Notes for MICOR Base station and repeater station conversion

By M. Scott Zimmerman N3XCC

*Disclaimer: The following are notes ONLY. This is not intended to be a complete how-to guide. I have used the following guidelines on every station I have done and they seem to work fine, however use them at your own risk.

Normal Backplane

Jumper Line driver pin 13 to line driver pin 23 with a 100k resistor to enable local speaker monitor audio. This audio level can also be adjusted with the pot on the audio/squelch module, however this *may* also adjust the audio level available to feed your controller. (See connections below)

DVP Backplane TCN1264, TCN1273, etc.

Jumper Line driver pin 6 to line driver pin 19 with a 100k resistor to enable local speaker monitor audio. This audio level can also be adjusted with the pot on the audio/squelch module, however this *may* also adjust the audio level available to feed your controller. (See connections below)

All Backplanes

If using keyed Tx channel element:

Do the mods to the station control module TLN4635 or TLN5970 under "keyed channel element".

Jump J5-14 to J5-19 for Keyed F1 Transmit element enable.

If not using Keyed Tx Channel element:

Jump J5-19 to GND for constant F1 Transmit element enable.

Ground J2-30 for F1 Rx enable. Ground can be found on pin J2-26.

A monitor speaker can be connected to pins J2-1 & J2-2.

Repeater controller connections

Connections to your repeater controller can be made in several different ways. I prefer using the signals available at the Squelch gate module location. I simply solder a pigtail umbilical cord to the appropriate pins of the squelch gate module and put an appropriate connector on the other end of the cable. It's a very simple interface.

• PL Encode - A PL encode tone may be connected to J2-16

• Discriminator audio - Buffered discriminator audio is available at J2-15

• Controller audio - A source of de-emphasized, buffered, PL filtered (If OEM decoder is installed) and squelch gated audio is available at J2-14 or Squelch Gate Module pin 17. CAUTION: This audio goes through the above mentioned pot on the audio/squelch board. If you use this audio source, set the Max. volume level before setting your controller's Rx pot. I normally use the 100k series resistor and turn the A/S board pot wide open. In doing this, I am providing the controller with as much audio as possible to help eliminate noise. If you wish to run a differing audio level, set this pot for your desired audio level.

• TX Audio - Unfiltererd Mic hi audio may be injected at Screw terminal 20 and also at Squelch gate pin 11. Jumper JU1 must be in place, and trace from Station Control Module pin 16 must be cut. Audio at this input will be pre-emphasized and limited by the exciter's audio circuitry.

• PTT - active low Push-to-talk logic is available at Screw terminals 12 & 8 and also at Squelch gate pin 18

• Ground - Ground is available on most of the chassis. Screw #1 is ground, as well as Squelch gate pins 1 & 23.

• 12v - A source of 12V is available at screw terminal #10 and at Squelch Gate pin 12.

• COS - An active high COS is available at Squelch Gate pin #5 and J2-13. You will need to build an inverter if your controller requires active low COS logic.

• CTCSS decode - If an OEM decoder is being used, active high CTCSS logic is available at Squelch gate pin 14 and at J2-10. CAUTION: This pin is driven high on an active signal. Use a series resistor to prevent an accidental short from burning out the transistor on the decoder board.

These notes were prepared by
M. Scott Zimmerman N3XCC; 3/6/2006
Revised 8/15/2025
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