BiTX20 se dezvolta!

By Blair Shock • March 9, 2009
By request, Info on PE1BWI’s PA4H’s CW Module for the bitx 20.  As a disclaimer: I haven’t built or used this module yet. It has been built by multiple people, who have had success with it’s use.

Above is the schematic of this simple mod. It works by inserting a carrier derived by using the BFO frequency, and adding 800 hz to it.  Very simple, very clean.
A little bit more info on the use of this module. The +12 volt input is hooked to a switch that when on applies 12 volts to the module.  This places the radio in CW mode.  If left on, and used in SSB, there will be a beat transmitted with the voice audio. The TX+ is connected to the like named terminal on the board. The key is pretty self explanatory. The line going to the base of Q11 must be shielded.  Bleeder caps are a good idea too.
Further information can be found at: Yahoo BITX20 Group (signup to yahoo groups is required)
Another great source of BITX information is KC0WOX’s Page
Most credit goes to Martien, PE1BWI PA4H, as this is his design.  The diagram above was made by me from the hand-drawn schematic of Martiens, so errors may abound. I think I got it right though.
Good luck building, and 73
Publicat de Costi la Tuesday, September 28, 2010

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