Jump to content
reuben

Uk Regulations - System With Best Range?

Recommended Posts

Hi, I have been enjoying reading through a lot of the posts on this forum.

I live in the UK and would like to buy a video transmitter/receiver pair which will give me a really good range (1K or more). I am aware that there are some regulations about the transmitter power that is allowed over here in the UK, although I have read conflicting values of 10mW and 100mW...

Do the 2.4G solutions out there (e.g. the 633 from airwave) have the potential for ~1k range, keeping legal in the UK?

Also, what would be the best type of receiver antenna for maximum gain, as i guess there are no regulations on the receive side...

Thanks for any advice. Price isnt too much of a problem.

Reuben

Share this post


Link to post
Share on other sites

Hi Reuben,

I am aware that there are some regulations about the transmitter power that is allowed over here in the UK, although I have read conflicting values of 10mW and 100mW...

10mW is the correct power limit for video transmitters and 100mW for r/c control, wifi and other digital stuff.

Do the 2.4G solutions out there (e.g. the 633 from airwave) have the potential for ~1k range, keeping legal in the UK?

Short answer is yes but the long answer is that it depends on your receiver, aerial, terrain and expectations.

Also, what would be the best type of receiver antenna for maximum gain, as i guess there are no regulations on the receive side...

Thanks for any advice. Price isnt too much of a problem.

I would recomend you start with a diversity system with sensitive receivers and 8dbi patch type aerials. If you have access to a helper to point your aerial for you then a 14dbi patch would be good.

Terry

Share this post


Link to post
Share on other sites

Thanks Terry,

Is 10mW also the limit for 900MHz systems? It seems that there may be pros and cons for a 900MHz system:

pros: potential for greater range (due to fundamentals) and possibly the 900MHz band is less crowded

cons: far less offerings in the 900MHz band;

The cons probably pretty much cancel the pros...

Also is there a 1.394GHz band which is license free in the UK? I have read that the power can be 500mW without a license in that band in the UK:

http://www.radcon.com/pdfs/cct1394.pdf

The same company also make a 10mW 2.4G system which is quoted as up to 500m and 1km with a large antenna:

http://www.radcon.com/pdfs/cct2440.pdf

The main difference of this system and the Airware 633 system seems to be the receiver sensitivity. Both of these systems are expensive.

I am thinking that I will first try a normal Airwave 633 module, with a standard 3dB omni aerial (is 3dBi the maximum gain allowed for this system in the UK?) and a receiver with an 8dB aerial and a low noise amplifier.

Cheers,

Reuben

Share this post


Link to post
Share on other sites
Is 10mW also the limit for 900MHz systems?

900Mhz is not an option here, it is used by other services.

Also is there a 1.394GHz band which is license free in the UK? I have read that the power can be 500mW without a license in that band in the UK:

yes this looks good, in fact I have just ordered my first gear for this band. On the plus side 500mW at this frequency means a dipole on both the TX and the RX should still give very good range. The bad news is the TX's that are availible are BIG and there is only one channel. Oh and a lot more expensive too !

I am thinking that I will first try a normal Airwave 633 module, with a standard 3dB omni aerial (is 3dBi the maximum gain allowed for this system in the UK?) and a receiver with an 8dB aerial and a low noise amplifier.

If this is your first step into wireless video then the 633 is a good start. you do not want to use a TX aerial with more gain anyway as it will have less gain above and below to make up for the higher gain to the sides. The 8dbi patch on the receiver is a good start and LNA will only realy help if your receiver is poor.

Terry

Share this post


Link to post
Share on other sites

Good point about the TX antenna.

Having looked into the 1.394GHz systems, I think this seems like a better idea now. However, I am struggling to find more offerings than the link I sent. Can I ask where you have bought your system from? I would prefer a module that I can include in my own system really, rather than something that is already boxed up.

Are you sure the 1.394GHz 500mW systems are legal in the UK and license exempt?

Cheers,

Reuben

Share this post


Link to post
Share on other sites
Are you sure the 1.394GHz 500mW systems are legal in the UK and license exempt?

Yes very sure, they are made for long range cctv use. The main problem is there is only one channel so if your unlucky enough to be close to a cctv link it could be very bad news.

Can I ask where you have bought your system from? I would prefer a module that I can include in my own system really, rather than something that is already boxed up.

I have not even received my gear in the post yet so will not give details until I have fully tested it. It is much bigger and more expensive than all the 2.4Ghz gear so unless you have a large plane 2.4Ghz will still be your best bet. 2.4Ghz is tryed and tested and there is not shortage of choice, for 1394Mhz is much harder, I will be making my own aerials and stuff.

Terry

Share this post


Link to post
Share on other sites
Are you sure the 1.394GHz 500mW systems are legal in the UK and license exempt?

The UK Radio Interface Requirement 2030 doc that I have lists the 1.394Ghz band for video broadcasting. 500mW EIRP is shown. It would be a Class 1 device, so I understand that airborne use would not be allowed (ground based transmission use only).

Also, such devices are not legal for license free use in the UK (or other participating countries) if they don't include the required Declaration of Conformity. So, if you want to operate it legally, it would be a grand idea to ask the retailer if the device is compliant before buying it. FWIW, the DOC related information would be found in the literature that is included with the sold RF device. The wording is something like this: "Hereby, [Name of manufacturer], declares that this [type of equipment] is in compliance with the essential requirements and other relevant provisions of Directive 1999/5/EC. The declaration of conformity may be consulted at www.worldwideweb.com/DoC.pdf"

Share this post


Link to post
Share on other sites

Thanks - yes it seems difficult to get hold of the certifications.

Another problem with the 1.394GHz systems are that there is no sound channel (if you need sound that is!). Am I right in thinking this?

Also, I was going to ask, if I get an 8dB patch antenna that a lot of people seem to be using here, I assume that is pretty directional? How directional is it? What sort of angle?

And finally, what would be the best Airwave pair to buy for 10mW? Which of their receivers have people have best success with (in terms of sensitivity)?

Cheers,

Reuben

Share this post


Link to post
Share on other sites
It would be a Class 1 device, so I understand that airborne use would not be allowed (ground based transmission use only).

OOOOPS, your right ground use only, looks like I have a super new video TX for my mast camera :lol:

We are well stuffed here in the UK, any recording will have to be done on the aircraft.

Terry

Share this post


Link to post
Share on other sites
Another problem with the 1.394GHz systems are that there is no sound channel (if you need sound that is!). Am I right in thinking this?

Music or speech, that is associated with the video camera's image, is allowed. But, perhaps audio is not common on the equipment you looked at because of the privacy issues?

I noticed that there are two RF power categories for the 1.394GHz video systems. One is 10mW and the other is 500mW EIRP. I'm not totally sure, but it appears to me that if the video signal is not live, directly from a video camera, then the 10mW EIRP limit kicks in. I suppose an example of this would be a household room-to-room video broadcast device. Terry may know more about the two categories since I'm a simple Yankee that is far away from the UK.

Share this post


Link to post
Share on other sites

I have struggled to find suppliers for the 1.394GHz systems - any suggestions?

Although, I do think that the 2.4G are probably still the best way to go just because of the better selection available and the price. What online companies do people use to buy the 2.4G systems and especially the aerials?

Cheers,

Reuben

Share this post


Link to post
Share on other sites
I noticed that there are two RF power categories for the 1.394GHz video systems. One is 10mW and the other is 500mW EIRP. I'm not totally sure, but it appears to me that if the video signal is not live, directly from a video camera, then the 10mW EIRP limit kicks in.

The way I read it is that the 500mW with no audio is for long range cctv that dose not use audio due to law and often uses 458Mhz for control of the pan and tilt.

The 10mW is for domestic video senders but I do not know of any makers of this, I guess due to it being UK only and the Jap guys won't wast their effort on it. Just like the 459Mhz r/c gear.

Terry may know more about the two categories since I'm a simple Yankee that is far away from the UK.

First off Terry missed that 1394 was for ground use only so I would not bet on it. :huh:

Second, you may be a Yankee but I think you are far from simple. ;)

What online companies do people use to buy the 2.4G systems and especially the aerials?

If you want to buy a complete set then Range Video would be my first choice, if you need modules the Active Robots are cheap. For patch type aerials I make my own or use ebay.

Terry

Share this post


Link to post
Share on other sites

Thanks Terry, I'll take a look at them.

Did you consider 5.8GHz? Is that legal in the UK? I suppose that it wont go as far though as its a higher frequency...

Share this post


Link to post
Share on other sites
Did you consider 5.8GHz? Is that legal in the UK? I suppose that it wont go as far though as its a higher frequency...

Yes I have considered it and I think they allow 25mW but the band still has wifi use, I admit not much just now but I read there are plans to change this soon. So it may be worth a stab but I think in the long term it will end up just a crowded as 2.4Ghz. Also prices of the equipment is higher and more limited.

In short if you feel brave give it a try, it may just be better but if you want the safe answer 2.4Ghz is still top.

There are things that can be done to improve 2.4Ghz use and still stay legal. Two 10mW TX's on different channels and a diversity receiving system is top. I have found that the wifi interference causes the diversity system to switch and so if the channels are one and four the wifi line is not seen as the as wifi is only on one channel at a time due to the way it hops up and down the band. This is not however a full fix as if two or more wifi can be on both channels at once.

The best way is to use a high gain aerial pointed directly at the aircraft but this is not always easy.

Another thing to do is do a sweep of your site before you take off and make sure your aerial is pointing away from any wifi.

My last idea which is a follow on is to use a tin lid to block an offending wifi, just set it up a few feet from your aerial in line with the wifi.

Terry

Share this post


Link to post
Share on other sites

I have purchased a few AMW630Tx/634RX modules and a wide variety of aerials (from no gain to 14dBi gain, both omni and patch).

I will be spending some time in the local fields....

Share this post


Link to post
Share on other sites

Got the basic system working tonight. Nothing special, just the normal antennas. Its good to know it works though.

Range tests tomorrow.

One question: testing it around the house I get various types of interference. I wanted to check what wifi interference 'looked' like? I reckon that is the kind which shows up as white bands which flit down the screen at regular intervals? As I go near my wireless router, this kind of interference gets worse...

Terry, I will be very interested to know how your 1.394GHz tests go.

I need to get some PCBs made up to test this stuff better, and rule out dodgy connections which I am thinking will cause a few problems.

Oh, another question, what is the best quality CCD camera for under £100?

Cheers,

Reuben

Share this post


Link to post
Share on other sites
One question: testing it around the house I get various types of interference. I wanted to check what wifi interference 'looked' like? I reckon that is the kind which shows up as white bands which flit down the screen at regular intervals?

Yep thats it <_<

Terry, I will be very interested to know how your 1.394GHz tests go.

It's not here yet but now I know it's not legal to put in the plane it's not too urgent either :(

Oh, another question, what is the best quality CCD camera for under £100?

You can't go far wrong with a KX131, got mine from Range Video.

Terry

Share this post


Link to post
Share on other sites

So, I had a quick play with the video system.

I need a bigger field. I found that with a normal antenna (no gain) on the TX and a normal antenna on the RX, the link was fine over the distance of the field (about 100m). No surprise there then. The slightly surprising thing was that the reception was pretty much the same without a RX aerial at all (just the SMA).

There was a fair amount of glitching (black lines occasionally flitting up the screen) instead of very steady video. Any suggestions as to the cause? Or is this just normal.

Also any comments on the no RX aerial findings?

Cheers,

Share this post


Link to post
Share on other sites
The slightly surprising thing was that the reception was pretty much the same without a RX aerial at all (just the SMA).

Thats odd, I get a good picture up to about 10m or so with no aerial but thats it. How far can you get with no RX aerial ?

There was a fair amount of glitching (black lines occasionally flitting up the screen) instead of very steady video. Any suggestions as to the cause? Or is this just normal.

Normal, no. Not sure what it is, dose it happen even a close range ?

Terry

Share this post


Link to post
Share on other sites

With a TX but without an RX aerial I can get to about 200m. It does have the SMA mounded though.

Good to hear the black lines are not normal. I am sure the PCB I am making will fix that issue.

By the way, the channel pins on the devices - I had assumed that no connection to these gives channel 4 as a default? Do they need to be grounded if not in use? Do you simply pull one high and the others low to use that channel? This isnt too clear in my datasheet.

Cheers,

Reuben

Share this post


Link to post
Share on other sites

I have not used these modules but I would guess that leaving the pins unconnected would give channel 4. Connecting a pin to ground should select that channel.

Terry

Edited by Terry

Share this post


Link to post
Share on other sites
Got the basic system working tonight. Nothing special, just the normal antennas. Its good to know it works though.

Range tests tomorrow.

One question: testing it around the house I get various types of interference. I wanted to check what wifi interference 'looked' like? I reckon that is the kind which shows up as white bands which flit down the screen at regular intervals? As I go near my wireless router, this kind of interference gets worse...

Terry, I will be very interested to know how your 1.394GHz tests go.

I need to get some PCBs made up to test this stuff better, and rule out dodgy connections which I am thinking will cause a few problems.

Oh, another question, what is the best quality CCD camera for under £100?

Cheers,

Reuben

Hi Reuben,

You're right to suspect house interference. We thought all of our gear was useless for the first few days when testing around the house. We never did nail down exactly whether it was WiFi, DECT, something else or just the mains in the building but it definately disappears when you get away from the house. That said, what you are describing does sound very much like WiFi interference to me if it gets worse near the wireless AP.

I don't really want to blantantly advertise on here but my Dad and I have a couple of CCD cameras available on our website www.firstpersonview.co.uk (We're a couple of enthusiasts - not in this for the money, just want to play with cool kit!)

All of the videos on our website are done with the CAM35 CCD which is a great little camera with built in 10mw 2.4Ghz TX and only 15gr.

On the legality issue my Dad checked all of this stuff out with the relevant bodies and got written confirmation that 2.4Ghz 10mw is legal for air to ground, but as I understand it everything else is (or was) out.

Hope this is of use.

Edited by Daytona

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×