RT 3600 / RT 3610
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Around 1969 the first radios started making their appearance in the field, if the dates on the various manuals should be believed. It was a versatile family, build around two very different transceivers: the middle range RT-3600 and the short range RT-3610 model. The RT-3610 is pretty straightforward, although it can also be used in vehicular installations with a adapted battery box that then takes the part of junction box.
However, the RT-3600 is a technical development I have never seen anywhere else - excepting it's successor, the RT-4600.

The RT-3600 is highly modular - as most systems of that period in time - but takes that concept one step beyond, so to speak. Where other radios will combine closed boxes into working systems, the RT-3600 will also fit different modules in boxes to make up those systems.
This is particularly true for the transceiver itself. The basic RT-3600 has an output of 2 Watt - but if more power is needed, the AM-3600 30 Watt RF-amplifier unit easily replaces the JB-3600 junction unit: they both fit in the back end of the housing that has the RT-3600 in front. Very flexible indeed.
Now, that canister that holds the RT-3600 and either the JB-3600 junction unit or the AM-3600 30 Watt RF-amplifier does not have a power supply. For that is named PP-3620 and again is only a module, fitting in the back of a slightly different housing. In the front slips either a AF-3620 control- and loudspeaker unit or a IC-3620 intercom unit.
So, in order to build the minimum RT-3600 vehicular radio one has to stack two elements:

RT-3600 combined with either JB-3600 junction box or AM-3600 amplifier
PP-3620 combined with either AF-3620 control/speaker or IC-3620 intercom.

This most basic vehicular configuration, a stack of two elements, can therefore take four forms:
Transceiver, 2 Watts, with loudspeaker
Transceiver, 2 Watts, with intercom connections
Transceiver, 30 Watts, with loudspeaker
Transceiver, 30 Watts, with intercom connections

Now, a stack can have three elements - and as we already have the power supply, the third one would of course be another RT-3600 transceiver. This gives a two radio set-up, where both radios can be long range or short range, and either tied up into a local loudspeaker control unit or in a intercom set - that off course can again include loudspeakers. There is a separate loudspeaker LS-3621 - Amplified Loudspeaker - that ties in to any C-3621 local communications box. The C-3621 is tied into the on-board net through the IC-3620 intercom unit. Actually, this is done with a pretty neat trick: the IC-3620 has two connectors for the C-3621 intercom boxes, and they daisy chain all around, back into the second connector of the IC-3620, using CX-361x cables. The x here stands for the actual length - and there are many! This daisy chain approach gives more reliability, as one connection being broken does not put the system out of operation.

But the system is not limited to one stack: it can have two. The maximum is a total of five elements divided over two stacks. And as each stack needs a power supply, the second stack can have only one transceiver. All three can be high power, low power or any mix between the two. In a full installation you will normally find both an IC-3620 intercom unit and an AF-3620 control- and loudspeaker unit.
Unlike what one expects to find, studying military radios, connections are made both on the front an on the back. On the back you will find connectors tying the individual elements within the stacks together, on the front are the connectors for power, on-board net and tying up the two stacks into one system.

Quite often the documentation discerns the various possible radio-configurations in terms of range:
RT-3610: 3 kilometres.
RT-3600: 8 kilometres.
RT-3600 with AM-3600: 30 kilometres.
The RT-3600 can also be combined with limiter RF-3610 which limits it's range to 3 kilometres.

This only scratches the surface, but more information is due at a later date - my time on hobbies is limited.

Last updated: 12-11-2003 23:22 +0100
Copyright 2001, 2002, 2003, 2004, 2005 A.J.M.O. Witkop. All Rights Reserved.