Amateur Radio And Electronics Site
Here’s the SV1EIA usb2sdr board controlling the Si570 chip on the vfo kit from K5JHF/K5BCQ, the MCU and display unit are of course removed. And the Si570 board is clocking the LA6NCA QSD unit. I haven’t calibrated anything yet, but it works fine.
Simple usb2sdr receiver setup. Top: K5JHF/K5BCQ Si570 board. Left: LA6NCA QSD board. Right: SV1EIA USB2SDR board.
Receiving wspr with the simple sdr setup.
Yesterday I received the Si570 Controller and Frequency Generator Kit by K5JHF and K5BCQ.
And today, after 3 to 4 hours work the kit was ready for a test spin. My unit has the LVDS Si570 chip, the FIN-1002 LVDS to LVTTL converter with the TC1-1TG2+ output transformer. Here are a few pix…..
The Si570 kit
A few hours work and the kit is ready and working.
Generator output @ 56.320Mhz
There has been some interest in the Picaxe GPS NMEA-0183 Decoder which I use to time the keying of my wpsr beacon.
The Picaxe chip decodes the time data in the $GPGGA sentence from the GPS unit and then print the UTC time on the lcd display. In addition it set a output at the start of every even minute for keying the wspr beacon. That’s all it do with the current 18X chip.
I am planning an upgrade to the 18M2 chip which is a lot more powerful and has got more functions then the current 18X chip.
With the 18M2 I am planning to display some of the other GPS information, like position, signal strength, number of satellites, etc. It’s not that the 18X chip can’t do this extra information bit. But these task will put a lot more strain on processing and communication so I fear the accuracy of the keying will suffer.
Picaxe GPS NMEA-0183 Decoder
 >> Download full size scheme <<
Have thrown together some parts on a plank here. The idea is to make a “lean” power supply to test my crowbar circuit.
Output is 630v with the current limiter (spot light bulb @ 120watt). And the capacity of the filter capacitors is about 1100uF.
This should be enough energy for the preliminary circuit tests.
Crowbar test supply
….to be continued if I survive 
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  )
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.
I have put my wspr beacon on the air for a test after the latest modifications. And so far it look promising.
Here is a picture of the mess
Picaxe wspr beacon. Bottom: Picaxe and DDS-60 :Top from right: 10MHz LPF, tripler and amplifier for clocking the dds-60 @ 30MHz
Here is a small update regarding my band hopping picaxe controlled wspr beacon.
I took the beacon of air the other day to do some revisions to it’s circuitry. And in this context figured out that I was in need for a filter to clean up the square wave shaped signal from the 10MHz reference oscillator, the GPSDO MKII. I did a little googling and found an interesting circuitry drawn by Jerry Mulchin – N7EME. The reason for needing this filter is that I have a passive frequency trippler for clocking the DDS-60 @ 30MHz, and this tripler need a sine wave to work right.
There is still some work to be done before I can put the beacon back on air. But as they say in broadcasting; Stay tuned, will be right back after….
PCB measures 60x20 mm and parts are SMT
Schematics
Measuring reflection (S11) with the minivna. Return loss is more than 26dB @ 10MHz.
Measuring transmission (S21) with the minivna. 1dB insertion loss @ 10MHz and cout-off at 12MHz.
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.
Here is the schematics of the circuit. And I must emphasize, this circuit is not fully tested yet!!!
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
Schematics
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.
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