Меню сайта |
|
Статистика |
Онлайн всего: 1
Гостей: 0
Пользователей: 1 URC |
Форма входа |
|
Поиск |
|
Категории раздела |
|
|
Приветствую Вас, Гость · RSS |
26.04.2024, 18:34 |
|
Two Versions of stacked 25-Ohm-Yagis (1,80 m and 2,00 m Boom)
|
Two Versions of
stacked 25-Ohm-Yagis (1,80 m and 2,00 m Boom)
The picture left shows
shows the 4x5-Element-25-Ohm-Yagis with 2-m-boom and a stacking distance
of 2,30 m. Two Yagis are connected together with Aircell-5 transformations
lines, the two groups are coupled with a power-splitter as described on
the "stacking page".
The Yagi-array handles 1 KW
HF without any problems and was used for a test in the Alpe-Adria-Contest
2010. The array works excellent with a very good antenna pattern. The
measured SWR of the complete group in the common feeding point is <=1,1
beween 144,0 and 144,8 MHz.
At not very good band
conditions QSOs from central Germany (450 m ASL) to middle Italy were
possible, distance 800- 1000 km.
The Yagis on the picture
are built with 8-mm-elements.
The lowest antenna is 6 m
above ground, with groundgain you can get 20 dBd gain! The Elevation angle
is only 3°, the 3-dB-angle vertical is also only 2,8°. Plots below!
|
|
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
|
998
mm
|
998
mm
|
998
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 9,1 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
|
The construction of DK5EW
and DF8GH
for the Contest-Station DA0Y in JN48MB |
|
Lengths and positions of the elements
Element
|
Position
|
8
mm |
6
mm |
4
mm
|
3,2
mm
|
2,4
mm
|
Reflektor
|
0
mm
|
1036
mm |
1040
mm |
1040
mm
|
1042
mm
|
1044
mm
|
Radiator
|
345
mm
|
978
mm |
982
mm |
989
mm
|
988
mm (4mm)
|
988
mm
(4 mm)
|
Direktor
1
|
735
mm
|
926
mm |
934
mm |
945
mm
|
948
mm
|
953
mm
|
Direktor
2
|
1410
mm
|
922
mm |
930
mm |
942
mm
|
944
mm
|
950
mm
|
Direktor
3
|
1970mm
|
891
mm |
898
mm |
908
mm
|
914
mm
|
920
mm
|
|
With the lowest antenna 6 m above ground with medium conductivity
and stacking distance of 2,30 m the gain of the array is 20 dBd!
The pattern shows an elevation angle of 3° and a 3-dB-angle of
2,8°! | |
Категория: Антенны УКВ | Добавил: URC (14.01.2011)
|
Просмотров: 1117
| Рейтинг: 5.0/1 |
Добавлять комментарии могут только зарегистрированные пользователи. [ Регистрация | Вход ]
|
|