| Details | 2-El.-2m | 3-El.-2m | 4-El.-2m | 5-El.-2m | 6-El.-2m |
| 7-El.-2m | 7-El.-70cm | 9-El.-70cm | 10-El.-70cm | 12-El.-70cm | 14-El.-70cm |
| Stacked 5-El-2m 25-Ohm new | 7-El.-2m 25+28-Ohm new | 8-El.-2m 28-Ohm | 10-El.-70cm 28-Ohm |
Two Versions of stacked 25-Ohm-Yagis (1,80 m and 2,00 m Boom)
 |
Version 1: The stacked 5-Element- 25-Ohm-2-m-Yagi, Boom 180 cm Gain of each Yagi is 8,8 dBd, F/B 23 dB 3-dB-angles hor = 49,6°, ver = 61,6° Gain of the stacked array 11,5 dBd 3-dB-angles hor = 50,0°°, ver = 25,4° Stacking distance is 2,20 m
|
| With two Yagis of 25-Ohm-impedance an easy stacking
is possible. We need two pieces of 5/4-λ-coax-cable
with 50 Ω.
The 25 Ω
at XX are transformed to 100 Ω at XX.
With both cables L1 and L2 parallel we get the 50 Ω for the cable to the TRX. The first 45 cm of the 175,5 cm long pieces are wound to a coax-choke for surpressing common mode currents. The two chokes are in the radiator-box, we do not need coax sockets and connectors. |
 |
|
| The left picture shows the choke,here are 45 cm of the coax wound
on a 25-mm-PVC-tube. The right picture shows the 2x50-Ohm resistors
(1/2%) parallel. With both chokes and two resistors of 25 Ohm, length of
2x2,04 m Aircell-5 the SWR is 1,0. Between 144,0 and 144,5 MHz the
impedance is 50 +/- j 0 Ohm.
On 143 MHz R= 49 - j 5 Ohm, on 146 MHz R= 51 + j 5 Ohm, the impedance with an analyzer is shown down: |
The two connected radiators with 2x 2,04 m Aircell stacked
Lengths and positions of the elements, radiator always 4mm
|
Element |
Position |
4
mm |
3,2
mm |
2,4
mm |
|
Reflector |
0 mm |
1034 mm |
1037 mm |
1040 mm |
|
Radiator |
355
mm |
898
mm |
898
mm |
898
mm |
|
Director 1 |
640 mm |
959 mm |
963 mm |
968 mm |
|
Director 2 |
1240 mm |
939 mm |
944 mm |
949 mm |
|
Director 3 |
1780mm |
907 mm |
912 mm |
919 mm |
|
|
|
|
|
|
 |
Version 2: The stacked 5-Element- 25-Ohm-2-m-Yagi, Boom 200 cm Gain of each Yagi is 9,0 dBd, F/B 27 dB 3-dB-angles hor = 47,2°, ver = 56,8° Gain of the stacked array 12,1 dBd 3-dB-angles hor = 47,8°, ver = 24,2° Stacking distance is 2,30 m
|
Lengths and positions of the elements, radiator always 4mm
|
Position |
4
mm |
3,2 mm |
2,4 mm |
|
|
Reflektor |
0 mm |
1040 mm |
1042 mm |
1044 mm |
|
Radiator |
345
mm |
989
mm |
988
mm |
988
mm |
|
Direktor 1 |
735 mm |
945 mm |
948 mm |
953 mm |
|
Direktor 2 |
1410 mm |
942 mm |
944 mm |
950 mm |
|
Direktor 3 |
1970mm |
908 mm |
914 mm |
920 mm |
