under progress

  • SWR bridge. First prototype was working, but broke down due to mechanical insufficiency
  • Fix the frequency wobble in the FT-757GX
  • low-tech recycling HB9CV antenna for the upcoming foxhunt

 


DC60: Conversion of the DCxx-Transceiver by Steve KD1JV  and qrpkits.com to 5353 kHz

English text below

Dank Hilfe von Steve KD1JV gelang mir die Anpassung des DCxxB-40m-Kits auf 5353 kHz relativ einfach. Ich musste die folgenden Komponenten abändern:

  • Quarz 5353 kHz (Restbestände anzubieten!)
  • L2: 26 Windungen auf T37-2
  • L3: 21 Windungen auf T37-2
  • L4: 40 Windungen auf T37-2
  • L5: 12 Windungen
  • C1: 100 pF
  • C4: 470 pF
  • C5: 1000 pF
  • C6: 330 pF
  • C9: 47 pF
  • C28: 47 pF
  • C33: unbestückt

Um starke Rundfunk-Interferenz durch China Radio Intl. auf ca. 5970 kHz (Sender Cerrik in Albanien, S9+30dB!) abzuschwächen, baute ich parallel zu L4 einen 1pF Kondensator ein. Markus HB9BRJ gab mir den Tipp, einen Saugkreis zu installieren: Dies geschah mit 13 Windungen auf FT37-61 und 68pF als Serienschwingkreis zwischen dem Antennenanschluss und Masse. Daneben ist auch JT65 als sehr hohe Tonfolgen hörbar.

 

Thanks to the help offered by Steve KD1JV I was able to adapt the DCxx-40m-kit just by replacing a few components:

  • Custom made crystal 5353 kHz (some are left, just send me a mail!)
  • L2: 26 turns on T37-2
  • L3: 21 turns on T37-2
  • L4: 40 turns on T37-2
  • L5: 12 turns
  • C1: 100 pF
  • C4: 470 pF
  • C5: 1000 pF
  • C6: 330 pF
  • C9: 47 pF
  • C28: 47 pF
  • C33: empty

In order to attenuate strong BCI by China Radio Intl. (from Cerrik/Albania, S9+30dB!), I added a 1pF capacitor in parallel to L4. Markus HB9BRJ gave me a hint to install a serial tuned circuit as suction circuit. This was done by 13 turns on FT37-61 and a 68pF capacitor between the antenna and ground. Now there is some high pitched JT65 left.

CTCSS subaudio tone encoder for YAESU FT-790RII

with Arduino / ATMega microcontroller using this DDS code as a basis. Modifications for lower frequencies in the code and the low-pass filter.

 

Here are the schematics and Arduino code.


Arduino based iambic keyer

no moving parts, with capacitive touch surfaces

internal keyer can be switched off

 

inspired by:

hardware (modified)

software (modified)

 

Here are schematics and Arduino code.

 

In a next version I would remove the buttons for speed control and use a potentiometer instead: Speed setting is saved, no bounce problems.