DC-40 - A Simple Receiver for 7 Mhz

I came across this very interesting design on the internet and decided to get on with the construction. The design is by VU2FAX OM Ashhar Farhan (Of the BITX fame :) ).

The Receiver is a simple Direct Conversion design for 7 Mhz (40 meters) .

The Frontend coil is wound on a 1/2.in Tap washer (US: Faucet) with 32 Gauge Magnet wire.
The frontend is followed by a Double balanced diode mixer. The mixer trifilar is wound on TV balun cores (bought them at 5 bucks per core) . The VFO is 7 Mhz LC tuned.The VFO is followed by a buffer amplifier (The Buffer amplifier also reduces the noise).
The Mixer passes on the weak AF signal to a Preamp. The  volume is further amplified by a 386 Amplifier.

I got all the Parts yesterday and finished the Preamp section today. Since I had a 386 amp which I had constructed earlier {I make 2-3 modules when I get time so that I can use them later}

The Only Problem Faced during construction of the Preamp is that I had mixed up the wiring first as all the transistors looked the same and wiring it up on a prototyping board was tiring.

I also got time to wire up a Passive AF filter with the parts I had in my Junk Box. The filter has a bandwidth of 3 Khz and is enough for SSB reception. A switch in parallel to the filter serves as the filter bypass (For CW reception) ........

This Filter was designed by VE7BPO

The whole cost of the receiver comes to around Rs.100 ( around 6$).

I plan to construct the receiver as a weekend project(spending just sunday evenings) and should finish this off within the end of this month.

Source of the article can be found here. 

I have compiled the document and converted it to PDF for
 printable format (8 pages) and readable format (11 pages)