Thursday, 30 July 2015

Tape Measure Satellite Beam - UHF Build, Pt 1

After a lot of deliberation, and careful testing (ok, waving about) of 1/4wave lengths of tape, I came to the conclusion that the cheap 19mm width 3m long tape I had was just as good as the 22mm I was going to us, and so have saved the slightly wider tape (which is also 2m longer) to use for its originally intended purpose.

Each of the five elements of the UHF section of the satellite antenna is between 11 1/2 and 12 inches long. Above they are all cut to the nearest higher whole inch. Below, they are cut to exact length, again using steel rule and digital calipers, the corners trimmed diagonal to remove the sharp edges, and the driven element cut into two halves

Next I needed to find a plastic tube to cut the plugs from. What I found was a two part PVC elasticated pole from an old toy pop up tent! Another one of those things I kept because it looked useful! from this, four 1inch, and one 3inch, plugs were cut, again just like the VHF plugs, using a pipe cutter for nice neat edges

Two things I have yet to decide on are A- Do I make a seperate UHF boom, or drill the UHF holes onto the VHF boom already made? And B- How to attach the feeder to the UHF elements.
Question A will be answered by examining the spacings on the VHF boom and the balun positioning. This antenna doesnt have to stay as intended and be separable into two for VHF ARDF, as ive more than enough materials to build a second VHF beam just for Foxhunting. Question B will depend on what M3 bolts I have and how sturdy the 3inch plug is when inserted into the boom.

A more pressing task for tomorrow though is to test the match of the VHF antenna, and add and adjust the hairpin match section.

No comments: