Gentlemen:
Based on what I know, one can make or buy an 18:1 transformer to get the
correct match for a pre-amp. One of the cautions is to not interconnect the
high and low impedance windings on the torroid, i.e., separate the two
windings so they are not overlapping. I believe Lance Johnson Engineering
makes the transformers and a remote controlled pre-amp, if one doesn't want
to build their own from scratch.
Based on W4ZV's comment about isolating beverages at one feed point, one may
have to use a coax switch that switches both the center conductor and shield
when selecting the 50 ohm output of the desired pennant antenna where
multiple flags or pennants come together at one center hub.
The problems not covered by Larry, W7IUV, with a high impedance input
pre-amp include making and remote switching 900 or 950 ohm ladder line and
designing a balanced input pre-amp with an unbalanced output. So, I vote
for a 18:1 BalUn.
IMHO, Whether you switch the pennant feed lines remotely or at the shack is
each ham's choice, depending on site layout.
73 Good luck
George K8GG
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