- January 27, 2007 at 4:31 pm #6815BluezplayerParticipant
Total posts : 2
Although music has always been my first passion ( I play keyboards, guitars, and do vocals, hence the Bluezplayer moniker ), I have also enjoyed this hobby, though for the last several years I had been pretty much inactive. I got the itch to get back into the radio hobby a few months ago when my oldest grandaughter became inquisitive about my Ham gear that was sitting on a shelf up in my home music studio. I have kept my license active, so I started putting the station together again. I started talking more to her about it, and she was fascinated to hear my voice over the radio.
That rekindled my interest in part 15 experimenting. I had built several kits along with some homebrew equipment over the years, with varying degrees of success, but they all got me “on the air”, on AM FM, and later the ham bands. I also built almost all of my antennas from scratch. Pretty much the only commercial antennas I’ve ever had were strictly mobile, although I’ve homebrewed plenty of them as well.
After spending several days checking the radio station guides, along with propagation and reception so that I could find relatively unused frequencies ( I live in a fairly rural area ), I made some “expected” coverage maps using finely detailed USGS maps that show houses. Then I went to a “local” electronics distributor ( 70 miles away ) a few week ago, and picked up the AM1C and a couple of the CanaKit type FM transmitters. I realized right away that the 3 stage FM transmitter was overpowered, when I could clearly hear my signal a mile away in the car, though for a non pll circuit it stayed fairly stable. The two stage transmitter gave much less range, but was very unstable.
So I started using one of my ( FCC Part 15 certified ) FM Modulators. It puts out a decent sounding signal that drops off the map at about 250 ft on my car radio, and a bit less on my Grundig. I have a few of them, so naturally I opened one up, and figured out where the antenna should go. I added a 62 inch piece of wire, and now the range is about 800 – 1000 ft or so on my car radio and about 600 ft on my portable Grundig receiver. That’s likely a tad over the limit, and I want to stay legal plus I realize as soon as I opened one I could forget the FCC cert, so I’ll use one of the other ones that I didn’t open but with an added ground wire. The grnd wire addition increases my range to about 400 ft on the car radio, maybe 250 on the Grundig. Think I’m safe there. I am well aware of the limitations of part 15 FM., so it’s kind of an afterthought at my station. There are 3 houses in my probable “legal” range. AM is a different story. There are probably 100 households, if not more in less than a 1 mile range. I was getting the AM1c to go 1/4 mile easily with the supplied 9 ft antenna and virtually no ground.
On AM I played with the AM1C for a bit. It was fun to build and I’m glad I did.. I modified a couple of parts and added a small fan which helps keep it fairly frequency stable. I would not however, want to try to do any serious micro broadcasting with it. The audio quality is rather poor, and it just has a cheap feel to it. So… this weekend I am building the AMT3000. I don’t necessarily aspire to be a full fledged part 15 broadcaster at this point, as I enjoy experimenting as much as anything, but.. later on who knows. I’m also going back to the distributor to pick up some parts maybe even another kit or two, for my granddaughter to build or help me build. More than anything else, I’m probably a bit surprised that in this day of computer technology, cell phones, etc, that a kid would have much interest in this stuff.. but I’m also quite glad that she does.
Part 15 stuff was where I got my start, long before I became licensed, but in truth, I think I enjoy it as much if not more than being a licensed amateur. Many thanks to the site admin and the forum participants for being here..
AJFebruary 15, 2007 at 2:37 pm #14815mlrGuest
Total posts : 45366
I don’t visit this forum as often as I should these days. Trying to get a start up business off the ground, being dad, husband, and stuff… But every now and again I run across something like this, and it just makes me stop and think “This guy is the reason Part15.us is here.”
Thanks so much for putting the iron to the solder!February 15, 2007 at 11:38 pm #14818RadioheadCGuest
Total posts : 45366
Nice story Bluezplayer.
I was curious. Could you please tell us what Part 15 **Certified** FM transmitters/modulators you have or use?
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