Amateur radio station since 1993
RA3WDK Homepage

This is Nuclear Radiation Detector

which has been modernized with Gamma detector tube Geiger Muller (SBM-20) and digital counter .

Once it saved health of my family !


  USB to serial UART RS-232 + PTT from DTR/RTS

PCB file (Layout v6 format)




Morse Code Beacon Keyer

My old design with AT89C1051 , for VHF beacon in repiter RR3WA, program (asm file)

My new design with ATtiny13 with long dash 10 sec. program (asm file)

ATtiny13 fuse bits




















My new design with ATtiny2313 with text " DE DL4KE" + long dash 2 sec. program (asm file)



10 MHz Rubidium Frequency Reference EFRATOM LPRO-101

I use Frequency Reference for operating on the microwave bands 5,7 & 10 GHz with narrowband modes (CW)

Click on an image for a larger version

PCB Sprint Layout 5.0 file

I use small power beacon with TXCO 10 MHz for control my microwave system from precision frequency of EFRATOM LPRO-101.

Beacon make many spurious - and have good level 5760 and 10370 MHz for comparison and calibration my LO XVTR 6&3cm.

Spectrum measurements with R&S spectrum analyzer



Spectrum measurements with Anritsu spectrum analyzer, Fnoise better 100dbc/Hz.


"Lazy" LC tuner 1,8 - 30 MHz


I like old vintage receivers. You can see photo my old USSR VEF-202 radio receiver.

Manufactured in Riga, Latvia, VEF

(my receiver was made on 1979)

Super-Heterodyne receiver

( only 10 semiconductor transistors) have LW and some SW broadcast band.

I added 19m and 17m bands.

(easy for this receivers, you need only free band-plate for make new band).

I have made also CW local oscillator (LO) in IF frequency 465 kHz. This LO mast be set near IF amplifier and receiver modification to enable them as CW/SSB-reception.

These are the VEF-202 IF filter modifications with ceramic filter 465 kHz.

The VEF-202 uses the simple LC filter 465 kHz with bandwitdh about 13-14 kHz and not good selectivity perfomance. You can install low cost ceramic IF Filter PF1P-õõ with bandwitdh 6-8 kHz. (also FP1P-õõ)

After you installed ceramic filter - you mast adjustment L32 L33 L34

and may be L36 for better bandwidth and min loss in passband !

You can see and listen my receiver after modification, i did not save voice from BC station, ....but saved CW and SSB in RadioHam`s 17 and 40 m bands:

Air 40m band

Air 17m band

Windows Media Video - WMV file

17 m SSB

17 m CW

40 m SSB

You can ask me about circuit diagram and all modification of VEF-202.



My evalution board for MSC-51





Homebrew evalution board :

CPU - AT89S8252

Available 2 Clock 24 MHz and quartz

ISP programming via LPT port

IRF port / Led port / 6x8 Segment port

IRQ port

RS232 port (max232)

Sound output , simple keyboard



My old time project

Home made Iambic paddle key (1999 year) , weight about 1,5kg , 4 ball bearings .


My new project

for portable and emergency QRV

size - only 30 x 30 mm








My projects and articles

in :

Filter for 7 MHz

Beacon , AT89C1051 with program

Add to G-450XL second overlap LED



Touch Paddle CW Key