit, containing the bracket, some loose hardware, the power cable, with fuse holder and speaker connection. Part number 0780086N01 is the bracket only.

Display Font
If you look at the A9 - DEK control head photo at the top of this web page, you may notice that there is no decimal point character in the control head "font"... just alphabetics, numerics, a space and these characters: < > ? / \ @ * ( ) - and the + sign. You would really expect the decimal point / period character to be there, since you would expect to be able to display frequencies (like "146.46" or "449.000") but it's not. Bob WA1MIK took the time and programmed every keyboard character into the RSS and loaded the strings into an A7 radio; there's no way to display a decimal point. If you program the keyboard decimal point into the RSS it displays as a backslash. The nearest you can get to a decimal point is the "-" (hyphen) or "=" (equals character), the latter shows up as an underscore. Or do without and live with "14646", "146-46" and "449000". Or use names for the channels like it was intended: "Simplex 2" and "Sunset 3". Interesting enough the "[" character (the left square bracket) can be used as a display segment test as it is translated into an "all segments on" character.

The reason you can't get some characters is that each position of the display is formed with 14 segments: one horizontally at the top and bottom, two horizontally in the middle, one each vertically at the upper left, upper center, upper right, lower left, lower center, and lower right, and four that go diagonally in an "X" pattern. There's just nothing there for a decimal point or lower-case letters. Here's part of a page from a Kenwood TK-981 manual that shows the possible display characters. It's similar if not identical to the Spectra:

Splits / Ranges
Spectra's come in many frequency bandsplits, called Ranges. Below is a list of the available ranges for VHF and UHF.

In order to determine the range of any particular radio you will have to do one of two things:
1) Read the radio with RSS (which may not work, see below)
2) Open it up and look at the part numbers on the RF modules.

Using a frequency counter to tell where it's transmitting will do no good. For example, if it was transmitting on 157 MHz (actually anywhere from 146 to 162) you could not know which of the two VHF ranges it was in without opening up the radio and looking at the part numbers on the modules. And it could have had a wrong range code plug stuffed into it or been programmed with a modified RSS... several eBay sellers have been discovered selling 403-433 range radios with a 460 MHz range code plug programmed into it, and 132-150 MHz radios with a 155 MHz code plug.
In short, the only way to really tell is to look inside and read the module numbers.

There never was a low band Spectra. The nearest to it is the trunk-mount low band Syntor X-9000 and I have it on good authority that only 1,500 of those were ever made. They are in demand by emergency responders as they will do 25-54 MHz in one range, and when coupled to an autotuning screwdriver antenna can do drastic changes in frequency while in motion (like switching from a 39/43 MHz CHP repeater pair to the Red Cross 47.42MHz frequency).

Very few high power remote mount / trunk mount Spectras were made in UHF Range 2 - that particular factory configuration is a good example of pure unobtanium... Several have been field assembled (and sold to unsuspecting hams) by taking a front end and exciter from a dead Range 2 front mount radio and installing it into a Range 3 trunk mount radio, and then telling the radio it's a Range 2 but the transmitter performance drops off drastically as you head towards 440-445 MHz.

All the high power radios are remote mount / trunk mount only.

Converting a Dash Mount to a Remote Mount
To convert a dash mount radio to a remote / trunk mount you will need a HH1446A, HH1447A or HLN6008A Remote Mount Field Retrofit Kit which contains all the parts necessary. I have no idea what the differences are between the three kits.

A detailed service manual covering most models of the conventional and trunked Spectras is Motorola part number 6880102W61 at about $45. Naturally, it's No Longer Available (NLA) from Motorola, but legal reprints are available from other sources.

Spectra articles and files here at repeater-builder:
(If you don't see what you are looking for, don't forget to check Mike Blenderman's site). Or if you have some information to share, repeater-builder is always looking for article donations.

. Spectra Sales Brochure An original Motorola catalog sheet with abbreviated specifications. 674kb PDF.

. Spectra Motorcycle Spec Sheet An original Motorola spec sheet with photos and abbreviated specifications. 189kb PDF.

. Spectra Conventional Radio System Operators Manual   Motorola manual part number 6881071C55. 4mb PDF.

. Spectra Parts Catalog 1mb PDF, and another version Spectra Parts Catalog. 240kb PDF.

. Info on the new Moto railroad locomotive cab radio based on the Astro Spectra. 140kb PDF.

. DEK schematic. 614kb PDF.

. One approach to adding a COR Signal to the Spectra DB-15 Accessory Connector By Nick Markovich N2XFX

. Spectra Control Head Ignition Jumper Information by Robert W. Meister WA1MIK

. Why a 900 MHz Spectra Won't Receive at 902 MHz and What You Can't Do About It by Robert W. Meister WA1MIK

. Interfacing External Equipment to the Spectra Mobile Radio by Robert W. Meister WA1MIK

. Recapping the Spectra Mobile (a.k.a. the Time-Bomb Capacitors) by Robert W. Meister WA1MIK

. Build Your Own Spectra Low-power and Medium-power Programming Cable by Robert W. Meister WA1MIK

. Build a Spectra Low-power and Medium-power DC Power Cable with Ignition Control by Robert W. Meister WA1MIK

. How to Hex Edit the Spectra RSS to Enable 900 MHz Amateur Frequencies by Robert W. Meister WA1MIK

. Spectra 900 MHz VCO Modification by Robert W. Meister WA1MIK

. Adding a Preamp to a UHF Spectra Radio by Robert W. Meister WA1MIK

. Miscellaneous Spectra Topics by Robert W. Meister WA1MIK

. The Spectra Desktop Station by (who else) Robert W. Meister WA1MIK

. Spectra Dash-mount Control Head Interconnect Boards by (yet again) Robert W. Meister WA1MIK

. Intro to Spectra Radio Configurations by (yup, you guessed it) Robert W. Meister WA1MIK

. Setting up and using Multiple Coded Squelch (MPL) by (tired of being a lonely author) Robert W. Meister WA1MIK

. Spectra Error Codes by (finally running out of things to write about) Robert W. Meister WA1MIK

. Spectra Hacks (Bitbanging) by James S. Vooght K2JSV     


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The photos of the A5, A7, two 900 MHz PA decks and the speaker-box-under-a-mobile photos are by Robert W. Meister WA1MIK and copyrighted by him.
The A9 / DEK head photo is by Scott Lichtsinn KBØNLY and copyrighted by him.
The Desktrac station photo supplied by A. Nony Mous.
The photo of K6CCC's truck radios by Jim Walls K6CCC and used with permission.
Artistic layout and hand-coded HTML © Copyright 2005 and date of last update by

Motorola® and Spectra are registered trademarks of Motorola Inc.

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.