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WB400/1400 and The ROC
ROC posts were all equipped with a WB receiver to hear the 3 minute warning issued to the public. The first Carrier receiver was a WB400 receiver it was simply a type of Long Wave radio complete with a dry cell battery and volume control. The signal was superimposed onto the private telephone wire “Teletalk” that connected the ROC post to its Head Quarters. The WB400 system was upgraded to the WB1400 system in the 1980’s this was a more sophisticated system but used the same carrier principle. Around the same time as WB400 was upgrades Tele talk boxes were also changed for a more modern device
This is a wallboard containing the Receiver Speech WB1401 along with a special loudspeaker for damp locations and filter to allow private wire line charging. The wallboard comes out of a real ROC post. At QQGU we have most of the WB1400 system functioning, there is more to see in the main operations room
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Private Wire Case 200
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WB400 Receiver
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Teletalk
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Teletalk Ver 2
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WB1400 ROC Post Installation Drawing.
The WB1400 Early Warning System The “Warning Broadcast” 1400 system replaced an older WB400/600 system. Both systems used “Carrier” which is a way to superimpose another telephone line on a standard line without the two interfering with each other. The Carrier used a frequency of 72Khz which is effectively a LW radio channel on top of a telephone line. The system was controlled by “Carrier Control Point’s” these were located at central police stations, the police could receive alerts and pass them to Receiver Points as well as controlling Air Raid and Flood sirens. BT ran a comprehensive network behind WB1400 to connect all of the UK Warning Monitoring Organisation
At QQGU we have the original WB1400 receiver, it is now connected to the CCP located behind the display using various parts from the WB1400 system.
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Bunker Blog Day 1
James has another bunker located in Edinburgh; it is one of four R4 type bunkers in the United Kingdom specially built as a Seat of Government, it is the only one in Scotland. I spent a good deal of time when I worked for BT in one of the other R4’s at Bawburgh which is just outside Norwich in Norfolk. A unique feature of James’s bunker is that it was built on the same site, in fact shares the same entrance of a World War Two fighter command centre complete with operations room and masses of associated rooms.
I asked James if I could take a look round last time I was at the Scotland Secret Bunker Museum and he agreed. We arranged a date for the visit and in the mean time I looked up all I could find on the web, the pictures I found, taken by “explorers” showed a very dilapidated and vandalised site. Vandals had started a fire in the R4 bunker which had blackened just about everything both in the R4 and the fighter control centre. James also kindly looked up the site plans which confirmed the likeness to Bawburgh, and the scale of the buildings.
The bunker is right in the middle of Corstorphine which is a rather nice suburb of Edinburgh, the entrance is from a middle sized suburban road, and the bunker cannot be seen from the road, the area looks to be a forest. There is an overgrown road leading to the bunker, on approach bright coloured graffiti is plastered all over the fighter command buildings, these are however substantial brick and re-enforced concrete with solid flat roofs. The bunker is on several levels as can be seen from the various levels of roof. Around the large parking area are quarry walls, sheer rock faces about 10 to 15m tall on the right side with trees surrounding the rest, the area is large even though it is very overgrown.
To gain entry John had opened a sealed window which was a fairly difficult task in its own right James and I entered with a couple of large torches. The fighter command building is vast; it has the well where map tables once sat and a viewing gallery which unfortunately has perished over time. The soot left over from the fire has stained everything but it was clear to see that the structure of the building is almost perfect, the roofs need some urgent work to seal them against water but they are easy to get to and solid to walk on or even land a helicopter.
We decided to go to the R4 as we had full charge in both of the torches; the tunnel is quite long, changing to a circular construction wall half way down. The main blast doors are missing and would need replacing and possibly re-fabricating. The stair well feels quite cramped as the main ventilation shaft passes down the far side, it is actually a big stair well the same as the other R4’s I have been in. We stopped off on each level and walked around the seemingly endless corridors and rooms. All the floors are concrete and have not been affected by the fire apart from some areas where cable ducts had wooden covers. The main operations room is in a bad way, I reckon there was a lot of wood in there to form the balconies and walkways. Some air venting and power conduits are twisted and damaged but it is clear to see where they should be. On the bottom floor we found the BT room which is in a sorry state down to vandalism. At the back of the plant room is the emergency exit which comes out at the bottom of a hill at the rear of the bunker.
Outside again we took a walk up onto the top of the fighter command then over the hill where the R4 bunker is buried, there are a couple of ventilation shafts and the base of two radio masts. Along the top of the quarry there is a fantastic view of most of Edinburgh, on the ground one would not know this were in a suburb.
Overall the bunker looks in a sad state but in reality the fighter command bunker and the R4 are very sound buildings. The R4 is a mainly a box made of 3m wide and deep re-enforced concrete so I am not surprised to see no structural damage or water ingress. Internal girders looked to be solid too; plenty of rust but nothing a grit blaster couldn’t clean up, same thing for the walls, floors and air ducts.
The place just needs emptying of all the vandalised junk then blasted and refitted. Similar for the fighter command building, I think the fighter control room would be a fantastic restoration, there are no others in the UK open to the public in their proper location and this one is a piece of Scotland’s heritage too. There is simply so much room to set up exhibits in the R4 cold war bunker it could make a great museum and cater for functions with a good mix of restorations and up to date interactive exhibits. Perhaps although the fire has caused a lot of damage it has made the job of replacing outdated electrics and allow for modern exhibits easier.
I came out of the bunkers enthused, the location is perfect for a museum and it is a blank canvas with a solid foundation waiting to be resurrected, I reckon in its new life it could be a great attraction for Edinburgh, with the amount of room available there is plenty of scope for a WW2 and cold war museum with a wide appeal. It needs to be different in character to St Andrews, in a way it already is as St Andrews has the history of being an operational radar station, and I would think it could be more interactive than the other bunker museums. Both bunkers here were linked to Anstruther, there are references of a Tape Relay S+DX circuit from the cold war period and references of voice lines during the chain home period, both are recorded at Anstruther, several references in the BT room the and others on documents from the WW2 display. The 2 sites may also have been linked by radio; I need to investigate this in more detail. I am not sure about MSX, it does seem the bunker went out of favour to some extent; it may be simply there is not a lot of recorded information.
James and I would very much like to hear from anyone who spent time at the Edinburgh bunker, it would be nice to build up some solid information about the life of this massive establishment. That is information from both the WW2 and form the Cold War period, any information is very welcome?
My e/mail address is paul@secretbunker.co.uk
Day 2
Well it didn’t take long for me to come back; I enjoyed working here last time so much I think it might become an addiction!
I had rebuilt a spare punch for the one printing re-perforator we have at the bunker, it was a fairly time consuming job as it had lived outside for several years before I acquired it with a load of other telex gear (including my own reperfs) it is still a little rusty but the moving parts are clean and working, I will tend to the cosmetics once it is fully working. So after an hour’s struggle to replace the old one and get everything aligned by guess work as I left my adjustment diagram at home it seemed to function. First test is made by rotating the motor by hand and moving the magnets armature to print and punch a few random characters. From last time I had found a fault with the motor trying to go backwards and had not been able to clear it so I also brought with me all the spare capacitors, RFC’s, brushes etc and replaced the whole lot, those I brought were in much better condition. I applied 160 Volts to the motor and the same thing happened, the motor jumped back a couple of degrees and stopped there buzzing! Once again I changed the motor with a known worker, exactly the same… So the reperf is back on the static display to let me think about it for a while.
While I was away a Cheetah in main ops has started playing up and the BT Room to Comcen link has stopped working. First up was the link, the Cheetah at the BT room end had some dead keys so I replaced the whole keyboard and now it is working again. At the same time I brought with me a new print ribbon for the Teleprinter 15 from home, these are becoming hard to get, they are the same as older typewriter ribbons and have two colours, red and black. The print on the 15’s is very good as the print head is simply a typewriter basket operated electrically now it can be clearly read. I checked the alignment of the S+DX units and they needed only minor adjustment as expected. I really wanted to get on with WB1400 so the other Cheetah will wait until later in the week.
James had found a few other WB1400 bits in a cupboard behind the BBC studio, amazingly I watched the still boxed parts passed to me, last time I saw the boxes I was at BT fitting them, that was one of my first projects after finishing my apprenticeship. We have some proper speaker shelves, back plates for the receivers, a new Receiver Speech WB1400, and finally to top everything a receiver signalling WB1400 on a back plate still attached to the old WB600 mounting box, unbelievable! My plan was to attach a modern power supply directly to the “Carrier Control Point” as we have no terminating units of any kind then to feed the X and Y path to the MDF, feed one into the Power Unit WB1401 and then on to the original Receiver Speech in main opp’s. As I turned round from the cabinet I spotted a level measuring set and another telegraph tester, so I decided to have a closer look, under the LMS was a terminating unit WB1401, this is the smaller one without the Power Unit but it allows the CCP to be hooked up via the cable rather than run wires directly into the back of it, how fantastic to find this, I reckon the power unit version will turn up soon. Anyway I took everything to the BT room and attached cables then went an installed the whole lot, luckily my multi meter reads dB and frequency, I didn’t think to bring any WB1400 test gear. Once everything was ready I opened the existing receiver speech to check the battery. These are way past their sell by and most are corroded, luckily they are at the bottom of the receiver so providing the unit is installed the right way up not much damage takes place. Out of 5 batteries I found one that would charge, it took a little while but I finally heard a faint and buzzing pip from the CCP out of the receivers loudspeaker. I checked the signal level and it was way lower than I expected so I worked back, the signal at the power unit input was good, around -10dB but the output was almost in the 40’s, this is a thro measurement so not too accurate but still way out. On removing the load and measuring the level was a healthy -12dB. I traced the cable and found a very old WB400 filter at the end of the frame and sure enough on bypassing it the signal level went way up and a clear pip came from the receiver. So now we can set off an alert or a call from the CCP and it blasts out of the receiver, one of the red handsets can then be used to speak into. Not satisfied with that I also hooked up the Receiver Signalling, it too worked, the relay inside can be heard operating as the WB1400 siren tones are received, I am thinking of simply hooking up a mains bulb to the switched line, or maybe a small sounder.
I wrote up some information labels to go with the display it will be a nice thing to show when there are tours, it is great to hear the WB1400 tick again especially in public, so many displays are just recordings. We could put a feed from the CCP onto the internet and have someone write a WB1400 simulator that connects to us via real or sip.
Between James and I we have enough equipment to display a fully working WB1400 system with the exception of BT exchange equipment if anyone out there can help us locate any parts falling into that category it would be great.
Day 3
Last night I went back to get a diagram from the BT room but noticed the Autex 100 on the bench, I had planned on fixing the power unit but didn’t get round to it during the day. It took a little time to fix the power unit but finally it is working and reliable, I will leave it powered up all day today to check.
I did a lot of reading at the bunker today; I finally sat down and went through the massive pile of diagrams in the BT room. I have sorted out much more information we need for the Tape Relay Centre rebuild, also on this I found the cable runs to the PJF were still intact, just cut off in the trunking, also the power cables are still there. I think I have enough information on the wiring of the PJF and the racks. The diagrams point to standard layouts and in addition to this there are several hand drawn pictures of the rack layout. The most important piece of information is the original work spec dated 1962. It makes a big deal about the power but has information on the wiring spec too referring to TG diagrams all of which we have. James seems to like the idea of restoring the room that is now a cinema, I hope we can find the other 3 teleprinter racks, we will be looking for Creed re-perforator 85’s (quantity of 9) and triple headed tape senders (quantity of 3) if anyone out there has any spare please let us know.
While looking for telegraph information I came across some details of the telephone exchange setup. There were 3 dolls eye manual boards in the BT room where there is not a display. So there was no automatic system here, same as in Bawburgh, there were relay sets associated with the switchboards. I have also identified the 3 boards 2 from those now in the comcen, and one on display in the BT room, they are labelled possn 1, 2 and 3, possition 1 is an older type which is more ornate and looks more pleasing!
I have been trying to work out how to get power back onto the test rack so I can use the oscillator and level measuring set that is installed there; this is the key to bringing back to life some of the really old transmission equipment that allowed QQGU to connect to the other bunkers. This is a transmission supply so is 24v, I followed the cables all the way from the test rack via the transmission rack bus bars to the far corner of the room where the clock resides, there the cables are cut, I cannot see where the power unit was located but it must have been in that area, I will need to find a suitable replacement ASAP. At the same time I cannot find any 50v power units in the bunker which is kind of surprising considering what I have located over these few days work. -50v DC is the staple diet for most old BT gear, switchboards, soldering iron, wrap guns, you name it it comes in 50v form. There are generally battery jacks around and they were mostly 50v, some repeater stations and telex exchanges had 24 or 80v jacks so it was always fun to plug a 5ov iron into an 80v jack and watch it glow red hot until the element burnt out. Anyway I need to get 50v back so will look out a suitable one from my own collection. The 50v supply had a battery too, for now I’m not too worried about that.
As I went over to the Synchronome master clock I thought it might be good to apply power, I disconnected all the batteries which are not in a good state. First of all I wanted to understand how it worked so gave the pendulum a swing, it just swung and didn’t do much except push a gravity arm up and down via a pallet attached to the pendulums’ arm. I notice an adjuster lever and a gathering arm which wasn’t doing anything; on closer inspection it became apparent that the gathering arm was missing its pawl so wasn’t moving the racket. I quickly made up a pawl from a teleprinter part and it begun moving the ratchet this in turn moves a vane that releases a catch that drops the gravity arm giving the pendulum a small shove, this is really nice, it needs minimum help to keep it running, except for a little power to lift the gravity arm from time to time. So I decided to power up, as the ratchet moved a relay in and associated box of tricks tried to operate but because the power is not smoothed (i.e it is AC as the battery float provided smoothing) the relay vibrated rather than operate fully. I didn’t have suitable capacitors around to smooth the supply so we will replace the battery rack with modern wet batteries, this will be less maintenance and much safer. Nice if next time we can go round and connect the pulse clocks, even better will be the sound in the BT room of the clock running, I Cannot wait!
I put a power socket onto the Receiver Signalling WB1400 in main ops, now we can connect a light or sounder to simulate an air raid siren being activated.
As I hadn’t achieved a lot in the morning I decided on getting a WB1400 feed to the ROC post display just on the left at the bottom of the tunnel. There is a genuine wallboard from a ROC post sitting on the table; it has the special loudspeaker unit built for damp conditions rather than the nice plastic unit normally used indoors. There are no telephone cables in the area so I ran what I thought was telephone cable from the BT frame all the way up through the manager’s office through a 3m thick wall up the tunnel a few metres and into the display, this took a while, I was a bit upset when the cable turned out to be alarm cable, I absolutely will replace it when I get time, I simply cannot leave it! Luckily the WB1401 box has an un-corroded battery, this is the only one I have seen recently, once connected it started to slowly charge, after an hour it was charged enough to press the test button and listen to the tick sound from the CCP in main ops. After the rest of the day the battery should have enough capacity to run all day, I will make up a bracket to hold down the test button rather than bypass it with wiring, that way if the battery does fully discharge it can be released and recharged overnight. I am going to make up new batteries for all of our WB1400 gear and bring them next time.
The Autex 100 was fine I added a directory entry and used several commands to verify it was working as it should, it is powered off now but some day I hope to get it talking to the MSX.
Web Link:mailto:paul@secretbunker.co.uk
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