4El10m  3El12m 

4El.15m  
4El.20m 
3Element12mYagi with 12.5 Ohm (Version 1)
Boom 3,50 m, narrow band version, high gain, high F/B (Version 2 see down)
Do not mount this Yagis with other antennas nearby. DK7ZBmatch with 2x50Ohm lambda/4 coax.
Short data for the Yagi at the begin, in the middle part and at the end of the band
Plot with the NECIIreference of YO7.2 by K6STI
The meaning of the data : Frequency, gain, F/R, radiation resistance (impedance), SWR and loss against a theoretical defined maximumgain Yagi with the given boomlength. Remember, that this gain is only available with very low impedance and extrem low bandwidth! 
Elements of the 12m12.5OhmYagi, lengths for one
elementhalf:

20x1,5 mm 
16x1,5 mm 
12x1
mm 
Position 
Ref 
1,00
m 
1,00
m 
1,05
m 
0 m 
Rad 
1,00
m 
1,00
m 
0,945
m 
1,235 m 
Dir 
1,00
m 
1,00
m 
0,785
m 
3,50 m 
Azimuthdiagram (horizontal pattern):
Elevationdiagram (vertical pattern):
Gain, SWR, F/R and Z versus frequency:
3Element12mYagi with 12.5 Ohm (Version 2)
Boom 2,85 m, narrow band version, extreme high F/B
Gain 5,4 dBd F/B > 30 dB 3dBangle hor. 64,6° 3dBangle ver. 107,8° Do not mount this Yagis with other antennas nearby. DK7ZBmatch with 2x50Ohm coax. 
Elements of the 12m12.5OhmYagi, lengths for one
elementhalf:

20x1,5mm 
16x1,5mm 
12x1mm 
Position 
Ref 
1,00
m 
1,00
m 
1,10
m 
0 m 
Rad 
1,00
m 
1,00
m 
0,965
m 
0,725 m 
Dir 
1,00
m 
1,00
m 
0,74 m 
2,82 m, 
Needed lengths of the Aluminium tubes (remember: the middle and outer pieces need an additional part for overlap!)

20x1,5
mm 
16x1,5
mm 
12x1 mm 
Reflector 
1x 2,00 m  2x 1,20  2x 1,30 m 
Radiator 
2x 0,99 m 
2x 1,20 m 
2x 1,20 m 
Director 
1x
2,00 m 
2x
1,20 m 
2x 1,05 m 