Batboard

I originally posted a question on Maxtracs, and got lots of good info:

[url]http://batboard.batlabs.com/viewtopic.p ... highlight=[/url]

In one response Nand linked to a PDF write-up for building a repeater cable from the 16-pin ACC jack. This is what I am having trouble with.

For background: Two Maxtrac 300's, VHF, 25 watt. RX radio is programmed for CSQ. Both radios RX and TX fine individually - both have 25 watts out to the watt meter.

RX radio's ACC jack programming:

4:External Alarm:output:no:high
6:NULL:input:no:high
8:CSQ detect:output:no:low
9:NULL:input:yes:high
12:NULL:output:no:low
14:NULL:output:no:low

TX radio's ACC jack programming:

4:External Alarm:output:no:high
6:NULL:input:no:low
8:NULL:input:no:low
9:NULL:input:yes:high
12:NULL:input:no:low
14:NULL:input:no:low

The cable is built per Nand's diagram. Pins 3 & 4 on the RX radio's front RJ45 are jumpered.

The RX radio receives fine and I get a blinking red front panel light on RX. I get nothing on the TX radio. If I measure voltages between TX radio ACC pins while transmitting with an HT (causing the RX radio to receive), I get:

Pins 7 and 2: -2 mV changes to 0 volts
Pins 7 and 3: 12 mV changes to 0 volts

Phew! Lots of info, though I'm sure I left out something key.

Any ideas?

Thanks,

Patrick

check your *COR make shure its working???

my 2 cents

Outa here

Patrick,
Not having played with this stuff in a while please bear with me. Are you going through a controller of sorts or just interfacing two radios back to back? With pin 8 programed for pl/dpl/csq detect you would also be concerned with 4 other pins on the accessory connector and they are:
3 = ptt
5 = flat tx audio
7 = ground
8 = pl/dpl/csq (the cor signal)
11 = rx audio
If your using a controller does it need to see (cor) go low or high

I'll end here for now until you supply a little more information.
Doug

I'm using the cable described in Nand's note's below:

[url]http://www.storm.ca/~nand/990/RICK/rptr.pdf[/url]

Patrick[/url]

Well Patrick,
Check the voltage change on pin 8 of the receive radio while receiving a valid signal, verify your getting cor.
Doug

That was a typo in my original post. Pin 8->3 (RX->TX) shows 12mV when no signal is being received, then 0 volts when a signal is being received.

Thanks,

Patrick

It's been too long since I've worked with Maxtracs RSS but I wonder if you have to enable some field for the accessory board in a hardware screen before programming the fonctions?

The second thought would be to separate the distance possibly 24 inches between the mobiles transceivers to prevent the internal VCOs from radiating into each other.

Dan

I'm at a loss, the only thing I can think of next is to verify your connections from rx pin 8 to tx pin 3. Go over your programing once again.
Check your mode configuration:
RX Radio
RX frequency = repeater input
TX frequency = Blank
RX squelch set for carrier
Busy channel lockout = N
TX Radio
RX frequency = repeater output
TX frequency = repeater output
RX squelch set for carrier
TX squelch set for carrier
Busy channel lockout = N
I'm not trying to insult you with the above information its just I have no idea of knowing your working knowledge with this kind of stuff
Good Luck...Doug

I'll chime in with a basic thing:

Disconnect your "repeater" cable from each of the radios.

With your TX radio, take a wire from pin 3 and put it to ground.. does it transmit?
If No, something is wrong with your TX radio
If Yes, then either a receiving radio programming issue or receiving radio hardware problem.

(It's a start, at least isolate the radios and go from there.)

tpg

PM, Look here for more info.

http://www.webimaging.com/echocomm/

clik on Product, then Repeater Module.


The Programming instructions come with it and the rest is plug and play. I think the instructions would work on Nand's wireing scheme also.

Hey Patrick,
Having any luck?

Hi Doug,

I tried a coupe of things.

First I tried grounding ACC jack pin three on the TX radio and it TX's just fine. I then double-checked the programming on both radios, and even swapped the radios. Same result.

Since the cable is none too complicated, I suspect a programming error, but I'll be damned if I know what it is.

Patrick

The COS/COR output from the MaxTrac is an open-collector transistor, so when you measure it with a voltmeter, it would need an external source of voltage to pull it up through a resistor. You can use something like a 10k resistor to the power supply. Then you would measure close to 14 volts with no input signal, and 0 volts with a properly decoded signal.

I believe the RSS can be programmed to set this line low or high upon receipt of an input signal. You probably want to have it go low. You should be able to directly connect this to the PTT input on the transmitting radio, as that would have a pull-up resistor on that line.

With everything connected, the COS/COR/PTT wire should be between 5 and 14 volts when idle, and 0 volts when the station is active.

Bob M.

With the radio UPSIDE DOWN and the rear facing you, the accessory pin numbers are as follows. The ODD numbered pin numbers are in the upper row (closest to the actual bottom of the radio). Pin one is the most right one (towards the center of the radio).
The row below this has the EVEN pin numbers. The most right pin is pin 2.

With nothing connected to the accessory connector, pin 8 should measure about +5 volts in a Maxtrac 300 when this pin is programmed for CSQ active LOW and NO signals are received. It is pulled up internally in the radio though a 4.7K resistor to the +5 volt bus. This line should go to nearly ground when a signal is received.

Make sure both radios are powered from the same power source and both have a common ground.

If all still fails, use another pin for COR, like pin 12 instead of pin 8. You need to program this pin like you would program pin 8.

Nand.