Hey Everyone, 

 
I have been reading this site for quite some time now and I was searching around for this info with out any luck. Our school UAV team is looking to add a 5.8Ghz real time video system to our UAV and are going for a range of a few miles. We are lucky to have to the funding to invest in a good camera for our plane but we are confused by the FCC rules. 

According to the FCC 15.249...

Fundamental frequency Field strength of fundamental (millivolts/meter)   
Field strength of harmonics (microvolts/meter)
902-928 MHz 50 500
2400-2483.5 MHz 50 500
5725-5875 MHz 50 500
24.0-24.25 GHz 250 2500

We want to use this plane in competitions and might even eventually have a camera switching system to switch between infrared and our FPV. We haven't decided on a camera yet but we are looking at 5.8Ghz so we don't interfere with our radio system. What I'm not sure of, is how those millivolts/meter or microvolts/meter relate to a watt rating for a 5.8Ghz reciever and transmitter. Thanks so much for any help! Also I am open to any suggestions on a quality camera system (some of the guys in the group are talking about modifying it to work with an GoPro HD but I'd rather have a camera dedicated to FPV).

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This is a great question, one I need to find an answer for as well.

If you are working to stay completely legal, I don't think your allowed to use anything without an FCC ID unless you have a HAM operators license, then you are bound by the above limits. 

This is from my VERY LIMITED understand, if anyone can provide a better more verbose response please do!

Thanks Neil. 

Unfortunately no one on our team has a HAM license so we are pretty limited. We have been told for our competition that they will be checking to see if we comply to the standards so it is super important for us to learn this. 

Also, I don't have a ton of experience with purchasing UAV parts, so is something like 

http://store.diydrones.com/5_8Ghz_500mW_Wireless_Video_Transmitter_...

a part that has an FCC ID and I am just missing it? Thanks. 

Thanks for the additional resource. I will also repost this question in there. After searching the site, I found lots of information regarding what is and is not legal to do with FPV but not power limits. 

It's legal if you have a amatuer radio license. For unlicensed use of 5.8GHz (ISM) you need to use spread specktrum radio technologies. I don't know of any analogue video TX that does that.

Are there any analogue video transmitters you can use without a amatuer license or other form of license?

I can't answer your power questions (the rules are different here in Australia), but can give a couple of tips for 5.8Ghz video. Firstly, that unit sold in the store seems to be a generic 5.8GHz tx/rx that is sold by many online FPV stores. I bought one (from another store) a while back and had some issues with it. I had to resolder a few parts that were loose. Plus it has a big heavy fan and heat sink that just adds weight and consumes power.

 

I'd stick with an Immersion RC 600mW transmitter instead - the quality is much better and they are smaller (no fan either). Note that immersion and the no-name brands use different frequencies, so you need to make sure you get a matching Rx.

 

The other thing to do is replace all antennas with circular polarised ones as the range and signal clarity will be orders of magnitude better. Usually a clover leaf on the plane and high gain helical or patch on the ground will get you very good range. I am getting 4km+ with a 600mW Tx and 13dBi helical Rx on the ground.

 

I hate to direct people away from the 3DR store, but for FPV, readymaderc.com is a great place to have a look around, they specialise in it.

 

If you do have to minimse your Tx power, make sure you use the antenna tracker functionality of the mission planner and get a good, high gain Rx antenna and you will still get a good range out of it.

 

 

to be legal you are to fly within line of site and you do not want your video Tx to overpower your rc control  

It depends on the competition they enter e.g. http://www.unmannedsystems.ca/content.php?doc=53&xwm=true

Which was 2km @ 1500ft. How you test it seems an unknown ;-)

"4) Outside mission boundary: In case the UAV gets outside the mission boundaries, the Air Program Director should be immediately informed. The Air Program Director may ask to terminate flight immediately." seems like an interesting requirement to terminate immediately!

This is almost taken directly out of our competition manual. We have a fail safe built into our mission plan and will have additional security measures in place for the competition. We have the newest ardupilot and receivers available I believe on 2.4Ghz. And, I believe that we are in fact working on an antenna tracker for our plane. I was just curious if anyone knew the maximum power we were allowed to use per those FCC guidelines. Does anyone know if the 600mW Immersion Transmitter is FCC compliant? 

By the way, our first competition is in June and it is a task based mission to unscramble some letters and login to some wifi stuff autonomously, but we plan on using this plane for future mission including search and rescue missions without having to redesign the payload (That's why we want to have a long term, good quality camera and possibly the ability to switch it out with an infrared camera.)

What receiver are you currently using to get 4km? I think that is probably close to our ideal range for the moment and then by adding our antenna tracker maybe push it to closer to 3 miles. Also, just out of curiosity what camera are you using or would you recommend?

Tyler, I'm using a diversity receiver so I can have both a long range and omnidirectional antenna for close in work - gives the best of both worlds. The receiver is here http://www.readymaderc.com/store/index.php?main_page=product_info&a... (it's a duo5800 - I have version 2)

 

The important bit is the antenna for long range work. I am using the antenna combo here http://www.readymaderc.com/store/index.php?main_page=product_info&a...

 

Range is tricky to give recommendations on. I am doing a lot of flying over the ocean right now for a project I am working on - 4km is as far as I have flown and the signal is still good. However, if there are hills or trees between you and plane, range will be significantly shorter.

 

For cameras, I have mostly used the security camera styles, but am about to try a gopro3 silver. The best of the security cameras I have found are the Pixim seawolf based chips. Something with high dynamic range (marketed as WDR or HDR) is good if you want both sky and land to be clearly seen.

Read this http://wireless.oldcolo.com/biology/ProgressReports2002/Progress%20... (it's informative)

At 5.8 GHz you'll need a license unless its a spread spectrum radio ( it's not ) its not illegal to sell, just operate without a proper license.

A ham license is easy to get, and only one of you need it. Once one gets it the questions above are obvious! That's the point.

Check with your local Amateur Radio club I'm sure they would be more than happy to help.

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