Mancorad November 12th 2011 Meeting – Jeremy KC9BWK with his Homebrew 80/20m Transceiver

Posted: November 13, 2011 in Mancorad Radio Club

At our November 12th 2011 meeting Jeremy KC9BWK gave an outstanding presentation on his 80m & 20m SSB Transceiver Project.

Jeremy KC9BWK used several references and worked out his own design, with each module built up as a separate entity.

Some examples – like the 5 kHz oscillator module in the candy tin feature cut-trace circuit boards.

Others like the mixer module standing on edge in the center featured boards he etched himself.

Where appropriate or where revisions required it “dead bug” and mixed building techniques are used. These are amplifier modules built around parts taken from old computer supplies. The smaller outputs roughly 20 watts and the larger design 120 watts on 80m.

Much of the transmitter portion is built inside a shielding framework, again with a mix of cut-trace and dead-bug design.

Most of us never think how there are a series of functional modules in our radio. This is Jeremy KC9BWK’s transceiver with frequency counter & display, filters and most components.

Much of the inspiration for his design is based on an excellent web-book “Crystal Sets to Sideband” by Frank Harris, KØIYE, the latest version (#12) which is available as a PDF or for online reading at http://www.wa0itp.com/crystalsetsssb.html and also in a printed copy (it is 436 pages to print out) at http://www.lulu.com/product/hardcover/crystal-sets-to-sideband—a-guide-to-building-an-amateur-radio-station/16249809 (I intend to order one at one of Lulu’s periodic sales).

Jeremy had to report that the current ARRL books were not very useful for this sort of work, though he did adapt one module’s design from an old ARRL Handbook. Compared to the Frank Harris K0IYE book he couldn’t recommend any of the main ARRL books.

Here is another view of the exciter portion of the transmitter.

Many of the controls have been remoted to allow eventual placement in a case.

The frequency counter uses a PIC chip, which Jeremy has offered to program member’s PICs if they want t build their own.

The modules mostly use coax with RCA plugs to interconnect.

Many parts are salvaged from old gear, with a handful of purpose bought components. Jeremy described how he mostly winds his own air-coil toroids rather than trying to wind on ferrite cores.

Many of the components are surface mount items!!

In general he does not drill his boards, preferring to solder leads to the face of the traces.

Here is a final shot of Jeremy KC9BWK showing off his handy work!

Well done Jeremy KC9BWK and thank you for sharing your inspirational project!

73

Steve K9ZW
Secretary/Treasurer

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