As an avid outdoorsman, many of my adventures (most in fact) land me in areas without conventional means of communication. More often than not, I rely totally on radio communications. My QTH (location) is in the central Mississippi hill country where the land is densely populated not with humans, but rather with conifers and old growth hardwoods that tower anywhere from 80 to 160 feet above ground level. Being a self reliant “off-grid” homesteader, when I’m not farming, I spend much of my time in the forest as a hunter/gatherer, harvesting what my family needs from the bounty that nature has provided. It is amazing how quickly weather can turn south, and when the clouds come over the canopy, the forest floor turns as black as night. This sometimes makes for a potentially dangerous (possibly even deadly) situation. The forest is teaming with large predators, including (but not limited to) alligators, panthers, bears, venomous snakes, and wolf/coyote hybrids. Weather is not the only concern, getting lost is easy to do anyway. Any RTK (Real Time Kinetic) GNSS (Global Navigation Satellite System) that I am familiar with is completely useless under the dense canopy (especially GPS). A compass is handy, but traversing a strait line is impossible as brambles and other obstructions continuously block the path. Therefore, a wild zigzag course is unavoidable, making navigating with a compass rather arduous. I have a local repeater located at my cabin (for which I am the trustee) which has greatly extended radio communications, but at 300 feet above sea level and a 30’ mast in a location surrounded by trees, there are great limitations with a dual band HT (handheld transceiver), and many times I cannot access the repeater.
I had been lost twice before with my young sons (once in a heavy storm), but the third time I was alone (thankfully). The mood turned ambivalent in a split second. When I realized I had lost my way, I also realized that I had no means for extraction due to lack of communications. It was dark and the temperature was below freezing. All my senses told me quite sternly that I was being watched from more than one direction. I could hear the faint sound of a footstep at long intervals, and a whistle from a distance. The whistle sound I had heard previously from a confirmed panther (on more than one occasion). Close by, I recognized a vixen (female fox) cry, which sounds like a human baby screaming (not dangerous, but certainly added an audible flare to the situation). I had a green light on my gun, two small flashlights clipped to my pocket, and a headlamp, but definitely not enough battery power to last more than a couple hours combined. I was prepared for the cold and there was zero precipitation, so theoretically I could make it through the night without issue (I felt like staying where I was until dawn was the best coarse of action in order to avoid further deviation), but sitting still without the option of scanning with a light could prove quite hazardous considering the nocturnal predators about. I was in a geographical depression which inhibited communications entirely if I stayed put. My mind turned quite despondent as I pondered the possible actions I could make. I ended up making the decision to stay put until dawn, at least that was my goal. About an hour before first light, under the canopy with very little battery power remaining from all the intermittent scans made thoughout the night, I made the decision to move. I would traverse only a short distance so as to be able to return to my original location, and I would do so in various directions, returning to my original location after each (unsuccessful) short venture. I ended up finding the original path I had used to enter the forest! I felt lucky, and the crazy thing was that I had only deviated by about 20 yards off course by the time I had noticed that I was lost! I made it back to the cabin right at morning twilight, greeted by a waking family that was quite concerned of my whereabouts. I made a pact to step up my game tremendously before my next excursion. What follows is an account of my efforts to reduce the chances of an incident like this being repeated (if there was to be a “next time”, I may not be so lucky).
Being immersed in radio telecommunications, alternative energy, chemistry, and electronics engineering as habitual hobbies (and necessities given my off-grid lifestyle), I set out to concoct a system with multiple redundancies that could replace GPS/APRS or any other conventional means of tracking location and/or communicating. What I eventually came up with was a combination of different redundancies, all of which lent themselves to my own particular areas of interest and/or expertise. This led me to take up new and interesting aspects of the same hobbies that I was already involved in. This also spawned new ideas for regular everyday life on an off-grid homestead.
The first step to a solution was simple (at least in concept). I felt really careless. Obviously, I was quite careless in insuring that I was capable of maintaining a line of communications when I got lost. As a radio operator (now humbled), that’s a humongous belittlement to the psyche. The adverse terrain and conditions had left me in a situation that was quite disheartening, but it was my own doing in every way. Next time I would have to be prepared to make contacts despite being under a canopy, in a low lying area, and unable to traverse reliably. A good, solid method for plotting location and relaying voice and/or data traffic to the cabin (and therefore the repeater) was of top priority.
FOXHUNTING: Foxhunting, in the pretense intended for this account, does not involve horsemen boasting red coats in pursuit of a four legged canine as depicted in many a painting, but rather is a term used for a sport practiced by ham radio operators worldwide. The sport involves using radio direction finding (RDF) equipment to locate hidden or offensive transmitters (or sources of harmful interference in the radio spectrum (RFI)). Equipment used for RDF can be as simple as a handheld transceiver using the operators body to distinguish a null in the received signal (body fade), to sensitive resonant directional or bi-directional antennas (or arrays), and even automated micro-controller based beacon locators that sense signal strength from an array of antennas based on time differential (∆t) of the received signal. This is a sport that I have had an interest in following, but not a practical use for (excluding locating RFI in motor vehicle circuits) until now. What I needed was to be able to triangulate my current location, and/or transmit a beacon from my location that could be plotted by another operator. My two oldest children have an interest in radio and electronics engineering so I felt like I could make the whole thing happen. My oldest son (KG5YEH) was sixteen, and had been a technician class licensee since he was twelve (and was currently studying for general). My eleven year old son had been studying the tech book, playing around on the MURS frequencies, and soldering circuits since ever he could hold a soldering iron. Surely together we could come up with a program that would fit the bill.
The first experimentation phase with short and long distance foxhunting (RDF) worked like a charm (lucky me!). A beacon transmitted from a baofeng UV-5R using an obsolete tiny mp3 player and some interfacing hardware I soldered up gets a signal out there to track. A home brew magnetic loop antenna for 145.000 MHz allows me to “sniff” out the beacon quite accurately. Being that my location is in the middle of the forest, multipath signals are what I receive, so the signal null is never in the actual direction of the transmitter, but rather it aims me at the strongest point of reflection. This leads me on a wild zigzag trajectory, but that works out quite well given the terrain. With a beacon previously set at my extraction point for a long hike, and one transmitting from the repeater at the cabin, I can triangulate an approximate location using nothing more than my HT and a small magnetic loop antenna (along with a few acquired skills).
Interfacing: I have been interfacing a smartphone with no sim card (no service) to various Baofeng models for a number of years thanks to some help from a fellow operator, KK6GIP (John Boiles). John supplied a schematic he designed for APRS (automatic position reporting system) to trick the phone into thinking it has a headset attached to it. I simply used the gerber files (files used to print the different layers of a PCB) he designed, and had Osh Park (a community driven, US circuit board manufacturer) custom make me some tiny PCB’S (printed circuit boards). I paid a mere $1.70usd for batches of three boards shipped. This enables encoding and decoding of data transmissions for various uses. SSTV (slow scan television) has been a favorite, but I also use the interface to send email over the air (no internet) using an open source android application called “andflmsg”. This is a lighter version of the same program I use on my Linux computer. The app also allows for text messaging and photo attachments (although I prefer SSTV for pictures). I use two android applications for SSTV. One for encoding, and one for decoding named SSTVencoder and Robot36 respectively. Robot36 runs in the background and files pictures as they are received directly to the gallery. Both SSTVencoder and Robot36 support a formidable list of modes with different characteristics.
The interface boards are tiny, and populating them with the tiny flea sized SMD (surface mount) components is definitely a task for someone very experienced with soldering. However, I recently was provided gerber files for an adaptation of John’s board that uses discrete (through hole) components. I had Osh Park print me a batch for the kids to build (they are going to use them for a RDF easter egg hunt this year). I prefer the smaller board for portability, but the discrete board is quite small as well and would suit most people just fine (alot easier to populate). There are only five components to solder on either version, three resistors and two capacitors. The only other components needed are a TRRS plug for the phone, and a Kenwood connector for the radio (I use replacement Kenwood mic cords).