Im trying to decide on a cheap, relaible data modem that has atleast 10 miles of range. i would like to adapt it to work with my standard tx and fly my fpv plane, and later with the paparazzi im going to build.
If the modem frequency is between 902 and 928mhz it is within the amateur band. All that means, in this case, is that amateurs are the "primary" on the band which means that they can interfere with you, but not the other way around. There are other restrictions to being unlicensed. If you find a modem that is "Spread Spectrum" you are permitted to transmit with 1 Watt of power. While that seems like a lot and many will claim you can get 20 miles or so of link it's unlikely. Attenuation from the atmosphere increases greatly with frequency, and at 400mhz I can get about 10 miles on a watt, but only just. I guess what I'm saying is: that is a challenge, the best you're going to find is a 1Watt SS modem, thats the legal limit. But, there is hope. An often overlooked system component is the antenna, and it is probably the most important piece. If you have line-of-sight to the plane and a high-gain antenna like a yagi pointed right at the plane you can probably pull it off.
I don't have personal experience with either, I worry a bit about the comment that the aerocomm's can interfere with the GPS. I think that could probably be dealt with, though. As far a brand-name goes Maxstream is slightly better known.
A couple guys in the robotics club were playing with two AeroComm AC4490-200 transceivers and BASIC Stamps this past Sunday. They were getting close to having them talking, but haven't yet. They'll be working on them later this evening, I imagine. I'll let you know how it goes. If they do get them working, I'll probably use them instead of the XBee modems I was considering.
yes an abandoned, military base miles of nothing. i would like to explore around because ive seen some cool stuff on google earth but the pictures suck and the roads are blocked but the airspace is not restricted. my slowstick can only go 1.5 miles before i start to worry, but my scratch build shadow has flights of over 30 min and still room for more mah.
If you stay low enough and away from airports, it wont really cause a safety issue. The military is really interested in developing automated collision avoidance. I imagine the eventual solution will be some kind of protocol that broadcasts location and predicted flight path of everything in the sky. Possibly combined with computer vision. Who knows.
As for the AeroComm transceivers...they weren't working on them tonight.
This already exists. It's kinda in it's infancy, but intended to replace the radar/transponder model used now. I'm sure they'll keep radars around, but it's much easier for other planes to just listen to a common radio frequency for updates to nearby traffic. I think it's called "TIS" for traffic information service. Computer vision would probably be a challenging and ultimately unrewarding way to do this. i think, because the government has a lot of control over what's in the sky. This makes it possible to implement sweeping changes such as TIS, or systems like it.
(warning topic drift to michaels flight area)
old Ft ord property too interesting? just watch out for the approach paths to monterey airport, downwind is often over the town of seaside itself and the ft ord properties themselves and is low, the planes are on approach remember?
In addition life flight(s) to/from CHOMP in carmel are often low(under 400ft), couple that with occasional low fast passes of private helicopters off the seaside beach(only just over the water) at fremont exit ,to the terror of the paraglider pilots locally.
A safer bet would be to stay to the eastern half of the ft ord property and also have access to the large fenceless agricultural fields surrounding all around, makes retrieval real easy, no fences of course you may have to pay for any crop damage you may cause, and you want to make SURE no agricultural aircraft are NOT arround(watch out for the skydiving ops at Ft ord airstrip.). Another hazard to watch for on landing/takeoff are those high tension towers that DONT show on google earth.
The area Michael is chatting about is excellent EXCEPT if retrieval needs to take place , unexploded ordinance and regular burns scheduled for this year occupy some of this areas flying spots , other than the above caveats michael excellent choice. I have just been over flying the are myself with google earth to get an idea what it looks like.