Man, I just bought 200ft of RG-58. but thanks for the info. I guess I have to find other cable.
But is 50ft still bad for RG-58 cable?
Ok and if I buy this LMR 400 cable (Found it good price) would i make a RG58 antenna and LMR400 feedline?
is LMR 50 ohms?
Check here for answers to your various coax loss questions.
Coax Loss Calculator
50' of RG-58 will get you 4.833 dB loss at 449.5 MHz, 50 Watts from the duplexer gives you 16.431 effective watts at the antenna.
100' of RG-58 will get you 9.666 dB loss at 449.5 MHz, 50 Watts from the duplexer gives you 5.4 effective watts at the antenna.
50' of LMR-400 will get you 1.343 dB loss at 449.5 MHz, 50 Watts from the duplexer gives you 36.699 effective watts at the antenna.
100' of LMR-400 will get you 2.686 dB loss at 449.5 MHz, 50 Watts from the duplexer gives you 26.937 effective watts at the antenna.
50' of Andrew LDF4-50A will get you 0.725 dB loss at 449.5 MHz, 50 Watts from the duplexer gives you 42.317 effective watts at the antenna.
100' of Andrew LDF4-50A will get you 1.449 dB loss at 449.5 MHz, 50 Watts from the duplexer gives you 35.815 effective watts at the antenna.
Please note that many pros report serious issues with LMR-400 (actually the whole LMR family) in duplex applications due to issues with PIM (passive intermod). Times Microwave does make some Low-PIM coax (the LMR-SW series) which runs about twice the cost of the similar sized regular LMR coax, but isn't nearly as easy to find.
The Andrew LDF4-50A is an industry standard coax for repeater use. It has great loss numbers, easy to find (connectors are easy to locate as well), and most pros are quite familiar working with it. Since it's a standard commercial grade coax it will be permitted on most shared tower sites, while LMR may not and RG-58 nearly always won't. It isn't cheap though, but you may find it used in fairly short runs (100' may qualify) new as an end-of-reel lot for fairly good prices.
