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There are several options.


1)  You can measure the impedance of said antenna and build an antenna tuner for it.  This would allow the use of said LMR-400.  You would get 1.397dB of loss in the coax (or with 100 watts in you will get 74.495 watts out) and a little more in the matching circuit.


2)  You can run said LMR-400 into a remote autotuner, more expensive than 1 above but requires less technical knowledge, and have similar loss numbers to the above.


I don't like these options as I typically limit myself to 1 dB of matched feed line loss, which is what I used above, although not everyone agrees with this.  However, if it were a temporary setup for a year or two, I wouldn't hesitate to use this setup.


3) 450 ohm window line or 600 ohm latter line to an antenna tuner on your desk.  Between these two, the 600 ohm ladder line will do better, but would be homemade (and the option I would prefer).  From here, I need the impedance data of said non-resonant antenna.  600 ohm ladder line starts with a matched loss of 0.224 dB (or 94.981 watts out with 100 watts in), but this is being fed into a "non resonant" or mismatched load, so said numbers can will go up quickly depending on the impedance of said load.  A 13:1 SWR, for example, would bring said overall feed line losses in line with what the LMR-400 naturally has into a matched load as stated above.


Most antenna tuners already have a 4:1 step up balun built in.  Putting a 4:1 balun between the 600 ohm feed line and antenna might or might not help depending on the impedance of said antenna.  In most cases, running in in step down mode would be better with a vertical setup, but its hard to say for sure without knowing said impedance.



The DB