Following on from http://m1kta-qrp.blogspot.com/2008/10/new-antenna-at-qth.html
Portable Cobweb:
Found a centre at GQRP rally last w/e, go to http://www.amtoolsuk.com/ANTENNAPLATECP1PAGE.html for the details and read the drilling instructions.
The centre unit is designed for 20mm conduit so for the cobweb 10m-20m you need poles 6' 6" long the poles I have are 4m poles from sky blue. The centre 2 sections are exactly 20mm at the base so I will use the centre two sections only. So will 'store the base and whip sections for something else. You could use thick walled 20mm conduit tubing, with some 'sag'.
The great thing about the centre plate is the option of use of the 4 pole 90 degree options for all sorts of antennas. Not just a cobweb, I can see a wire beam as per spider beam should be possible as well.