IRLP Link Radio
IRLP Node #1240 is on the
UHF VE6SBR Repeater - 444.800 MHz

A 103.5 Hz CTCSS access tone is required.

Edmonton IRLP  Internet Radio Linking Project



Update - The VE6SBR repeater no longer exists
but this page was left for the information and ideas it may provide.

December 2000

Following are pictures of the link radio built to interface IRLP node 1240 to repeater VE6SBR.

An ICOM U2 UHF handheld radio, a
power supply and the IRLP DTMF tone
decoder interface board were installed
in an old computer back-up tape drive
LEDs indicating DTMF Tone Detection,
Receiver COS and Transmitter PTT
were relocated from the IRLP interface
board to the front panel beside the
Power On LED.
The enclosure rear panel has the
radio BNC antenna connector, the
radio channel selection switch, the
25 pin PC parallel port connector, the
PC sound card interface cable, & the
ON/OFF switch, fuse, & AC line cord.

Enclosure Internal View
The link radio assembly on top of
the IRLP computer.

It was soon discovered that the "old" ICOM handheld had seen much better days and had numerous problems. Each time one problem was cured, two more seemed to develop and the radio would never be able to be counted upon to provide reliable service due to component and soldered connection failures resulting from old age and hard use. After countless hours of work, the radio was finally made acceptable for temporary service while a replacement radio was found and prepared.

February 2001  -  New WR-1454 Link Radio

The link radio is at the home of James, VE6SRV, who provides the IRLP internet connection. He had a UHF antenna available for the link radio, but being antenna poor this left him having to use a VHF antenna on his UHF handheld to communicate with the VE6SBR repeater for IRLP conversations. The combination of the handheld's low power plus the less than ideal 3rd harmonic UHF match on the VHF antenna resulted in James having a less than full quieting signal into VE6SBR. It did not make sense for James to have to transmit his signal 12 miles just to access the IRLP link radio sitting several feet away from him so I designed the new link radio for dual purpose use. It provides both, the link radio function for IRLP and also functions as a standard radio for James to use for local VE6SBR repeater access. This is accomplished with some special audio path switching.

To function as a standard IRLP link radio, the radio's receiver COS and transmitter PTT signals must be connected to the computers IRLP interface board. Also, the radio's input and output audio signals must be connected to the computers sound card. For James to also be able to use this radio as a standard radio, it has to be further modified so that -

1. When the IRLP node is active and James uses the radio to transmit to the repeater, the normal receiver audio fed to the computer must be replaced with the local mic audio and the receiver COS signal fed to the IRLP interface board must be replaced with the mic PTT signal so that the mic audio being transmitted to the repeater can also be sent to the IRLP system.

2. When the IRLP node is active and the radio is transmitting received IRLP audio to the repeater, the normal receiver audio to the radio's audio amplifier must be replaced with the received IRLP audio being feed to the radio's transmitter. In addition, the receiver COS signal that un-mutes the radio's audio amplifier must be replaced by the IRLP interface board PTT signal that keys the radio's transmitter so that the received IRLP audio can be heard locally.

The following photo shows the front of the modified radio spread open and the board wired into the radio that was constructed to provide the required COS, PTT and audio switching. For such a small board it is unbelievable how many interconnecting wires are required. The large gray conductors are the two 1/8" shielded wires to & from the sound card. The small gray conductors are the 1/8" miniature shielded wires used within the radio.

Also on the board is a relay for radio channel 1 / channel 2 selection, CTCSS tone encode/decode circuitry and a DTMF decoder that eliminates the need for a separate IRLP controller board.

Link radio control board, wired into the radio, but before the radio is closed up.

Original radio top view before
removal of the tone access board.

Original radio bottom view before
removal of the 4 channel crystal
oscillator board.

Modified radio top view showing
bottom of the new IRLP control board.

Modified radio bottom view

CLICK HERE for an animation of the radio in action. (1 MB)
(Sorry, but the animation no longer works due to the way newer browsers work)
(Hopefully I'll be able to find time before too long to fix this.)

Using IRLP, you only hear the messages of the node accessed, never the node that you are on.

For local users, the following buttons have been provided to play the node messages of
Edmonton VE6SBR repeater (node 1240) and Alberta SARA Linking System (node 1260).
(Note: The following buttons no longer work due to the way newer browsers work)

VE6SBR Node 1240 On Message   SARA Node 1260 On Message
VE6SBR Node 1240 Off Message   SARA Node 1260 Off Message
November 2005
A number of requests for Western Radio information have been received from others finding the same thing I did, that WR information is hard to find. To save others having to also request what information I have, it has all been scanned and can now be downloaded as PDF files using the following links. Note: Some files are large and will be slow to download without a high speed connection, but I prefer that to sacrificing image quality and smaller files. It has been a while since I have worked on Western Radio's or have seen these files so not sure how accurate they are. Proceed with caution, as one should always do, and you should have no problem tuning and making use of WR VHF & UHF radio's. And if anyone ever finds a copy of a UHF manual, I would really appreciate a copy.
wr154.pdf & wr155.pdf are the important pages of 2 VHF radio manuals I have. General information, that most never read anyway, was not included to keep the file sizes reasonable. Some pages have notes made by previous manual users that I know nothing about so do not waste time writing and asking me about them. wr154.pdf
wr1454.pdf is a partial schematic for use when working on UHF radios. Except for RF sections, WR-154 VHF & WR-1454 UHF radios are basically identical so the schematic was created by simply copying a VHF one and making a few changes seen in my UHF radios. Most of my radios have an extra circuit board with crystals for 4 channels and a few have boards with other features, but they are only used where a basic single channel radio is needed so I start by (a) removing any additional boards and wiring. Then I (b) print a copy of the wr1454.pdf schematic and (c) mark any changes and how the radio ends up being wired on the schematic and then (d) the schematic is kept for a record of that radio's wiring. wr1454.pdf
wr1454r1.pdf started out as a wr1454.pdf schematic and documents the first UHF radio I worked on and placed on my 444.800 repeater frequency. It includes some of the radio's RF circuitry and of greatest importance, without other UHF radio documentation, this drawing provides information to calculate receive and transmit crystal frequencies. wr1454r1.pdf
wr1454irlp.pdf is similar to wr1454r1 but includes more information yet and is a schematic of the special UHF IRLP link radio. wr1454irlp.pdf
irlp.pdf is a 4 page schematic of the VE6SBR repeater WR UHF IRLP link radio I made and of the special IRLP circuitry that was added. irlp.pdf
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