KG7TR's Magnificent 75S-2B Receiver -- Tubes, an Si5351, an Arduino, a Bit of Collins, and a Bit of a Drake 2-B

 

Oh man, I share this with much trepidation because the last time I posted something about the work of Mike KG7TR,  Pete N6QW said he felt like putting all of his own work in the dumpster, so much better was the artistry of KG7TR.  This receiver is so cool and so well-done that we now  might have to post a guard outside the N6QW shack -- heck Mike even has an Arduino Uno and an Si5351 in there!  Don't do it Pete!

I was led to this magnificent receiver by the very humble 6U8 tube.  Scott  WA9WFA and I have been learning (mostly from Grayson KJ7UM) that the much used and sometimes loved 6U8s (three of them in our "Mates for the Mighty Midget")  might be a bit long in the tooth, old even by Thermatron standards.  I was worried when I remembered that my Drake 2-B has a 6U8 in it -- V2, the first mixer.   So I Googled for more info and was led to this amazing receiver, a 2018 creation by KG7TR.  How did we NOT see this for almost four years?

Here is more info and pictures: 

http://www.kg7tr.com/75s-2b-receiver.html

Here is Mike's write-up of the project: 

http://nebula.wsimg.com/c2281e9bdf3b54da42ca4b0b541b4ec9?AccessKeyId=D18ED10DA019A4588B7B&disposition=0&alloworigin=1

Mike KG7TR's web site:

http://www.kg7tr.com/ 

As for the 6U8s, well Grayson says the tube has been getting something of a bum rap.  And  KG7TR has two of them in this receiver, so I will obviously have to give the 6U8 another chance.  

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I didn't know that Lew McCoy had his own crystal and crystal filter company: 

http://www.kg7tr.com/the-real-mccoy.html

KG7TR Describes his Homebrew SSB Rigs (Video)

We have posted before on the amazing homebrew creations of Mike Bohn KG7TR. 

Today I watched this 54 minute video in which Mike describes his rigs. (Thanks to Pete Eaton, WB9FLW for pointing me to a site that has this video.)    

Quote from KG7TR:  "I have never destroyed a pristine Command Set." 

Wonderful tribal knowledge throughout, especially on the metal work, parts acquisition, front panel work and toroid placement. 

Clear you schedules.   This is really worth watching. 

Octalmania -- KG7TR's Amazing Thermatron Rigs

Grayson in Turkey alerted us to Mike's homebrew rigs:

Bill, Pete:  

  

I had to pass along photos of the latest work of Mike Bohn, KG7TR.  Mike is a long time thermatron home brewer, having built several SSB receivers and transmitters.  He is famous for his “octal mania” designs that only use octal tubes. His present SSB transceiver is no exception.  Some of his work is shown in my HSD book.

 

 

This is SERIOUS homebrewing, a work of art.  According to Mike he spent “six months of pretty much full time work (6-7 hours per day, 6-7 days a week) to get the radio to the state shown in the pictures.  Probably 750 to 1,000 hours. I retired in January and this was one of my bucket list projects.”

 

This is way more time than most of us who still work ever hope to devote to a homebrew project, but it gives me  hope.  Someday we will hopefully retire.

 

This is a 80,40,20 meter rig with a pair of 6146’s on the output.  Tuned the good old fashion way with 5-5.5 Mc L/C colitis oscillator.  It does have an IC freq counter as the frequency display.

 

 

Even though the metal work looks like it was done in a well equipped machine shop, Mike says “The sheet metal work was pretty onerous.  I don't have the tools to shear metal or make right angle bends, so everything had to be done with a jig saw, angle stock and files.”   This also give me hope, but I have a hard time believing he doesn’t have a numerically controlled, laser mill!

Thought you would like to see some super nice work.  Certainly “raises the bar”

73

Grayson

TA2ZGE - Ankara, Turkey

KJ7UM

Follow the Hollow-State Design Blog

hollowstatedesign.tumblr.com

 

Pete's STUNNED reaction:
 

Hi Bill,

 

Thanks –you have ruined my day –almost wants me to take all my radios to the scrap heap. Those are not radios but works of art. Lots of man hours in those projects and more amazing is finding many of the parts – the thermatrons are easy to find –it’s the other stuff that is nearly unobtanium.

 

Pete

 

 Much More Here:  http://qrz.com/db/KG7TR

 

 

 

SolderSmoke Podcast #183 Pete's B'day, Simple-Ceivers, Binaural Bliss, 160 or Bust, GOOD BEHAVIOR, MAILBAG

Bill's Frankenstein R2 receives 7 MHz signal and generates I and Q outputs

SolderSmoke Podcast #183 is available. And it is GOOD!

http://soldersmoke.com/soldersmoke183.mp3

20 December 2015

-- Foxes in the Backyard
-- Pete completes another orbit
-- Simple-ceiver Success!
-- Frankenstein Receiver: IT IS ALIVE!  AND BINAURAL!!!
-- 160 Meter AM OR BUST!
-- Fun on 40 AM -- Lots of Multi Elmac AF-67s!  Who knew!
-- The Amateur's Code, and violations thereof.
-- Negative Frequencies? I don't think so.
-- Capacitor Offer from our Secret Benefactor: EXPANDED ELIGIBILITY
-- Projects for 2016: Pete goes Raspberry Pi, Bill goes DX-100
Mailbag:
-- Croation Creation
-- Salvadoran 2B
-- N3FJZ's Homebrew QSL
-- WA7HRG's LBS-ZIA-Simple-Ceiver Mashup Rig
-- KC0IZR turning VCRs into Mighty Mites in NOVA
-- AB1YK Starting with DC RX, going BITX
-- G8GNR puts Mighty Mite on AM!
-- G3ZPF Modulates THE SUN (Amazing)
-- VK3YE's Simple Superhet
-- Grayson in Turkey drools over KG7TR's Octalmania
-- N7REP reaches for the Zantac because of Arduinos and Surface Mount