High Power PA with YL-1050

YL1050 PA for 432 MHz

(OZ9ZI design)

The mechanical description is very good and it is no problem to follow it. The housing and the special parts, which have to be made with a turning lathe, must be made by an expert. All other things can be done by yourself. I preferred to make powersupply- and PA-housing in separate and use standard 19" technique. It would be interesting to make the HV-supply by switch-mode, but first experiments with that failed. So I use heavy weight (50kg) transformator. With the power-supply I wanted to go my own way. I made some interesting experiences, which I want to share with the community.

600V Screen Supply
HV Regulator

600V Screen Supply by G3SEK (DUBUS 3/90 Archives)

G3SEK published a very interesting screensupply in DUBUS 3/90. The idea is to use a current source and a shunt-regulator in series. This circuitry is able to sink and source current.

The circuitry survived some flash-over due to wrong tuning, but died two times. I think ist difficult to make everything "fool save" with that high voltages.
The PA is not easy to tune, you must follow the tips from OZ9ZI !

HV Regulator by DL8MX, DB1NV (AA5C)

DL8MX and DB1NV published a very interesting idea (from AA5C) to regulate the HV-output of a transformator in UKW-Berichte 2/88.
The advantages of this circuitry is, that the anode-voltage remains within +/- 150V (at 3kV rating), even if the mains goes down due to the high load. Second, you do not need start-up sequence for the transformer (let the ref. voltage of the comparator rise slowly after switch on).
This circuitry works very nice.

PCB of the two circuits

left PCB is HV-regulator, right PCB is Screen Supply and 12V/24V Supply

©FDbt, Oct.2000