| Theory of the DK7ZB-Match (new) | The "classic" DK7ZB-Match | Full symmetrical 28-Ohm-Match by DF9IC | "Sperrtopf" by DF7DJ |
The DF9IC-Match for 28/50 Ohm
|
Especially for 70cm has a full symmetrical feed advantages, although the patterns of the "classic" Yagis with the DK7ZB-Match are good. You need only an additional piece of lambda/2 of coax. The best choice is PTFE-cable RG-179 with 75Ohm. Henning, DF9IC, has developed an epoxy-board for the cables, look for the photos. |
|
|
The picture shows the scheme of the full symmetrical match from 28 to 50 Ohm by Henning, DF9IC For shortwave, 50 MHz the normal two lambda/4-cables wound as a choke would be a good choice. For 144 MHz a loop is ok. For 70 cm you can get an advantage with the DF9IC-Match. Download the PCB-Layout at the DF9IC-website: |
The following pictures show all details of the DF9IC-solution for a group of 9-El.-70cm-28-Ohm-DK7ZB-Yagis
|
|
|
 |
The production of 9-El.-28-Ohm-Yagis for the contest-group DR9A ...
The antennas in use by DR9A
