I have a Rainco ground station antenna I bought from Graham Thompson
about a millennium ago. The construction is 2' of 1" diameter aluminum
tube at the bottom with a 4' whip on top. The coax attaches at the base.

My problem is it's VSWR at 123.3 is 2.5; at 118.1 it's only 1.5. I'm
assuming it's too long, but maybe there are coils or such inside that do
the adjustment. Does anyone know how to tune this antenna?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl