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The Daniels MT-3 Subrack
By David VanHorn KC6ETE
The subrack provides all the wiring necessary to interconnect the cards, and extensive voltage transient protection, plus some jumper options on clearly labeled jumper points. There are large barrier strip terminals for the 12V and 9.5V power inputs, though the 9.5V input is not needed if you have the system monitor card installed. (more on that, later).
The subrack has a master fuse on the rear.
Not covered below, are two connectors on the rear of the backplane: the Auxillary Control connector labeled P2 and the Control connector labeled P1.
The P1 connector mirrors the connections available to the system control module. The P2 connector has a limited subset of those connections. These two ports are where you would connect a third party controller, like the Arcom RC-210 that I'll be using.
The P2 connector is a 48-pin female DIN connector, made by Harting. Digikey part number 1195-1329-ND, manufacturer's part number 09062486823. A photo is shown below.
The Subrack has pre-defined positions for the following cards, from left to right: (looking at the front of the subrack)
Notes on the above modules:
You can place any receiver in a receiver slot, and any transmitter in any transmitter slot. At first glance it is not obvious, but the transmitter housing is actually narrower than the receiver, and this prevents you from physically inserting the wrong module into the wrong slot. This careful design is good thing when the nearest replacement module might be several expensive weeks away.
The RF modules all have their RF connectors on the front, rather than the rear. This means that you end up with cables coming to the front of the rack, but to do anything else would have been a serious compromise in signal integrity. All of the modules I have seen use N connectors, but there may be other versions.
A typical TX module is set to about 4W output. This is somewhat under the module's actual capability, but it keeps the module operating well within its safe area.
The transmitter and receiver modules are entirely useful without the subrack. The subrack is simply a convenient way to tie them together. If you get the appropriate DIN female connectors from Digikey (photo below), you can wire direct to the modules, or remove the backplane in the subrack and just go direct to the modules. This is also a very good way to work with the modules, in the process of realigning them. Daniels sells an extender card, which is still a current product, at $220, but all you really need to do an alignment, is some good clip leads, or a DIN connector.
Some of the TX and RX modules have an internal relay option. This is an isolated relay, which can be used for switching any non-RF signal.
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Text copyright © 2005 by David VanHorn KC6ETE
Hand-coded HTML © Copyright 2005 Mike Morris WA6ILQ
This page last updated 17-July-2005
The information presented in and on these conversion pages is © Copyrighted 1995 - (date of last update) by Kevin Custer W3KKC and multiple originating authors.