My Search for the ROC Inter-group Radio Links

Introduction

This topic describes my search for the path taken by ROC Group HQ radio links. How the radio links were used by the ROC is described elsewhere on this site. The related topics may be found at the bottom of the page.

Background

The situation at the end of the 1970's was very different from today. There were very few lattice towers to be seen in the countryside, unlike now where mobile phone masts may be found every few kilometres. The cellular phone did not make its appearance until the late 1980's. Those lattice towers that did exist were usually marked on maps as significant features. The use of the masts could be relatively easily determined by visual examination. Home Office masts could be easily identified by their VHF 6 element Yagi aerials used to link the hilltop sites to the police or fire controls. No other services were permitted to use VHF radio links.

With the help of the local library I had gained quite a bit of information about how the police and fire radio schemes worked. The Home Office Department of Telecommunications published quite a lot of detail including the frequency bands they used. The band from 97 to 103 Megahertz was used for the Emergency Services much to the consternation of our European neighbours, who used it for broadcasting. People used to listen into the police and fire transmissions using their Stereo's (VHF FM radios) but reception of the AM signals were poor. Scanning receivers were not available to the general public at that time. The Emergency services moved to another frequency band during the mid 1980's freeing up the band for commercial VHF radio.

The Initial Discovery

A number of factors came together around 1979. Firstly a friend, who used a cheap radio to listen to the fire brigade link frequencies, reported his reception blocked by a very strong signal containing white noise. This turned out to be on 147.000 MHz, as this was in the Home Office band, it did not take much effort to trace the signal to the nearby hilltop site at Old Gorse. (Not a secret - The local newspaper carried an article when a new mast was installed for the 'Police' at Old Poor's Gorse) This signal persisted for a few weeks then disappeared, I assume the fault was cleared. The final thing was changing jobs and as a result had to visit ROC sites. Details of their exercise were available which indicated when radio tests were being performed.

On the first occasion that I was aware a ROC exercise was taking place, I decided to try to find their frequencies. A hunch made me listen on the frequency where we had heard the white noise. Much to my surprise, there was Bedford talking to its posts. Further tuning between 147 and 147.3MHz revealed other frequencies in use. Unlike the On-Off transmissions to the posts, these were continuously on and carried S+DX. I had stumbled on some of the frequencies used for the Inter Group links although none were coming from Old Gorse, but from the North and South.

Hunting down the Masts

The next thing was to pay Old Gorse a visit to see what was going on there. High up the mast were yagi aerials pointing in the expected directions for the police and fire services. However lower down the mast were two VHF yagi aerials pointing north-westerly and three pointing south-easterly, these had to be for the ROC. Next came a visit to Bedford ROC HQ, in Bromham Road, Biddenham. This had a wind up tower, currently in the down position, containing loads of VHF 3 element yagi aerials. Two pointing North East, Four South and Three East-ish. Additionally a 6 element yagi pointed North-westerly in the direction of Old Gorse. However there were three aerials at Old Gorse but only one here at the ROC. On the way home, I spotted a Home Office mast at Twinwoods Farm, Oakley, just North of Bedford. On diverting to pay it a visit there were the expected Police yagi's pointing into Bedford. Again lower down the mast, two 3 element yagis pointed toward ROC Bedford matching the two 3 element yagis there, pointing north-easterly towards us. There were two 6 element yagis pointing north-westerly towards Old Gorse. This completed the match in a northerly direction, but opened up questions why two radio links came via Twinwoods to Old Gorse, and one went directly (answered later). It seems so sad to say it now, but I planned my 1979-80-81 holidays so I could visit as many ROC locations in the East of England as possible and trace out the links by looking out for masts on the way. As I said previously many were marked on the map, so this was not too difficult.

Hunting the Frequencies

Finding the Regional Government Headquarters (RGHQ)

My friend visited Norfolk fire brigade headquarters in Hethersett and remarked he could see a Home Office style mast about two miles away, but the aerials on the fire control pointed elsewhere. I planned my holiday to take in Norwich and Lincoln, as they were both ROC Group HQ locations. I investigated the mast my friend had identified and wandered into the woods beside the mast and spotted a bungalow with blacked out windows and various air vents nearby. I had read in the daily papers about Regional Government bunkers disguised as bungalows. I had struck gold and the location was Bawburgh.

The mast contained a few VHF yagi aerials that appeared to be ROC links. There were thirteen UHF yagis, my scanner revealed seven UHF carriers emanating from the site. One of these on 466.025 matched 452.025 being transmitted at the Norwich ROC group HQ. The UKWMO booklet showed a link from Group HQ's to RGHQ's, so I concluded I had indeed found gold. Up until now I had not paid any attention to the UHF yagi aerials although I had seen them at all ROC group headquarters. There were numerous UHF yagis on Home Office hilltop sites pointing in all sorts of directions but I had no explanation of their purpose until now. A strong signal on 452.125 in the vicinity of Norwich City Hall had a matching link at the Bawburgh end on 466.125, although they did not appear in the UKWMO booklet, council headquarters had links to their RGHQ.

Later in the holiday at a hilltop site near Fulletby in Lincolnshire, I started paying attention to the UHF yagis, which pointed in various directions, but strangely four were pointing eastwards, not in the direction of any habitation centres. Eighteen years later, when I stumbled on the SUBBRIT web site, I discovered that a RGHQ had been located 9 miles away at Skendleby which fell almost directly on the line I had drawn on the map in 1981. If only I had driven down that line.

Similarly at Reed hilltop mast, there were twelve UHF yagis, a carrier on 451.150 matched a 465.150 signal I traced to Sovereign House, Hertford. However being totally unaware of the locations of the RGHQ's I had just assumed this was like the other UHF links at Bedford ROC (466.125) and Council HQ (466.175) which connected to Twinwoods (452.125 & 452.175) then via Twinwoods (452.150 & 452.225) on to Reed (466.150 & 466.225). There were two other links at Reed on 466.025 & 466.150, not traced. Mistakenly had assumed that all these links eventually led back to Bawburgh and not that Sovereign House was itself a RGHQ.

Conclusion

Due to the ease in which Home Office hilltop sites could be recognised and that the ROC links were always lower down the structure than the police and fire links, the job of tracing parts of the ROC network was made easier. It is interesting to note the ROC was the poor relation, it used one aerial for both transmit and receive whereas the police and fire had two separate aerials.

Duncan Campbell's War Plan UK would have been a great help in locating the RGHQ's, but I was unaware of its publication. Had I not moved home in 1981, which stopped further investigation, more may have been revealed. In the mid-1980's the network described here was replaced and the radio frequencies used for other services.

As a total outsider I was pleased with what I had discovered, I am sure people who worked for the Home Office Department of Telecommunications (DTEL's) would laugh at my pathetic attempts. I would love to know if the whole UKWMO network was documented and perhaps before my death the archives may be released to reveal the true path of these links and confirm if the frequencies were indeed correct.

The Network as Discovered by 1982

A change of job in October 1981 and a house moved forced an end to it all. This is the final map I drew in 1982 - Click Thumbnail to Enlarge. This network was replaced during the mid-eighties, by different system using multiplexed links on frequencies in the 1600Mhz band. The ROC was stood down in 1992 bringing an end to all these radio systems.

FEEDBACK - The North Wales ROC VHF link Network

As result of reading this page Martin sent me a copy of a drawing he found blowing around a carpark near a home office hilltop site that was being cleared 10 years ago. This was a hand drawn sketch of a diagram CB429 showing the UKWMO vhf radio links. The sketch is of particular interest as it dates from 1978, the same era as my research. I have redrawn the original to improve readability. Click Thumbnail to Enlarge I am most grateful to Martin for this information and would appreciate any help, you the browser, can offer on this subject. For frequency planning purposes a larger picture would have been needed, is CB429 one of a series of drawings for the ROC links or was the pencil sketch an extract of a country-wide document?