Planning the Progressive Receiver's Construction Layout
Choosing the Enclosure
Generally speaking, we QRP enthusiasts like "small" radios. However, as I was considering building the Progressive and looking over the schematics, I came to the conclusion that I wanted plenty of room inside the enclosure. This facilitates easier modification and changes. So I chose a the largest Ten Tec enclosure available, wanting something roomy with a divided sub-chasis, and lots of front panel space.
The Receiver Modules
The Progressive design itself facilitates a "neat" construction layout. Another conclusion I came to very early in the project was that I would need to "stack" modules to optimize space inside the enclosure. The mixers and the 40 meter oscillator use the same size pcb boards with identical hole spacing to allow stacking with standoffs. The preselector and the 80m bandpass filter also use the same boards and are stacked inside the enclosure.
To minimize unwanted "birdies" in the receiver, I chose to use shielded cable for all the audio lines. The VFO and BFO use feed through capacitors in the +12 V lines for shielding as well. In addition, the VFO and BFO are both housed in shielded homebrew enclosures. I built these enclosures with pcb material, soldering them into boxes to house the VFO and BFO. The local hardware store also stocks brass sheeting material which is ideal for making small enclosures and the BFO lid is made of this material. It holds solder very well.
Building a Transceiver?
If you intend to eventually build the Progressive into a transceiver, it is important to shield the VFO circuitry and place it in an area which is relatively isolated from the transmitter. I plan to build the transmitter on the bottom of the sub-chasis, while the VFO is located on top.
Temporary Front Panel
Why use a temporary front panel? At first this sounds like a simple question, but with strong advice from "Mike," W3TS, and after spending $60 dollars on a fancy enclosure, I didn't want to "botch" the front panel. Therefore, to protect my investment, I built a temporary front panel out of pcb material. This way I could change the placement of controls without destroying the enclosure, and when I was finally comfortable with the front panel layout, and only then, I could drill and cut permanent holes for a neat, "professional," presentation.