FM transmitter suggestions

[debtoews]

Hi everyone!  Im looking for suggestions for FM transmitters that can transmit at least 1/4-1/2 mile from the point of origin.  Of course, low cost.  Im working with a neighborhood consisting of over 120 homes that decorate static displays only.  We want to have Christmas music and announcements playing in the cars as they tour the neighborhood as it takes quite a while.  Like always- appreciate your your input!

[zman]

So there are many choices out there. I have experience with Ramsey and ECM units. Both great choices.

 

You may want to re-think how far you broadcast and get familiar with FCC Part 15 rules. Going out that far may cause you problems you don't want or need.

 

A rule of thumb has been to keep it within a 200ft radius of the transmitter, but there is very specific verbiage around the radiation levels in microvolts per meter.

 

I can flip you a copy of a presentation done by our Electrical guru in the PacNW (Pete Peters) who did this at our CLAP meeting, and has presented the same topic at Christmas Expo the past 2 years. PM me your email address if you are interested.

 

The choice is inevitably yours, but at least you know what the rules state.

[tmeyermn]

Hi debtoews,

 

I bought this one last year and it will reach this far but it may depend on your terrain. 

 

http://www.amazon.com/gp/product/B003FO4UHW

 

However, I think 1/4 - 1/2 mile range is outside what is "legal" with the FCC.  You may want to check what the limitations are, I'm thinking the broadcast range has to be under 200 ft but I could be wrong.

[Old Sarge]

That is a very good transmitter to use..  You may think more long the lines of getting a few to cover your area and run them as repeaters...

 

Thats isnt hard to do you just will need to connect one to each radio of yours and set it for the same channel as you get farther away from the first source of sound..  If you get a echo in your radio from it it means you are still to close to another one... I would be careful about running it on full power because as others said...

 

you dont want the FCC knocking on your door and taking them all away from you.. Also you want to make sure you are not on a station freq. that is already in use or bleeding over on another local... PAYING station..

 

http://radio-locator.com/cgi-bin/vacant?select=city&city=93550&select=lonlat&latd=34.408382&longd=-118.123596

[k6ccc]

Hey Sarge, Please explain your concept for repeaters.  They way I'm understanding what you are saying absolutely will not work.  I hope that means that I'm not understanding what you're suggesting.

[George Simmons]

Deb - that transmitter linked above has performed flawlessly for me for 3 years now.  Avoid a telescoping antenna.  The rubber ducky one does a fine job and far less fragile/nuisance. 

 

The radio frequency locator Sarge referenced is wrong more often than right.  Confirm EVERYTHING by listening for yourself both during the day and during the evening hours before making a tune-to sign.

Edited August 26, 2015 by George Simmons

[Old Sarge]

k but like I said check the freqs in the area... set one for just example.. 88.7 transmit to your radio.... plug on into another radio at the very edge where the signal starts to fade out... plug another transmitter into it but set on on a complete diff freq example 97.3.... etc...... and like I said the timing my be off just a little or you may get a little echo depending on the signal strength.

[Steve Constantino]

These work very well.
http://www.broadcastwarehouse.com/bw-broadcast/tx1-stereo-fm-transmitter/22/product

Steve

[k6ccc]

k but like I said check the freqs in the area... set one for just example.. 88.7 transmit to your radio.... plug on into another radio at the very edge where the signal starts to fade out... plug another transmitter into it but set on on a complete diff freq example 97.3.... etc...... and like I said the timing my be off just a little or you may get a little echo depending on the signal strength.

 

That was sort of what I expected, but your comments about having to make sure that they are at the extreme edge of range does not make sense.  You should not be getting an echo under any circumstances.  That was what confused me - thinking you were trying to do on-frequency repeating (the only way you should get echo).

 

Provided you can find the free channels (a real problem in this area), get the frequency separation as far apart as possible.  For example if trying to cover a single street from your primary site at one end of the street and three repeaters, a frequency plan might look like this:

 

Main transmitter:  87.7

 

First repeater:  receive 87.7, transmit 107.1

 

Second repeater:  Receive 107.1, transmit 88.5

 

Third repeater:  Receive 88.5, Transmit 107.9

 

You do NOT want to let any hop get at all noisy, and you will need to be VERY careful to keep levels correct in order to preserve audio quality.  With a single repeater location, you can likely get away with a fairly simple setup and still maintain audio quality, but beyond that will require quality equipment and some knowledge in setting it up to make it sound right.  OK, I will point out that I have worked as a broadcast engineer, and audio quality ranks right up there with Godhood, so I am a bit picky about broadcast audio quality.  I can also tell you that listening to a light show with poor audio quality will really reduce the enjoyability of it.

 

If your primary transmit site is in the middle of the string, the frequency plan may look like this:

 

Main transmitter:  87.7

 

North leg first repeater:  receive 87.7, transmit 107.1

 

North leg second repeater:  Receive 107.1, transmit 88.5

 

South leg first repeater:  Receive 88.7, Transmit 107.9

 

If someone has specific questions about setting up a repeater network like this, please feel free to ask.  Better yet, PM me a phone number and we can talk about it.  I've been designing, building, and maintaining repeater systems for about 35 years (although primarily for 2-way radio systems), and worked as a broadcast engineer for a few years; so I do have some idea what I'm talking about.

[EmmienLightFan]

Could the laws about transmitters be any different here in the UK?

 

I suppose it is port of a pirate radio station. I will be broadcasting copyrighted music without a licence.

[mpageler]

If you do a thread title search by "fm transmitter", you'll find a number of past threads on the subject.

EDM is a popular brand but a little pricier, which I went with.  With transmiter in the basement,signal goes 3/4 of a block away.

[gmac]

Were doing something similar that you want to do, the way our home is located the display can be viewed from 3 streets and so we use a Ramsey FM30 and we broadcast 1/4 mile sometime 1/2 mile if weather conditions are right.

I had a radio engineer help make the decisions for me and although we are illegal under FCC guidelines, I was told the key is to get a unit like the Ramsey that has a very clean signal because there are cheepie units out there that splash there signal so bad it can interfere with emergency transmissions such as fire and police and that's inviting a visit to your home from the FCC.

 

Also do like George stated check in the day and night for commercial broadcast frequencies in your area so when you choose your frequency your not stepping on their broadcast.

I'm far from an expert in this area but that's how we have done it for 4 seasons now and with no problems