Today we have added a page all about the SDS Network to the site using info kindly donated by Aux Unit News and are words of the late Arthur Gabbitas.
The Special Duties Branch was set up in 1942. Around 1000 civilians, men and women, unknown to each other and from all classes and occupations acted as coast watchers, observers or ‘Agents’. Messages would be relayed to civilian radio operators who would then transmit intelligence to the control or Zero stations.
They had been trained to identify vehicles, high-ranking officers and military units, and were to gather intelligence and leave reports in dead letter drops. The reports would be collected by runners and taken to one of over 200 secret radio transmitters.
They used radio telegraphy called TRD (transmit, receive, Dabbs) sets. They also used runners and dead letter drops. There were 43 ATS Subalterns and 69 Royal Corps of Signals personnel to back the ‘Agents’ up. They reported to Auxiliary Units Special Duties Section IO’s. Their HQ was based at Hannington Hall until it was relocated to Coleshill in 1942. These civilians were unpaid and sworn to everlasting secrecy. They had a motto – ‘Be like Dad – Keep Mum’. The SDS Auxiliers and their identities were rarely recorded on any WW2 records.
Hi, My understanding (very second hand) is that the TRD set was a locally designed and produced VHF Simplex Radio Telephone operating around about 60 Mcs; a band of frequencies that had been vacated when TV transmissions closed down at the start of WWII.
As 60 Mcs was a band of frequencies not intended for R/T it was considered the chances the Germans would not search for signals there or have equipment able to intercept the resultant signals was considered minimal.
This set used speech not Morse (CW), as there was insufficient time to train the operators in Morse Code.
It had the minimum of controls so it could be used with the less than an hour of training.
The sets transmitted and received on the same frequency or channel, with only one end of the link transmitting at a time. And the operator sending “Over” to pass transmission from one end of the radio link to the other.
Sorry inverted logic; correction:
As 60 Mcs was a band of frequencies not intended for R/T it was considered the chances the Germans would not search for signals there or have equipment able to intercept the resultant signals was considered high.