Take cover Arizona! Turnkey low power FM for business info.

August 12, 2009 7:26 AM

Need turn-key low power FM setup for broadcasting business information 1/2 mile or less. Who sells these? What licensing concerns do I need to worry about?

I don't want a Ramsey kit, or some cheap Ipod transmitter. I need a decent, professional level transmitter kit that will allow me to play a recorded loop of info. I see these at car washes, truck stops, and drive in theaters all the time. Where can I buy a ready to go kit that will just require me to record my message, turn it on, select a frequency, and go?

posted by cosmicbandito to Technology (8 answers total)

If your objection to a Ramsey kit is building it, you can order them assembled. See also this discussion. Of course you'd still need something to play the audio into it.

There is a FAQ of sorts here. Quote:

As a very general rule-of-thumb, a transmitter operating with the maximum power allowed by FCC regulations and using the antenna that came built-into the device can be expected to have an effective transmission range of at least 150-300 feet. In practice, the transmission range will be affected by many variable factors such as the local terrain ... and by building construction....

I think the need for FCC approval is a reason it's hard to find a turnkey solution. What is your budget?
posted by exogenous at 7:55 AM on August 12, 2009

Response by poster: budget is around $5000 total.
posted by cosmicbandito at 8:16 AM on August 12, 2009

It seems that the 1/2 mile coverage you want would fit most conveniently under Low Power FM services, which are limited to non-commercial entities. You can run an unlicensed operation on the AM and FM broadcast bands if you're fine with a coverage radius limited to approximately 200 feet (as covered under Part 15 of the FCC's rules), otherwise you'll need to apply for a broadcast station. At that point, you get into finding sufficient empty space to transmit and not disrupt other services, which can be pretty hard in most suburban or urban areas.
posted by filthy light thief at 8:49 AM on August 12, 2009

A Talking House is probably what you're familiar with businesses transmitting stuff, but it's way less than a half mile, as other people have said due to FCC. They seem to have range extenders and other stuff, and they'll probably have advisors to help you find an applicable setup for what you're trying to do. I have a couple of these in my basement (rummage sale finds!) and they get a bit beyond my yard, but nowhere near a half mile.
posted by AzraelBrown at 9:25 AM on August 12, 2009

Part15.us has a wealth of information and runs ads for companies that sell turnkey solutions, both AM and FM.

Part 15 of the FCC regulations deal with unlicensed broadcasting and output power. You won't find anything that operates legally without a license and can be picked up 1/2 a mile away by your average listener. That isn't to say that you can't do it, just that you probably can't do it and still be in the good graces of the FCC.

Realistically you will not be able to get a license for what you want to do, especially not an LPFM license.
posted by ChrisHartley at 9:28 AM on August 12, 2009

Or just go to hllyelectronics.com and get the lowest-power transmitter they have. They all have "standard" audio inputs, so you can attach it to a laptop or whatever, select your recording, and set it to repeat.

I imagine that if you take, say, their 5-watt transmitter, complete with antenna (which is a very non-optimal, cheap antenna, with non-optimal cable), and do NOT make any effort to put the antenna at a good height, etc., you can probably cripple the effective range of the signal enough that it falls within legally acceptable limits. Probably. I would say you could just run it WITHOUT attaching the antenna, but that'll probably cause the whole thing to burn out, so . . . don't do that.

Plus, it's WAY within your budget.

Five or six people are now going to follow this comment with recommendations AGAINST buying this thing. But it works really, really well, especially considering the price.

. . . or so I've heard.
posted by CommonSense at 9:56 AM on August 12, 2009

Er, sorry, that link should've gone here.
posted by CommonSense at 9:57 AM on August 12, 2009

The "Talking House" unit that AzraelBrown links seems to be what you're after. It's AM instead of FM, but the regulations appear to allow for better coverage with AM.

Similar devices are the Chez Procaster (there is an add-on to play MP3s) and the Rangemaster (you supply audio source).

By the way, I see a number of Talking Houses on ebay for a lot less than they cost new.
posted by exogenous at 11:14 AM on August 12, 2009