Post by turner15429 on Sept 14, 2016 17:36:11 GMT -6
Hi I am new to the forms and I am currently writing a fictional paper on how id make my own pirate radio station. I live close to downtown denver USA 1.75 ish miles. I have a good background in telecommunications I used to be a tower climber so I have a basic knowledge. I am looking to broadcast to most of downtown denver. I have an idea on how my setup would be. It would consist of a 1.5W/15W stereo PLL FM transmitter that feeds to a assembled 60Mhz-120Mhz 300W FM transmitter power amplifier module board which is connected to a yagi antenna pointed towards downtown. I am open to thoughts and suggestions. I know 300w is allot and it will be an isor for the FCC but what if I constantly stepp the power up and down will that make it harder for the fcc to find me? I was also thinking of putting 10 or so small transmitters that run off a stream from a prepaid cellphone on utility poles all around denver and then I can always be many steps ahead of the FCC.
Im looking for some leadership if anyone wants to guide me in the right direction.
Post by ogrevorbis on Sept 21, 2016 21:33:13 GMT -6
When you mentioned "60Mhz-120Mhz 300W FM transmitter power amplifier", I think I know which one your talking about. It that Chinese board from ebay with the two round transistors. It's probably OK, but if you're new to this and don't want to have a ton of frustration, I'd go with a broadcastconcepts amp and a pcs-electronics transmitter. The reason is not because the Chinese board won't work (it likely will), but often the impedance match from a Chinese transmitter is not very good; this will cause a high SWR into the amplifier, and may cause the transmitter to oscillate and create spurs at an unwanted frequency. I've seen this on a spectrum analyzer and it's usually fixed by just adding or removing a capacitor on the input of the amp to get it matched properly. If you don't have an analyzer, you won't know this is happening. It's much better to go with the non-Chinese solutions I mentioned, if you don't know what you're doing.
The better ones also have temp-compensated bias. This means they will reduce power when overheating to save the transistor if there is a problem. Broadcast Concepts Link
A carrier current AM transmitter my also be of interest to you. I wouldn't try "real" AM though, like with an antenna. It's not efficient enough to really get much range without a real antenna tower at least 150ft tall.
