Since my article on Simple Wideband Yagi’s appeared in September AR I have had a number of people contact me advising that it would be better to use the grey electrical conduit rather than the orange version I did. This is based on the fact that the orange version is intended for inside or underground use where there is little exposure to sunlight and as such it does not need to be very UV stable, and it will in fact become discoloured and brittle with continuous exposure to the sun. The grey version being intended for external use is supposedly much better in this regard.
While I can not find any definitive statement to this effect in the various manufactures literature/web sites, and certainly no hard data on exposure times etc. there are hints that this may be the case. In the case of the original prototypes which have now been up in the air for just over 12 months I can report that they are still performing very well though the orange colour has faded slightly. I haven’t had any reason to try to subject them to the sorts of stresses where brittleness would be evident so fingers crossed this will not be an issue for some time.
The only problem I am aware of with using the grey conduit would be that it is slightly thinner walled making it a bit harder to find a good size match for the inner dowel or broomstick.
It has also been pointed out that I didn’t mention how I attached the Yagi’s boom to the mast. While many variations are possible and mounting of the mast to the boom behind the reflector is the purist’s way, I actually simply used a standard TV antenna U bolt with a couple of holes drilled through the boom at a convenient spot. In particular I found which two elements the balance point was between and then put the clamp in the middle between those two elements.
Also below are the original pictures and figures from the article as well as a couple that didn’t make the original. Hopefully they are a bit easier to see in this format.
73 Paul VK3DIP
