i've looked up creation / assembly on multiple sites, and was wondering if anyone had any tips. the largest specific step-by-step instruction was only around 3-4 mile range. does anyone have tips/knowledge on this topic?
Tell me what you want to know, and I'll tell you. I was setting one up before, but something happened and the plan got flushed. I was going to be building alot of the equipment myself, as it's alot cheaper. I got some circuit diagrams and text files. I'll give them to T.Wedd and he might be able to host them on the Rorta main site.
A tip though. Powerfull transmitters are expensive, so buy say, a 4 watt transmitter (really cheap and really weak) and then get an amplifier and you can turn it into say, a 200 watt transmitter. It works out cheaper to get a weak transmitter and strong amplifier, than to buy a powerfull transmitter.
Some people are only alive because it's illegal to shoot them...
well, i understand the basics, but i have no clue about filters, compressors, dummy loads, SWR meters, VOM meters, and some other stuff. i know i wouldnt need most of these for a small area radio broadcast, but i also don't think i would need a 200watt station. i was thinking more along the lines of 40-50. do you know how much a 4 watt transmitter would cost? i can afford only a couple thousand (US) on the project on the whole project. i can make an omnidirectional aerial myself (i think?) and some other stuff, but i dont know where the line is drawn in legal issues. i know i cant just walk into a radioshack and ask for a phase lock loop transmitter with 2000 watt capability, so where should i start?
Karma, most the accessories you listed above you won't need. It will just be a waste of money.
Filters: Mostly used to supress TVI (Television Interference) High and Low pass filters just help prevent your transmission going through nearby televisions. Radios have built in filters to regulate the radios audio.
Dummy Load: It's mainly used to stop the transmitter radiating when testing the radio with an oscilliscope etc. It's resonate at 50ohms and mimics an antenna without actually broadcasting your signal.
SWR Meter: (Standing Wave Ratio) It just displays the resonance of your antenna in a ratio. 1:1 is perfect, and the higher the SWR the poorer the antenna will radiate. About 1:3 is hitting the danger zone. At this point your radio will only be transmitting poorly, plus the TX finals will begin to heat possibly causing failure after prolonged use.
If your antenna is store bought, it's pre tuned for the frequency application stated on the antenna. So a SWR meter isn't really needed. Plus most HF rigs have an in built antenna tuner that automatically achieves near perfect SWR regardless of the antenna.
As for walking in to Radio Shack and buying a 2000 watt transmitter, quite simply nobody can. These power levels can only be acheived with a linear amplifier. And all new radios will be PLL (Phase Locked Loop), which is just a fancy name for a chip to acheive frequency synthesis as opposed to old crystal methods.
Try to stay away from purchasing a "kit" transmitter if you are serious about the station. Most kits are overpriced, underpowered and lacking in basic features.
I would suggest purchasing an older modifyable HF radio, which can be easily modified to work on the commercial AM band. These will generally give you 100 watts output, and are reasonably cheap to purchase.
This combined with good coax cable running to a cheap multiband HF trap vertical will be perfect. Or you can even use a length of copper wire cut to size if finances are limited.
If you need help locating a radio, let me know and i will get some URL's of radios on Ebay that can be modified to what you want.
Cheers... T. Wedd
Last Edit: Sept 19, 2003 5:07:13 GMT -5 by T. Wedd