Hello. I don't know where else to post (I mean, where else on the entire Internet). I was hoping that maybe some folks here could help me out. I apologize for the length, but I come to you tired and disappointed, after doing as much homework as I possibly could before simply begging answers off smart people without doing the work.
I have always been interested in radio, but never really good with electronics. With my dad's help I built a Ramsey FM-10 when I was in high school and marveled that I could "broadcast" my CD player 10 feet away. As the years went on I became less interested in having my own "radio station" and more interested in, well, the best comparison would be wireless in-ear monitors that musicians now use on stage. I have since learned a bunch about electronics, and gotten into the Arduino scene too. But I'm finding two things to be true: First; I learned electronics way too late to ever be an effective "hacker" or "maker," and secondly, if something's not popular, all the Googling in the world won't get you anywhere.
I have several problems currently that I could solve with wireless IEMs, and it doesn't so much matter what they are, but I can't take on the cost right now (a good transmitter and receiver pair is about $800, and I could use at least three). Low latency is important so Bluetooth is not an option. I much prefer the speed of light in this circumstance. I live in a really rural area, so I'm not at risk if I radiate 251mV/m at 3m, but on the other hand I'd rather not be broadcasting in a public band anyway just for a little privacy-through-obscurity.
I'm asking here because I don't know where else to go. I will be more than happy to take suggestions on broadcast-band solutions so that I'm not scolded for being off-topic, but I'd love to start playing with, say, FM MPX in the ISM/license free UHF bands (500-900MHz). But I have been Googling literally for months and I can't find anything except unconfirmed GIFs on schematic websites of "UHF RF transmitters" without stereo encoding circuity, or widely-available low-bandwidth ASK/FSK transmitter ICs that are unable to carry audio. The other thing that seems to be dominating search results is "audio/video transmitters," the wireless packs you see on video cameras at live events. It's like nothing I need exists and Shure, Sennheiser, and Nady are custom-designing every IC and circuit they sell, which I know is not the case. I have no problem with hand-soldering TSSOP, QFP, though I'd rather not, and I long for the days when you couldn't get stuff in anything but DIP.
I have been playing with the Silicon Labs Si4703 (FM receiver) and Si4713 (FM Transmitter) chips which are available on breadboard-friendly breakout boards through Sparkfun and Adafruit, but they're made to sit 2" from a car radio and transmit your MP3 player to it. I've made the right length monopoles and dipoles, and I've run random-wire the length of the house and they still fade and multipath behind interior walls. It's ridiculous, honestly, all the technology we have and I can't throw an FM signal through a couple of pieces of drywall without static and fading. There's also a low-mid-size media market about 30 miles from my home and I'm sure part of the problem is there are no unused FM frequencies anymore. There's even a high power Christian network on 87.7 there, which of course splatters into 87.5 and 87.9.
It seems like every lead is a dead end. For example, the holy grail: Texas Instruments makes a line of "PurePath" wireless audio link tranceivers that auto-frequency-hop and coexist in 2.4GHz with wifi and everything, and the chips are less than $4 on Digikey and require a minimum of external circutry to function. Feature set is excellent, and it can be used with or without a microcontroller. Has automatic handling of frequency congestion and just seems to be the perfect chip for the job. It's only available in a 40QFP package, and it has a ground pad. So, essentially, since I don't/can't afford a wave solder machine, I am unable to use this chip, even if I could get a board fabbed for it. TI makes a "development kit" which is two fully-built transcievers on PCBs for $150, and I personally don't think $75 for a breakout board housing $12 worth of ICs is a good investment.
Are we at the end of the DIY age? The "makers" would say no, except I'm sick of making yet another project that just makes LEDs blink at the expense of a 16MHz microcontroller. Did I just learn electronics too late in life? Or am I missing something obvious? I totally accept the concept of integrated circuits and I have no issue using them. But as far as I can tell, there are NO chips that will do what I want, that are available unless I'm a big business with a fabrication department and a large R&D budget.
Again, I understand I'm not talking exclusively about unlicensed operation in the FM/AM broadcast bands, but I'm starting to believe that doing so at a legal power level is useless. I'd honestly rather roll my own solutions, so I learn and can add features, than buy a commercial LPFM transmitter, and as I said I'd like to be in license-free bands anyway. Is there someone here with knowledge and experience in this area that can take pity on me? Even the $900 Sennheisers are essentially 1930s-era FM tech but in a different band. That simply cannot cost $900 to do in the iPhone era.
Thank you,
ej