South Hills ARC (Admin)
|Posted on Saturday, December 06, 2008 - 05:54 pm: |
I purchased my Kenwood TR-7930 in 1983. It didn't have the TU-79 tone encoder, so a few years later I breadboarded a tone encoder using the schematic Kenwood supplied with my 7930 and using identical components.
Piexx TU-79PX, $59.00 + S&H
About 3 years ago, I bought a TR-7950. Once again, it lacked the tone module. I purchased a TU-79PX tone encoder from Piexx in August of 2004. I purchased it online through their website. They provide the installation instructions, programming codes and several pictures of the product on their website.
After I placed my order, the next day, I received a confirmation email from one of Piexx's staff, confirming my order, telling me when it would ship and also asking me what (3) PL tones I desired, so they could pre-program it for me!
The Piexx unit is physically identical to the size of Kenwood's TU-79. They provide a copy of the manual, the harness and mounting stand-offs to mount the unit inside the radio. I would however, suggest using a 4-40 tap on the holes in the Kenwood chassis as they appear to be un-tapped and the threads on the male/female stand-offs can strip.
Installation took around 15 minutes. I didn't even have to set the deviation adjustment. I found the encoder deviation to be already set to the right level. You can change the (3) banked tones by bridging solder across designated solder pads. It would have been nicer to have DIP switches for each of the three banks, but obviously this would increase the size of the printed circuit board, causing it not to fit inside the radio.
Today, I see many 7930's and 7950's being sold on Ebay. The majority of them do not have the tone encoder board. If you're looking for an easy way to add tone to your 7930/7950, you can't go wrong with this product.
- South Hills ARC