Topband: Reverse feed system...

[Donald Chester]

>    As another suggestion, try radials of two different lengths to give you
> two points of low SWR within the broad 75/80M band.

> Gene Smar  AD3F

If you are talking about a vertical, you should be looking for maximum RF current at the feed point, or better still, maximum measured field  strength, not the  lowest SWR.  A 50-ohm resistor dummy load will give you a perfect 1:1 SWR.

For example, a short vertical or inverted-L may present something on the order of 10-12 ohms resistive at the feed point once the reactance is tuned out.  With a 50-ohm feed line, that would show up as a 4:1 to 5:1 SWR, with a GOOD radial ground system.  With a poor ground system having 40 ohms resistive loss, the SWR will read nearly perfect 1:1.  But the good ground system, despite the mismatch, will radiate a lot more RF than the poor ground system that gives the perfect match.

More than once I have heard a ham say he tried laying down some more radials to his vertical, but took them back up because the new radials made the SWR higher.

Don k4kyv