PicoKeyer

The QST article about PicoKeyer by N0XAS has bee found. It's very simple key using Microchip 12F629 and 2N7000 for the keying. It is the issue of December in 2003. The keyer software of 12F62o has been stored into the catalogue of qst-binaries.
The software is here.

RF Power Amplifiers

High Frequency Electronics manage had interesting arcticles about PA in 2007. They are Part 1, Part 2, Part 3 and Part 4. Part 2 describes techniques for RF Power Amplification. Class E that I mentioned at the 2N7000 article of this blog is also described here.
Figure 7 of a single-ended PA is a good picture to understand the basics PA.

2N7000 for PA of QRP Rig

A small MOS FET is often used for PA of QRP rigs. Here is the specification of the FET. The maximum Power is 400mW but QRP rigs are used for 1W power output PA. The schemantic of DC40A has 2N7000 for PA and there is no loading resistor. Once the gate of 2N7000 gets the RF voltage, the FET acts as a high-speed switching element. Therefore, the element generates a large power at the switching cycle.

The schemantic shows that the output of Q3 2n3904 is 8V p-p and its of Q2 2N7000 is 45 p-p.

The artcile of MOS FET amplifier is usefule to understand MOS FET. You should understand the properties of FET and how to use FET for the amplifier.

Antennas : Service and Education, W4RNL

L. B. Cebik, W4RNL writes the set of excellent reference articles for antennas. I should read them for my study.

MMR-40

The Hendricks QRP has been announced the rig called MMR-40. It is the good shape of the CW/SSB rig with 6W. The planned shipping is from March 21, 2007.
It is also very reasonable cost ($105 for US, $110 for DX) for CW/SSB rig.

Since there is the PDF doc file in homepage, I'd like to investigate it in detail.

Rockmite power-up

I've check the interesting article about hi-power Rockmite. Here is the article that I've read. You can use 2N7000 for Q6 to get over 1Watt. It's pretty inexpensive to get it.