John Oram wrote: > Do you have any objective analysis for that last comment below or are > you just offering a personal opinion?
Drive up US 65 from Little Rock to Branson. Halfway up, when you get to Leslie, if you still have a signal, hit the 'scan'. If it is on the FM band, it'll pull in *1* station from Harrison, and another from Marshall AR. [that's a period] And if you switch to AM, you get a Christian fundy station. When you do scan on the AM band, it runs down the numbers again, and stops at... the same Christian fundy station. The Rock stations from Little Rock usta remind us several times an hour that they were putting out 100,000 watts. I aint heard any of them say that in a while now. Maybe they are still at it where you live. But in the Ozarks, between the mountains and the fringe signals, just about everyone has switched from broadcast to satellite dish, and get the Little Rock stations off the dish. No doubt, the station managers have figured this out, and dont get all worked up if their signal dont go so far any more. Do you spoze the car manufacturers are installing weaker FM tuners so as to encourage their customers to buy the new Satellite radio stuff? Wouldnt the cable and satellite outfits like to *disempower* the broadcast outlets? If the stations have found it too expensive to hire a local disk jockey, and as we see, get their audio from a national feed, then they'd be interested in saving 50$ a day in the cost of wattage to the transmitter. But of course, they aint interested in talking about it. > > > With your technical electronics background I would think you could > offer facts to go along with your comments ... Anyone really capable of setting something up wouldnt depend on me. They'd download a Yagi design program from a Ham link, and look at the specs from TI, Maxim, or whoever on RF amp and tuner chips. That stuff is getting close to plug and play, but I'd like to have a 200mhz oscilloscope before soldering shit together. Still, there is a wide variety of notch filters now that'd keep an experimental transmitter from walking on some one else's signal with FM harmonics or whatever. The news from the 2.4 gig people about going 15 miles on 15 miliwatts suggests that tuners might be designed for lower frequencies that could do the same on the FM band, where 250 milliwatts is *already legal*. I have bought a few FM transmitter kits, and even the "FM-1 Radio Transmitter" from 'Cebek' for 25$, already assembled. 9-15vdc, 50ma input, or 750 milliwatts output. I havent traced the circuit, (a scope would be nice) but the 1000 ohm resister in the feed to the 2n2219 transistor could prolly be shunted with another 1000 ohms, and up the effective power to a couple watts. But now, back to the Yagi software. tell it how many watts, and what the db is of the antenna, and it'll tell you the range... using ordinary FM tuners, I'd expect an 8 foot boom with a tuned Yagi to go 15 miles to an appropriately aimed tuned Yagi for the receiver. What I've not been able to find out, is whether you can include separate dipoles on the antenna for receiving and transmitting. Seems like the longer would simply act as another reflector and the shorter like another director. And like the 2.4gig pringle's can, I can see using 1" aluminum tubing rather than the usual pencil diameter stuff seen on TV yagi antennas, which would up the bandwidth by 5% or so for frequencies between 50 & 150mhz. > > > Day Brown wrote: > >> Yeah, thanx for the links. One cited a 24db antenna. Doing that with a >> 100mhz Yagi would be a challenge. >> But- the people with cell phones tell me of dead air all over the >> Ozarks. You cant hardly go 5 miles on any road without loosing it. If it >> aint the hills, its the timber... and maybe acid rain, which not having >> a neutral ph, is conductive, grounding out the signals in wet woods. >> >> Nor do I see where any local group would impinge on the bandwidth of >> their own emergency services. >> But most folks I know already have the dish, and dont even get the local >> TV off the yagi. >> I suspect that the broadcast transmitters have been cutting power; the >> fringe signals are fading faster. Electricity is expensive. >> >> >
