View Full Version : Coverage with FM-10A
08-09-2002, 12:46 AM
I purchased and assembled the FM-10A kit last year in hopes of using it to set up a station to promote our haunted house. I was disappointed to find that the signal could not be heard any further away than about 100 feet. I even built a tuned copper J-pole and that seemed to be no better. I am thinking of buying the LPA1 amplifier kit to see how much this helps. Does anyone have any experience with this setup? If so, what type of antenna arrangement do you use and about how far is the typical coverage area.
The store suggested I buy the FM-25 kit and use the LPA1 with it, but I just cant afford that option right now. If I can get a solid 1 mile radius from the FM-10A and the LPA1, I would be tickled. The haunted house is located only 1 mile from a major US Highway and we have billboard space that I could list the frequency on.
Thanks in advance for reading this, and for any suggestions.Haunted Productions Online (http://www.hauntedproductions.com)
The FM10A is really far to unstable [frequency wise] to use with any sort of linear amp.
What were you using as a receiver? Range with all FM microbroadcasters seems poor when used with a cheap FM radio - the sensitivity of some cheap radios is so bad that they will only pick up very strong signals. I have a FM25B which works wonderfully but only cranks out a 60 ft radius or so with a cheap radio - yet I can pick it up over a mile away with my Delco car radio!
If you amplify a transmitter with poor frequency stability, you're just asking for trouble. Even though you may go to great lengths to find a clear frequency, it will wander onto a not so clear frequency, mess up someones reception and then the FCC will be at your door.
I've heard that some FM10As are fairly stable, but even if it seems stable, the extra amplification could throw it off.
Years ago, I built an FM10A. Without any boosting, it would wander about 1 meg up the dial e.g. from 92.1 to 93.1. I hooked it up to the LPA1 and it wandered up to 108 mhz and beyond into the air band. Needless to say, I turned it off immediately!
Don't get me wrong - the FM10A is a fine little FM transmitter starter kit which kids of all ages can have fun with. For many of us adult kids, it whets our appetite for something better, and Ramsey has some terriffic microprocessor controlled, highly stable FM kits to choose from.
08-09-2002, 09:04 AM
if you very concerned with range with using LPA1 or FMBA1 (in power amp mode), very good grounding is required, same as good antenna
TM100 and FMBA1 are my suggestion, which has very good filtering, without messing up other users
and FM25B/FM100B are very stable, for FM10A, the major bug is stablity upon power supply and temprature, why don't you pay more for stablity?
FM100B is very-well grounded, which is much more compatible with power amp (it has 1watt international version, but you have to be aware it may be illegal to use in states)
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