Saturday, November 10, 2012

Pixie 2 based Feld Hellschreiber transceiver

I've figured out that my keying of the CRK-10 CW transceiver is flawed and that I'm not shifting frequency so I've decided to start work on a dedicated Feld Hellschreiber transceiver based on the popular Pixie 2 design.


This clever little design uses the output transistor as a mixer during receive and my modification is to key it with rectified audio from the computer. It's putting out a very pleasing little signal (barely moves a power meter but thats fine for a mode like this) but my audio keying circuit needs work.

4 comments:

Honestpuck said...

I thought computer geeks had indecipherable jargon but you radio guys have got us beat hands down . "Feld Hellschreiber" is a good one

Peter Marks said...

Yes I can't get enough of this mode. It dates back well before computers and is a kind of one line mechanical fax.

Stephen, the chap I'm communicating with sometimes uses a valve transmitter at his end.

Murray VK3ACF said...

I really like the concept and am following with interest. For too long I've been struggling to learn CW. This mode may be the alternative fuzzy mode but I see next to no Hell activity on the bands. We should try for a QSO once I get my antenna back up - and it'll be nearly all valve at this end apart from the PC!

Peter Marks said...

Yes let me know when your antenna is up and we'll try for a contact.