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Dec 20, 2011, 10:30 PM
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900mhz legal in usa?

Hi I'm new to RcGroups and FPV, i was thinking of puting a 900mhz FPV system because of its penetrating power on a rc car, so is 900mhz legal in usa and how many mw can you use it at with out a HAM license, and if not what other mhz/ghz can i use at what mw ?????? THANKS
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Dec 20, 2011, 10:34 PM
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branflakes's Avatar
you have to have a tech class or greater license at any mw on 900

its legal on ch 1

it is not hard to get the license if you go through it your experience w be 10x better

you study one or two websites with flashcard type material, instant feedback, for a few weekends and take the test in a couple weeks when one comes around to most cities.

the whole test can be taken and passed in under 3 minutes, for sure. not hard, the study material takes some work but the websites feed it right to you, free
Last edited by branflakes; Dec 20, 2011 at 10:39 PM.
Dec 20, 2011, 10:38 PM
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branflakes's Avatar
if you want to be able to use non restricted ground based fpv its possible. sells a cheap $100 setup, correct mw on 2.4 that does not require a license.

the receiver station even if maximized with better antennas etc doesn't require a license, its the transmitter and in this case the weak ~8mw 2.4 security cams are legal off the shelf. the antenna connection on the receivers for these cheap units is not often connectable to fpv quality items like patch antennas etc they have fixed, short range pig tails (most of them)

if you will take and pass the ham test you will be really happy about having legal access to the good equipment. Its an excellent step, benefits you in many ways. out of the box, the $100 set will transmit across the street from your house and thats about it on the ground. instantly you will want the full ham gear, after the first run. what you are asking about is how I cut my teeth on rc/fpv

The math is 4th grade division and multiplication on the tech class
the terminology is 10th-11th grade physics

its like a semester exam, not hard.
Last edited by branflakes; Dec 20, 2011 at 10:48 PM.
Dec 20, 2011, 11:56 PM
Registered User
hey thanks for the information but i don't what to get a license or take a test just to drive a fpv car around my house and i don't what to use 2.4ghz cuz I'm using that as my control is there any other frequency i can use thanks?
Dec 21, 2011, 12:07 AM
Registered User
branflakes's Avatar
they make 75 mhz controllers for ground use that will transmit well. farther than your video even if you run 900 mhz. to drive around your house all you need is the 2.4 ghz video that is legal.

you had asked about the license/frequency and thats the answer, 900 requires a license. its no different than choosing to go hunting without a license just because you can...since the license is $15, lasts ten years, and can help you get jobs (looks good on resume/tech skills) its better than not buying one and using the gear illegally. the test is so easy to pass, Im playing up on the hint you had originally asked about the license, thats good you asked about that. not enough do.
Dec 21, 2011, 12:20 AM
Registered User
so 2.4ghz video is legal at all mw? and can i use 5.8ghz video or does that not go thru walls as good?
Dec 21, 2011, 12:31 AM
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CaliDave's Avatar
For the majority of video transmitters used in FPV ranging from 900mHz, 1280mHz, 2.4G and 5.8G a technicians license is needed for legal transmission.

Some 2.4G low watt transmitters are okay (I think), but I couldn't tell you which those are.

You'll spend much more time and money learning FPV theory needed to be successful than you will to do it legally.

I recommend spending the little time it takes to get your HAM license if you want to transmit video or long range 433mHz systems. There are legitimate reasons we are required to use those transmitters.
Dec 21, 2011, 12:40 AM
Registered User
OK i think I'll look in to getting a HAM license but you think 2.4ghz 200mw is probably ok with out a license.
Dec 21, 2011, 01:08 AM
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CaliDave's Avatar
Originally Posted by RcFlyingKid
but you think 2.4ghz 200mw is probably ok with out a license.
No, I don't.

Maybe something like 10mw, you need to check and see. Only VERY low mw TXs will be legal in 2.4.
Dec 21, 2011, 01:27 AM
Registered User
o thank for your help.
Dec 21, 2011, 01:48 AM
Registered User
Daemon's Avatar
There's a difference between "legal" and "license free".
423-447Mhz, 910-925Mhz, 1243-1290Mhz, first half of 2.4Ghz band, and I think all
of 5.8Ghz band are "legal" to use for ATV (Amateur TV), with a minimum of a HAM Techician's license.

License free means device can be operated without a HAM license but requires
1. Device meets the rules for FCC Part 15 compliance (with regard to max power, not spewing Rf noise, and accepting noise from other devices) and
2. Actually has an FCC Part 15 sticker indicating it has been tested for compliance.

If it lacks either of those, it can not legally be operated without a HAM license.
The only commercial video transmitters I know that actually have the FCC Part 15 sticker
are commercial baby monitors and some X10 surveillance cams. That's about it.
If they don't have the sticker (indicating they've actually been through FCC Part
15 compliance testing) then it doesn't matter if they have 1mW or 1000mW of
power, they can not technically be operated license free.

There's a lot of misinformation about the maximum power allowed as well for license
free operation. People toss out anywhere between 10mW and 200mW but if you dig
through the actual FCC Part 15 regs, it says that for analog transmissions (all of
our video Txs are analog) that the max power allowed comes out to about 1mW
(they specify in dBm units, but converted to mW that's basically what you get)

Technically the only legal way to operate *any* video Tx in the US with enough
power to be suitable for FPV, you should have a HAM license. Does that mean,
everyone does? No. The FCC itself is unlikely to come after you directly (there
aren't FCC cops roaming about with scanners), but other licensed HAMs very well
might report you to the FCC, if you're stepping on "their" ATV channels, especially
with really high powered video Tx's. It's one of the reasons I advocate a basic principle
of HAM operation that a lot of people like to ignore.
Use only enough power to get the job done, and focus on the quality of your antennas.

Side note: All the available UHF control systems, operate in the 433Mhz HAM band,
at levels above what is allowed for license free operation. Devices that operate
there license free, are things like remote thermometers and other weather station
telemetry at *extremely* low power. I'm lucky if I can get a good signal from
my remote temp sensor, 30 feet from the base, through one exterior wall.

In parts of Europe some of these limits are different. For instance they have a 10mW limit,
in some places, although I'm not sure if it's legal max, or license free max.

Last edited by Daemon; Dec 21, 2011 at 02:07 AM.

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