A 40 Meter Direct Conversion Receiver from M0NTV -- With some SolderSmoke Comments

Nick's video appears above. 

First, let me say FB Nick.   It is nice to see you making use of the AGC amp designed by Wes and Bob,  using the board from Todd's Mostly DIY RF, using a mix of homebrew pads and Me-Squares  from Rex, and finally the Franklin Oscillator that we spent so much time talking about on SolderSmoke.  

But here are some comments:  

-- I still don't think you need that RF amplifier in front of the mixer. And I suspect you would be better off without it.  We did not use one in our high school 40 meter project, and never missed it.  In fact, on one version of the high school receiver I even put in a simple 10k pot as an attenuator (no RF amp).  Even up on 20 meters, I do not have an RF amplifier ahead of the diode ring mixer on either of the Mythbuster rigs I have built.  Nick,  maybe experiment a bit more and try the receiver just going from the BP filter into the mixer and see what happens.  

Note that Wes W7ZOI DID NOT have an REF amp ahead of the diode ring mixer in his original 1968 40 meter Direct Conversion receiver (the one that launched the solid-state DC recevier revolution): 

-- The Franklin oscillator is an interesting, but complicated circuit.  The gimmick is, well, gimmicky.  Here is the thing:  You can achieve similar levels of stability using simple conventional, single transistor oscillators.  We dispensed with the variable capacitors, and used PTO--style variable inductors. They worked fine.  This Franklin oscillator still does seem to drift a bit, right?   I would ground the board to the inside of the metal box.    

I would also try putting all the stages on a single ground plane.  This might help.  

Charlie "Red" NJ7V Builds an Oscillator -- Manhattan Style

https://www.youtube.com/shorts/7t_E5N4CQxg

Red did a nice job building, then explaining, this 18 MHz crystal oscillator.   I especially liked his use of Manhattan techniques, and the way he explained his effort to make the new circuit work.  Too often builders expect a circuit to work right away.   This often doesn't happen, and the new circuit requires some troubleshooting.  Red did this with this circuit and got it working.  

Red has a nice YouTube channel: https://www.youtube.com/@RedSummitRF.  It is focused on POTA, but we hope it has more and more homebrew stuff like this.  

Thanks to Rogier PA1ZZ for sending me this. 

The Importance to Bell Labs of Lunch or Breakfast with Harry Nyquist -- "The Communicator" -- Bimonthly Publication of the Surrey (British Columbia) ARC.

This is a good sample (!) of the great content to be found in "The Communicator." This is the bimonthly publication of the Surrey (British Columbia) Amateur Radio Club.  You can find the publication and digital back issues here: https://ve7sar.blogspot.com/ 

There is a lot of great material in this publication. 

Pete N6QW Has Hybrid Rig On-The-Air

 

A thing of beauty on a wooden board.  Pete's post: 

https://n6qw.blogspot.com/2024/11/11252024-1st-dx-with-40m-hybrid-rig.html

"Them that know can make it go!"  Indeed.  

Pete talked about the history of this rig, and especially of the Thermatron portion of it, in the most recent episode of the SolderSmoke podcast: 

https://soldersmoke.blogspot.com/2024/11/soldersmoke-254-audi-and-video-versions.html

Thanks Pete! 

Oscar 7... and Oscar 11 (aka UoSat-2)? Did Oscar 11 do much the same thing as Oscar 7?

Above is a pretty good video by Retro Rockets.  Some will quibble about the technical details presented, especially about early radio, but I think the video does a pretty good job of describing the early production of ham radio satellites.  

As I watched this video however, I started to wonder if OSCAR 7 was in fact unique in coming back from the dead.  Back in 2018, I watched signals from OSCAR 11 (aka UoSat -2) as it tumbled through space with its battery dead, powered by a direct connection to its solar  panels: 

https://soldersmoke.blogspot.com/2018/12/ghost-ship-oscar-11-tumbles-through.html  

This was what Retro Rocket said was Oscar 7's claim to fame, right?  

In both cases, what happened was pretty cool, but did OSCAR 11 sort of repeat the supposedly miraculous rebirth of OSCAR 7?