Friday’s success with the 1.2GHz repeater coupled with the long weekend of hiding from shopping crowds allowed me to put my nose to the grindstone and work on one of my own D-Star projects, a non-Icom UHF repeater.

I’ve been working on this for months, very slowly. I’ve had a hotspot running with various levels of success during that time. My biggest problems were getting the audio levels set correctly without a deviation meter or oscilloscope, and, it turns out, hardware failure.

The GM300 I was using appears to have a problem where after a few days of use, it simply stops. It won’t TX or RX until power is removed for while.

On Saturday I decided to dig into my portable analog repeater and make it hybrid analog/d-star. This machine doesn’t get used at all; I built it a few years ago out of surplus parts mostly as a learning experience and since this D-Star repeater was a continuation of that learning experience, it seemed like a good fit. I keep the repeater on my shelf in case it is needed for an ARES event or an actual emergency, so it was still there waiting for me.

Today I finally finished it up, made the appropriate interface cables, set the levels properly (and hopefully permanently) and fired it up. It worked first try, and after some testing I decided to button the whole thing back up. Amazingly it is still working quite well even after all the screws have been put back.

For the digital repeater controller I’m using a Mini Hotspot GMSK Node Adapter from Mark Phillips. It was originally designed by Satoshi Yasuda 7M3TJZ, but he has closed up his design after a temper tantrum so I choose to go with what was available at the time. Satoshi has some nice new features, I’ll probably purchase one of his boards once he stops requiring you to buy a new preprogrammed PIC for every software update. I have experience with his code already and I’ve found buggy and updates were required frequently. I don’t have a problem with fixing code, but even though his price for updates is only $7 waiting 2 weeks for post to deliver from Japan for each update is unacceptable for me in the age of Internet delivery of a .HEX file.

The Node Adapter requires a PC to operate, and it uses the pc’s Internet connection to do D-Plus linking and D-PRS location reporting via the DVAR HotSpot software package.

Essentially this is a full duplex complete D-Star repeater with one single exception: Callsign Routing is not supported. This bugs a lot of people in the D-Star community, but it’s been my personal experience that callsign routing works poorly at best and it’s implementation imposes a number of restrictions that I’m quite happy to live without. Chief among these restrictions is the requirement for each repeater to have a unique callsign and that callsign also cannot be shared by any user anywhere on the network. This puts an undue burden on the FCC to issue these additional licenses, as well as individual users such as myself who would then need to create a “club” in order to officially then request a club callsign for their D-Star repeater. If callsign routing worked as well in practice as it should, it would be worth the hassle, but Icom’s implementation leaves much to be desired and at least currently, there is no alternative to their implementation.

So to sum it all up, the hardware is as follows:

  • Transmitter: Motorola M120
  • Receiver: Motorola GM300
  • Mini Hotspot GMSK Node Adapter
  • Cellwave 440MHz Duplexer
  • Motorola GR300 cabinet with small “jet turbine” cooling system.
  • HP ePC 42 running Windows XP