Hello, I'm just planning my first setup to get some of the local underground talent on the airwaves around my area and would like a bit of help trying to figure out what kind of PA and antenna I am in need of. At the moment the plan is to pre-record shows, get them onto an ipod or similar device and then drive the ipod up to the remote tx site inside a pine forest on top of a big hill and leave it running for a few hours off a car battery and then collect the ipod, exciter,PA, limiter and battery once the recorded material is finished.
I live in a fairly rural area, we have little towns which have a radius of roughly 1/2mile dotted all around said pine forest on top of the hill which is roughly 600foot above the small towns below. We have no pirate radio at all around us and only a few legal stations broadcasting leaving plenty of free space on the FM dial. If I could get a good clean signal out to a radius of about 5mile I would be a happy man as this would cover my target audience and not reach out to any of the cities nearby. A few hundred yards from the planned tx site there is a huge TV/radio relay mast and also an airport roughly 10miles away from the site. I obviously don't want my signal to reach the airport or to interfere with the relay mast nor do I want the mast to interfere with my signal. Does the planned location sound like a good idea or bad news?
I plan to buy the required equipment and build the rig once I'm sure of the power required for the distance I want to cover, from reading about on the web I understand calculating power requirements isn't an exact science and everybody's situation is different. Most of the info I have found related to inner city towerblock setups and my location is very different so that's why I'm asking for help here as I don't want to stick a 150w rig up on the hill and send my signal as far as the eye can see.
The kit I plan to use so far is from nrgkits.co.uk, I was looking at a 1w PLL kit with a mono limiter and a 10w FM PA. As for the antenna I'm still unsure on that one, I have been thinking about a High-Gain Vertical Half Wave from the same supplier as it looks pretty easy to erect in a dense pine forestand with a decent gain of 4.2dB. Does this setup sound like I will get the coverage I want in my location or should I be looking at a larger amp? The next size amp they sell is a 40w PA which sound a bit over the top to me, what do you think? I know this kit is designed to run on 13.8v but I assume it should still work on a car battery just with a slightly lower power output?
As you can see I still have a lot to learn and will keep reading and learning but would really appreciate your feedback on my plans so far.
Forgot to mention there is also a HAM repeater less than a mile away from my planned site if that makes any difference, I had planned on climbing the thing and installing the rig up and there and using a 10GHz link to broadcast but after thinking about it I decided it's a bad idea to mess with a large group of radio enthusiasts. I'm sure it goes without saying but I don't want to interfere with their communications either.
..I had planned on climbing the thing and installing the rig up and there and using a 10GHz link to broadcast but after thinking about it I decided it's a bad idea to mess with a large group of radio enthusiasts. I'm sure it goes without saying but I don't want to interfere with their communications either.
That might not be a good idea.
FCC finds your rig: "Oh man, paperwork. I'll just destroy the rig."
Well I'm from the UK so I don't suppose the FCC will be finding my rig although we do have OFCOM over here who play a similar role in policing the airwaves, I've updated my profile now to show this
So does my planned TX site sound OK to you as long as I avoid the nearby masts? The more time I spend zooming in on this area on Google Earth the more masts I am finding, this is obviously a pretty good place for broacasting although I would be the only one hiding in the forest and not having a few concrete structures surrounding my mast.
OFCOM is pretty much a slacker until somone complains, like our Industry Canada. From what I've gleaned at AlfaLima.net, they seem more interested in shutting FM pirates anyway, so be careful.....
There's lots to go wrong being near other TX/RX sites, like intermod and "beamriding" (I forget the technical term. It's not intermod, as there is no mixing.... one carrier just rides atop another. Used to be a BIG problem with CB and TV signals in the 70's and 80's). I can't recommend a yes or no without physically being there to survey the site, sorry.
Thanks again for the info cmradio, I guess checking for TV interference is easy? I just get people all around my transmitter to check through the TV stations when I am doing a test broadcast and look out for a messy signal on any of the channels? Some kind of handheld scanner to use whilst at the TX site when doing a test broadcast to check for sprogs on any other band? Also scanning the entire FM band looking for sprogs? Is there anything else I need to be doing to check for RFI when I am testing?
Well, I'd use a scanner and double check for piggy-backs on carriers emitted from the site, especially commercial and ham transmissions. Monitor them when you're on the air.
