Chinese FM Transmitter

[@Meitoc]

i love fm transmitter but i can't transmitter over 500mW. The goverment doesn't allow 😢

[@zjp-tvpolskiepiosenkiwiers1578]

I have a 5 watt transmitter ... Distance up to 15 - 20 km (depending on the weather) 1/2 dipole antenna at a height of 8 meters

[@sparkidee]

My friend has a 15 watt transmitter it is a silver box with a blue LED display. He said it cost him very little money and all he did was have a mix on his decks and use the audio from his amp that went into the transmitter. It got as far as 7 miles away which wasn't bad but we found he was on about 3 other different frequencies to the one he was on! But it seemed the other frequencies he was on had vanished a little way down the road and the actual frequency he was transmitting on remained. He either went on in the middle of the night or in day time in the week. He hasn't been caught and this is in the UK. I was fascinated about the transmission and how it looked so painless and easy to set up.

[@luoni3417]

NIORFNIO？

[@markmilmag999]

That transmitter s*cks... overheats so fast knowing that there is no heatsink provided for the power transistor...

[@GeorgeChristofi]

it uses the bottom of the case to act as the heartsink. I fitted some teflon sheet between the front of the device and pcb to make sure it had good contact at all times. it should have a proper heatsink I agree, but as it stands... its ok.

[@DJMIGHTYZION]

Hi I have one of the Chinese transmitters I put a 1/4 wave antenna up in my attic my tv antenna is also up there it knocked out the signal do you think if I put the antenna outside on the roof it will be ok ? Let me know if you can please

[@GeorgeChristofi]

yes, move the transmitter aerial as far away as possible, either inside the attic or better still outside.

[@DJMIGHTYZION]

@@GeorgeChristofi yeh I wanted to hide it but obviously not a option In my attic because the tv antenna is like 3 meters away thanks for the reply 👍

[@DjSmoothNY]

Great video. I was wondering if you could go into more detail about filters. I have 4 big huge filters connected directly to the amp board via a solder. After a repair was made the connection came loose where the filters connect to the amp and I wonder if that's what caused us to experience spurious emissions. Any feedback would be great.

[@Wenlocktvdx]

Ofcom would be on your doorstep quick smart if it went to an aerial. ACMA in Australia would turn up pretty quickly too. Probably many of these around I wouldn't doubt

[@GeorgeChristofi]

It's true. Though they have scaled back in recent years, if there is a report from a broadcaster they jump within hours. If you are getting interference then it's a slightly different situation.

[@Wenlocktvdx]

ACMA charge for interference investigations these days.

[@brettcooper3893]

Thank God for the funds-strapped FCC here in the US. I've been running a LPFM station for about 6 months now and so far so good, and I'm using a Chinese transmitter (derisively called "splatter boxes" by the legal Part 15 hobbyists) that's actually very clean and it's actually putting out a little over 8 watts (the transmitter was advertised for 7) and I'm getting nearly 12 miles by just using the supplied antenna. Only real downside is the preemphasis is set for European and not US, but only someone with a trained ear would notice the difference...I hope.

[@GeorgeChristofi]

@@brettcooper3893 I can't remember exactly where I saw it but there was some information about switching the pre-emp to different standards. I used to get confiscated transmitters from the guy who had the job of busting pirate radio stations in London. A useful source of parts, some were really nicely built, others were vomit on a pcb.

[@hughcumming9701]

I noticed on Bangoods website it says '70M to 90M can provide' I always wanted to have a wee play with stereo on amateur radio so this is begging to be fired up on 4m. Any idea if it is a link change internally to get it on 4?? GM0HSC

[@GeorgeChristofi]

Not sure. The reason for the alternative frequency range is the Japanese market where the FM radio band is 70-90mhz. It might pull south as standard but I would have thought it might need a coil tweak. George, G0JKZ

[@randomixchannel7279]

What is the transmitting distance of this transmitter? Is that good for 3 kilometers?

[@GeorgeChristofi]

With a proper antenna mounted high up in the clear, 3Km is possible for sure.

[@randomixchannel7279]

@@GeorgeChristofi thank you so much sir for your reply. God bless

[@mattdalby1210]

I tried one of these and it was quite good with no sprogs, then tried a 15 watt that had sprogs on low 3 watt but good on 15 watt power. I blamed my aerial and the fact it’s a lcd choosing your frequencies. A good transmitter is made just for the selected frequency. These things are on air band for about 100 yards up the road then it is normal on frequency. Might be because of aerial?

[@GeorgeChristofi]

Having an aerial that matches closely to the transmitter frequency will remove a lot of standing waves on the feeder cable which could remix and cause issues or just make the unit hot, again, taking the output device into unwanted behaviour. As a unit, it seems to work reasonably well. I may revisit this box in the near future.

[@georgemart1860]

How is the real output power ??

[@GeorgeChristofi]

Around 3 watts I think it measured on the tester.

[@old64goat]

That is a real nice FM transmitter, i would not want to risk try transmitting with this..LOL

[@GeorgeChristofi]

It is certainly not legal to use in the UK outside of a Faraday cage! I think it should be ok if I run it into a dummy load without any sheilding on it as a test transmitter but i'f I put it into a real antenna... I would give it 24 hours before they were taking me away in cuffs.

[@NicholasCoulter]

@@GeorgeChristofi A'lot of pirate stations use similar transmitters and haven't been caught for years, Ofcom who regulate the air waves don't have the time and money to go driving around the country looking for pirate stations. You'll only get caught if a neighbour or member of the public complains to Ofcom about it at which point they will investigate.

[@GeorgeChristofi]

@@NicholasCoulter Indeed. They respond a lot faster to radio stations who complain because they pay a fortune in licence fees.I remember the time before ofcom when you had the RIS, they were much more active because there were a lot more of them. Actually working in the radio industry meant that I got to know the local guys. These days, with the cutbacks and privatisation there are very few left nationally. My luck though, there would be one based in my street!

[@keefs3987]

Dave Lee Travis tests pirate transmitter.

[@nocomment389]

can you limit the range if the antenna is short (down)

[@GeorgeChristofi]

not on this model because there is no vswr protection on the output stage. The only way to do it would be to put an attenuator in line between the tx and the antenna. I found that reducing the supply voltage did reduce the power but I didn't do many experiments to see how stable it was. Hope that helped, thanks for stopping by.

[@TheOpenAirGarage]

Nice little FM transmitter.

[@GeorgeChristofi]

It is really a neat design. Just a shame I can't legally use it to it's capabilities.

[@TristanYT1]

Is it only 3 watts?

[@GeorgeChristofi]

Yes, it was vastly overestimated by the manufacturer, considering the lack of proper heatsink on the final transistor. Yes, you can get more power by increasing the voltage supplied but at the risk of killing the unit.

[@TristanYT1]

@@GeorgeChristofi i live in island here lol i wasted my money on this over estimated product. Im planning to put heatsink paste on the transistor to prevent over heating

[@GeorgeChristofi]

@@TristanYT1 I would suggest mounting the transistor on a proper heatsink and using thermal paste.

[@Rysiu589]

What did you do to cut the output power down?

[@GeorgeChristofi]

I found that reducing the voltage on the supply would do it to a point as well as running it into a dummy load. I could never legally put it on air here in the uk because there is no provision for a domestic fm transmission licence but I could run a 'leaky feeder' system to limit the range significantly.

[@Rysiu589]

@@GeorgeChristofi I have the dummy load. I'll experiment with supply and see what happens. just using it for the house and when I'm in the yard. Thank you for the help!

[@cartoonhead4506]

Got the as you mine won't turn on I read got press the button HELP beg you

[@martinjones6694]

Gotta love those cheap Chinese boards... you cant even make one yourself for twice the price....

[@GeorgeChristofi]

That was the dilemma Martin. Do I build it myself out of scrap parts and have to go through designing and making a board, building and testing just to cost me hours of time or get one from China. If I had nothing else to do I might have built one but....

[@martinjones6694]

I know... I have been making an EEPROM programmer for an add on for my mini CNC mill to run a series of custom commands on startup. it was supposed to be a quick 2 hour project putting it together, one arduino mini, a couple of shift registers and a 28c16 and a birds nest of wires on a breadboard plus a day and a half of programming.... or less than a fiver from aliexpress......

[@Aron102]

Bit like marmite these Chinese transmitters. So people like them some hate them... but interesting video all the same. Thanks for sharing, I’ve subscribed Aron