When and if your ready to try ... feel free to ask.
Thanks. It may be awhile. I was out of ham radio and "off the air" from 1967 (when my non-renewable Novice license expired) until April 1, 2013 when my Amateur Extra license, call sign AC8NS, was issued by the FCC. I half-jokingly say the "NS" part of my call sign means "No Station," but that isn't entirely true. I bought an Elecraft KX3 HF transceiver to celebrate my re-entry into ham radio, and later added a KXPA100 linear amplifier. What I don't have is a permanent antenna to transmit and receive with.
Before retiring to Florida, we lived on a small lot in Dayton, OH with virtually no room to erect an antenna. We now have a largish corner lot with no HOA or antenna restrictions, but also no amateur radio budget for antennas. I went to the Orlando Hamfest last year and came back with a set of nesting aluminum poles, originally intended for the deployment of camouflage netting. Each pole is a bit over four feet long, so I figured to stack five or so of them to make the end supports for a dipole antenna... or maybe stack ten of them to support the center of an inverted "V" and then use three or so on opposite ends to support the lower part of the antenna a few feet above ground. Easy peasy, I thought, until I realized we now live in the lightning capital of the world. Those aluminum poles will have to come down before and during every thunderstorm. I still plan to eventually erect a dipole antenna, but Plan B is to build a magnetic loop antenna that sits only about ten feet or so above ground, supported on PVC pipe, and ground the copper loop of the antenna during thunder storms.
Thanks for the encouragement and the good news that your RC hobby is finally within reach of the common man. I thought for many years that hobby electronics was out of reach of the common man, but that is no longer true today. Of course my notion of the electronics hobby as being component-level design and experimentation has yielded to the availability of inexpensive modules that the hobbyist simply wires together. The same appears to be true with RC models. As you stated in another post, no one messes with the radio-frequency "nuts and bolts" part of hobbyist RC design. Well, almost no one. As a retired electrical engineer with a hobbyist amateur radio license I am free to legally delve into that realm. Perhaps someday I will.
Hams are heavily involved today in
digital communication modes that offer increased range of communication at quite reduced power, or "QRP" operation as it is known by its Morse Code "Q" signal designation. This is mostly used in the hobby to pursue QSOs (two-way conversations) with distant worldwide (DX) stations, "just because" it can be done using various propagation modes such as ionospheric reflection, meteor scatter reflection, and moon-bounce reflection... to name just a few methods to wrap a radio-frequency signal around that pesky globular Earth. Hams also employ line-of-sight public repeaters that receive signals on one frequency and re-broadcast them on another different frequency. This would not be a reliable method of extending RC range, though, because the repeaters are shared and may not be continuously available. Less well known, at least in the amateur radio community, is the application of digital techniques to ensure error-free transmission and reception of
data. Some form of digital error detection and correction is probably incorporated in the the latest RC electronics, unless youse guyz are still stuck on PWM analog controls, which I seriously doubt but haven't investigated yet.
I was a bit confused about your statement regarding multi-rotor aircraft not being safely controllable beyond about fifty feet without using a FPV camera for visual feedback. Until I realized that beyond fifty feet you can hardly see the darn things, much less control them! Then I visited the dji.com website to learn about their Phantom Pro series of quad-copters with high resolution camera and imaging collision avoidance system. Wow! The more than a thousand bux "entry level" price seems to be quite reasonable given the performance capability, but your inexpensive approach seems more in the "hobbyist" spirit to me.
I think I will start off with a small, inexpensive, electric airplane with a FPV video camera for visual flight control and obtain some "pilot creds" before even thinking about moving up to a multi-rotor platform. And I will certainly try to find a local club or organization with someone willing to mentor a newbie. That was a huge problem in the 1950s: newbies learned by the "crash and burn" method of flight instruction, just as the Wright brothers did at the turn of the century. It was pretty discouraging to wreck a model you had just spent months building (or re-building) and preparing for flight. Having an experienced "co-pilot" to fly the plane while I select still images to store on-board sounds like a good idea too. We happen to live on one of the approach paths to Venice Airport and see a lot of low-flying aircraft every day. Surely we don't want to compete with any of them for airspace.
In an earlier life I worked with the intelligence and reconnaissance community to support digital image processing. Back in those days the buzz words were "sensor fusion," meaning the combining of data from various imaging sensors into a coherent whole that humans (or machines) could use for decision making. My first attempts at this were rather mundane. We had purchased a (then) brand new mechanically scanned forward-looking infrared imaging (FLIR) system with two focal-plane, liquid nitrogen cooled, photoconductive IR detectors, one doped for 3μm to 5μm infrared and the other doped for 8μm to 12 μm infrared.
A beam-splitting mirror directed the scanned image field to both detectors simultaneously, a scanning procedure known as image dissecting, but only one of the two IR detector outputs could be displayed on a TV monitor. As it turned out, the horizontal scan rate was not up to NTSC standards, being only about half as fast and sinusoidal rather than a linear sawtooth scan. Also, because miniature galvanometer mirrors performed the scan resonantly, the scan was sinusoidal in velocity. The OEM digitized the sinusoidal waveform, representing horizontal scan position, and used the results as an address into a random access buffer memory into which the sampled and digitized video was stored. This occurred during both the left-to-right and the right-to-left scans. Now the tricky and clever part: to make NTSC compliant video, the buffer memory was read out
twice in the period occupied by
two NTSC scan lines. No one seemed to notice that each consecutive pair of horizontal scan lines displayed on the monitor contained exactly the same data, obtained from a single horizontal scan of the galvanometer mirror.
I, OTOH, realized that if the data were being duplicated every other scan line, maybe we could just switch back and forth between IR detector outputs every other scan line to display both IR bands simultaneously. That turned out to be almost ridiculously easy to do with a high-speed video switch and some minimal logic. The results were impressive, and since the switching was all controlled by logic gates, it was easy to implement A-B comparisons at the flip of a toggle switch. Management was happy and I received either an "attaboy" or a "brownie point" for my efforts.
But I couldn't just leave "well enough" alone. For my next "trick" I tried to combine a CMOS CCD camera image with the FLIR images so we could see the infrared image superimposed on a visible light image at the same scale. Now this is pretty much normal practice today, but in the early 1980s it was apparently considered sensor fusion and classified at a level above Top Secret, for which I did not yet have a "ticket" to be privy to. Management quickly shut me down and assigned me to another project. It turns out that there are many imaging sensor platforms whose data can be combined in a similar manner to produce a result that has more information than any individual source... radar (including ground-penetrating and back-scatter radar), sonar, laser Doppler interferometry, hyper-spectral imaging and probably some I don't know about yet. The process of sensor fusion is all very math intensive, especially if real-time results are needed as, for example, on the battlefield. Even the method of results presentation is open for further consideration as technology evolves. Fascinating work, and too bad I am retired and so not involved any more.
Hop
