An alternative to the 6M7JHV antenna for 6m / 50MHz
So the antenna is now complete and all that remains is to put them on the tower and try it out!
The first task is to take down the 6M7JHV stack
It's a good job I did because I found the old stub mast that had been in use for nigh on twenty years in a rather bad state! Another winter of strong winds could have resulted in a snapped stub mast!
I found it best to mount the bracket on the stub mast first and then attach the antenna using the four M8 bolts. I have to say that this is really a two person job and my XYL duly 'volunteered'. Leave the bolts slightly loose so that the antenna can levelled once it has been bolted to the bracket.
Tip: Always use some Vaseline on the screws before doing them up as this prevents the stainless steel screws possibly locking up!
To tune the antenna bring the reflector down to about a foot off the ground and adjust the loop for the best SWR. The initial dimensions are about right - all I had to do was to increase the width by 3mm on both sides. When testing the SWR I found it best to have the antenna 6 foot off the ground.
Seal the coax connections with weatherproof compound.
I have seen the coax being placed through a hole in the boom but I'm not keen on that as water might get inside the boom.
To make adjusting the loop easier, just hook the rule over the far side of the boom and add 19mm!
Then measure to the very outside of the loop - 1mm can make all the difference!
And at the bottom.
The photo below shows a single antenna up in the air for initial testing. The rat's nest of cables is the phasing harness which was not being used for testing a single antenna.
I did have one problem! The antenna is slightly too long and could touch my chimney - I thought it might, but was not sure until I tried it. It's not too much of a problem as long as I don't lower the tower more that 6" from the bottom. I'll put in a wooden spacer to ensure I never do this!