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.

DC40A is released

Hendricks QRP has introduced the new kit of QRP (DC40A, 30A and 20A). It is the upgraded version of DC40 and more than 1W power with 13.5 Volts. I built the DC40 kit and had a few contacts. The DC40A is also using 74HC4053 for mixer and the front end RF amp is 2n3819. The PA of TX is 2N7000 for more than 1W output. It's the same as DC40, but the output of buffer amp is higher because the resister values of the buffer amp is lower than ones of DC40.
This basic diagram can be also used for 30A and 20A for higher frequencies.

I'm really interesting in the capability of the kit for both RX and TX. I may change TX circuit for old DC40 to get much power than the original DC40 circuit.

The DC40 has the issue on lower audio output and I'd like to know how much it is improved for the DC40A with the RF amp. I may add LM386 audio to get more AF power for the DC40 if it's needed.