Thursday, 7 September 2017

28Mhz Yagi Build

couple of weeks ago i completed the build of a 3 ele 28mhz yagi.
i had been looking to buy a yagi from innovantennas, but i decided to try and build one.
using mmanagal antenna modelling software i optimized a 3 ele design.
my main parameters were, having a 50ohm feed point and a good bandwidth.
i could of got more gain but the feed point impedance dropped and i would of needed to use some sort of matching device. i dont like using matching devices.

so, here are the dimensions I ended up with from mmana gal.

these are the final dimensions


i had been given a 3 ele yagi years ago and never used it. it is a trapped yagi of some design, but with a phasing line from center element to the rear element.
i dragged it out of the sehd and dismantled it. the inner sections were just right for the element lenghts. it also had the boom, boom to mast bracket, element clamps which are insulted.
time to set about putting it togethere for real.

elements. boom.
element clamps. test set up


test set up. checking with MFJ 259B.
Balun. FT240-43. RG142.

Stub mast to boom bracket set up.

element detail. 1" 1/5 dia.

More to follow.

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