I have a 6'/2M aluminum ladder & plan to use that with wire radials
when portable with my homemade Outbacker-type whip (once it's
done :) . Total cost, including the antenna: ~$50. The shelf is
made of plastic; I'm going to use a small piece of aluminum w/a C
clamp to mount the antenna & connect the radials. This way, I won't
have to worry about ground losses, as has been covered by Bonnie &
others (for which I thank those involved; that was a great
thread "chock-full" of info!).
