Background info page 2


Where you live affects what antenna you can have. My previous QTH had a small back garden and virtually no from garden and was surrounded by houses all in very close proximity. My current QTH - whilst still residential is blessed by having a decent sized garden with relative privacy - although I am still unable to have any tower or similar structure. My first QTH taught me loads about antennas - what makes them effective and what must be done when using compromise solutions. The ideal location is yet to be found..

Below are photos of the reality of the garden and the current doublet in situ. The centre is mounted on a 40ft sectional fibreglass mast going up the trunk of a birch tree and the two ends fixed to 20ft of sectional mast. Its fed with approx 50ft of 300ohm ladder line that connects to a 1:1 current balun that then feeds approx 50ft of RG213 to the shack.

For info I made a terrible mistake when I put up the antenna - I inadvertently made the 300ohm ladder feedline a 1/4 wave in length of the antenna, this resulted in massive RF in the shack until realisation dawned. Since then I have shorted the ladderline, now feeding it with coax via 1:1 balun and problem sorted.

The modular poles are very strong - there is a small flex as they get extended - I dont mind as it helps tension the wire without worry of snapping any wires when windy.

dipoletree1
dipolecentre1
fencedipoleend1
sheddipoleend1
balun1
colinear1




© m0mrr 2021