In message , Cecil Moore
writes
Ian Jackson wrote:
Cecil Moore writes

| |
| coil coil |
+-------------/////FP/////-------------+
| || |
| || |

Connect a 80m quarterwave S/C stub (preferably twin feeder) across
both coils (ie from the outer end to the outer end). That will leave
the coils O/C on 80m and S/C the coils on 40m.

A somewhat weird looking modification for a center-fed
vertical antenna. I suppose the two stubs could double
as guy wires. I might be tempted to accomplish the switching
with a large open frame relay or two.

From the original ASCII diagram, it isn't too clear what the
configuration is. Is it actually a 'single-ended' vertical version of
your diagram above of the horizontal balanced antenna? The two loading
coils (original diagram) would in series on 80m, with the stub shorting
out the lower one on 40m. This would enable freer adjustments of the
resonances of the antenna on the two bands. It would also help explain
the original description that the stub was connected 'across the
feedpoint' (although it isn't).
Ian.
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