D-Star – WB3GCK QRP Amateur Radio

My Hotspot is Back From the Dead

While trying mobile DMR last month, my (relatively) cheap hotspot experienced an untimely death. I set the hotspot aside as a future troubleshooting project.

While the Pi-Zero board appeared to be working, the MMDVM board was dead as a doornail. The OLED display was blank, and the RF side of the hotspot was non-responsive. It also wasn’t interacting with the Internet at all.

The other day, I came across a posting on a Facebook MMDVM page that shed some light on my problem. Some users reported shorts between the internal boards and the aluminum case. This tidbit of information prompted some further investigation.

I removed the top of the case, reinstalled the antenna, and applied power. To my surprise, the hotspot booted up and came back to life.
I let it run for a while without the case to verify that all was well. It was.

I noticed a solder connection that extended a little beyond the edge of the MMDVM board. It appeared to be a power connection, so I suspect that might have been what shorted. I also noticed that a single screw and the header pins are all that secure the top board. I’m guessing the board shifted a small amount while mobile causing the short.

My disassembled hotspot. If you look closely, you can see the electrical tape I added inside the top cover.

To remedy this, I applied electrical tape inside the top cover of the hotspot. Not being 100 percent certain where the problem was, I covered everything except the vent openings. I used a razor blade to trim the tape around the OLED display and antenna jack openings. I also took a file to the little solder blob I had noticed. (I exercised extreme caution in doing this since I’m sometimes prone to creating new problems.)

I reassembled the case and powered it up. Voila! It still worked. Hopefully, this fix will avoid any reoccurrences and make it withstand the vibrations of mobile use.

Although you’re far more likely to find me on CW on the HF bands, I do monitor Brandmeister TG-3142 (Pennsylvania State-wide) on DMR. And, on occasion, I listen to D-Star REF20A.

73, Craig WB3GCK

Delving into D-Star

I mentioned in a previous post that I was going to venture into the digital voice modes. Well, I did. I was successful in getting a hotspot up and running, although I did hit a snag along the way.

Yeah, I know; as usual, I’m late to the party on this stuff. Up until now, I’ve had only limited experience with D-Star. Years ago, I used a borrowed Icom ID-1 for 1.2GHz data during a couple of ARES-RACES exercises. I hadn’t used D-Star again until I bought a Kenwood TH-D74A six months ago. Even then, I had only used D-Star to check into a local ARES-RACES net over a nearby D-Star repeater.

My local ARES-RACES group here in Chester County, PA, held one of our monthly Tech Rallies using Zoom. Jim WA3NOA gave an interesting talk on digital voice hotspots. Inspired by Jim’s talk, I went ahead and ordered an MMDVM hotspot from Amazon.

While waiting for the hotspot to arrive, I started studying up. I found lots of great articles and videos out there. W6GPS’s videos on the TH-D74 and D-Star were particularly helpful. Following one of his videos, I picked a hotspot frequency and programmed it into my radio.

The hotspot arrived a few days later. I was immediately struck how tiny this thing is. The instructions that came with it were sparse but clear enough to get started. I was able to successfully connect my laptop to the hotspot’s internal WiFi hotspot and access the Pi-Star configuration screens.

Long story short… Before too long, I had the hotspot connected to my home WiFi network and had the D-Star section configured. I keyed up my radio and received the expected D-Star response from the hotspot. Then, I tried to connect to some reflectors. No matter which one I tried, I got a “reflector is busy” message on my radio. Hmmm…

I sent screenshots of my hotspot configuration screens to Jim, but he didn’t see anything out of wack. I next focused on my WiFi router. I tried connecting the hotspot to other WiFi networks. No joy.

Finally, I went out and checked the status of my D-Star registration. That showed that my registration from way-back-when was missing a Terminal ID. An email exchange with WA3NOA confirmed that was likely my issue. My D-Star registration password no longer worked, so I reached out to Jim W3BIF, the admin for the W3EOC D-Star repeater.

My faulty D-Star registration. This turned out to be the cause of my hotspot problem.

The next morning I had an email from W3BIF saying he had straightened out my incomplete D-Star registration. Within minutes, I was connected to a reflector and having a QSO with a ham in Georgia. He reported that my audio sounded great.

I used to be one of those guys who thought this stuff isn’t real ham radio. I guess I’ve come around a bit. I won’t be giving up CW any time soon, but I will admit it has been fun playing around with this new (to me)mode over the past week.

Over time, I might branch out to try some other digital voice modes. In the meantime, you can often find me monitoring D-Star reflector, REF20A or REF30C.

73, Craig WB3GCK

My Activities of Late

I haven’t been posting much here lately. The COVID-19 pandemic and other family obligations have been cutting into my ham radio activities. Nevertheless, I do have a few projects in the works.

A few weeks ago, I started another project in my ongoing series of speaker wire antennas. This one will be a variant of the bi-square antenna. This antenna has the potential to be a little more field-friendly than the delta loop I tested last month. It’s all built; I just need to get out somewhere to set it up and see how it works.

I’ll file my next project under the category of Old Dogs/New Tricks. Back in December, I bought a Kenwood TH-D74a HT. That gave me the ability to reach a nearby D-Star repeater. This week, I purchased an MMDVM hotspot to go along with it. I plan to spend some time in the coming days getting it set up. I’m hoping to be able to eventually connect to the DMR talk groups used by my ARRL section and local ARES-RACES groups. Fortunately, my local group has some experienced hotspot users I can consult if I run into any snags. Wish me luck.

Sadly, our camping season with our little QRP Camper is off to a late start. State park campgrounds in our area have been closed due to pandemic. We have reservations at a state park in Maryland next month, however, and it looks that might be our first trip of the year. I’m looking forward to a little QRP-portable operating from the camper.

My local QRP club has started making plans for Field Day. We have a set of social-distancing guidelines we’ll be following this year. We’ll be limiting the number of participants, keeping our tents at least 10 feet apart, and eliminating common eating areas. Also, we won’t be sharing stations and equipment. This year’s Field Day will be different, for sure.

Other than that, I’ve been active on our local ARES-RACES nets, and I have been checking into the Pennsylvania NBEMS Net on Sunday mornings.

You can also find me on 40M or 80M CW in the evening. I usually hang out around the SKCC watering holes.

I’ll be posting more on all of this stuff in the coming weeks. Until then, stay safe, and I’ll see you on the air.

73, Craig WB3GCK