Am I the only one bothered by videos showing a violent tornado devastating a small town, killing one and injuring 19, while the tornado chasers sit idly by amazed by their good fortune?
Based on some years-ago testing, I concluded that using 5-watts for APRS position beacons for tracking during public service events was pretty much a waste of time. But I was wrong. Sorta.
The reasons: Low power and congestion on the national APRS channel, 144.390, caused my testing to have more lost packets than good ones. It was possible to drive a number of miles between position fixes captured on APRS sites and apps.
Granted, a very close digipeater or just a receiver at net control might hear packets that don’t get repeated thanks to being close, but I was still unconvinced.
Last years’ testing, using a two digipeaters and an empty channel worked far better, but even two mobiles set to smartbeacon at short intervals got very congested.
These experiences made me not very interested in using APRS, but I keep getting dragged in, mostly because I own a lot of gear.
APRS can work
Several weeks ago, I was part of the APRS team for a bicycle ride in Stockton. This was a 100-mile course with shorter courses embedded within it. The course was long and narrow but very flat. The main “hills” were levees, but they could block signals in some cases.
The course, in the San Joaquin River Delta, was about 40 miles end-to-end but only 15 miles across. Needless to say, the start/finish was at the south end of the course and the turnaround at the north. Here is a link to the course map (PDF).
Several days before the ride, Mike, KJ6KDJ and I drove the course, sending packets about every minute to see where we had coverage and how many packets are missed. I used a Yaesu FT1D and a small cartop antenna for this test. Power out was 5-watts.
It turned out there was only one short stretch that seemed to lack APRS coverage and enough packets got through that I was easily able to follow myself on an iPhone APRS application. Of course, the app could also send my APRS packets, too.
On ride way, we ran five mobiles, each with a 5-watt APRS station. Net control was very happy with the APRS locations provided and my occasional checks of the iPhone app confirmed that the system worked well enough to send the right unit to the right place when needed.
A few caveats
The reasons this worked so well:
- Elongated course spread the mobiles across a wide area.
- Using only five mobiles meant their locations needn’t be super accurate to be useful.
- Super flat course.
- Digipeaters that were close to the course provided needed coverage.
- Mobiles were almost always moving, looking for riders needing assistance, so position reports were helpful.
- Most important: We drove and tested the course in advance. By the start of the ride, I had decent faith that our project would be successful.
- Asking mobiles for their location would have been just as effective (with only 5 mobiles, 15 would have been different) and a lot less work.
- Besides, the mobile were speaking often enough that it was easy enough to keep track of them in control operators’ heads.
- On a smaller course or with more mobiles, radio congestion could become an issue.
A Party Game for Hams?
I was impressed because the APRS system worked and net control felt it contributed positively to their conduct of the event. I am still of the opinion that APRS is essentially a party game for hams, but it is a came we can win, at least occasionally.
Many times, route markers are just spray-painted onto the pavement, often alongside marks from other events, past and future. This can be confusing for event participants, who must remember what color arrow to follow and sometimes decide which “red arrow” is the correct one (usually the one that looks most freshly-painted).
Recently, I ran over — literally since they were in use at the event — a sticky, brightly-colored die-cut paper marker designed to disintegrate after the event. That leaves the pavement clean and because the markers are fresh and bright, ends participant confusion.
The markers are called RouteArrows and there is a companion product, RouteLines, that is not die-cut and can be used to mark hazards, start/finish lines, etc. The arrows are 3-inches tall and almost a foot long. Just peel them off the roll, apply to pavement, and stomp with your feet to securely attach the arrow to the pavement.
“RouteArrows and RouteLines are just paper, with non-toxic water based ink and adhesive,” the RouteArrows.com site says.
One of the challenges supporting a bicycle ride is the need for sag drivers to be essentially everywhere at once, able to quickly solve participants’ on-the-road troubles. Having multiple courses and a handful of mobile units make this an impossibility.
How do we provide excellent support in such a circumstance?
Most riders, we’ve noticed, carry cellular phones. And oft-times some or all of the course has cellular coverage. Even if not, another rider can make a call for the stranded rider from further down the course where coverage is available. If most riders how phones. how can we make them useful during the event?
The solution is to print a telephone number where riders can call for assistance on the ride “cue sheet” (directions) and maybe even other materials (wristbands, numbers, etc.). This number is answered at net control and the closest mobile can be dispatched to offer assistance.
But, what number to use?
Thanks to Comm Boss John Litz, NZ6Q, of the Stockton Delta ARC for these suggestions:
1) Get a Google Voice number (Stockton was looking at 234-7220 (Stockton Bike Club+0) )
2) On the day of the ride Call Forward that number thru the Google Voice Portal to a cell phone located at net control
3) Riders calling the Gvoice number then ring into “dispatch” for SAG help
4) After the ride, forward the number to the main info number for the Bike Club until the next event
- The same number can be used for multiple rides and can be forwarded to more than one cell phone
- Cell phones of the “dispatch center” remain agnostic and can be different every ride or even changed during the ride
- Event coordinator can be programmed for ‘overflow calls’, but “dispatch” gets the calls - or 2 phones can be programmed to “hunt” incoming calls on larger events.
That sounds great and either the bike organization or the ham provider can get the number. I am a little concerned that free Google Voice numbers may be going away, but there are other providers who offer the service for a fee.
I carry a MagicJack VoIP dongle in my go-kit, allowing me to make and receive calls from any location where broadband is available. The number never changes and can be forwarded to a cellphone if I need to operate where broadband is not available.
Of course, there is no reason why net control must be physically at the event, at least if you are running on a repeater. Having net control someplace else means all the resources of the operator’s shack are available to then event.
Regardless, the idea to print a “helpline” number for participants is a good one. Just make sure it is thoroughly tested before the event takes place. Like weeks before.
We are presently operating a Yaesu SystemFusion repeater at our Gopher Ridge site near Copperopolis. It is on 444.400 and operates in Yaesu digital mode or analog mode (PL 114.8). The repeater has sensitivity problems so we plan to move it closer to Stockton where it might actually be useful.
If you have one of the new digital Yaesu rigs, send your telephone number and we can setup a time to test the repeater in digital mode.
In the interim, 444.400 is not linked to 147.015 PL 114.8.