- April 29, 2005 at 3:40 am #6345jpjanzeKeymaster
Total posts : 500
Need advise Pronto!
I’m ready to rock on the air, so I hooked up my Ramsey 100b X-mitter on top a wall locker in my garage, then ran 10 ft of coaxil to a decent but legal size antenna 5 feet above it in the attick and began testing at 104.9
Darn if the signal didn’t BOOM out in a crisp clear manner for 2 miles in every direction then finally fade at the four mile mark. I’m on the highest hill in the area, about 50 feet higher than town with flats around me for miles. So this is not what I’m trying to do, I’m only trying to hit the little town of 200 homes just below me and really just want to get my FM signal out about 1/4 mile radius in my own neighborhood, so as not to attract the FCC or complaints, then try to hit the rest of town with my Part 15 AM signal. Going out as far as it is gets the signal into two small cities and I’m sure the local commercial stations would not be pleased. So I’m considering shortening the actual antenna and/or lowering it down into the garage so it just goes out a few blocks. But I’m no engineer.
Also I ordered the Metzo AM x-mitter but it hasn’t arrived yet. Hopefully it will get out 3/4 mile and thats all I’ll need, wanted to go with the Rangemaster but $$ prevented it at this time. May upgrade later. So if anyone has any experience with the Metzo or advise on the above FM problem I’d appreciate it.
Also some Part 15 guys have said its illegal to put an external FM anntena on the FM X-mitter and some have said its fine to do that.April 30, 2005 at 5:26 am #12164JoshGuest
Total posts : 45366
Just turn your transmitters output power down, it looks like a little yellow screw on the inside of the case but don’t get it mixed up with the audio level screws because they look the same. 😀 Also check out the form at http://www.ramseykits.comApril 30, 2005 at 10:45 am #12165tregonseeGuest
Total posts : 45366
1. There is no “legal” antenna size for Part 15 FM operation. The only criterion is signal strength (max 250 uV/m at 3m from the antenna). Most Part 15 FM boxes are designed for maximum legal signal strength using an integral antenna of a certain size. Upping the antenna without dialing the RF power back puts you over the limit.
2. If you’re getting out clear to 2 miles, I’m pretty sure you’re over the limit. Legal strength should get you out probably no more than 1/4 mile, maybe 3/8 mile. I’d take Josh’s advice and dial your output power down.
3. I have no experience with the Metzo, but your antenna is a big item on Part 15 AM. There’s a “Range” topic regarding Part 15 AM started by broadcastman that has 40 replies, and is worth a look. Also, the antenna with the big coil (obviously AM) that’s shown on the Part15.US home page has attracted a lot of interest.
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