Thursday, February 22, 2007

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.

Sunday, February 04, 2007

Frequency counter with PIC

QRP rig is needed to know the frequency of receiving and sending signals. This frequency counter can be easily built for QRP rig. It uses PIC16F628 and few parts to construct it. The frequency range is 1 to 50MHz with 5 digits.

We may build it for QRP rigs to see the exact frequency of the band.