144 MHz
Antenna plate and installation



Making the antenna plate of 16mm Rigid-uPVC and non-conducting Normafix clamps. The mechanical properties of rigid PVC (uPVC) are very good; the elastic modulus can reach 1500-3,000 MPa.




Accurate marking the lines, because the 6.5mm holes has to be onkly just on the outside of the 40x40 boom.

The two Normafix 35mm clamps will match the glass fiber rod of 36mm


Boom to mast clamp with uPVC and Normafix clamps is ready for use.

Temporary installation of the yagi in a small 6m tower. Unfortunately there is no adapter 7/16-N, therefore this strange N-BNC-7/16 adapter has to be used ;o)


Test @ 6m height

Very close to the tower:
Best Frequency 141.222 @ 1.14

to close to the tower, distortion of the pattern and reflections


Test @ 1.5m height

Best Frequency 145.307 @ 1.75

to close to the ground, distortion of the pattern and reflections


Test @ 3m height

Very close to the tower:
Best Frequency 144.491 @ 1.37

All right!:
Although close to the ground, the pattern seems to be promising. The yagi should perform better when it has free space and positioned in the rotating tower.



Althought the 40x40x2 boom is not really bending, to prevent this when the antenna is positioned @ 135 ft, this clamp is the solution. Using the same Normafix clamps and uPVC material. The first idea was to use wire tensioners, but in the end only non-stretching rope with eye bolts is used.


Special non-streching rope with is made of aramid fiber, and delivers a strength-to-weight ratio that’s five times greater than steel. They have excellent dielectric properties and eliminate electromagnetic interference (EMI), radio frequency interference (RFI), white noise arcing, and other potential interference that could compromise your amateur radio operation.


First idea: rope knot -->
Second idea --> eye bolt (A2)



The boom halves can independently be adjusted. For safety reasons there is an extra TY-wire attached to the knot.

Ready for lifting....

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