APRS @ 5W with the Yaesu FTM-400DXR Part 1

The Yaesu FTM-400DXR does APRS.  The radio has RF outputs at 5, 20 & 50 watts.

Being a foundation license, this limits me to 5 watts. I didn't buy this radio with my current license in mind. I plan on upgrading, so this is me purchasing for the future.

The radio also does WIRESX. 

There aren't any relatively close WIRESX repeaters around - certainly none that I can key up at 5 watts. I didn't buy it for that anyway - the lack of nearby repeaters and my power limits set that expectation very early on.

What I did really want to fiddle with was APRS. The nearest APRS repeater though is north of Ballarat, and I'm way out to the south, so my expectations were low. It worked OK whilst in the shack - connected to my discone that has the benefit of height. But what about an antenna stuck to the side of my car? It's hardly a great position for an antenna. It has a ground plane around half of it, and it's a sedan, so height is not something it has the benefit of.

After installing it in the car, I was happy to find it worked reasonably well. Except I'd only been around town. The signal indicator for transmit shows a red, almost foreboding signal strength, making one feel that it's really not enough juice. Especially when the receive signal comes in at full strength. 

This past weekend it was time to pop out of town to go collect the harmonics from the XYL's parentals. I've had a cold (great during a pandemic), and I'd managed to get a day or so rest while the ratbags were elsewhere. My first out of town trip with the radio installed.

The first thing I did was set the radio to a repeater about 100km away. The WIA news was due to be broadcast on it at 11am. I suspect that's a pretty reasonable test given it's on a car. 

 

For the 50km journey, the news was on for most of it, and we heard it all. Clearly. We were driving in the direction of the repeater running the broadcast, so it's reasonable it shouldn't have gotten any worse as we progressed.

The APRS was doing it's thing as well, every few minutes beeping. 

When we arrived, I pulled up the APRS tracker, expecting to see massive gaps, possibly showing some random point on the way where it lost us, but alas, no. Our final destination - 50km away from us is in fact only 48.4km from where the same repeater is located, so it worked out well. 

There seems to be a couple of points along the way where it looks to have missed a couple of the transmits, but otherwise it's pretty well spot on. 

I'm reasonably impressed that despite the terrain (especially early on), it was able to transmit data over that distance at the same power as the average handheld. 

The big test is coming soon. I'll be traveling interstate briefly, and I don't see too many repeaters anywhere near where we're going. In fact, for the entire journey, there's one that will be about 40km away at its closest, and it's currently 140km away. No guarantees that any of those repeaters to APRS either. I haven't checked. So this will be interesting - interesting to see where I loose contact with the world, interesting to see how far the receive signals come in from, and where I'm recorded sending them from.

Anyway, always interesting to work out what one can do at 5 watts, especially once you get out of town and away from those repeaters.