Walter KA4KXX spotted an error in the schematic of my 2014 "Off the Shelf" regen receiver: The source resistor on the MPF-102 should be 2200 ohms, not 2.7 ohms. See: https://soldersmoke.blogspot.com/2014/09/schematic-for-off-shelf-regen.html Walter's e-mail caused me to take this old receiver off the shelf. In this video you can listen to it in action on the shortwave broadcast bands. In a second video I put it on the 40 meter ham band and listen to some SSB ..read more

Chinese Radio Licenses and Operating Certificates David Cowhig (aka WA1LBP,  aka Gao Da Wei) was Hambassdor for 73 Magazine on Okinawa when I held a similar "position" on the island of Hispaniola.  David is a real Asia hand, and is fluent in both Mandarin and Japanese.   He is uiniquely sitated to provide info on ham radio in China.  In a recent post he provides this info, and describes how we may soon be hearing from ham Taikonauts in space:   https://gaodawei.wordpress.com/2024/05/22/2024-ham-radio-in-china-soon-chinese-hams-in-space/ Thanks David!  ..read more

Wow, very cool.  On Hack-A-Day this morning: https://hackaday.com/2024/05/26/homebrew-computer-from-the-ground-up/ It caught my eye because the architecture seems similar to that of the MostlyDIYRF PSSST rig.   There is a lot to learn from this little machine, especially for an analog guy like me.  Mostly DIY RF PSSST ..read more

Blogs come and go, but (hopefully) YouTube is more permanent and accessible.  This morning I re-found Pete N6QW's YouTube channel.  When you use it, I suggest you click on "oldest" first.  This will take you back 14 years,  to Pete's time in the Pacific Northwest.   The video above (him playing guitar) was shot just before he and his XYL moved back to California.   Here is Pete's YouTube channel:   https://www.youtube.com/@N6QW/videos This is a tremendous resource for ham radio homebrewers.  It should be preserved and protected.  ..read more

Version II of the 15-10 rig is mostly done. I did a lot of work on the AF amp, balanced modulator, Mic amp, carrier oscillator, and filter. Dean KK4DAS and I continue to test and measure the RF power amplifier. I describe the brutally simple, non-sequenced T/R switching arrangement, and the spread-out open air construction style. Version I of this rig is on its way to the Dominican Republic. Version II will stay in Virginia. I have already worked a lot of SSB DX with this rig, including, Thailand, Taiwan, China, India, Kenya, Australia, American Samoa, and others. This video was inspired by ..read more

It is truly a thing of beauty.   I really like that variable capacitor.  (Where did that come from?  How can I get one?)    Charlie's calculations on each of the stages is -- as always -- really nice.   I like the J-310 infinite impedance detector,  Charlie's use of solder wick,  the wooden base, and his decision to keep the circuitry visible.    I also like Charlie's decision NOT to put that VFO in a metal box.  Too often we see projects that try to convince us that the receiver just won't work unless everything is hermeti ..read more

  I saw this on Facebook today.  G1AVQ (SK) Rig The G1AVQ rig reminded me of the N3FJZ rig that I worked in 2015: https://soldersmoke.blogspot.com/2015/10/hb2hb-n3fjz-n2cqr-si5351-and-bitx-tias.html I am a big fan of breadboards, and have recently been flollowing the lead of Frank Jones W6AJF in using pine boards as the bases for my homebrew rigs.  Mine are more horizontal, but we see here from N3FJZ and G1AVQ that a vertical orientation works too.   ..read more

Hack-A-Day has an article today about using a laser for data transmission.   This reminded me of a discussion I had with Mike KL7R about similar systems.  My son Billy and I built a very simple version in London in 2007.  Check out the podcast above.  Scroll foward to 19 minutes 15 seconds and you will hear how we did this.   This was Mike's last podcast.  He was killed in a car accident in Hawaii about 10 days later.  RIP Mike.  73 OM.   Mike KL7R ..read more

In the video above (from 16 years ago) we see Jeff Damm, WA7MLH's  band-imaging receiver for 75 and 40 using an IF of 1.750 MHz and a VFO of 5.2 - 5.7 MHz,  For a signal at say 3.579 MHz (!) you subtract the signal from the VFO and you end up at the IF.  For a signal at say 7.030 MHz you subtract the VFO frequency from incoming signal and get to the IF.  (By the Hallas rule you get sideband inversion on 75/80 meters, but Jeff was on CW so this doesn't really matter.)   Sixteen years ago this receiver was a work in progress and Jeff was having some trouble with ..read more

This old QST article caught my eye, largely because my father was also in Hollandia on that  Christmas day in 1944.  He was in the Navy hospital there, recovering from wounds received in the battle of Leyte gulf (in the Philippines).   Hollandia, also known at Humbolt Bay, is now Jayapura, Indonesia. The picture above shows the harbor in 1944.  Rod Newkirk W9BRD went on to write QST's inspirtional "How's DX?" column for many years.  -----------------  From S/Sgt. R. H. Newkirk, W9BRD, "Christmas, 1944" QST, January 1946, pages 25 and 102. Christmas, 1 ..read more