With regards to the XA/40 interaction:
I have found that the new M2 version XA has a 40 meter resonance on the boom.
This is due to the element mounts now being metal (conductive) which means the
elements provide loading to tune the boom resonance down to 40. I have my 36XA
9 feet from a 40-2CD. When the two are 90 degrees to each other (elements of 40
parallel to boom of XA) the SWR on the 40 goes up to 2:1.
I strongly suggest when you build the XAs you insulate at least the D3 from the
boom to shift the resonance. This could be done either by using the old KLM
style plastic boom mount (available from DX Engineering) or by using an
arrangement similar to the driven elements from M2.
A report on results of this would be important new information...
TowerTalk mailing list