[UK-CONTEST] A3S

[Chris Tran GM3WOJ]

Hi Steve et al

It most likely is a trap problem, but I would still take a small 50 ohm 
dummy load with me up the tower and have a friend test the SWR with this 
dummy load replacing the yagi - I have had trouble with 7/16 DIN connectors 
that I thought were perfectly fitted, but were not.

In some trap yagis e.g. the TH7, the parasitic element traps use aluminium 
wire but the driven element traps use copper wire, so in the driven element 
trap you have a mild steel set-screw holding copper wire onto an aluminium 
element - corrosion is inevitable.

Often trap covers are fixed in place by small dents - you maybe have to 
either drill these out (a drastic solution) or just force the trap cover 
off, taking as much care as possible to avoid damage.

You'll probably find something corroded or melted.

73
Chris
GM3WOJ