Way back in 2008 I started thinking about how to improve the Heathkit SB-
This is the third attempt at this project, the first two having failed at the design phase to find sufficient space for the additional electronics inside the existing SB-
The VFO will be a Vackar format with isolating buffer, SSB offsets and RIT. The frequency display will be a digital counter and LCD display.
This page will plot the (sometimes slow) progress of this project.
Step 2 -
The original PA compartment chassis was used as a drilling template for the major tuning components which are mostly in the same place as the original. Note that the 80m and 160m PA inductors are now wound on dust iron toroids, the 40-
Step 1 -
The receiver and transmitter backends will be contained in one or more screened compartments on top and underneath the chassis to the left of the PA compartment (viewed from the rear), including the detectors, modulation sub-
The initial part of version 3 of the overall layout is shown below to the right followed by the full layout.
Step 3 -
With all of the paper layouts fixed in place the chassis is now ready for drilling.
The blank area on the lower left of the chassis is for a screened enclosure below the chassis to contain the solid state circuits. The area above the chassis will contain a small sub-
The rear panel of the chassis will be drilled and punched in a separate process. The original Heathkit 11 way power connector has been replaced with a 12 way rectangular connector in order to accommodate the additional pins for the 12v DC supply.
The picture to the right shows the mostly drilled chassis, less the front panel, with some of the components and sub-
As the front panel will not easily accommodate all of the additional controls, a small number of the variable controls have been combined using concentric potentiometers. This required some re-