| 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 |
Cheap and simple VHF-/UHF-Yagis by DK7ZB, extreme lightweight for portable use
These Yagis are constructed with cheap leightweight materials for electric installations and you can mount and dismantle them without any tools. The boom is made of PVC-tubes with 16mm, 20mm or 25mm diameter, the element holders are the clamps for these tubes.
As a mast you can use a telescopic fishing rod or thin Aluminium-tubes for tents.
Max. mounting lengths of the PVC-tubes for the boom:
| Diameter | Without additional support | With Kevlar rope above the boom |
| 16mm | max. 1,00m | max. 1,50m |
| 20mm | max. 1,50m | max. 2,00m |
| 25mm | max. 2,00m | max. 3,00m |
The elements are made of aluminium welding rods (I used AlMg4 or AlMg5) with 4mm or 3mm. A 4-Element-2m-Yagi has 7dBd and a weight of only 280g! For easy construction look carefully to the pictures.
All Yagis have an impedance of 50Ohms and are feeded with a lambda/4-choke for 2m and a 3/4-lambda-choke for 70cm. You can use the same chokes for 2m and 70cm! The radiator is a stretches dipole with 10-12mm insulation between the two parts. The insulated part is a piece of glass-fibre (from a broken tent of my children!).
The given length in the tables are from tip to tip. The Yagis are optimized for 144,3MHz to use them for SSB/CW.
The radiator box with RG-188-PTFE-coax (for 2m and 70cm), 250Wtts on 144MHz and 100Wtts on 432MHz
Another box for 2m with RG-174, 100Wtts on 144MHz
|
Coax-cable |
V |
Length |
|
RG-174
(Full-PE) |
0,667 |
34,5cm |
|
RG-188
A/U (PTFE) |
0,71 |
37cm |
The middle part of the 4-El.-2m-Yagi with the boom clamp
This picture shows the boom from the side
|
|
The mounting of the elements Drill a hole (3,9mm for 4mm-elements or 2,9mm for 3mm-elements) and push the elements through the holes. Ready! If the elements are not fixed enough on the boom, put two windings of PVC-tape around the boom and clip the clamps then on the boom. |
A little bit more difficult is the reflector, because it is longer than 1m, the welding rods have exactly 1m length. Make two pieces of 50cm length and take an aluminium tube 6x1mm. Then you can drive in the 4mm-rods with a hammer.
