Thursday, September 03, 2009

IGate issues

Ever since I was a child, I have been fascinated by maps. My attempt to receive signals from satellites led to my finding out more about Automatic Packet Reporting System (APRS) and I became interested in trying its position tracking capabilites, as well as the potential it offers for ham radio-based text messaging. So I'm currently awaiting the arrival (hopefully today) of a Yaesu FT-8R APRS-capable HT in my shack.

While I was waiting I decided to set up an APRS Internet Gateway or IGate, so that my position when I'm out and about with the VX-8R can be monitored on sites like findu.com, aprs.fi and OpenAPRS. This wasn't something I wanted to tie up the Elecraft K3 and DB6NT transverter doing, so I set up my FT-817ND to act as my APRS receiver, using my computer's integrated sound card (I have a separate SB Live 24 card for use with the K3.) For the IGate antenna, I reinstalled in the attic my 2m Slim Jim. However, last night while making some PSK31 contacts on 80m with the K3 I noticed that my IMD Meter was showing a poor signal again.

For some reason that I do not understand, having the Slim Jim connected to my station upsets the K3 and makes it produce a distorted signal. At the time, I put it down to having too many antennas in not enough space and I took the Slim Jim down. But now I need it. Disconnecting the Slim Jim from the FT-817 cures the bad signal from the K3, as does disconnecting the FT-817 from the shack power supply. It was a short step from this to finding that operating the FT-817 from its own independent power supply rather than the Diamond GSV-3000 that also powers the K3 leaves the signal clean. At least, it does on 80m. I haven't tested on any other bands yet. Unfortunately the only other power supply I have that's suitable is a small switcher, so now I have a clean PSK31 signal but warbly noises wandering around the HF bands.

The other problem related to the IGate that I haven't yet solved is what software to use for it. Like most newcomers to APRS (I guess) I started off with UI-View32. This is quite a nice program that displays APRS position reports on a map, offers APRS messaging capability and also has a built-in IGate. However, it is no longer being developed or supported as its author is a silent key. Also I preferred a standalone IGate that I could leave running all the time without the overhead of position tracking on a map.

The only alternative I could find is AGWUIDigi, from the same author as the AGW Packet Engine that I use. I think this works, but it appears not to post its own position beacons to the Internet, so when I run it my IGate does not appear on any of the maps. This is a significant limitation to me, as I want my station to be shown so that others can see that there is APRS activity in my area, and hopefully encourage more use of this interesting mode. Perhaps it's a simple configuration issue, but I can't see it.
Post a Comment