The AM Forum

Hola,

Lots of activity on 6M lately and hearing lots of plans from
the guys.

I've designed up three simple 6M Yagis that anyone
can build. The 5el and 4el here have been built by several guys
already and work FB.  I plan to build up eight of these 3el Yagis
for a low height, high angle array for E skip propagation.

These are all Yagi "YO" COMPUTER designs and element lengths
have been compensated to allow you to use 6" X 3" element to
boom plates to hold the elements to the boom. All elements
are bolted/grounded to the boom. The driven element uses a
"T" match to bring the input up to 50 ohms. . Look it up in the
handbook - I will post a description of it later on.  F-B is about
22 db on all Yagis to allow for the best forward gain compromise.

Each Yagi is designed for a particular element diameter stock.
If you use something other than what's shown, I will design
you up another. Aluminum is cheap at the scrap yards!

-----------------

Yagis good for 50-50.4 mhz, centered on 50.135 mhz.

*Add about 5.5 db to gain figures for gain over ground
in the real world..

*Double the 1/2 length for total element length.

*Ref= reflector el, DR=driven el, D1= director 1, etc.


--------------------------
3 element 6M Yagi on a 6 foot boom, 5/8" els:

..............Position on boom...... 1/2 length
REF.........0"........................... 59.015"
DR.........37.659".................... 57.140"
D1..........72.08"...................... 52.849"

Gain: 7.81 dbi (free space over isotropic]
Impedance: 25 ohms

--------------------------

4 Element on a 15 foot boom, 0.5" els:

............Pos....................1/2 length
REF.......0.......................59.248"
DR........42.75"................56.247"
D1........97.983"...............53.246"
D2.........179"...................51.745"

Gain: 10.27dbi
Impedance: 22 ohms


-----------------------

5 element on a 23 foot boom, 3/4" diameter els:

............Pos................1/2 length
REF.........0....................58.273
DR...........43.152"..........55.302"  
D1..........106.245"..........54.009"          
D2..........194.222"..........52.986"
D3...........270.832".........52.953"  

Gain: 12.52 dbi  Impedance: 11.3 ohms
-------------

73,
Tom, K1JJ