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[aprssig] APRS experiment along I-40, mapping vs. voice alert vs. local info

Alex Carver kf4lvz at yahoo.com
Tue Jul 13 20:40:05 UTC 2010

I haven't been a fan of Voice Alert and never really tried out anything with local info but I figured I'd give it a decent test over the Independence Day weekend.  During that weekend I drove a rental truck from Columbus, GA to Los Angeles, CA.  I took the most direct route:  US 280/78 (Columbus, GA to Memphis, TN); then I-40 from Memphis, TN to Barstow, CA; then Barstow, CA to Los Angeles via I-15/I-210/CA-134.

I left mid-morning on July 2 and drove until near midnight making a stop in Arkansas.  The next day, July 3, I drove from early morning (before 9 AM) until about midnight again, stopping in New Mexico.  The third day, July 4, I again drove from early morning through 2 AM to arrive at my destination.

The APRS equipment I had was a Kenwood TH-D7A(G) v2.0 (fits in carry-on unlike a D700), an external 1/4 wave mag-mount, and my GPS.  My family and friends kept an eye on my progress via the various APRS mapping sites primarily because I was making the entire drive solo in a large rental truck.  For anyone unfamiliar with US rental trucks, regular drivers (non-commercial drivers) can rent a large box truck under 27,000 pounds for personal purposes (like moving belongings which is what I was doing).  Unfortunately, because the trucks are driven by non-commercial drivers, they tend to be sorely abused to the point of being dangerous so my family wanted to keep watch in case I got into trouble.

I had the D7, a cell phone, a CB radio, a Uniden scanner and my NOAA weather radio all with me just in case I needed to make emergency contact or get alerted to foul weather.  Hurricane Alex had made landfall earlier and the remnants were moving into Oklahoma and North Texas.  I was also driving through Tornado Alley in the summer.

Coverage was spotty in a few places in the middle of the country but I did hear my packets being repeated (the MY POS beep) and I would get info back from friends and family when I took rest stops along the way.  Coverage in the western states was better because of the higher stations.  I used WIDE1-1, WIDE2-2 with a beacon time of three (3) minutes for the trip to try and ensure entry into an I-Gate.  You can pull up my trip history on one of the mapping sites like aprs.fi to see where I managed to get into the network.

That part of APRS (mapping, tracking) worked fine for the most part.  A few coverage holes here and there showed up due to geometry of the system (the truck blocked half of the antenna radiation pattern), digipeater coverage, or just low power (5 watts maximum).

Local info I can't say too much about for this trip because the D7 really would only fit in a cup holder and that takes my eyes off the road.  This truck had broken suspension so I was constantly having to look for bumps and holes in the roads to avoid flipping the truck.  I think I may have seen one or two announcements for a local repeater but nothing else comes to mind (all new positions beeped as well).  I had the radio set for full screen operation just to be sure I could see more of the packet.  If anything was there I wasn't receiving it even though I did get other packets from weather stations and digipeaters.  I think the inability to look at the screen safely when driving is going to hinder the local info objective.  I simply couldn't look away very much if ever (depending on road conditions).  I tried when I thought it was safe but it just took too much effort.  If the packet vanished from the screen because of another packet or just the
 timeout then it was going to take button pushing to get it back.  It's not worth flipping my vehicle over for that.

Voice Alert failed completely.  Over a road distance of 2,200 miles on one of the busiest travel weekends of the year there was not one squawk from the D7's speaker indicating a nearby station.  I know it's been hashed out several times here that people perhaps don't know about it, don't have it set up correctly, don't have a two-way radio that can utilize it, etc.  Honestly, I think that it's just not as interesting to operators as some may have us believe.  I was on the air for 14-16 hours a day during daylight and evening hours  beaconing my position once every three minutes in all kinds of terrain and many populated areas.  Surely if it were as important and popular as we hear then I should have heard at least one packet burst come through.

These are only my observations so please, by all means discuss and debate.


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