Jump to content

Recommended Posts


I will buy one FOX-2500 for a Twinstar II:

Transmit Power:2500mW

Frequency:1.2G / 1.3G



Channel(Tx): 8CH AV frequency in-phase

Unobstructive Effective Range: 2~4 KM

Package:12CH receiver, transmitter, 2antennas, 2AV cables, Power supply

It's for flyght in Europe. So, I will use 1,2GHz band for video (2500mW), 2.4Ghz band for telemetry (50mW Xstream modem with tiny from paparazzi project) and 35MHz for RC control.

I'm worried about the interference. What's your opinion?

Have other solution for Portugal?

Link to post
Share on other sites

I think 2.5W of RF at 1.3Ghz is way too high, how far do you expect to fly on 35Mhz ?

You are using 50mW for telemetry so why do you want 2.5W of video ?

2.5W will also use lots of power !

I surgest 500mW or 600mW would be more than enough for your project.

I use 100mW up to 1.5 miles with no problems.


Link to post
Share on other sites

Yes, you are right. But last summer I tested a video system with 2.4GHz - 1000mW and I had some bad results when the aircraft turns and hided the antenna. But I think that the problems was in UAV carbon material and tx and rx antenna.

With a 1000mW system, and a good patch antenna I will gain more range. Right?

I will change the frequencies, because 1.3GHz require radio licence, fees and write requests.

I will have to use 458MHz band for telemetry and 2.4GHz for vĂ­deo.

So, 500mW or 600mW would be enough for my project? I will need a good video signal about 3 miles.

I'm thinking to build a tracking patch antenna to help.

For autopilot I will use tiny board from pararazzi project. Did you know?

Link to post
Share on other sites

do you have a GPS on that plane ??

1300MHz video will block your GPS.

with just 100mW TX system at 1300MHz

I need MUCH more distance from the TX to GPS compared to 2.4GHz 500mW.

the whole idea about 1300Mhz is the longer range at lower power compared to 2.4

also have you got a license for 1300MHz ? check the rules in your contry,

the first two channels are reserved for radioamateur legal use.

Edited by ThomasScherrer
Link to post
Share on other sites

Paparazzi project?

So you will fly over peoples with an aircraft with a lot of equipements over long distance to take some photos.

It's illegal in many countries to take photos or film with an r/c plane and sell them, you need special license. We do not reccommend to fly r/c plane over crowd. R/c plane are not reliable, a Twinstar will all the equipement is heavy and must not fall on people. Generally peoples fly over feild.

Perhaps I misunderstand your goal?

Link to post
Share on other sites

"So you will fly over peoples with an aircraft with a lot of equipements over long distance to take some photos."

No, I don't will fly over peoples with an aircraft. It's a project for an controlled UAV for special missions. For police, military, scientific people or rescue corps.

The photos don't was for sale. It's only for missions. It can be used for agriculture camps, roads projects, etc.

I'm trying ro built an controllable UAV with a 2.5/3 miles maximum range.

Link to post
Share on other sites

Hi aerodolphin, this is a great project and really exciting :-)

I don't know in which place you live, and so there might be certain rules/laws different from here. If you want ot make this UAV device available to other people, sell it to firms, institutions or whatever, make sure that it's equiped with sufficient emergency case functionalities. It is a good idea, for example to have sensors onboard to determine a rapid (uncontrolled) loss of altitude (="falling") and an algorithm that automatically kicks in and stabilizes the object and induce a controlled landing in the closest, unpopulated(!) area.

Just to make sure that laws of airspace are taken care of.

I don't want to sound nagging, but since our stuff is getting extremely powerful and breaks lots of limits that RC controlled "toys" usually have, it's no more a simple "toy" but becasue of its capabilities the criteria is getting merely towards those of "real" planes, we're entering the airspace of sports planes, helicopters, and actually everything occupying airspace.

For example, a sports plane is allowed to fly as low as 150m above non-populated area, and about 600m above populated areas under certain circumstances. So with our rc controlled or even UAV objects we easily enter these areas, and everything is fine as long as nothing happens. Just as soon as we get involved, no matter how, direct or indirect, we are held responsible for the things that happen. For example it's enough that the object crashes close to a busy street, some person driving a car panics and swerves and hits another car or a street sign.

No matter how good our skills are, glitches and interference may always cross our way and we can't predict them, so it's not always in our hands.

This is something that can happen easily, and normally we don't think much about those things, but they might happen indeed.

Therefore, in order to keep risks at a minimum, I think it's good advice to learn about the laws applicable to "the real planes", which are made to keep the airspace safe.

I hope that was not too much nagging. I just think we need to remember those things from time to time, to not forget them ;-)

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...