Total newbie with a few questions

Hi! I'm ready to dive deeper into the world of quadcopters, and an absolute requirement for that is a good transmitter. I'm trying to figure things out on my own and I've read the FAQ and getting started guide, but a few questions have arisen that I can't find a practical answer to.

I currently have a cheap brushed model I'm training on, but I'd like to eventually get a Hubsan H501S (and maybe eventually build my own, but that'll come much later). Thing is, Hubsan's transmitters leave me cold - the standard one is considered less precise (which is bad for aerial video), but the advanced one is significantly more expensive and only works on Hubsan stuff. I'd like to get the standard package and put the money that the advanced one would cost toward a Devo transmitter with a RF plugin, which I could also use with the brushed cheapie and other future models.

• Should I get the much cheaper 7e or splurge on the 10? I understand that the 7e can be hacked to enable the signal amplifier by bridging a diode with an easy soldering job and two switches can be added with trivial surgery; with Deviation installed this gets you 8 channels and most of the power of the Devo 10.
  
  Are those enough for a H501S with its camera and GPS-related features? The stock transmitter is specced on geekbuying as "10+ channels", but the quad has several features I have no use for. What I absolutely need is standard 4ch directions, camera video control, GPS-lock and RTH, and I'm given to understand another channel is needed for receiver initialization. It also has follow-me mode but I'm uninterested in that (and it requires the stock transmitter's GPS anyway), and I don't know if photo control uses the same channel as video control but I don't care about that either. I can make do without headless mode too, as FPV makes it somewhat superfluous. I don't know if it's relevant that the H501S is an altitude hold model - to the best of my knowledge you can't dynamically switch on and off that feature from the controller.
  
  I'm a hardware hacker by heart so the thought of a cheap transmitter Frankensteinized into a much better one is very appealing to me, but since I plan to fly such a (relatively) complex quad I don't know if all the hacking would still leave me with insufficient features compared to a TX that is better to begin with.


• What's the deal with this module? I only have a limited understanding of the explanation, but it sounds a lot like a "learning remote", in that it learns the signals from an existing transmitter and adopts them to control pretty much anything. On paper it sounds like the ultimate deal, but I'm obviously missing something, otherwise RCGroups wouldn't have so many posts of people going "will this quad bind to my Devo?" - if this module really did learn everything everybody would have it and the question would surely be moot.


• In any case, should I get that module or just this 3-in-1 (which explicitly supports Hubsan models and a whole bunch of others)?

Thanks, and apologies if these questions are silly - I've been obsessively binging on quadcopter videos for the past two weeks and I might have a slight bit of confusion (and quite possibly insanity) in my head.

First you won't need the range mod for the hubsan protocol. That only affects the protocols that use the CYRF module, most notably the DSM and Walkera families of protocols. The hubsan protocol isn't one of them.

There are twocritical questions to ask yourself about the 7E vs. the 10. First, do you find that small form factor really attractive? That's one of the critical reasons (beyond price - but more below) to get the 7e.

Second, how much hardware hacking are you willing to do to make the functionality easy to use? That's the critical question. All the deviated rx's are 12 channel Rx's, though that does depend on the protocol. The 7E with two extra switches will probably do everything you want, mostly because of the flexibility of deviation. For instance, you can turn the throttle trim into a multi-position switch, where each position makes the other switches do different things. But that's hard to set up, and probably even harder to fly.

The solution to that is to add extra real switches. There are at least two other options for the 7E beyond just adding switches: adding an arduino with extra inputs tied to the PWM input, and the "ultimate 7e" mod that starts by replacing the µcu with one with more memory. As a software hacker, the limited memory on the 7E is what bothers me most. It runs a slightly stripped-down version of the software, and that's only going to get worse. And it's harder to install because the protocols aren't compiled in. If you're really a hardware hacker, the 7E mod may be the way to go.

That module on BG isn't a deviation module, it's an external RF module for transmitters with a module bay. The give-away is the dial. That's used to select the protocol it sends after you set your transmitter to PPM mode. The 3-in-1 is definitely a better choice, as it's designed to work with deviation. One particular difference is the way protocol support works on them. On the 3-in-1, protocol support is in deviaiton, so you get new protocols by upgrading deviation. For the first one, protocol support is on the module, and deviation just uses PPM. You won't get new protocols until they are ported to that module.

There is a 4-in-1 module designed for deviation, but it's really meant for the 6s/8s/10/12s. It replaces the CYRF module. The 7E uses a different module, so you have to solder it in by hand. On the 7E, the main advantage it has is not having to do the range mod and having one antenna instead of two.