Learning about digital ham radio

Yesterday was one of ARRL‘s Rookie Roundup contests, so some of the CARS members organized a rookie radio day to show off some of the digital amateur radio modes.

The idea is pretty simple. Instead of piping the audio output of the radio signal to speakers, it’s sent to a computer (with some intervening hardware) where the digital signals are decoded and displayed by software. The computer’s sound card generates audio tones that are sent to the radio for broadcasting and for other computers to decode. Everything is handled through the computer and software (fldigi in this case) using pre-programmed F-key macros (manual typing works too) except for changing radio frequencies (with the right set-up, even that can be done on the computer). Pretty neat stuff.

There were three of us rookies around and we all got to play digital RTTY (radio teletype) radio, sending out calls, responding to other operators and learning how to use the software. I think we made a total of 6 contacts, which isn’t huge but there might have been some power and/or antenna problems. It was still a good learning experience.

Another member set up a battery powered radio with a 40m dipole antenna and demonstrated sending emails over the radio via Winlink, another pretty cool amateur radio service. Find a reachable Winlink server to broadcast to, compose your message and the software sends the appropriate signals to the radio (via intervening modem) to the listening server, which in turn sends out the emails over the Internet. You can also download any received emails stored up for you. Using this method, even if you’re out of power, have no other form of internet access, or are in some other kind of emergency communication mode, you can still send out emails to other people as long as you can reach a server with your radio. Pretty awesome stuff. The data rate is pretty slow, but you can still get communications out.

It was a fun three hours we spent playing radio, and a good introduction to digital radio. Makes me want to do more

Radio upgrades?

Now that I’ve had my VX-8DR for a couple of months (and even used it a few times), I think it’s time for some upgrades.

After a recent road trip, I’m thinking it needs more antenna because getting a signal from another handheld radio that was more than a mile away just wasn’t happening. Being inside a big metal box on wheels probably didn’t help things much either. There aren’t too many quad-band antennas out there, but I did find a Diamond SRH-999 that would probably work. I’ve seen mixed reviews about it, but generally favourable.

I’ve also been researching making my own antenna and looking at different Yagi designs. Small portable ones are pretty easy to make and there are a lot of plans for them out on the web. I think building my own Yagi will be my first radio project. If I do it right (by which I mean if I remember), I’ll even make it so that I can use my monopod as a stand for it.

I’ll also probably need to build some kind of wall mount to hold all the portable Yagi’s I’m eventually going to build.

Then there are the radio accessories that I’m deciding I want now, like the handheld speaker/mic and the GPS attachment, because it’s always nice to know where you are.

Soon I’ll be ready to upgrade myself to Extra class, and then it will be time to start thinking “ham shack”.

Weekend radio fun

Thanks to Tom/AJ4UQ, this past Sunday I got the chance to play radio once again on the USS Yorktown operating as WA4USN. This time Connie/NR4CB/@Bionic_Nerd was there and we managed to work almost 40 contacts from 4 countries including St. Croix and Croatia (Connie was doing most of the working). I think 4 or 5 of the contacts were me operating. Whenever Connie got on the air there would be people piling up to make contact.

I also got on the air using my own call sign, but wasn’t getting any responses back. Still working on getting used to talking on the radio, but Connie was a big help with prompting me on what I should say.

It was a lot of fun getting to play HF radio again. Looking forward to getting my own rig set up one of these days.

Yaesu VX-8DR X-ray Take 2

Radiographs of my VX-8DR that show the innards a little better. 81 kV, 5 mAs, small focal spot.

The battery (which is actually two batteries)

The radio itself

The antenna. If you look closely, you can see some internal structure now, compared to the fluoro image from earlier.

Yaesu VX-8DR X-ray

Put my VX-8DR under a fluoro unit I was testing today. Fluoro generally doesn’t provide the greatest resolution images, but enough to see what the innards of my radio are like. Will get a regular radiograph later.

This is the antenna. Not a whole lot going on aside from a lot of metal.