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Old 9th Sep 2017, 6:06 pm   #1
robinshack
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Default Memories and other stories from Pye etc PMR engineers.

Moderators, please move if it is in the wrong section.
From a reply to the WANTED section Pye Whitehall, with my memory suitably jogged, I have now started this new thread.
I am sure there are other PMR service people on this forum who may comment or share personal experiences?
It may provide some insight, knowledge or entertainment to other forum members of the less serious side of our job maybe?
Firstly, continuing from my Whitehall post and the repeater control box.

Firstly, this home brew system violated the terms of my amateur licence!
Other "naughty" moments with this control box were when I was once mobile, wanting to use the repeater, and a fixed station was in qso with another FS via our local 2M repeater. I was able to tx about 5khz off frequency of the input (I forget exactly how it was done now). This then took advantage of the noise squelch circuit on the Pye R18fm base rx that the repeater used, and, with this rx thinking it was noise, (ie low signal) it closed the squelch. Me doing this quickly, it gave the impression of an intermittent microphone. They ended their qso to investigate their microphones and i was then able to use the repeater as a mobile.
Totally wrong, not the ham spirit, I know, so please don't shoot me down!
It was decades ago and back then I more than did my part helping out with the local 2M and 70cm repeaters. Sometimes, a 2m aerial and base or a QQVO6-40 was offered as a raffle prize at repeater group meetings! I wonder who donated them?
It is now 25+ years since I was a regular on 2M mobile. Hopefully I have served my sentence!

Another modification I did within my transit van radio systems comprising 5 aerials drilled (Yes, a large colander when sold!) Comprising 2M, 70cm, Highband customer, Highband my own licensed channel and of course Lowband for Pye transport scheme. The LB Pye W30AM I modified to additional PA output (possibly 15W, loads of audio) to feed a horn PA speaker behind the radiator grille. Useful for talking to riggers up a mast was the excuse.
My best man, Mick, I often visited on a Saturday morning and he was always reluctant getting out of bed. So, outside his house one Saturday morning, I found my Pink Floyd dark side of the moon cassette, played it at decent volume into the microphone. "Time" was the track. Yes, all those clock alarms and chimes in a quiet residential area. Quite a few curtains twitched.
Another trick some of us engineers sometimes used (most had an amateur callsign) was to tape a neon bulb to the tip of the aerial so it glowed when on tx. Looked good if in convoy!
Those were the days (Apologies to Mary Hopkin!)
I am sure others may share memories as well?
Rob
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Old 9th Sep 2017, 6:21 pm   #2
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Default Re: Memories and other stories from Pye etc PMR engineers.

Another story from back then in the late 70s early 80s.
Firstly, please understand that my "highly tuned up" W30AM on 72.35MHz tx was quite potent as regards qrm, EMC, call it whatever you wish. I was after all quite distant from my "local" base station.
One day, I had a service visit to RAF Barkstone Heath. Sight of Bloodhound missiles I think? I was told no way was I allowed inside the gates, with the man pointing at a sign referring to the danger that could be caused by digital watches and other electronic items.
So, being a good boy, I parked just outside and ran my mains extension lead into the guard house.
I wonder what effect over and above a digital watch my 30W of AM caused to them whenever I communicated back to base?
I didn't hear any bangs though!
Rob
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Old 9th Sep 2017, 6:32 pm   #3
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Default Re: Memories and other stories from Pye etc PMR engineers.

Yet another memory.
Locally, we had the sugar beet factory. At the top of the s48000 ton silos was a comm site mostly Pye f30AM.
Because the lift to the top (198ft) was sometimes out of order, it meant a long climb up ladders to restore the AA or Securicor comms which were both F30AM.
Us engineers often campaigned for the gear to be moved to a hut at ground level with low loss LDF4-50 feeders to the aerials at the top. Surveys were done, "NO, it costs too much". So, we put up with this situation. (These days, H&S would have a fit!)
One day, i arrived to do a repair. There was a brand new sign next to the ground floor lift door. "Glass is prohibited beyond this point" or similar.
YES!! I had in my hand a QQVO3-10 valve in a carton. So, I went to see the silo foreman. He nearly had a fit! Quoting the regulations, H&S, and whatever else he could think of, I was NOT to proceed. Get ff the site! So, buck was then passed to my controller.
24 hours later, I was told that "our" glass was exempt!
To the day it was demolished, afaik all the tx/rx remained at the top of the silos!
Rob
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Old 9th Sep 2017, 7:31 pm   #4
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Default Re: Memories and other stories from Pye etc PMR engineers.

In the late-1970s while still at uni I was as a sideline working on a project for water-companies who were starting to use 5-tone selective-calling: both to define individuals/call-groups of user radios in their voice-radio vehicle nets and also for early experiments in polling 'digital outstations' that when triggered would send back their status and data [river/outfall flow rate, for flood predictions] using a train of 5-tone data-blocks.

[The 'outstation' radios were a version of the low-band Pye Europa designed to be wall-mounted, fitted in little brick-built cabins beside rivers and sewage-farms, and connected to a box of digital-fun based around PLL tone-detectors, a bit of TTL and a 2708 EPROM that defined the particular outstation's ID]

This was the time when the movie "Close Encounters of the Third Kind" had just been released - and yes, as chief geek I had my personal 5-tone code as the Close Encounters theme,

https://youtu.be/-JpIjv6XSLM

which caused some amusement when the system was demonstrated to a bunch of high-level Whitehall types!
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Old 9th Sep 2017, 7:58 pm   #5
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Default Re: Memories and other stories from Pye etc PMR engineers.

Ah, Selcall! Pye transport scheme used the 2 tone sequential Pyecall, ie 2 audio tones, sequentially sent to call a mobile. Third tone was for group call afaik.
Being a field engineer, based from home, when on call, the van was outside and needed constant monitoring to see if I was called.
Then having got hold of a lowband am PG1AM 2 tone pager, I embarked on mods to my mobile transceiver to enable the pager to "listen" to my mobile tx frequency. Thus, when I was selcalled as a mobile, my modification enabled a tx transpond with my unique 2 tone code and my pager responded to this same code. Brilliant, I could watch tv indoors and be assured I would never miss a call.
Unfortunately, a wiring problem put a low ohm resistor acros the tx keying voltage. Result upon my first transpond was a lot of smoke and burning smell of a resistor.
I had instead invented "Smellcall"!!!
A few minutes with a soldering iron rectified the problem and it was a success from then on. Used almost until the end of my employment, when mobile phones took over.
Rob
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Old 9th Sep 2017, 8:43 pm   #6
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Default Re: Memories and other stories from Pye etc PMR engineers.

Our local area sewage treatment plants were part local authority and part Anglian water.
We installed simple telemetry at about 100+ stations. Early ones were MF5AM (Motafone) or MF6AM (reporters). These used a dual tone call system for a few seconds, followed by a pre-recorded cassette tape using a basic style Philips EL3302 similar mechanism. All TTL and contained in a hefty die cast case. Later upgrades replaced all these with a 5/6 tone system using M293. UED6 at the base control station with a small printer.
The latter system worked reasonably well.
The only problem I had was the stench at some outstations when repairing. The gear and other pump controls usually being in a sealed fibreglass cabinet on the ground. The fumes (from the cable ducts down to the sewer) were such that the pcb would all turn black within weeks! I remember a few stations where the following procedure was adopted upon arrival. Hyperventilate, hold breath, open doors, release a few screws, retire and hyperventilate again, remove more screws and wires, repeat this until the gear was removed to a safe distance within my van. Replacement was a reverse of the above!
Just touching the metal case of the alarm or radio left an unpleasant smell on your hands. Other jobs entailed replacing the reed switch sensor that was used for loss of rotation and located 2cm adjacent the rotating sewage aerating biodisc drum! I used to wear a face mask dipped in pine disinfectant to reduce the horrible smell and had a bucket with water and more disinfectant for washing my tools.
I remember one day being geared up like this and a local council suction tanker lorry with 2 blokes arriving. They started a de-sludge routine (let you guess what that was!) and left their pump running, emptying the cesspit. The stench was absolutely disgusting once this happened. I started to clear my tools to leave immediately. "What's up mate" "don't ye like it?" they asked from their open cab window, sitting there eating their sandwiches!
Rob
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Old 9th Sep 2017, 10:01 pm   #7
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Default Re: Memories and other stories from Pye etc PMR engineers.

I did a few months working on fresh water treatment plants, so the smell wasn't there, but still lots of nasty chemicals about. Plenty of adventures as a field engineer though. One day we got to the transmitter site near Sedbergh, in Cumbria, to find the compound had a little group of placid looking sheep happily munching on the long grass, having gained entry through a hole in the perimeter fence. I said to my mate, "no bother, I will get rid of them" (being a country boy) and proceeded to shoo them towards the open gate. Unfortunately the sheep had other ideas and suddenly decided to turn round and stampede towards yours truly. The only option I had was to dive out of the way onto the mud, much to the amusement of my oppo. Another time at the same site halfway along the track there was a JCB parked up. Now that should have raised suspicions, but we thought nothing of it. A few hours later when we were going home, yes, you've guessed it, there was a lovely deep trench dug across the road and no driver to be seen. A little bit of inginuity with the landrover coupled with the desire to get home for food got us across.
Alan.
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Old 10th Sep 2017, 11:59 am   #8
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Default Re: Memories and other stories from Pye etc PMR engineers.

We used to look after a network of dispersed / warden alarm systems which communicated with their base station via VHF high band, all using Pye M290 PMR radios. They communicated via selcall tones for control / identification purposes. The M290s were a little bit unusual in that they were modified for electronic (Pin Diode) antenna TX/RX switching rather than using a relay as was standard for those. They also had an 8085 based microprocessor control / selcall PCB stuck on one side.

One deficiency of the system design was that the outstations, which were battery backed with a 12V lead-acid battery, had a rather unpleasant habit of locking up with the transmitter stuck ON if the power was removed at site for any reason and the battery allowed to run down to about 9V or so. This happened quite often because the outstation was usually in the outhouse of an (elderly) tenant and powered from their mains, so if anything happened to the tenant social services or relations would promptly have the power cut off.

With a transmitter stuck on, the entire system (which worked on a single VHF frequency) would be disabled and we would find ourselves out on a midnight foxhunt - in the middle of June if we were lucky, but more likely in January, trying to find out which transmitter was stuck on. We could get close using a receiver with an S-Meter, and might find ourselves on an estate where there were five possible culprits. At this point the signal indication would be at full scale no matter where we were on the estate. We would then go by each possible site using a scanner to listen for the much weaker harmonic on (3 times f) coming from the stuck transmitter.

Eventually, we got the technical bods to add a control centre feature which would record all mains-fail reports received from outstations so that as soon as we obviously had an instance of this problem, we could just check that short list and find the relevant site relatively quickly.

Ideally the outstations should have had a voltage monitor circuit which cut off the battery once the battery voltage fell to about 11.5V, but there were well over a hundred sites - we just didn't have the time or the manpower to go around modifying them all.
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Old 10th Sep 2017, 6:51 pm   #9
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Default Re: Memories and other stories from Pye etc PMR engineers.

Reminds me of the original alarm units at local S. Lincolnshire sewage pumping outstations. It is very FLAT around here! Just ONE alarm input that was a "high level" (get your wellies out)! These were the Pye RA2 box, coupled to either a MF5AM or MF6AM via a 15 way "D" connnector. Using twin in band tones 885/1670 for "Key" or 970/1850 for "minor". These were decoded by af filters to trigger talkthrough only if "key", this was for the duty standby crew at night. ALL alarm tones triggered a tape recorder in the office to record the RA2 cassette (EL3302 style) continuous loop message.
The design problem here, was that the mechanism was permanently engaged in the play state, ie the pinch wheel sandwiching the tape against the capstan pillar with the motor stopped. Needless to say, being left 24/7 in this position, occasionally a tape would stick and mangle itself.
Hence, the alarm signal was the correct twin tones, then ....silence, or just a squeak sound!
Oh well, plan B, wait for residents to complain about blocked drains!
The old tape system was later on replaced with the M293 combined with a separate identical aluminium housing alarm unit comprising 5/6tone EEA selcall module (based on a modified TED6) interfaced with a cmos 9 state input alarm trigger module. This was the TRA6. A very good system really. It was monitored 24/7 at the base office end with a UED6 decoder/encoder and a thermal printer.
The beauty of this also included a transportable unit that the standby team took home at night and the ability to interrogate the status of every alarm station 24/7.
The sewage station pump apparatus comprised main and standby pumps. Also associated reflux valves. Alarm status codes (5 digit EEA, the fourth and fifth digit being variable) might be as follows, the 00 being only when interrogated.
XXX = the unique station id code.
XXX00 = all ok. XXX01 = duty pump fail. XXX02 = standby pump fail. XXX03 High level (of sewerage in the well) I forget the rest, but "Loss of rotation was used for the bio-digester drums, 09 was a mains fail I think.
In all, this proved to be a very reliable system. Most problems were caused by false alarm inputs. eg The reed switch I mentioned before. I think I may still have a spare TRA6 module....somewhere.
Being the main engineer responsible for all of this scheme, (Possibly 120+ outstations) I was issued with a FOGA5 selcall test set. It was the only one outside our depot! A brilliant piece of German engineered test gear. I still have one that I bought from Telecom back in the 1990s.
BTW, the talkthrough base station was located at the top of the sugar beet silos and was a 24V trickle charged battery powered setup. Yes, the T30AM had an inverter psu within instead of a mains transformer. The ONLY one I have ever seen. That is, when visible under the obligatory complete white covering of sugar dust!
Rob
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Old 11th Sep 2017, 2:57 pm   #10
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Default Re: Memories and other stories from Pye etc PMR engineers.

I remember the TED6 enc/dec module. We used them with M290 radios in some of our older fleet vehicles. I can still clearly recall the awful squawk they used to make when called. I think they used to slide into slots on the radio upside down and replaced the original front panel and switches. It's a long time ago. Regarding the silent Tx syndrome, we used to have a certain vehicle wiring fault condition (negative supply fuse blown to the set) that caused permanent silent transmit which would not be obvious to the user. No Tx led, display looking normal, and ...wait for it...still transmit when switched off at the control head, because everything was controlled by a microprocessor. I won't mention the name of the manufacturer. I have lost count of the times driving about in the small hours trying to find the rogue transmitter with an S meter etc. It's a big county to cover. Of course it used to jam the system up. The main Tx's would time out after broadcasting busy pips for too long. We cottoned on to asking people to check the temperature of their radio. The hot one was the rogue and had to have it's fuse pulled...panic over. The engineer was then deemed a hero!
Alan.
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Old 11th Sep 2017, 5:55 pm   #11
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Default Re: Memories and other stories from Pye etc PMR engineers.

Alan, the radio pcb was always upside down, (ie Vol/on off button at the top of the front panel thus the TED6 was right way up.
I recall a job fixing an old AM10B bootmount on a Hymac excavator on a building site. Probably late 70s. About 0800 start as the site was very local. The developer owner must have been a millionaire, but was always nice and polite with me and never questioned my advice. He was always smartly dressed. He must have been in his late 60s? He had a Mercedes coupe as well as another car or two he used to ride round in, all fitted with pmr on his high band talkthrough channel. His own callsign was "Delta". I suppose because everything involved or flowed through him? (The Hymac driver callsign was, well, Hymac!)
So, before looking at the alleged problem with the AM10B in the cramped cab of the digger, the driver engaged in general conversation. As you sometimes do when first meeting someone. This turned to the subject of the boss and if ever he would retire now he was getting on in years. I truthfully related to the driver that during my last discussion with the boss, he was suggesting he would like to retire to the south of France on his luxury yacht and be surrounded by beautiful young girls! BTW, he had a lady partner who was a fellow director and a formidable woman.
Well, after a minute or two I was suddenly aware of a high pitched whistling noise. Yes, It was the AM10B HT inverter, it was jammed on TX!
I released the microphone from where it was wedged next to the cab side window. I heard the click in the loudspeaker of the talkthrough base TX carrier as it released.
Hoping the fault may have been a modulation problem, I hesitantly pressed the PTT and spoke "Pye engineer, any mobile for a test please?". Instantly, a growl like voice of "Delta to Pye engineer, receiving LOUD and CLEAR!"
I just wished the Hymac could have buried me there and then!
However, upon returning to the office, the boss was there and never said a word about the incident. Just a thank you for being so prompt with the repair.
I must say, we always got on well and I had a respect for him and his position, he a respect for me as being the person he could rely on to fix his pmr.
When I was made redundant in 1990, he cancelled his maintenance contract with Pye (Philips telecom) and took out a contract with me.
Rob
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Old 11th Sep 2017, 6:02 pm   #12
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Default Re: Memories and other stories from Pye etc PMR engineers.

I remember with some happiness the appearance of the Pye "Shaver" microphones that had a built-in transmission timer (usually 90 seconds but becauae they used an electrolytic as the timing component it could be rather variable) in them.

They freed many networks from being jammed by the muffled sounds of someone cursing the traffic and surrounding drivers as they drove around unaware that they had the mic wedged under their bum and the PTT keyed.
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Old 11th Sep 2017, 6:17 pm   #13
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Default Re: Memories and other stories from Pye etc PMR engineers.

One outfit I sometimes did work for was a cattle-haulage business that ran a fleet of Volvo trucks fitted with low-band AM Olympics. Being trucks they were 24V and so each Olympic was backed-up with one of the black-diecast-cased 24-to-12V droppers that looked the same as the A200 linear-amp.

One truck regularly blew its dropper-box. Like every 6 weeks or so. After 3 or 4 replacements their fleetmaster did a bit of checking against the driver roster and found these failures were associated with one particular driver using that truck for an 'overnighter'.

Turned out he was uncoupling the 2 inline fuseholders between the inverter and the Olympic, and using the 12V to drive a 12-to-240V inverter to power a TV to watch while he was parked-up. The poor Pye voltage-dropper sacrificed itself in the valiant struggle to supply something like 10 Amps.

The driver got a bollocking but kept his job on a "do it again and you get your P45" basis.
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Old 11th Sep 2017, 6:18 pm   #14
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Default Re: Memories and other stories from Pye etc PMR engineers.

I think only used with radios on repeaters? Although most MF6AM and all M293/294 used the ladyshave mic, none were fitted in my area. My customers all had their own base, simplex or talkthrough. The beauty of that microphone was that with a small change of components it could be either am or fm. One downfall was the clip stud rivet often broke away, leaving a steel washer rattling around inside and no means to fix the mic into the dash mount clip. They were a natural shaped microphone to hold in the hand though.
Rob
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Old 11th Sep 2017, 6:22 pm   #15
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Default Re: Memories and other stories from Pye etc PMR engineers.

Yes, the VR200. Reminds me of the time I met at a rally someone looking through my wares of A200 and other bits. I asked if it was high or low band he wanted. He said UHF! I assured him no such thing existed. He retorted that his mate was a Pye engineer and had one! I calmly replied that I also was a Pye engineer and that they did not exist. He went away calling me an idiot who didn't know what he was talking about, or similar!
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Old 11th Sep 2017, 6:28 pm   #16
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Default Re: Memories and other stories from Pye etc PMR engineers.

The timer microphones were also used on non-repeater nets: they were "the latest new thing to be seen with" and plenty of people I knew with legacy Westminster/Europa-based networks had drivers clamouring for the new microphones so they could be seen as on-trend!

A few minutes arranged the mic's +10V supply for the electret insert from the radio by a judiciously-soldered link.

Shortly after, microphones with a DTMF keypad became the "must-have" even if there was no DTMF infrastructure on a particular network. A company called IQD [Interface Quartz Devices] down in the South West of the UK made a killing selling these.
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Old 11th Sep 2017, 6:28 pm   #17
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Default Re: Memories and other stories from Pye etc PMR engineers.

I used to use a Europa 12v to 12v isolated inverter box (for changing the -ve earth Europa to + earth) in series with my van 12v battery to power my 24V weller soldering iron. That was until I got a 12v Weller TCP1.
BTW, a TCP1 with a 2BA steel screw inserted rather than a tip was great for lighting cigarettes when the element barrel glowed red hot!
Another wheeze one day was to put some pre-cooked but cold bacon in tinfoil and place it on the Transit 1600 exhaust manifold for a few miles. Then arrive at a customers with a sandwich smelling of hot bacon!
Rob
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Old 11th Sep 2017, 7:12 pm   #18
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Default Re: Memories and other stories from Pye etc PMR engineers.

My Favourite add-on PCBs for the M290 series were the TEDX and the CX290.

The TEDX was a combined Selcall and CTCSS board with (in the more advanced version) a 4-digit LCD display. Radios fitted with these normally useless PCBS - useless in the sense that only Pye dealers could change their programming - came onto the market at amateur rallies so I set about writing a new swap-in eprom for them which made them function as an amateur specific 1750Hz Toneburst, CTCSS encoder (only) and squelch defeat.

There was a G3 (I forget his full callsign) who also independently did the same kind of thing with the TEDX but he took it a lot further, adding a further 4094 serial-to-parallel latch in series with the two already embedded in the unit - the third 4094 was used to output a parallel channel select code, electronically replacing the mechanical channel switch and therefore giving the radio the ability to scan, among other things. The most advanced TEDX version of all also included a CB-style BCD channel encoder switch and 2-digit channel display, either 40 channel or 80 channels in 2 40-channel banks. These were comparatively rare. There was also a 'dumb' version of the 40/80 channel front panel without any microprocessor circuitry, they were a little bit easier to come by.

The CX290 was an 8085 based microprocessor controlled board which worked with the 'E31' system. As far as I could ever tell it originally made the MX radio it was fitted to behave in a cellphone like manner, when the 'cells' which supported it still existed. As with the TEDX, anyone wanting to use a CX290 equipped radio as a simple transceiver originally had to take these off, throw them away and fit a basic BCD switch channel control setup, but again, I spent some time writing new firmware which made the CX290 unit act as a toneburst, frequency readout and up/down channel selector. Since it had a numeric keypad, I also made it so that you could go straight to a particular frequency by typing in the last three or four digits. The result was arguably the nicest looking of any of the MX series which could be got running on 4m / 2m or 70cms. (See attached image of the original 2m / 25Khz step version).

I've seen quite a few of these at rallies over the years, and an amateur group over in Holland took up the modification with great enthusiasm as there were apparently a lot of surplus CX290-equipped sets over there. It may subsequently have been taken further by them and others since I did notice my code had been disassembled back into native 8085 assembly source code - which was interesting to see, because I originally wrote it with a Z80 assembler, inserting defined bytes inline for 8085-only instructions like RIM and SIM.

There was another (trunking) control panel, visually similar to the CX290 but with four vertical front panel buttons and a completely different (8031 based) board behind it. This was the TSM30D, which I only ever found fitted to band III MX295s. Although I had some of these and intended to do the same sort of rewrite for them, I never actually got around to it.

Tanuki, I still have a few shaver mikes with and without the timer PCBs in them.
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Old 11th Sep 2017, 7:18 pm   #19
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Default Re: Memories and other stories from Pye etc PMR engineers.

A lot of the Band-III trunking MX295s were used by British Rail and their trackside contractors; there was a brief bit of potential amateur interest in them when it was rumoured that we might be getting a '220MHz' allocation like they have in the US.

But it never happened.
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Old 11th Sep 2017, 7:26 pm   #20
G6Tanuki
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Location: Wiltshire, UK.
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Default Re: Memories and other stories from Pye etc PMR engineers.

I had a fondness for the A200 in its various variants: they were a quick-and-dirty way to give an Olympic or 5-watt Europa a bit more 'oomph'. And could easily be secreted under the seat or in the spare-wheel-well of a car so that OFTEL wouldn't spot it when they came to check your installation.

But - who in Pye was crazy and passed the design with *that* power lead? I saw a couple comprehensively vapourised inside after someone had wired a 13A plug to the thick white cable with the familiar blue/brown/green-yellow cores. Usually the big smoothing-electrolytic took the load and PCB tracks turned to gas - amazingly - the two power-transistors often survived!

There was one A200 variant designed for the old "police band" around 96-105MHz. These were eagerly sought-after by the smaller pirate-radio stations.
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