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:

Download

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