For information on the Zepp, see sections 9.1.1.1.1 for the Zepp and 9.2.3 for the double-Zepp in the English edition of Rothammel’s Antenna Book (Krischke, DARC Verlag 2019). John F5VLF

Resistance in series with L4 will upset the tuning and maybe lower power. It will definately take the finals out of class E, not suggested. One way is to isolate the DC feed to Q6 and run that voltage

Excellent. So I have three options: Barefoot QCX QCX driving Juma PA100-D Homebrew valve tx with a qrplabs vfo. I'm looking forward to it! 73 Peter GM0EUL

Brent, Of course the U3S gives easy QRP and far more versatile WSPR options. With the QCX you'd possibly get around 13dBm WSPR by bypassing the PA. Otherwise I'd try an independent adjustable

I think everything should be welcome! To qualify as "QRP Labs" for the purposes of the QSO party, some part of the station used, should be a QRP Labs kit. 73 Hans G0UPL http://qrp-labs.com

Allison, I agree with you about the different lithium technologies. I am guessing that you are an engineer as you are obviously a technical person. Dave. N2SN ex G4FEB

Moments ago I finished installing my new QLG1 board in a clear plastic crayon box I got from Wal-Mart. It is exactly the right size, being 92mm X 70mm inside dimensions. It is tall enough to

I have a question maybe someone has run into. I'm building a 40m qcx+ in a different enclosure that's designed for this machine. My original 40m qcx has a page in the manual where it shows you the

Allison, Thanks for responding to my question. I guessed that the question must have been asked before which is why I apologized right up front for asking it. Anyway, the 31AWG made winding T1 on the

I have just completed the Clock and GPS kits - worked the first time, (thank you). I now have the aluminum case for Clock, which is very nice. I'd like to put the GPS board in a convenient

I’m thinking of experimenting with resistance in series with L4, but need to get a round-tuit. Maybe someone has already been down that road and cares to share? Mike WM4B

Complain all you want the only ones that can do that is ARRL the publisher. They can change it and you can't. That and it was written a few years back. Its old news. As to velocity or propagation on

I just replaced the 7805 voltage regulator on the QCX with an LM2940-5 LDO regulator, .I also bumped C37 up to 47uF for stability and still have the reverse polarity diode in place.. I was curious

Just realized that my title may have created confusion... This is a QCX radio on 40 meter band. It is NOT a QCX+. A better title is "QCX40 & 50W amplifier".

If it's still available I'll take it

I'd still like to see it covered in the book. You can't leave good enough alone can you , Alison ? "The End fed zepp is nothing special " well it is something special c/with the Black magic and BS of

The End fed zepp is nothing special and the "phasing section" is not. Its a quarter wave transformer to feed the high impedance end of the half wave wire (one leg). Performance save for feed point

On average its asked once every 6 weeks. You may find #31 a bit fine for handling. However wit will work otherwise. Yu may have to trim off a turn depending.

As someone that has long progressed to adoption of Lithium tech its several things that have been the primary reason. Good discharge curve and excellent high current capability. Good shelf life for

Crunchbird... One error, fully charged they are 4.2V for a whopping 16.8V. Once you runthem a bit depending on vendor the nominal is 14.8V. The yabut is that for LiPo... The Lifepo4 flavor the full