3 replies to this topic

[noman]

i want to implement a project

1-possibly i use 433Mhz band
2-tx & rx
3-i waant to use RSSI for controlling the pan as well as tilt

please guide me about the controller & other necessary detail

[Terry]

Not sure I understand the question, can you give more details?

Terry

[Helix1]

Noman - also not sure what you mean, but I suspect you are talking about using a constantly on rf downlink of some type? What signal type did you have in mind, if any? - a dedicated rf signal of sorts (modulated with a "beep beep ..."?), or an existing modulated signal(e.g. if you have video transmission onboard?) - or some other kind of rf signal?

Using a received rf signal [strength] is not the easiest way to go about pointing an antenna if you are centering everything around a single ground station. There are a few issues that have to be factored for to get such a system working as relaibly as you'd want it to entrusted with a model plane (meaning quickly enough & accurately enough), but it's not impossible. There is (or was)a rather nicely written up university thesis in PDF somewhere on the web: some guys used a tripod mounted parabolic grid between to axial mode helicals or yagis (using the helicals/yagis to get the differential & comparitive rf measurements required to point the parabolic grid). They posted up a uTube video as well - it seemed to work perfectly well.

If its the experimental nature of the exercise you wish to tackle, then go for it, but if it's just a working tracking system you wish to get up and running, then investing in one of the well tried, tested GPS co-ordinate based systems made for RC model flying, would be a better choice in my humble opinion. They are relatively cheap, quick, accurate, easy to incorporate or add-on to existing onboard hardware, and have proved to be quite reliable.

Building an "RSSI" type system from scratch will involve a not inconsiderable investment in time, and, I would think ultimately extra expense as well. It's not likely to be as accurate as a GPS based system, which may or may not be an issue(?). On the plus side, you'll sure learn a lot though in the process.

Edited by Helix1, 20 October 2010 - 12:33 AM.

[Helix1]

http://epubl.luth.se/1402-1617/2005/296/LTU-EX-05296-SE.pdf


..... good read - has some interesting info in it