Heathkit HW-5400 with DDS and Filter Mods by KE9NS

Audio sample of my original 1985 Heathkit HW-5400 2.4khz crystal filter, and my mods that added a custom cpu controlled DDS LO board , and a custom cpu controlled DDS IF BFO board, and 4 & 6khz TX/RX crystal filters. I programmed the keypad to not only allow direct frequency entry, but allow RX/TX filter selection. The IF shift knob now allows RX and/or TX IF shift. The DDS is driven by a TCXO
The operators on 3.630 are operating 6khz wide hence the beautiful RX audio
Recorded with my iPhone
Darrin
KE9NS
ke9ns.com/heat...

[@Mach7RadioIntercepts]

Ha! I recognized those voices right away. Very nice work on your Heathkit - it sounds great.

[@ardilla8651]

WoW, FB audio. Fine job.
73 from Spain, Jon EA3BV
I use now powerSDR with my 1500 and very Happy, many many thanks for your support.

[@n8sdr473]

Well that sounds like N9HLL Rick and NU9N John, - and John K9JSP-nice job Darrin

[@michaeltrager4381]

Nice job Darrin! I built the Heathkit HW-5400 in the early 80's and it was fun. Everything worked at first turn on:) It would be nice if I still had it and could add your mods! It must have been a big project for you to do? You must also be very smart with programming and writing code which I could not do....

[@ke9ns]

Years before I did the DDS mod, I had reverse engineered the original CPU logic so I could control the radio with my own CPU. The DDS project was to learn how SSB was generated and how to control bandwidth and IF shift. It definitely took some time.

[@wb8cxo]

Very nice! Sure that's not a SDR? LOL

[@ke9ns]

I was re-arranging my shack (to make room for a 3rd monitor) so I had to move my Heathkit. Just checking if I got all the wires back correctly. :)