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Showing posts with label thermatrons. Show all posts
Showing posts with label thermatrons. Show all posts

Sunday, September 27, 2026

The WN2QHL N2CQR Drake 2-B

I was telling Steve KW4H and Scott K6AUS about my Drake 2-B (Serial #11976): 

I got mine when I was still a novice on April 11, 1974. I still have it and use it.  It had been spared the Magic Screwdriver, because the previous owner was my Elmer, Hilmar WN2NEC. Hilmar was a no-nonsense German immigrant, a tech who knew which end of the soldering iron to grab.  

The only real mod that it had was the installation of a Jackson Brothers reduction drive. This slowed the tuning a lot, and I lost the calibrated dial skirt, but I think it was worthwhile.  I have tuned "normal" 2-Bs and they seem a bit fast to me. By the way, I think you can tell a true 2-B restorer if he has replaced the string on the tuning mechanism of the 2-B, and he has done it often enough to get good at it!  I am sure Steve is in this category! (Can you imagine a modern rig that actually has a STRING in it?  I can't.  I think those tuning dial strings capture a lot of the charm of these older receivers.)   

When Hilmar sold me the receiver, it had a  really cool big knob on the front.  But he had specified that I had to give that knob back to him -- he had borrowed it from a device at work!  Of course, as a teenager, I dallied.  "I really need that knob," complained poor Hilmar. I found a replacement and gave the knob back to him.    

Years later I think I replaced the power supply capacitors with a replacement from Hayseed Hamfest. 

My 2-B opened up a world of DX for me.  Only two days after I got it, I worked ZL2ACP on 15 CW.  And of course on that same day, I worked KP4USA on 15 meter CW.   The operator was Steve, who is today KW4H.   With my earlier general coverage receiver, I could barely hear 15 meters.  With the 2-B it was easy to tune.  

I have more than 70 Drake 2-B articles on the SolderSmoke blog.  Check them out: 

Thursday, September 17, 2026

Grayson Evans' Modest Proposal: NO MORE VALVES! NO MORE TUBES! THERMATRONS FOREVER! (and a great video)


First, a big THANK YOU to Grayson KJ7UM and to Zeynep, his wife and video editor.  The above video is a really excellent look at not only the technical characteristcs of thermatrons, but also at the history of their development.  There is a lot to be learned in this wonderful video. I am glad that no one was shocked in its production. And I am glad that SolderSmoke is no longer the only podcast/videocast using a "shamless commerce" segment! 

Grayson's video and his "modest proposal" are eerily timely for me.  Just yesterday I dragged out my old thermatron 80/40 receiver and got it inhaling.  It uses 6U8s and 6EA8s which were featured in this video.  This morning I used this old thermatron receiver to listen to Tim WA1HLR, who has been using thermatrons for many years. 

I have also been talking about Compactrons -- specifically the 6T9 -- on the podcast.  This prompted Jeff Tucker, W9TH to send me the PC board for the simple 6T9 circuit that I should have built as a teenager.  I also got words of encouragement from Mike WA6ARA.  The pressure is building!  

Finally, this gets us to Grayson's "Modest Proposal."  See:  https://kj7um.wordpress.com/2026/09/16/a-modest-proposal/    He proposes that we STOP calling these devices "tubes" or "valves" and instead refer to them as thermatrons.  I am with him on this.  But I warned him that his proposal (even with modesty) would provoke HOWLS of protest from the many, many change-averse radio amateurs in the US and, especially in the UK.  I know from personal, lived experience (four years in London) that the Brits love their valves.  But, hey, Grayson is right!  So I will pledge -- whenever possible -- to use his preferred term.  Gentleman, don your Kevlar now!  

Thanks Grayson for the video, and for the modest proposal!  

Get the Third Edition of Grayson's excellent book "Hollow State Design"  here: https://www.hollow-statedesigns.com/books

Friday, February 13, 2026

The Mahbood Radio Service Company of Hyderabad, India


Our friend Farhan sent this today.  It is really beautiful and captures very well the magic of radio.  Thanks Farhan. and thanks too to Mohammad Moinuddin of the Mahbood Radio Service. 

“Before television and smartphones, Hyderabad listened to the world through radios. And in those days, my father ensured that the city stayed tuned in.

My father, the late Shaik Mahboob, founded Mahboob Radio Service in 1933 in Dabeerpura. At a time when radio was still a luxury, he began selling and repairing sets for households across the Old City. In 1948, after Hyderabad’s accession to the Indian Union, he shifted the shop to its present location in Chatta Bazar, where it continues to stand even today.

Interestingly, he did not begin with radios. In the late 1920s, he was involved in the PVC pipes trade. But as radio technology slowly entered Indian homes, he recognised its future and transitioned into the business of radio sales and repairs. That decision shaped our family’s destiny.

Like my father, my brother and I grew up surrounded by valves, wires, and wooden cabinets. After school, we would sit beside him, carefully observing how he handled brands like Murphy, Philips, Bush, Marconi, and later Sony. Those were the golden years of radio in Hyderabad.

Among our customers were prominent families of the city. We even serviced radio sets for the palace of the last Nizam, Mir Osman Ali Khan. Payments would arrive in a sealed lifafa — a gesture that felt both formal and special. In those days, radio wasn’t just entertainment; it was how people heard news, music, cricket commentary, and the world beyond their homes.

Over time, technology changed. Transistors replaced valve sets. Then came television. Now, smartphones have taken over. Radio sets are no longer common in households. Many shops that once repaired them have shut down.

My brother, who shared this passion with me, is no more. But I continue to open the shutters of our shop every morning. People still travel from different parts of the country — some carrying radios that are older than me — hoping to restore a memory. I repair them not just as machines, but as pieces of someone’s past.

Today, in my late seventies, I sit at the same wooden table where I learned this craft as a boy. Because this is not merely a business, it is continuity. It is a responsibility.

On World Radio Day, my only wish is that people remember the warmth of gathering around a radio set. I also hope today’s radio jockeys continue to create thoughtful and meaningful programming. Because radio is not outdated — it is timeless.  As long as I am here, Mahboob Radio Service will remain tuned in.”  

– Mohammad Moinuddin, Mahboob Radio Service