All posts tagged homebrew

Here is a line of homebrew circuit board that I have made for a amplifier project I am working on. (Which by the way takes forever to comlete ­čÖé┬á )
These boards are designed by Dominique F1FRV which have laid down a tremendous effort in designing these boards.
Dominique has done some minor changes to the design since these boards were made, so cards made by his latest instructions will look a bit different from these.

Have been working on a crowbar circuit for my universal high voltage power supply for some time now.
And here is a early preview of the circuit. This unit is meant to bolt right on top of my 5kV 100uF filter capacitor.
As the picture shows I have cut a air gap into the PCB to strengthen the isolation between high an lo- voltage areas on the card.

HV crowbar unit

Here is the schematics of the circuit. And I must emphasize, this circuit is not fully tested yet!!!
Crowbar circuit

Here is a Hi-Pot tester I have just finished.
Hi-pot tester is good for 11Kv at the terminals and the leakage current is 3uA.
I’m pretty happy with the result.

Testing a Burle 8792 transmitting tube. Leakage is 3uA @ 7Kv

Inside view from the top


EDIT: Transformer listed in shematics is not correct. You must use an linear type. The one listed is electronic and no good for this use.

Here are some pictures of my second GPSDO.
This one, like my first GPSDO is based on the G3RUH James Miller desing.
Whats new with this is that I have added a Picaxe controller and a display unit for decoding the GPS NMEA-0183 sentences.
The display show various information decoded of the gps sentences.
But the main reason for building the MKII was that I needed it for controlling my DDS based WSPR Beacon.
GPSDO 10Mhz output drives the DDS and the micro-controller which steers the DDS.
The picaxe gps decoder take care of the keying of the beacon at the start of every tx period.

Ii’l will come back with a┬áseparate post regarding details of the wspr beacon.