Those Radio Amateurs desiring a Plug-N-Play radio should consider some of the used very reliable ex commercial units such as the Motorola and GE models described here.  Yes you will need to make up a simple cable for the GE and Motorola radios but hey! - you're a licensed ham radio operator so this simple project will be a breeze. 

If you are challenged at this, please post your questions to the IRLP Yahoo group http://groups.yahoo.com/group/irlp/  

Please do not waste a perfectly good dual band mobile or HT or worse yet a multi band/mode HF rig.  We received almost daily queries about adopting IC-706 and FT-847 radios.  Look on eBay or your neighbourhood Hamfest for one of the following bargains that make outstanding reliable node radios.

NOTE:  While surplus commercial radios are by far the best choice for IRLP nodes, ALL commercial rigs require proprietary programming software and hardware.  While there are many sources in most communities for this type of programming, it is best to check first with your area ham buddies who work in the commercial field before acquiring the rig.  Barring that, you can expect to pay between $30-50 to have a couple of channels programmed at a commercial shop.

MOTOROLA M SERIES RADIOS
with 16 pin option connector

You should check eBay for the following search words.  GM300, MAXTRAC, M120.  You must make sure the radio has a 16 pin option connector.  The 5 pin radios DO NOT have COS at the plug .

GM300 shown here

Pin -Outs for ALL Motorola 16 pin radios

TX audio in=2 * a 10UF Non-polarized DC blocking cap in series may be required

PTT = 3
Gnd = 7
COS = 8 active low on carrier or valid PL
     NOTE: on 16 & 32 ch models, this pin is 
               programmable for other functions

RX audio out = 11

NOTES:

1. As long as the microphone is inserted and hung up on the clip, the PL will be enabled. To operate the node without a microphone plugged in,  make an RJ45 mic plug shorting the PL line (PIN 3) to ground (PIN 4). To enable the front panel speaker, jumper 15 to 16

2. On most of the Maxtrac radios, the feature which forces PL to be enabled when the microphone is hung up (clip button on back of microphone grounded) can be DISABLED when programming the radio.  This is under the radio-wide options screen along with the TX timeout value which can be set to OFF. Neither of these are default settings.   TNX Bob AC0KC

Pre-made cables are also available from Jay KP4EOP at http://www.gpscables.biz/7.htm

Useful Motorola Links

• http://www.repeater-builder.com/maxtrac/maxtrac-index.html

• http://www.batlabs.com/gm300.html 

Find a Motorola radio on eBay MAXTRAC    GM300     M120   M10

LOOKING FOR A PRE-MADE CABLE? 
 CLICK HERE for pre-made cables from Jay KP4EOP.
CLICK HERE for pre-made cables from Marshall KE6PCV

A great resource for Motorola Radios including 5 pin Radius models can be found at Batlabs  www.batlabs.com . Model specifics can be here........ http://www.batlabs.com/2way.html

GE PHOENIX (S or SX models)
by Rob N1NTE

The GE Phoenix radios make nice IRLP simplex nodes. Normally, a Phoenix puts out around 25 W on UHF up to 40 W on VHF. If you are not planning on using a fan on the heat sink, then it is recommended that you turn the RF power out down to about 10 watts. The power out potentiometer is R120 located on the bottom of the radio under the metal shield. There is a hole in the metal shield that allows you to gain access to it.

Here are the connection details:

There are two connectors on the back of the radio - J911, the microphone plug and J910, the power/speaker plug. J911 is an 8-pin connector and J910 is an 11-pin connector. If you are looking at the top of the radio with the rear facing you, J911 is on the left and J910 is on the right. (See diagram below)

Pin 2 on J911 is the PTT
Pin 4 on J911 is the TX audio
Pin 4 on J910 is the RX audio
Pin 2 in J910 is the COS (active hi (10v) on valid CTCSS tone)
Pin 8 on J910 is GROUND

Below is a diagram. Notice that you need to add a diode in series with the COS line and its polarity. The shield of the cables connecting the sound card should be connected to ground.

Thank you to Paul Cassel, VE3SY for the original post to the IRLP General email list detailing the hook up information. Please send corrections and modifications to Rob Bellville, N1NTE  n1nte @ cox . net

An Improved Interface for GE Phoenix RX audio

The above interface requires very minimal knowledge of electronics however the audio transmitted FROM your node to the network will be thin with few lows.  This is due to the fact there is no de-emphasis being performed.  This can be over come by taking audio direct from the speaker terminals and keeping the speaker audio very low so not to overdrive it.

A better solution is to use the simple circuit below from Sean N0PBA of IRLP node 3239 which not only provides the needed de-emphasis but also adds some audio gain to make up for the low level from the radio.   This circuit would be added in series with the line from Pin 4 of the radio to the Line-IN of audio card.  The 12 VDC can be tapped into Pin 1 or 11 both of which usually have 12 VDC from the power plug.

Useful GE Resource

http://www.rtzaudio.com/kg4lne/phoenix.asp

Find an Phoenix radio on eBay CLICK HERE

GE MVS IRLP Wiring Instructions
by Warren Paulson VE3FYN

email: ve3fyn at shaw dot ca

The option connector is found by removing the metal plate from the bottom of the radio. Two Torx screws hold the plate on. With the plate removed, locate the 13 pin option connector, near where the power cord enters the radio. Pin #1 is closest to the back of the radio.  Note that the GE-MVS manual refers to pin #10 on the MVS as an audio mute pin. However this pin generates 5 volts DC when a signal is detected, making it useful as a COS pin.

Download the PDF original GE MVS manual here. This will provide operating information, and in-depth background to the mods shown here, including block diagrams and schematics.

Ground DB9 pin 6, and audio jack ground to one of the screws near the option connector. Ensure that the radio and your computer share a ground.

From the point of view of the MVS Option Connector, the connections are as follows:

Audio Levels

This method of connecting your radio is simple, but you will find that the audio level from the radio is low. To boost your audio output, follow one of the two suggestions described in the "Improved Interface for GE Phoenix RX audio" section on this page. If you are going to take audio off the speaker (the simplest approach) the following photo locates the speaker connection.

Follow the board where the option connector is located toward the front of the radio. Remove the ribbon cable temporarily. Toward the front of the radio is an orange two wire cable. This is the speaker cable. To tie in directly to the speaker, connect to the pin closest to the transistor (in the photo, a blue wire has been soldered to the pin.) If you're not sure which pin to use, get out your ohm meter. With no power to the radio, measure each pin against ground. One pin will show 0 resistance against ground. Use the other pin.

Find an GE MVS radio on eBay CLICK HERE

ALINCO
DR-135T - 144 MHz  "D" model requires removal of TNC
DR135T/E MkII
DR-235T - 222 MHz
DR-435T - 440 MHz

These Alinco models have a DB9 connector designed for packet radio and work quite well for IRLP.  Pre-made cables are also available from the following sources

1. Jay KP4EOP at  http://www.gpscables.biz/6.htm

2. Marshall KE6PCV at http://www.irlpcables.com  

Other Radios
If you have detailed info on radio interfacing please drop the webmaster a line at