All posts for the month January, 2012

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

Been testing Opera for few days now. And I must admit there has been some head-scratching. 🙂
First of my microham digi keyer II which is hooked up with my TS-2000x did not produce much results. This duo works great in other modes but not with opera. I’m not sure what causes this but I suspect that my USB hub may be the problem. Anyway, I changed to my second digi keyer (mk1) and the FT-1000mp and the results began to show.

I have not yet enough experience to say anything about it’s ON-Air performance.
The software itself is very CPU hungry but this may me rectified (I hope) in later revisions. In fact new revisions are commeng all the time, sometimes several in a day.

Last night I tested for the first time the new weak signal beacon mode opera. It only ran for a few hours and I think there must be something wrong for I have had several clearly audible signals here but only one decode.
I will let it run through out the night to see if I can catch something.

Opera screen capture

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.

I’m trowing in a couple of pictures of the FOX DELTA ST2 Antenna Tracking Interface that I have build.
Unit works great, but on the bench for the moment. Antennas ain’t finished yet. 🙁
I’m in the proccess of building a 144Mhz 4×7-Element-Yagi array for EME. ETA not known.











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 separate post regarding details of the wspr beacon.
















I have now shut down my old web site and I am in the process of moving my stuff over to this site. (stuff worth keeping that is) Old site lacked everything and was terribly hard to run and operate. This site runs on my own servers and for the moment I am testing the WordPress blogging tool and content management system. (which is free and open source by the way) In addition I am using the K2 template for the wordpress engine with the 1:40am style and various plug ins and some small customisation.

Hope you like it. And thanks to all you guys making all this nice stuff available for free.