Archive for category Equipment

D-Star Repeater

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

D-Star 1.2GHz DD Success!

I’m posting this from a laptop using an Icom ID-1 for Internet connectivity via our D-Star repeater and gateway.

It was frustrating, but in the end I’m glad I’ve participated in this project and that I ┬álearned all that I have. This entire D-Star endeavor has been very rewarding.

Now it’s time for some more clean up and some additional documentation for users to teach them how to connect ID-1 radios to our gateway.

Heathkit GC-1000!

Ok, one of the two timepieces that I’ve wanted since I became a ham is the Heathkit GC-1000 (the other is a Geochron). Today I received 2 of them. Maybe 1 1/2, but probably 2.

Most hams would be familiar with it, but for those who aren’t it was released for Christmas in 1983 for the low low price of $299.90 if you built it yourself, or $389.95 if you bought it “wired and tested.” If you adjust those numbers for inflation that’s $640 and $832 as of January 2009. here’s the original advertisement from it’s debut in the 1983 Christmas Heath Catalog which explains what makes this unique among clocks.

Heath Kit GC-1000 Debut, Christmas 2003

Heath Kit GC-1000 Debut, Christmas 2003

Yes, today modern WWVb “atomic” clocks and disciplined GPS outputs make this partially obsolete. What’s your point? It’s still a true Stratum-0 device completely independent of the GPS network and it’s accuracy is maintained realtime 24/7.

A friend in Canada stumbled upon a friend of his who was cleaning out his house and found one in an old dusty box. Also in that same box, was a 2nd, partially assembled GC-1000 in unknown condition!

Rather than selling it on eBay for what would almost certainly have been a tidy profit, he sent this box to me (he already has 2 GC-1000’s of his own) for which I am truly grateful. It arrived today. More correctly it arrived yesterday, but I was out sick so I got it today.

So I have 1 that needs some cosmetic work and a once-through to check out, and one completely unknown puzzle.

According to my research I really want to look at the electrolytic caps and get rid of the 7805 regulator that Heath used. They run that 7805 really near it’s max limits, and there are several pictures on the internet of it actually scorching the FR4 circuit board area around it. There is a nice modern switching regulator that is drop-in compatible. It generates almost no heat and rumor has it that it doesn’t produce any interference with the RF portion of the clock.

It may take a week or two before I can dig into this project, but I’m looking forward to building my first Heath Kit!

New D-Star User!

Last night just prior to the DMRAA meeting I was in the hallway showing someone some details about my D-Star Hotspot project and Rod Ivers popped into the local repeater calling CQ. Rod mostly lives in Kansas City having retired and abandoning us in Des Moines a couple years ago, but he travels all over creation in a very nice RV.

I’ve always thought that he’d be a great D-Star user since he travels so much but it took him a while to get on the bandwagon. He purchased a new ID-880 at a hamfest last weekend and he’s learning all about it.

Icom ID-880

Icom ID-880

Cheers Rod, looking forward to hearing from you during your journeys!