typically these are for those ones that do allow tx on 2mts and/or 70cm.
though to be honest, i've only ever found the royal 1200 to be worthy of
bothering with.
you might as well use a wet piece of string.

mike

"jarekts" wrote in message
...
urm.. a discone is a wideband aerial, hence it has no one resonant freq
for you to vswr it to! it is multiband,,

But it has some adjustable parts...