7ele homemade DK7ZB yagi for 70MHz
I based the construction of this antenna on the
boom, and element mounting of an old defect
2m 15ele CUE DEE yagi
The CUE DEE boom disassembles easy into 4 pieces, making
it excellent for portable use
I tweaked the DK7ZB design to fit the CUE DEE boom length (72mm shorter than the DK7ZB design), such that I can re-use the mounting holes for the reflector and the last director. I also found the right element lengths for the 6mm rod elements used with the CUE DEE. The result was as follows:
|
Element |
Element-position |
Element-length (6mm) |
|
Ref |
0 mm |
2131 mm |
|
Rad |
581 mm |
2028 mm* |
|
Dir 1 |
1103 mm |
1987 mm |
|
Dir 2 |
2203 mm |
1941 mm |
|
Dir 3 |
3553 mm |
1914 mm |
| Dir 4 | 5196 mm | 1910 mm |
| Dir 5 | 6443 mm | 1878 mm |
* The dipole is made from 12mm Alu tube. Length is end-to-end, not sum of the two tubes.
The other elements can be cut from two 6m long rods. If you need to cut them for transport, cut both at 4.01m.
SWR plot
Feed point box
Length of matching cables = 300/70.15 (freespace wavelength) * 0.85 (velocity
factor SAT752F) * 0.25 (quarter wavelength required) = 909 mm
The finished antenna in action in JO20XC
This antenna activated the following sqaures: JO56PA JO66BA JO44IW JO20XC JO64GX JO74MX JP40KS
