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12...Although there have been no instances reported of this happening, a problem that can occur with repeaters built along these
lines is that both transmitters lock in transmit mode simultaneously. This causes permanent ‘dead-keying’ on both frequencies and
will badly effect your comms!
A crude but effective way of making sure this doesn’t happen, is to fit a single, 8 to10 Amp, self-resetting fuse in the supply line.
If both transmitters switch to transmit at the same time, the current required will exceed the capacity of the fuse and it will blow
so switching them off. A little while latter, it will reset itself and if the problem has cleared, then all is well and operation will con-
tinue as normal.
13...Although the cross-over cable is a standard part available from Team Simoco, it can also be made up by you if required. The
positioning of the two radios may actually dictate this as the cable comes in only one size. The maximum length you can make
them up in is about 3 metres but at this length, screened CAT5 cable should be used along with ferrite EMI filters where possible.
14...The terms ‘Rebroadcast’ and ‘Repeater’ are used almost interchangeably in this document. In fact a UKSAR ‘convention’ is be-
coming established where ‘Rebroadcast’ refers to the two-frequency-simplex system adopted by the Lake District and it’s near
neighbours. Whereas ‘Repeater’ is now more often used to refer to the wide area duplex system used by some teams. This latter
system is where the radios receive and transmit on different frequencies and normal simplex (back-to-back) operation is not possi-
ble. Strictly then, our system as used in the examples in this document, should be called ‘Rebroadcast’.
15...The Simoco radio model immediately before the SRM9000 series was the PRM8010/20 series. A number of teams still have
these radios and they are still good, workhorse sets. It’s possible using a small external circuit, to set up repeaters using these
radios. If anyone wants details, contact Rob Brookes (details at the back) and I’ll send them to you.
16...Due to the fact that the architecture of the SRM9000 vehicle radios is very similar to that of the SRP9100 handsets, I asked
TMC if it would be possible to make repeaters using these handsets. The answer is basically, ‘Yes’, but the handsets are not in-
tended for this use where the vehicle sets are. As such a couple of small differences exist that, in theory, could be overcome ex-
ternally so making this possible. I will take this one up with TMC and see if we can get some practical instruction as to how this
might be done.
17… If you are setting up two SRM9000 radios for use as a rebroadcast system even if one of them is also going to do service as
your vehicle’s main comms radio, the ‘Mute Speaker During FFSK’ option must NOT be checked. Doing so will prevent the data
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