well seeing as all the advice I got here I thought you deserved to see a few pics, it's still a work in progress, but it is working very well,
Couldn't find any alluminium plate, so used some wood I had in the shed instead, and braced it to make the X section, I have now sourced some cheap alli plate online, so might change it for alli, but the good thing about using the wood is that the whole antenna is isolated from mast. Downside is that I had to use short jumper cables to connect the radials to each other and to the SO-239. Started with almost 23' of radiator, after finding the tapping point on the coil I had to shorten the radiator about 6 inches to get the resonant point where I wanted it (27.555MHz). The insulator is PVC, but it isn't anywhere strong enough, so I have a slight lean on the antenna which you can see in the next pic, I'm thinking a piece of fibreglass here would be better, looking around for a fibregalass fishing rod to cannabalise
This was put up at my house for testing/tuning, I have around 1MHz of bandwidth and a 1.1:1 swr where I want it, however, I tuned it using 10W of RF (all I have available at home), even on the 10W I managed to work a station on the beach in Ireland, maybe 75 to 100 miles away from my QTH. When I took it to the hilltop and used 100W, minimum swr was 1.3:1 at the resonant point. I think it's the way I've routed the feed up the inside of the coil, rather than the outside, and I'll be changing that soon. I have no real means of comparison to see how it is working, but I managed a contact into Kings Lynn in Norfolk, I just checked the distance on google maps and its over 150 miles away, something that I rarely managed when I was using the A99 out portable, so overall I'm pretty impressed. With some more tweaking I think I'll be very happy
Finally, here we are on the hilltop, no, that isn't my van, some inconsiderate sod parked behind me while I was putting up the antenna......
