In case you guys didn't have anything to read this week, I wrote a novel: ------------------------------------------------------------------- Preliminary results from SnoCo, WA Mock Search held April 22, 2000, from an APRS perspective: ------------------------------------------------------------------- Bob was in the command vehicle filling their heads with APRS possibilities the whole time. I think that helped a great deal. The computer in the command vehicle was busted, so the only computer they had to help with the search at all (Excell, etc) was the APRS computer. That was an extra bonus 'cuz we helped them out in another needed area besides APRS. We deployed two vehicle trackers and three backpacks. We could have deployed more if I hadn't been so busy and could have caught more of the teams as they went out. We probably need two people initially to get the trackers checked out and deployed at the start of a search. I'm sure I'll get better/faster at it also. I expect they'll get quicker at deploying the first few teams into the field as well. Only one backpack tracker and one vehicle tracker reported in during the exercise, but even those two were enough to show the command people what it could do. I'd call it a smashing success, even though only 40% of the trackers reported in. The one backpack unit that did report in was a person with the dog team, and we got quite a few good reports from it. The vehicle tracker that worked was in one of the two vehicles that actually found the subjects later in the day. That was cool. Quite a few people joined me at the back of my Jeep after the event and asked about the trackers and the purpose for them. Many of them were hams. I got to close up shop, go out on a search team myself and tromp through the snow for several hours, so I got some training too. I'm working on fixing the problems we had and will see what else can be done to promote the use of trackers in SAR. What we did was an excellent first step and seemed to be very well accepted. One vehicle tracker that was deployed was able to be replaced before the truck went out. The first one that I TRIED to deploy wasn't working (the one I built naturally!). I had put an older Garmin in that box so that I could pull out the GPS-III+ to put in a backpack. The Garmin 45 lost lock quickly when it was put in a vehicle and never regained it. That was with a Garmin amplified antenna on the outside of the ammo-can. :-( Another backpack tracker had it's DCD light on when it came back to me. I suspect that the DCD circuit did not get adjusted properly before the TinyTrak was packaged up. My fault. I'll fix it for next time. >From a SAR member/ham who was there: > From my limited vantage point I thought what worked was fantastic. We had > numerous hardware problems and didn't get the big picture like we thought we > would? Pretty darn good first shot though. We should maybe think about > making the hardware more robust and operator friendly? I didn't hear what > the actual problems were. Any ideas? Antenna placement of both GPS and radio antennas is critical. Putting the ammo-can inside the vehicle without an external 2-meter and GPS antenna doesn't work. The vehicle that DID work well had the GPS on top of the truck, and the 2-meter antenna inside. It would have worked better with a mag-mount 2-meter antenna on the outside of the truck. Putting a handheld and GPS inside a backpack without an external antenna doesn't work very well. We were lucky to get a few positions from the dog team. The TinyTrak/HT/GPS were all together inside two freezer bags, and stuffed into the top of an internal frame pack. Ultimate placement of the HT antennas and/or GPS antennas were unknown. Antenna placement at Base Camp should have been on top of the 40' mast. I had the coax for it, just didn't have the time. I used an Isopole on a 10' mast leaned up against a small pine tree. All of the equipment deployed powered up and stayed on just fine. When the equipment came back it was all still powered up and running. I was worried about the non-locking toggle switches getting turned off on the TinyTrak's. All equipment should be powered up before the teams go out, and the symbols should be showing up on the map. If they're not, then the equipment doesn't go out. All HT's, TinyTrak's and GPS's should have their batteries checked before they go out. I missed checking one GPS (the one I carried) and had to borrow a set of AA's from someone during the hike. Of course I forgot to throw a few sets of AA's in my pack, but had plenty at the Jeep. Ammo-can's should also have their Gell Cell's checked and charged before each event (I did this). Digipeaters located at strategic points would have helped a great deal, ammo-can trackers with batteries would work well for that. It would have helped our team to report in if the truck we took down there had a high-powered ammo-can inside it. It would have worked as an excellent digipeater to relay our position back to base. We must have had other problems though as the SAR radios (above 2-meters) were able to talk to base camp during our hike, but the APRS setup did not. The SAR antenna was mounted high above the command vehicle though. One thing to keep in mind: Nearly all of the equipment used was borrowed, and two of the radios used (mine!) were partially broken but were able to be used for specific purposes. We won't have more than perhaps three backpack trackers and one ammo-can tracker for the next search, that being all my equipment plus somebody else's HT's. Even the laptop(s) were borrowed. What I'm working on now is "brush" antennas for the backpacks. Bob mentioned that search dog teams sometimes use very flexible wire antennas encased in flexible plastic sleeves. I'm pursuing stainless steel TIG filler rod as a possibility. What I'm thinking about is a somewhat stiff 1/4 rod sticking out of the end of a weatherproof housing (tupperware?) that can be stuffed inside the top of a backpack easily. I'd have a loop in the end to prevent injury. Another possibility would be rubber tubing with solder-wick inside for the antenna element. I need something that will remain vertical, but not knock the searcher off balance if the antenna hits some brush. Oh yea, another interesting problem: All of the equipment was checked out beforehand, and so the laptop we were using had valid positions from most of these trackers, where the initial position was somebody's house. When the next position came in on Mt. Pilchuck, the software drew a nice trackline from the house to the mountain. It would be good to wipe out the stored database before each search starts to avoid that. 7.62mm ammo-cans seem to be about the right size for a low-power setup. 50 caliber ammo-cans are just right to hold a Kenwood TM-261A or Alinco DR-1200 radio for a high-powered setup and have plenty of extra room for batteries, TNC, and cables. ------------------------------ What I'll try to do next time: ------------------------------ Bring extra of all types of equipment (Did this). Make sure all antennas are oriented properly and batteries are charged. Keep the base antenna high. We had a 40' military mast sitting there that we didn't deploy. Make sure the vehicle GPS antennas and APRS antennas are located outside the vehicle. Have brush antennas for the backpacks and more durable containers to keep things waterproof and oriented properly. I'd also like to remove all of the AA's that I was using (GPS/HT/TinyTrak) and just go to one 12V Gell Cell for powering all. Wipe out the database from the APRS software before starting. Deploy all equipment possible. Deploy digipeaters if the area requires it. Use the truck's ammo-can units as digipeaters as well. Use GPS's with parallel receivers in all cases. Don't accept a 1/2/3 channel GPS for this purpose. We're in the trees out here. Label all equipment as to callsign and owner (Did this). Have at least two sets of backpackable equipment ready to stuff into backpacks as soon as I arrive on site. The hasty teams head out awfully fast, and sometimes the dog teams or the man-tracking teams as well. Turn off any APRS equipment in other vehicles around base camp. We were getting desensed because of this. Buy a set of Gators, a good wide-brimmed waterproof hat, and a camelback or muleback water bag (doesn't have much to do with APRS though, does it?). I've been wanting a camelback for a while, and one guy there took the bladder out and stuffed it inside his internal frame pack. When he wanted a drink of water the tube was readily available. Gotta' get one. Anything else Bob? Bob answers: Just got done with the report. If desense was an issue, it was an APRS transmitter digipeating/position reporting that was desensing a commercial radio receiver. The more I think about it, the less I beleive that was a problem - that dirty/ineffective PTT switches in some of the radios was responsible. If virtually all the searches are in back-country, a 'launchable' antenna might be faster, and probably higher, to set up. Thinking of something like a twin-lead j-pole with coax and a heavy object attached. Also, for porta-digies, you should look at some of the work on 'stealth digipeaters' - i.e. digi built into a PVC pipe, ground plane, radio, tnc, and batteries. PVC painted camo, if you don't want it stolen. Curt: Yea, I usually bring a braid antenna (I think you mentioned to me that it was a 1/2 wave) to hunting camp, and can throw it over a tree. Height in a hurry. Big piece of mini-8 coax to go with it. Curt, WE7U. 04/27/2000