DC40B Construction: Day 3

Toroids. Today it was winding toroids. I really don’t mind winding ’em, it is stripping and tinning the leads that seems to be annoying. Nevertheless, I got the four toroids done (two simple, one bifilar transformer and one regular) and installed on the board. A simple continuity check between the pads indicates that all is well.

Should be really easy to finish the radio this weekend, just need to install the transistors, ics, a couple of electrolytic caps, and then power/speaker leads.

Midway DXpedition, courtesy of my HW-8

Well, as I was heading off to bed, I was reminded that there is currently a DXpedition operating from Midway island using the callsign K4M. A quick google revealed that they were operating on 7.078 SSB, so before heading off to bed, I decided to power on my HW-8 (ever since I got it, the FT-817 has been side lined) and see if I could hear anything. And, voila, here is K4M responding to G0HNW (in England). I just grabbed a small snippet of audio, but it gives you some ideas as to what you can hear with a radio like the HW-8.

K4M answering G0HNW on 7.078 SSB, October 15, 2009 07:05 UTC


Same recording, but with noise reduction courtesy of Audacity

Addendum2: I was wondering what algorithm Audacity actually implemented for noise gating. It’s spectral noise gating. I had previously blogged that papers by James Moorer provided some details of similar algorithms, but it appears that my previous links to him had decayed, so there is a fresher one.