12m, 5el monobander from Hy-Gain scrap
As described in the previous post I have been working on a 12m 5 element monobander that I designed from old Hy-Gain scrap we had lying around at the station. Last sunday I picked up Thomas SMØCXU/PY2ZXU and Hans SMØBYD who also took theese pictures. Myself and Thomas made the Beta match feed arrangement for the beam. The calculated Beta match length was 15 cm but it became rater 30 when we hoisted the antenna up for tuning. Driven element tips had to be shortened by 2 cm on each side and that gave a perfect resonance in the middle of the 12m band with a flat 1:1.1 SWR over the whole band. Now I will build a similar 5 element design for 17m and after that both antennas will get a new home in a WARC band tower.
Here's the design measurements for the SMØW 5 element 12m yagi.
|Boom 5,08 cm – Place||T1 – 2,225cm||T2 – 1,113cm||Total|
All measurements are in meters if not otherwise noted. All tube diameters are hy-gain standard diameters, I recalculated "inch" into cm for the design.