Hello, my name's Joe. I'm new to this forum... discovered it by chance when searching Goggle for technical information. For quite sometime now, I've been running a low power analog TV station (approximately 30 watts at 48 feet) on UHF Channel 25 (539 MHz). I recently acquired a large RF power amplifier that a UHF TV station retired from service after they upgraded to a new digital transmitter. It has two 600 watt pallet amplifiers and is supposed to be able to turn 30 watts input into 1200 watts output. I tried feeding this high power into my existing antenna system (e.g., LMR-400 coax running to a simple dipole made with 1/2 inch copper pipe). The coax cable got very hot and within minutes melted at the N-type connector that screws onto the back of the power amp. I pretty much knew ahead of time that something like this would happen, but my budget doesn't allow for the purchase of the really thick Helix hardline coax normally used at higher power levels.
Want to ask if anyone other there has any experience with alternatives to expensive coax? Thinking about the problem, I am wondering if this might be a solution: Take a length of #12 or #10 insulated solid copper wire (like used in ordinary house wiring). Run this through a rubber tube (or perhaps a thin garden hose). Then run the tube through ordinary (and cheap) metal electrical conduit pipe. In other words, the center wire carries the high power signal to the antenna, with the metal conduit pipe acting as the grounded shield. This would somewhat simulate the characteristics of Helix hardline coax... or at least I'm hoping it will...
I would appreciate replies or suggestions from anybody out there.
Second, making your own hardline is possible if you have a little engineer blood in your veins. Making your own ladder line is easier and use a balun at the source. Or check out these guys: therfc.com/coax.htm
Third, posting the same thing around the forum in random threads several times is very bad
Hello Joe! - how long you been on the air? - (and here I THOUGHT I WAS GOING TO BE THE FIRST PIRATE TV GUY!! - still shooting for "in my state" - so there!
;-). I'm gathering "stuff" - will still be a few months for me, PC is almost done - still have to coaless mp2/mp4/DVDs into a simblance of "order", but an antenna and a decent Rohm telescoping pole (to get your height - stuck at 20' now ;-/ with sorry pole).
Couple of questions if I may (sorry not an EE so I can't help you with your problem). Is your 30 watter from Berkley, if so how is the picture quality. and what is your range (radius)?
I have the 30 watt FRB unit VHF version myself and wondering what to expect when I power-up (assuming it works - lol, you never know ;-/...........).
oh yes if you curious as to planned programing - refer to my two posts on the matter here somewhere.
old 70' brit TV shows (UFO/ Saphire and Steel/ Blake 7) and foreign movies that no cable channel (IFC used to 20 yrs ago) nor theaters (outside of NYC -arthouses) offer the public.
in otherwords obscure and forgotten (sadly) stuff. I've also found a few worthy amatuar stuff from Youtube over the last few months and saved.
