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Channel Jumper wrote:
Unless there is something special about this coax, or if you are just going to use it for a television antenna, or something that you are only going to receive on - THROW IT AWAY! I will be careful how I use it, keeping in mind it's history. once you exceed the minimum bend radius you open up the braid and the coax is never the same again. THROW IT AWAY! I don't have any reason to think that the minimum bend radius was exceeded. Coax has a shelf life - for example, Belden 9913 has a shelf life of about 10 years. Even though it was never exposed to sunlight and it was never taken out of the shed and was never exposed to the elements, after about 10 years, the coax starts to degrade and break down and then it is junk. I had the same piece of rg-8/u running up my tower and feeding assorted antennas -- it was there from 1986 until 2007. I never really looked it over for any signs of wear and tear, although once in a while I would run my analyzer through it to test the assorted antennas. If I'd noticed anything unusual I would have taken some action, but because it continued to serve it's purpose, I continued to use it. I'm glad I didn't know about shelf life and all the other stuff about coax or I might have had ulcers by now. The kind of stuff you see at a swap meet, where the owner is still trying to get top dollar out of it. I knew most of the vendors at the markets and while we always wanted to get the best from our product, I don't think anyone would take advantage of a fellow ham. Good Coax pays huge dividends in performance. 'huge dividends'? Maybe a little gain or less attentuation, but certainly not enough to consider it huge. This was free -- just passed on by a friend. If all you are going to do is hook it up to a Ringo Ranger and put it on a tower, above the garage door of a fire station, and the county repeater is only 2 miles away, then yes - the quality of the coax doesn't matter much - other then the fact that it might show a false VSWR. Like others has said, there is no way to predict what will happen when you go to use it unless you attach it to a Time Domain Reflectometer and sweep it! Something I doubt most hams would have - unless they work in the cellular telephone industry. No one can predict, but there is intelligent guesswork. A TDR might tell something, but putting the coax in a live situation usually works well enough for ham radio purposes. I run an amateur radio station, and if everything had to meet mil-spec I wouldn't have had much. I did have my trusty MFJ-259B SWR analyzer, which while it is not necessarily as a TDR, did serve me well, and as far as the coax which led to this discussion goes, it did test OK when fed into a dummy load over the HF bands. The criterea which I lived by over 56 years of ham radio was 'did the signals sound good, and could I make contacts?' -- and using old hand-me-down wires and cables, and reusing various connectors I was totally satisfied. It was ham radio on a budget -- I would hever throw out something I might have been able to fix up and reuse. It kept me very happy over the years and I'm not about to change now. My two bits worth. Irv VE6BP |
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