Thursday, December 29, 2016

N6QW 1st QSO, and Hacks for the BITX 40

I have my Bitx40 on the air and all seems to be going well. Good reports just that the signal is not 40/9.  
  • I suggest have two wire bundles with a red and black wires instead of the brown black. As this would prevent an accidental connecting the right wire to the wrong connector. In the board I have the PTT header is right next to the header that is the main power to the board. If you got those two connections wrong say after removing the connectors and re-installing them a lot of magic smoke.
  • Provide a note that if you hook up a homebrew DDS (and not your board) to be sure to include an isolating cap, as you are feeding directly into the base of one of the transistors.
Here is a video of the 1st Contact on the Bitx40.
Pete N6QW

Monday, December 26, 2016

A more stable Bitx40 (fun with ceramic resonators)

Peter VK3YE has a very neat hack for the BITX40

He explains :
If you don't wish to add a DDS to the Bitx40 (eg need low current consumption) I now have an alternative.  A cheap as chips 4.92 MHz ceramic resonator can be substituted for L4 in the VFO and be pulled by over 100 kHz.  I discuss and demonstrate the ins and outs of this and other VXO approaches in this video. 

Sunday, December 25, 2016

Troubleshooting the BITX40

Here is how you can troubleshoot your BITX40 board's receiver with just a piece of wire and a Volt-Ohm-Meter. Keep a print out of the circuit handy while you troubleshooting it.