[amsat-bb] Low-Power FM (broadcast band) Transmitter?

Jim Walls jim at k6ccc.org
Thu Apr 2 20:44:07 UTC 2020

On 04/02/2020 11:27, Scott via AMSAT-BB wrote:
> Can anyone recommend a low-power transmitter for broadcast on the commercial FM radio band?  An LPFM license can be acquired asap, but the first order of business is finding some hardware.
> As you can imagine, church gatherings are out of the question so I've been asked to see if I can locate a "drive-in theater" type transmitter for short-range broadcasting to car radios.

Getting a LPFM license is not as easy and fast as you think.
As for Part 15 transmitters, there are lots of them out there. There are 
also many available that are claiming to be license free, but not really 
meeting the Part 15 limits (especially if you put a "real" antenna on 
them).  One of my other addictions is running a music synchronized 
Christmas light show.  Almost every person running a music synchronized 
light show is running their music over an FM transmitter - sometimes in 
addition to outdoor speakers. There are several very commonly used 
transmitters.  Search Amazon for CZE-05b and you will find lots of hits 
- that's what I'm using. In my case, I have a homebuilt "real" antenna, 
but I put a in line attenuator between the radio and the antenna to keep 
at least close to Part 15 limits.

As for the drive-in theaters, my assumption is that they are supposedly 
operating under Part 15, but I would be willing to bet that a lot are 
exceeding the field strength limits of Part 15 by at least a bit - 
directional antennas come to mind.  I do know that the last time I did a 
FCC license search for the FM band, the nearest drive in theater (with 
their four screens) did not show up in a licensed listing.

Jim Walls - K6CCC
jim at k6ccc.org
Ofc:  818-548-4804
AMSAT Member 32537 - WSWSS Member 395

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