The BITX 2040 has moved from the bench to the operating position and is producing a steady stream of contacts on 20 and 40 meters. In the picture above it is the rig with the copper-clad front panel (the BITX 17 is below it). It has already crossed the pond on both bands.
I get significantly more power out on 40 than on 20: about 7.2 watts PEP on 40 and about 4.4 watts PEP on 20. I saw a QST article that showed similar frequency/power out variations from IRF510 amps. But I notice I get more power out from my 17 meter rig. On that rig I am using trifilar (9:1 Z) transformer instead of the standard BITX bifilars.
My 40 meter receiver is LOUD. Too much AF out. I am not used to having this problem! On this rig I am using the same discrete component 2n3904 2n3906 transformer-less circuit that I used in the BITX 17. But AF out on 40 was so loud that I had to go back and add 20 k ohms to the top of the volume control pot. I didn't have this problem with the 17 meter rig, and I didn't have it on 20 with this rig. Any ideas why this rig would be so loud on 40?
I still want to go in and fine tune the crystal filters in both rigs. I am studying the various software packages out there (especially Wes's LADPAC). I hope to get rid of the ripple.
In most of my contacts with these rigs, I end up describing the circuit and its Indian origins. Most people are really fascinated. Yesterday W1IDL in Michigan suggested that I contact my Indian friends and get some assistance in making some Hindi or Urdu labels for the rig and the controls. I think that is a very cool idea.
In response to popular demand, "SolderSmoke -- Global Adventures in Wireless Electronics" is now available as an e-book for Amazon's Kindle.
Here's the site:
For the print version:
For shipping from a printer in the U.S. (probably better for N. American buyers) Click here: SolderSmoke USA Version
For shipping from a printer in the UK, Spain, or the USA (probably better for UK and other European buyers)
Click here: SolderSmoke EU Version
The two versions are identical, except for a minor difference in the paper used. That's why the prices are a bit different.
Bill's OTHER Book (Warning: Not About Radio)
Click on the image to learn more
W4HBK's QRSS Grabber: The Amazing Pensacola Snapper (Live!)