Version 3.2 14th October 2005



There are six main 143 – 156 MHz  wideband boot mobiles, which have been used by Police & Fire brigades in Great Britain since approximately 1986 through to the present day.  All with approximately output power of 25 watts. AM or FM switchable.

1. Marconi.
RC675/07  240 channel 12.5 KHz spacing AM / FM.
RC675/04  16 channel 12.5 KHz spacing AM / FM.
P Band 79 – 102 MHz earlier version.
Originally made by GEC McMichael in Slough.

2. Marconi.
RC690  256 channel 12.5KHz spacing AM only.
RC640  99 channel 12.5KHz spacing FM only.

3. Burndept
BE536MU       400 channel 12.5KHz spacing AM only set.
BE544MU       400 channel 12.5KHz spacing AM / FM set.
BE540MU       10 channel 25 KHz spacing UHF FM repeater set.
BE540CU       400 channel repeater VHF-UHF control box.
BE536CU       400 channel control box.
BE536LPCU  2 channel remote control box, waterproof.

Cleartone MB7000  256 channel 12.5KHz spacing VHF-UHF AM / FM.
For motorcycle use, using slim line vertically mounted flush green red button control box.  For VHF-UHF talk-through only.
Combined UHF 99 channel talk-through system.
(Circa 1990 plus).
Cleartone CM7000/A4 256 Channel 12.5 KHz spaced VHF-UHF AM/FM.
For vehicle use using horizontally mounted flush green red button control box.
For VHF-UHF Talk-through and UHF-UHF Talk-through.


CM7000RP / CM7500RP 12.5 KHz VHF-UHF & UHF-UHF Repeaters
Desktop mounted VHF-UHF repeaters using CM7000FS VHF AM/FM mobile unit and two CH650 transmitter-receiver units as a 5 watt UHF-VHF talk-through unit with fitted internal duplexer.  No 2 metre or 70 cms conversion available yet.

Desktop mounted VHF-UHF AM/FM repeaters using CM7000FS VHF AM/FM mobile unit and two CH650 UHF Tx-Rx units as a 5 watt UHF-VHF talkthrough unit with fitted internal duplexer.  No 2 metre or 70 cms conversion available.


Programming Instructions for Early  Cleartone CM7000-CM7500 VHF-UHF mobiles.

All of these sets are now becoming obsolete due to TETRA & trunked public radio systems coming on line since 2001, starting in Lancashire.  Most recently (November 2000) a large auction took place, organised by RAMCO of Skegness Lincolnshire, of Metropolitan Police and others VHF-UHF radio schemes.  Several second-hand radio dealers, e.g. Richard Allport Comms PMR, have been selling large quantities at radio rallies in England and Wales.  This is only the tip of the iceberg, as other forces and brigades start to (hopefully) dispose of there analogue VHF-UHF schemes. 

Fire Brigade schemes (in England and Wales) are exclusive Low Band. 70.5 - 71.5 MHz receive.  80.0 - 82.0 MHz transmit.  Using Low Band  wideband versions of the Marconi & Burndept sets. 

All of the above sets are  EPROM'ed varicap synthesized for wideband frequency 143 –  156 MHz including 2 metres.  70 –  72 MHz and 80 – 82 MHz transmit & receive including 4 metres so to convert them to 2 or 4 metres requires virtually no tuning other than EPROM replacement.

Also keep a look out for these sets fitted in transportable suitcases, used as emergency portable base stations and talk through systems.  These suitcase sets are usually in mint condition having not had a policeman’s or fireman’s boot placed on them!  Or fixed station sets built into RS boxes desk mount.


The Marconi RC675/07  143 - 156MHz AM - FM.  Boot mounted mobile 240 channel.

Beware!  RC675/04  79 MHz – 102 MHz P Band old police band sets look identical to the RC675/07 version - read the serial plaque carefully.  These are only good for donor bits to mend High Band version.

Beware!  There are two control boxes...................

MTR110 is 16  channel only
MTR111 is 240 channel and is noticeable by the extra BCD type switch inserted on the front panel of the control box labelled 1 to F.

The 16 channel control box can be modified with a 15 way BCD type switch which can be found surplus at rallies and in junk boxes.

There is one EPROM to change to put the set straight on 2 metres AM & FM switchable 12.5 KHz channels.


The Marconi RC690 256channel 143 – 156 MHz & 71 MHz AM only.

Some 9750 RC690/A1 sets for Simplex were bought in 1985 – 1986. 
High Band 2500 RC690/A2 Duplex VHF-VHF repeater sets were also bought.
950 RC790/A3 fixed station mobiles High Band & Low Band.
6100 RC690/B1 Fire Brigade Simplex sets bought for use on Low Band.
275 RC690/B3 for the VHF section of VHF-UHF repeater Low Band .

Marconi RC640  99 channel 143 – 156 MHz FM only.  Used by Metropolitan Police.  One internal battery backed ram memory chip for frequencies, if removed from socket goes blank almost immediately.  An ESQUARED PROM / EPROM can be put in place to bring set onto 2 metres using a 2716 EPROM.

As the RC690 is AM only and its control box is difficult to change channel fast due to having to press the *  button and enter channel number required.  It is a poor set to put on 2 metres.

Marconi RC790 is a RC690 in two base station 19 inch rack trays, which will only have 99 channel capability.  The second tray holds a 12 volt Switched Mode PSU that powers the RC690 in the first tray.

The RC640 is a shorter boot mounted set but looks the same as the RC690.  It is FM and channel change on similar control box method to the rc690.  But can only be used on 99 channel 12.5 KHz.  160 channels are required to cover 144 – 146 MHz 12.5 KHz spacing.



BE536MU 400  channel AM only 143 – 156 MHz and 71 MHz.  Some 2000 sets bought
BE540/A4  VHF-UHF repeater mobiles.  Some 3250  bought circa 1985
BE544MU  400 channel AM / FM  143 – 156 MHz and 71 MHz.
    Probably the nicest sets to mod for 2metres.
BE536MU  AM only.  But easily modified to FM by adding 10 components to the existing unused FM discriminator chip and noise limiter IC.  Makes the receiver AM / FM switchable or FM only.  Change two EPROMs IC315 and IC314 for 2716 PROM or 2816-2817A E2 PROMs and it will come straight onto two metres.

Transmitter easily can be converted to FM by feeding attenuated AM audio into the synthesized oscillator and hence wobbling it up and down.  As per the standard conversion of a Burndept-DYMAR M2080 synthesized set 256 channel capability with easy to push up and down flip switches.  See more detailed conversion notes at the end of this article.


BE544MU  AM / FM version  400 channel   *** GOLD STAR RECOMMENDED ***
Identical set to the BE536MU but dual mode AM / FM. 

No conversion required.  Change the 2 EPROMs or 2764 or reprogram the two fitted E2 PROMs and it will go straight onto two metres.
Both sets can be used with the BE540 VHF-UHF talk-through control box, to give a crossband 2 metre / 70 cms repeater facility.  If used with a Pye w15ut talk-through Westminster UHF or a BE540  20 watt 10 channel crystal controlled Westminster replacement set.
Ideal for RAYNET purposes......
If you have no EPROM’s available to put the set on a 2 metre frequency, you can fit in the EPROM sockets two 8 way bit switches and switch the address lines up and down to get the synthesizer on to 2 metres, to test the set and control box out OK.  A toggle switch can be fitted to switch AM / FM per channel or why not have 128 channels AM and 128 channels FM in pre programmed EPROM’s.


Cleartone MB7000  256 channel AM / FM  VHF/UHF mobile system.
(motorbike mounted)

Cleartone CM7000.A4 SAME SET
(Vehicle mounting.)

1990’s boot mounted mobile system.  One of the much later sets based on the CM7000. which comes fitted with two CH650 99 channel portable sets (less batteries) transmitter-receiver units.  One is receive only on UHF 99 channels.  One is transmit only on UHF 99 channels.  And one Cleartone CM7000 boot mounted set VHF 143 – 156 MHz AM / FM set.  All this in one black crackle finish enclosure boot mounted set, to give talk-through VHF-UHF and UHF-VHF.  2 metres – 70 cms.

The accompanying Control Boxes are very flash in red-green/red white with no protruding knobs, all flush touch buttons.  If the control box to boot set lead is missing, a standard VGA monitor lead female to male will work instead.

But BEWARE Pins 6 and 7 may have to be REVERSED in such a lead in order to work with some CM7000-CM7500 sets.  The fault will manifest itself as the set appearing not to power up properly and lighting up control box all lights together.

There are E2PROM’s to change.  One in each portable set and one in the main set.



B:    A PM100 Programmer which looks like a CH650 but has a programming lead that comes out of the external microphone socket on the side of the set and plugs into the mic socket of the set to be reprogrammed.

see Picture on the website of this unit.


A PM200 Cleartone Programmer which looks identical to the PM100 Programmer.
All CH650s will also require retuning of the front end and of course the VCO in order to work on 70cms OK.
I HAVE NOW RUN THE SETS ON 2 & 70 USING some Cleartone software very successfully.

CM7000 VHF sets will lock up straight away upon 2 metre frequencies when entered.  But I do find that the squelch control and set-up pots as shown on the bottom metal plate cover are very touchy and it seems very difficult to set them up to trip the squelch sensitivitly?

Some CM7000-MB7000 VHF or UHF sets can be reprogrammed using a PM300 Cleartone Field Programmer unit which is identical inside and outside to a PM200 Programmer.  This uses a CM7000-7500 type microphone plug lead To a CH650 type microphone plug.

So this programs through the microphone socket but I believe that you can also program through the rear D type 15pin plug of the sets.  This would be the preferred way as some of the repeaters and base stations have their front CM7000-7500 front panels missing as they are used as  boot sets only.


 You cannot plug the PM300 programmer into the front panel microphone socket of any CM7000RP -CM7500RP  or any Dual Band VHF UHF Cleartone front panel.  These sets require the Programmer to plugged into a temporary front panel plugged onto the internal front of the CM7000-7500 boot set .

So if you can only program through the microphone socket, then you need to have a CM7000-7500 Front panel assembly with microphone socket  to plug on to the programmer lead then unplug/remove this DUMMY front panel after programming is complete.

Please note if you are unlucky enough to only own either PM200 or PM300 then you can copy the EPROM from one type and use it in the other type.  Or you could possibly using the chip select pin on the EPROMs then piggy back them in the programmer and switch between the two devices?  I have not tried this so if anyone has done then can they please let me know.

 CM7000 VHF sets using Poli 1.5 or Poli 1.73 Software can be set for AM-FM per channel by the PM300 Programmer but CS11 software (which has variable squelch) appears not to be programmable AM-FM by a PM300 Programmer.  This software can be used in a CM7500 UHF Mobile as UHF is FM only.

To find out what software is fitted look carefully upon switch on and in the first few seconds the software number appears in the LCD window of the set. 

By using a Computer Cleartone interface and program software CM7000-CM7500 is another way of tackling the problem of getting the sets onto the Amateur bands.

CM7500 UHF Sets (after Programming of 70cm channel frequencies with the PM300 Field Programmer) will require retuning of the VCOs and front end trimmers to lock up and work upon 70cms.  The receiver is easily done by using a scanner and setting a signal generator or 2 metre portable transmitter with dummy load fitted to RB0 433.000MHZ for example.

Then tweaking the receiver VCO trimmer, as marked upon the bottom metal cover of the set until the signal generator or 2 metre transmitter signal is heard in the loud speaker of the scanner.

The transmitter can be set up by using the scanner to listen to the lowest 70 cm transmitter frequency programmed in the set, and tweaking the transmitter VCO trimmer until it locks the VCO and the scanner bursts into receive.

According to the Service Manual both the transmitter and receiver VCOs should be set for 7 volts DC at the VCO Test Point as marked upon the bottom metal cover of the sets for both VHF and UHF Types.


Also there are some very clever people around now who are capable of extracting the E2PROM information out as raw data and rejigging its program codes to enable all of these above sets, (including Marconi and Burndept types) to work on 2 metres - 4 metres and 70 cms. I am however not able to do this and rely other Radio Amateurs to do this for me.

The Control Boxes that stand vertically (not horizontally) are for Motorbike mounting - MB7000 see pictures.

Note two colour types RED-GREEN and WHITE-RED but both seem to be identical.

Cleartone CM7000/A4 is just the two transmitter-receiver CH650 portables and separate CM7000/A VHF boot mounted unit with horizontal GREY BUTTON CONTROL BOX or the upgraded RED-GREEN flush control box for VHF-UHF / UHF-UHF Talk-through and normal VHF or UHF comms.


CM7000/A4/T (ALPHA Numeric Ranger Series sets) and Cleartone PUMA CH150 200 Channel plus UHF Portables.

All The MB7000 - CM7000 sets above are channel readout only.

ClearTone sets  marked CM7000 A4/T are Alpha Numeric Display sets which allows text in the display of the Control Box or front panel so these can be reproggammed with text readout in them per channel.  They also use CLEARTONE PUMA CH150 200 Channel UHF portables in the VHF-UHF repeater section instead of CH650 Sets.  Again using a CLEARTONE computer interface and software the CH150 can be reproggammed to 70 cms with ease and a bit of tweaking of the VCO etc.

Pictures of CM7000 VHF FM 256 channel mobile
© Karim SU1KA 2005


Second-hand prices are approximately
        Sets only 15 to 25 Pounds.
        Control boxes 5 to 10 Pounds.
Depending on whether complete or not.  The first BE536 released were scrap ones bought at a Leicester Rally in approximately 1990 from an Burndept engineer who was selling off the prototypes from the workshop / laboratories of FKI Burndept DYMAR.  At auctions the control leads tend to get split up into stillages and sold separately to scrap metal dealers etc.  The Burndept/Marconi sets RC675-RC690-BE536-BE544 all use standard Home Office 36 pin D type female to male leads which can be easily be made up from multi-core cable.

The RC640 requires a 15 pin D type female to male lead.
The above sets and control boxes all require an identical facilities 15 pin D type plug to be made up with audio and PTT straps in it.

There are three straps to solder across in the facility plug 15 pin D

Pin 7 to Pin 15
Pin 5 to Pin 13
Pin 4 to Pin 12

One must be plugged into both set and control box or audio/PTT won’t work. 

The BE536 single Control Box also needs a 8 pin DIN plug at the rear marked LPCU (Low Profile COntrol Unit) with shorting links.

In order for them to pass audio and work properly, the links in the Plug / Socket are


The Cleartone CM7000 and MB7000 do not require these plugs.  All microphone plugs are 5 pin DIN of the Pye Telecomms type but not the same connections.  All power plugs are 30 year old 12 volt specification  6 pin Pye Vanguard type.

Please retain the AM / FM function on your sets when converted and lets get AM back on 2 metres.



Both the BE544MU AM/FM and the BE5365MU AM sets share the same PCBs board layout as each other.  But the BE544 being both FM-AM, has the FM discriminator, the FM modulator and the AM/FM switching components added.  Therefore it would be possible to convert a BE536 to a BE544 by just the addition of extra components.  The 20 watt - 25 watt PA unit at the back is identical in both sets and further more is wideband from 143 MHz - 156 MHz.  Also the manual states that it is capable of running 70 watts out.

So here are my modification notes for transmit-receive to FM/AM on the BE536MU..


  1. Locate IC2, MC3359P, 2ND mixer IC, on the BE536 RX PCB side.
    This is the identical IC used on the BE544 AM/FM SET as the FM Discriminator/2nd mixer.

  2. The following components are required to carry out the RX Modification :-
    3 off 0.1µF capacitors 25v DC working.
    1 off 100pf capacitor.
    1 off each 15KΩ -- 68KΩ -- 220KΩ resistors.
    1 off 2 pole changeover miniature toggle switch.

  3. Solder a 220KΩ resistor and 100pf capacitor in parallel across PINS 13 and 12 of IC2.

  4. From PIN 12 IC2 Solder one 68KΩ resistor in series with
    one 0.1µf capacitor in series with one 15KΩ resistor.
    Then the other end of the 15KΩ resistor onto PIN 10 of IC2.
    PIN 12 - 0 --- 68K --- 0.1µF --- 15KΩ --- 0 - PIN 10

  5. As above then solder another 0.1µF to earth from the centre connection of the 0.1µF and the 15KΩ resistor.

  6. Solder the 3rd 0.1µF cap from PIN 13 IC2 to the centre pin of one pole of the Toggle Switch.

  7. Locate the junction of the existing C68 0.1µF and R62 22KΩ, on the PCB and split this junction apart. Then wire to one side of the Toggle switch, for AM/FM Switching see diagram

  8. Mount Toggle switch through side of BE536 BOOT SET case and AM-FM Switching of the receiver per channel can now take place.

  9. The second pole of the toggle switch will be used to switch the AM/FM For the BE536 TX Modifications to FM .



  1. On the TX PCB side of the set locate the Junction point of existing C386 & R377.
    Then insert the second pole of the Toggle switch, previously fitted in the RX Modifications.

  2. On the TX PCB side of the set locate the Junction of existing C322 & C307-L301.
    Then insert one 10k Ω resistor, in series and remove C307 -- 0.1µF.
    Then solder the new FM modulation line, from the toggle switch pole to the 10KΩ resistor Junction with the C322 on the PCB.



Please retain the AM / FM function on your sets when converted
Lets get AM back on 2 metres.

Kenwood PMR Products K4 Repeater System

Consists of two Kenwood TK809E UHF mobile sets and one TK709 VHF AM-FM set all in one black boot mount box with a PMR Products control head for switching repeater VHF-UHF and controlling the VHF & UHF sets together.

On the boot set there is a standard 37 way Home Office D Type socket.  At the control head there is a fifteen pin D Type socket.  At the control head end a fifteen pin D Type plug on a tail lead terminates in a breakout box that contains both the 15 way cable which taps off the first fifteen 1 to 15 pins of the 37 way lead and feeds these pin for pin onto the 15 way lead.  Also at the breakout box there are two speaker cables to feed VHF and separate UHF audio out.

These sets have recently been sold by Norfolk Police and have been decommissioned from the said channels they were on.

The software used in the control head and sets is copyright of PMR Products, Chepstow , Monmouthshire and Kenwood program software will not work with these sets so they at this point in time remain unmodified for 2 metres and 70 centimetres unless you install and program three standard Kenwood non-police mobiles which will reprogram  on standard Kenwood software. Then the PMR Products software will allow the sets to be used on 2 metres and 70 cms.

Unless someone out there knows better, in which case please EMail me with your solutions please.



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