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Hey i have been trying to find out how to make an fm transmitter for quite some while now but i cant find out how anywhere. Can you help me we can work together.anyone got some ideas?




3 years ago

I been thinking ? I bought a fm transmitter for the car stereo that I can .play my a portable device on it.shop I have a 500 wait AM And FM TX.Star .leanerapp. put the transmitter though the app. And the portable device . Go Mollie. Shop what do you think ? Let me know. Nite001 ltn71659@gmail.von

I ran a pirate station for a while until I found out the local FM classic rock station wanted to serve me a cease and desist. We only ran once a week for about 2 hours. So word spreads and people do come looking. We were running 5 watts and could clearly cover about a mile and a half radius around my house.

You would be better off buying one unless you know how to make transmitters from scratch most people buy them off a rig doctor www.ravedance.net

as long as it doesn't #1 transmit very far and #2 doesn't interfere with other equipment, it shouldn't draw any attention.

If you are in the USA, the FCC is one of the controling entities involved...

Regardless of popular misconceptions, it is not legal to broadcast on FM at low power, or at any power, without a license from the FCC. It doesn't matter if you are less than 100 watts or less than 1 watt. That is why the FCC has been trying to institute LPFM - to provide a legitimate license to very low power operations.

The only exception is that you are allowed to broadcast on FM without a license if your transmitter produces about 1/25th of a watt, or 25 milliwatts. This is only enough power to go about 100 feet, under the best conditions. It is actually not the power but the field strength that the FCC measures. The way the FCC checks for compliance with the law is whether you exceed a measurement of about 250 microvolts/meter on a field strength meter, which is a tool that is specifically designed to measure the strength of electromagnetic fields. This rule is designed not for broadcast transmitters, but more to allow for wireless microphones and similar devices. Because many garage door openers and computers accidentally exceed these limits, through poor design or breakdown of some sort, the fact is that FCC field agents actually spend very little of their time looking for illegal radio operators, but instead, are spending their days tracking down malfunctioning pieces of equipment like this that are inadvertently fouling up the electromagnetic spectrum.

Oh that is an excellent phrase 'inadvertently fouling up the electromagnetic spectrum' it sounds like the kind of crime I would commit...

Remind me to turn off the transmitter before bed dear, I'm worried about our electromagnetic footprint...

It could cause the new coffee maker to go off early (or not at all) and heaven knows what it could do to the microwave's computer.....

Hmmm, when I have a little time (ha), I might fiddle with the Alice program in this respect. Could be interesting :-)

Yes I too may get banging away on photoshop... but I have numerous other worlds to create first...

Isn't 1/25th of a Watt .04 Watts not .025 Watts(25 milliWatts?

Hmm, yeah, you are correct. I will have to see where I got that from to see if they had a reason for such an error.


5 years ago

this is gonna be sick

The FCC will be up your a** and around the corner. I like the thought though.

i dont know how to read the circuit diagram: this thing:

C:\Documents and Settings\Owner\My Documents\My Pictures\Screenshots\fm transmitter.JPG

> i dont know how to read the circuit diagram . Then you probably need to buy a kit. . . Assuming you don't know how to solder yet, get a kit with big parts, eg, DIP instead of surface-mount devices. Practice soldering on some junk parts/boards before attacking the kit. If you have a knack for soldering it may only take you 15 minutes to get the hang of it; if it's not natural for you, it may take an hour. The trick is to do it quick, so you don't overheat the components (sometimes a hotter iron is better because you get the joint finished faster, before the component can heat up). . . I bought a FM modulator kit back in the '70s and it was very easy to put together. But I had been soldering since I was 10 yo. Not to scare you away from soldering, just practice a little before you try putting the kit together.

i am pro a soldering bud, and don't assume because you make an ass out of u and me lol.

. Then you should have no problems with any kit. . . I'm kinda of curious as to how you managed to learn how to solder without learning a little bit about electronics along the way. What have you been soldering on? . . If it makes you feel better, replace Assuming with If, as it was meant. ;)

A plumber ? Oh right, they don't solder anymore either.

Oddly enough my mum took a plumbing course instead of having someone fix the new house's plumbing and plumbers are still taught soldering, the course was like a basic apprenticeship course so new apprentices would know what they were doing when they started, I plan on having a nip over there and going through the courses for some metalworking, I have a rather extravagant art project in mind...

I suppose it is necessary on some old fixtures....over here, they are, by law, supposed to "replace" the metal fixtures with the plastic, but if one is fixing and not replacing......yeah it would still be a needed skill. It is really the same thing as soldering wires, only with a small torch instead of an iron :-)

Did this schematic come with a parts list? If not, it would be difficult to read. One would need to know the pinout of the IC also, if it was not supplied (that ic is a dual opamp, but which one is anyone's guess).

Google "schematic symbols" or "electronics symbols"

If you can't read a circuit like that, you probably won't be able to build an FM transmitter.

I have set up a number of radio stations It can be rather daunting at first, trying to compile all the information you need, and understanding the process. You can read further information here at www.themulcher.com

0.17 seconds in Google:



All I did was type fm transmitter circuit, and what do you know, I got a load of fm transmitter circuits!

Actually, that last one looks easy enough for a solder-clutz like me...

Erm Hey I Was Look Thru Thinking About Makin My Own Radio Station And Jus Looked At You And Thought Like You Knew All The Rules And Regulations And How Everything Works So If You Got Time Can You Get Back To Me Ooh And If You Have Msn Or Any Think Like That Ma E-mail Is badboy_470@hotmail.co.uk If You Want To Add It Thanks !

I'm no expert, I was just showing how easy it would have been to google for the answer. If you want to make your own station, check the links I gave, and check with your local law-enforcement agencies or broadcast regulators to see what licenses you need.

BTW - not clever to post your email address on an open forum, it can get harvested by robots.

Lool dont worry about the robots i dont mind ! and thanks for the advice jus thing is like i havnt got a clue what i would need to make the transmitter and that so like i just need help with all of it if you know people will you tell them for me? plz and thanks again

Like I said, check the links - they have circuits and component lists.

Hey nice links! I gotta save that last one as well.

. You are probably looking for two separate boxes: an FM modulator and a power amp. Feed your audio source into the modulator and the mod output to the power amp/antenna. . Most of the "transmitter" circuits that Kiteman pointed you to (you really do need to learn how to use a search engine) have an output measured in low mW's that have a range of a couple hundred of feet. You'll need a power amp (sometimes called a linear amp) to get any range.

Trouble is, any range that could be picked up outside your workroom would get you a visit from serious-looking men in suits asking awkward questions about licences. I don't know about the US, but it is possible to get a license for small transmitters (1/4 mile range) for special events (rag weeks, festivals etc).

. True, but as long as one is just experimenting for a few minutes at low power (say, 100W or less) and doesn't mess with the neighbor's TV too bad, I doubt much will be said. Kinda like rolling through a rural stop sign at two in the morning; not legal, but what the heck. . Now if he/she hooks up a 50KW amp and tries to run his own radio station, that could be a problem. Kinda like blowing a downtown stop sign at noon.

Correct, if the power is low enough that it stays confined "in house" it should be fine. As soon as you "broadcast" though you have become a rouge station (assuming no license to broadcast was bought), and so in my area anyway, the FCC would be at your door faster then the IRS after declaring support of 89 children.

How about those mp3 FM modulator/ transmitter that plugs into the car's cigarette lighter socket.. Are those illegal in the UK? Since the signal can be picked up by the car next to you..

They're illegal to use at the moment (but perfectly legal to own!?) - apparently "they" are changing the rules soon to allow them to be used.

Good To See Some Of My old Topics Are Being Found