FM Transmitters

[Vic]

Hello All,

I am doing some quick research into FM transmitters.

I am after one(s) that will transmit signal a few hundred meters or more.

Any hints or suggestions out there?

Regards

Vic

[SYOS]

What frequency range do you want to operate in? I use the Listen Technologies at work for hearing augmentation systems with great results and can easily get 200metres out of them in and around buildings.

http://www.listentech.com/lt-800-150.html

This particular model I just used for Sea World and Movie Worlds installed systems and am getting 200+ metres without any issues. They don't required a licence as they are outside of the regulated frequency band.

[Vic]

Hi,

Thanks for the reply.

These look great, however I am wanting to transmit onto common radio frequencies found on car stereos etc.

It is for a remote location with no other building or anything to transmit into.

Regards

Vic

[Ben M]

Sent you a message Vic.

[Alastair Reynolds]

Hi Vic, what you're wanting to do in the Broadcast Services Band is classed as an Open Narrowcast Service and as such must be licenced by the ACMA . (Or they get upset and fine you)Start by looking herehttp://www.acma.gov.au/WEB/STANDARD/pc=PC_90180.

The ACMA runs Auctions every few months and prices range from $200 to > $10,000 depending on location. If you are in a remote area you can usually get one for $200 plus apparatus licence and various other "red Tape " charges.
There are kits available for unlicenced "flea-power" transmitters from Jaycar and the like , but these tend to be close to useless for anything more than about 20 metres (on a good day).
A good 1 W transmitter is available from Fordray Electronics , based in Orange. Good Australian made Narrowcast transmitters from 0.25W up to 500W in fact you can buy a complete kit including 2W transmitter, Co-ax and Antenna for a "Low Power Open Narrowcast" setup.
http://www.fordray.com.au/Products/LPON/lpon.html.

If you only want to use something for a point to point link, there are solutions using Radio mic transmitters as per TV crews with directional hi gain antennas, but none of this comes cheap.

best of luck

[Vic]

HI Alistair, Ben and Dan,

THanks for your input into this.

It looks like I have found a unit at Fordray in Orange, which I have just purchased over the phone which will be couriered overnight.

So will get it just in time to do some testing then for a peformance on Saturday.

The performance will be on a remote stretch of the Sturt Highway near Narrandera.

I will have an upright piano installed on a dam ridge that is viewable from the highway. And the other side of the dam ridge will be a dancer, Victoria Hunt. We will transmit the mic'd up piano sound to the car radios of passing cars.

[rob]

nice! Performance Art. Be sure to include the ACMA if they pass through!

[Alastair Reynolds]

Aha !! Cool use of broadcast spectrum.
Such things can be short term licenced as a narrowcast Special events licence. We do Grand Prix Radio in Melbourne each year and used to do radio FISH-FM on Fraser Island and Sydney NYE fireworks radio using special Events LPON licences and Fordray Kits running 10 Watts into a Co-Linear antenna, similar to the kit you got from Warwick. Best of luck , let us know how it all goes.

[mylesgm]

sounds very cool, pity it's so fleeting.

[Manning]

Very cool little project.

Do try to get a video for those of us who don't travel the Sturt Highway on a regular basis... (which I think covers nearly all of us

[Vic]

Luckily we have a film maker coming to film in so she will cut together a short version which I will post a link to on here when it is done. Now we just have to hope the rain holds off on Saturday.

[Vic]

Well, so far, it is a success.

The Transmitter arrived in time.

The farmers made a firebreak so we can get our cars up on top of the dam walls.

The Farmers next door are arriving first thing in the morning to take the upright piano onto the site.
And I just did tests with the Transmitter and it works a treat.

As I left the frequency chart at home during the testing, I only had it tuned into a station that was already broadcasting and it was strong enough to over power that station for quite a distance.

Now, i am changing it over to its own frequency and suspect I will get a great range with it.

The instructions say to mount the whip antenna on top of a pole which I might do tomorrow. I wonder if it can just be taped up onto a pole?

Vic

[Chris H]

Sounds like a great community project. Keep the progress reports coming. Two of these for the antenna should do the trick.......( not that you didn't already know. I just wanted to post a pic of a U bolt on an audio forum.......I think it might be a first.)
........unless the metal interferes with the signal? what would i know, i'm no tech!

U-Bolts.jpg

[Alastair Reynolds]

Hey Vic, the big question is how did it all go ?
did you achieve the desired result ?

[Vic]

Hi,

Well it all went very well. I am still waiting on all the video documentation but below are two pictures that I have so far.

We had many cars stopping, taking photos. The transmission went well, travelled for about 600 meters in either direction, then there was another interesting zone for quite a while where it crackled in and out, still sounding very interesting. I had a mic'd up upright piano on top of one mound.

It was all run by a truck battery and an inverter.

I'm really happy with the FM transmitter and can't wait for whatever the next project might be with it

We played for over an hour.

Thanks for everyones tips on achieving this. I'll post more pics and video when they arrive.

[rob]

excellent ... I love this stuff

[Manning]

I just wanted to post a pic of a U bolt on an audio forum...

I thought a U Bolt was this...

[mylesgm]

Hi Vic,

looks great! Looking forward to seeing/hearing the video stuff so I hope you put it up on youtube.

M