It is subjective to the country in which they are to be used..

But yes there is...

http://www.roke.co.uk/resources/data...llocations.pdf

27Mhz is dedicated to Glider type aircraft and powered aircraft, 35Mhz is dedicated to powered aircraft,
40Mhz is dedicated to water based craft.

__________________
Eccentric millionaire financed by 'er indoors

 

Hi again.

@tcmtech
- Very little of the stuff on here has any practical use. This site is used by hobbyists, who're obviously only pursuing their own interests. I'm not in this because I *need* long range transmissions, but because I figure I'll learn something useful along the way.

@Nigel Goodwin - "Not on UHF it hasn't".
- Perhaps not, but my goal was never trans-atlantic transmissions. Furthermore, I came to this thread looking for constructive advice, from people who are clearly knowledgeable about the subject. It's been dissappointing to have only received repeated warnings regarding interference, given that I thought I'd made clear that I didn't plan to violate any applicable laws. This is an electronics forum; I didn't come looking for legal advice. If you feel the need to warn me about breaking the law, it it would have been nice to have had some advice about the electronics as well.

@Chippie
Yeah, that's right. Ofcom have a section on it here:
OfW 311 - Radio Controlled Models | Ofcom

 

No, you've made it VERY clear you ARE planning violating laws - many people here (including myself) are radio amateurs, and we take a very dim view of such proceedings.

There are various licence free modules available, I suggest you look at those - although I doubt any are available that will meet your ten mile range?.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

"VERY clear"? - Sorry, I don't see how you get that impression . At worst, I figure what I've said could have made my intentions ambiguous. What did I say that made you think that?

 

Google "wolf lowfer" (don't use the quotation marks). This will give you some ideas. Also, consider QRSS mode (very slow Morse code). Both can span great distances with tiny amounts of effective power. And they were developed for license free use.

 

Wanting to use an illegal and unlicenced transmitter in the UK - how do you imagine that doesn't violate laws?.

Incidently, while we're talking low powers - years ago we had TV interference at work, wiping out TV reception over a couple of square miles. It turned out to be an unstable masthead amplifier - just one transistors, drawing a few milliamps, yet it had a massive effect.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Thanks for the info re the 27MHz legalities. When I was a kid my friend had some RC stuff from his planes and cars, we used to hook servos up to stuff in the backyard and try to spring mousetrap cages, set off firecrackers and other kids stuff.

Having no experience with RC hobbies etc I never would have guessed that was in violation of the rules.

 

We get a lot of rogue market traders who import illegal stuff...'toys from China' that are mainly R/C model aircraft that are running on 40MHz...Quite illegal, of course the Trading Standards people have a field day rounding them up and impounding their wares...

__________________
Eccentric millionaire financed by 'er indoors

 

So what was wrong with using the XBee 9x modules? They can do 10miles with the right antenna.

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com/

 

If they can manage 10 miles, it sounds an excellent option.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

XBee-PRO 868 OEM RF Modules - Digi International

• 868 MHz short range device (SRD) G3 band for Europe
• Software selectable transmit power
• 40 km RF LOS w/ dipole antennas
• 80 km RF LOS w/ high gain antennas (TX Power reduced)
• Simple to use peer-to-peer/point-to-mulitpoint topology
• 128-bit AES encryption

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com/

 

Very nice

But I suspect he's looking for something a lot cheaper?.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Thanks for the replies guys.
As for the XBee - I was really looking to design something, rather than buy it. I know it'd be a lot simpler, and probably cheaper, to buy a pre-built module, but I'm interested in learning how to do it myself.

@Nigel Goodwin
Can I just clarify this with you: would it be illegal for me to to construct any transmitter, even if it was otherwise in compliance with the regulations? So, for example: I couldn't duplicate an existing RC plane controller, as I'd need to get it checked before using it?

If so, do you think it would be possible to reappropriate an existing piece of equipment, such as a walkie-talkie type radio, to circumvent that restriction?

Thanks again.

 

FRS walkie-talkies don't have that kind of range. You can legally (depending on your country) build a DIY transmitter without a license but it's power output will be very small.

If you're so interested in learning about RF transmitters why not join a local HAM club. They can help you get your license.

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com/

 

Legality is just a personal perspective. If your a law abiding person a few words from someone else is all it takes to prevent you from doing something.
However I prefer to just obey the laws of physics myself! They are self governing!

I have yet to have someone explain what classifies something as an RF transmitter Vs a device with incidental Rf emissions. If a multi milliwatt RF transmitter is illegal how can millions upon millions of devices give off countless watts of Rf energy in a broad spectrum legally?

As I have stated a few times before in other threads I do not have any RF transmitters that I operate to any great degree legal or other wise. BUT I do have a 30KW " broad spectrum RF hash generator" I run for hours a day at times with absolutely no concerns what so ever of being reprimanded for it!

Its my 105 amp plasma cutter and it uses a HF switching power supply too!
When my friends are using it I have seen it mess up every TV in my house even with all of my TV signals being feed through coaxial cable coming from a shielded satellite receiver! I suspect that there is a load of RF pouring out of it in order to grossly interfere with shielded coaxial wiring 100+ feet away! My nearest neighbor has commented on being able to pick it up nearly 1200 feet away on his AM radios too when I am out in the yard cutting up scrap iron with it!

If you build an Rf transmitter circuit its illegal, but what if you build an "LED flasher" circuit that just happens to give off an "unknown to you" Rf tone that just happens to be in the frequency your sending the purposed Rf dits on? (wink wink nudge nudge )

Laws and their interpretation are a very big Grey area!

Go nuts with your milliwatt dit n' dotter! I promise I wont tell anyone!

__________________
"Issue a general safety warning. Then look the other way and allow stupidity the chance to eliminate itself." -- tcmtech
"Those who can, Will. Those who can't, will achieve positions of power over those who can and then promptly stop them." -- tcmtech
"Your impossibility may just be my day to day routine." -- tcmtech