Listen to Latest SolderSmoke Podcast

Friday, May 31, 2019

KG7SSB -- Homebrew SSB in Tuscon -- Learning from the BITX40 Module

On Sun, May 26, 2019 at 1:45 PM William R Meara wrote:

Dale: 
  I was talking to Jim W9UD on 20 SSB today.  When I told him I was running a homebrew transceiver he mentioned that he talked to another guy who is on the air with homebrew SSB gear -- you! 
There are so few of us Dale.  I felt compelled to send you an e-mail.  
What are you running?  
After several years on DSB, I started building separate SSB receivers and transmitters, mostly for 17.  Lately I am running versions of the Indian BITX transceiver. 
Please send info on your homebrew SSB projects. 
Thanks,  
Bill N2CQR

Hi Bill, 

I have two radios that are completed to date. I started out building the BITX 40 transceiver from scratch and also a companion 60 watt solid state linear rf amplifier. Then I decided to construct the second transceiver for 20 meter using some of the BITX design concepts and mixed with the UBITX design for additional rf amplification. It too is amplified to about 25 watts output. The 20 meter rig is my favorite radio at this time but I am going to go a different direction on my next build. It's presently just in the design stage but I'm thinking about using the MC1350 integrated circuits for the IF amplification and for the front end I may try using a FET rf amplifier. The beauty of the bitx design is the use of wide band amplifiers that don't have a tendency to oscillate. But, the new design I'm working on will have more shielding between critical circuits and I will use a small amount of negative feedback in the high gain circuits. The reason for changing the radio to a higher impedance design is to simplify the design build. I will basically build a receiver that I can reverse the signal direction over to transmit using the same amplifiers and filters. This will cut in half the amount of circuit building however it will increase the switching circuit complication associated with this new design. 

Today I'm beginning the build of a 100 watt rf linear amplifier design using the kit parts from China (minipa 70) amps. This provides the transformer components and circuit boards. I purchased two kits of parts and I have a large heatsink to build it on. I'm working on a current sensing circuit for protecting the final FETS.  It  will run 4 IRF530's tied together with a splitter and combiner for the input and output matching transformers. It should produce at least 100 watts at 75/80 meters and maybe a little less on 40 meters but 20 meters it will drop off to about 60 or so watts. 

I'm just having as much fun as a guy can have playing around with the homebrew radio's and like you say there's not many doing it these days. I love operating a radio that I built vs. running a factory made radio. I have two commercial rigs on my bench and a couple of Collins radios but the homebrew takes the lead. 

Jim W9UD has become one of my ham friends this year. We end up talking every week or so on the air and keeping touch with local weather conditions.
Side Note:
I wanted to build a SSB radio since I was a young lad with a technician license in the early 60's. SSB came into the picture many years after I was first licensed.  Then move forward to 2015 my ham license had long ago expired during my time in the Vietnam war. I spent several weeks studying the tech, general and finally the extra class exam information and passed on through that adventure. So I decided it's time to build my own radio from scratch. So I started to look online and in books and I still didn't have the confidence to begin building. Then I ran across Farhams BITX 40 and I thought why not buy this radio and just use it as a model of how sideband circuits work. So I did just that and I got it working fine I took the radio and placed it on the test bench and began circuit analysis and signal level evaluation until it all made perfect sense. This is accomplished while transmitting so the levels can be seen on the oscilloscope. Just kill the voltage on the final stage of the bitx. I put a 1khz signal on the mic input. That was just about the only thing I used the bitx 40 rig for and I still keep it handy when I need information. 

Good hearing from you I hope I haven't over done this reply but I really enjoy talking about this subject.
73's Bill.... keep up the building and good luck on your next radio. 

Dale KG7SSB

-----------------------

And of course, Pete N6QW knows Dale and has been talking about SSB with him for some time... 

Sunday, May 26, 2019

DIY Waterfall -- A Quick and Easy Panadaptor Using a Sig Gen and O'scope (video)



I've been getting waterfall envy.  The panoramic frequency display is the one thing that could lure me to the dark side (SDR).   Heck, they now have 3D waterfalls!  What next?  Holographic waterfalls? Virtual reality waterfalls?  This is almost too much. 

Anyway, in an effort to counteract all of this waterfall seduction and to show that us analog HDR guys can go panoramic too, I decided to try to create my own panoramic display without resort to SDR.  

Of course, this is a very old technique.  It was invented in the 1930s by Marcel Wallace, F3HM.  He was the inventor of the Panadaptor which was the forerunner of today's waterfall.  Panoramic reception was used by the armed forces during WWII.  In 1946 Hallicrafters marketed a Panadaptor for its ham radio receivers (see below). 

In figuring out how to do this, I thought back to my use of my Feeltech signal generator to scan the response of a crystal filter.  The Feeltech has a very handy sweep feature.  

In this case I set up the Feeltech to sweep from 4.85 MHz to 4.75 MHz in one second.   With the 12 MHz IF of the BITX40 module, this would result in a sweep from 7.150 to 7.250 MHz. 

The sweeping Feeltech just replaced the VFO on my BITX.   I hooked up the Rigol oscilloscope to the audio output of the BITX.  I set the horizontal scan rate at 100 ms per cm.  This would have the trace go across the whole screen in 1.2 seconds. 

After a bit of fiddling, I could see signals on the 40 meter phone band.  But my display would kind of drift along the screen making it hard to know the frequency of the signals I was seeing. 

Alan Wolke W2AEW provided the solution.   He advised me to put a big stable signal at 7.150 MHz near the input of the BITX, then use this strong signal to trigger the 'scope scan.  The HP8640B signal generator that Steve Silverman gave me (and that Dave W2DAB picked up for me in NYC) provided the triggering signal.  

I put a piece of tape across the bottom of the scope display to calibrate the display.  See video above. 

It works!   It is not as cool as the SDR waterfalls, and it does not convey nearly as much information, but it was a fun project. 








Saturday, May 25, 2019

KJ5VW's Cool uBITX Mods (Video)



Beautiful work Gary, and great to see that you are putting ideas from Pete and from Don Cantrell in your rig.  

Gary wrote:
Don and Pete,

I thought you would be interested in the QRP station accessory I added to my version 3 microbitx transceiver.  In addition to using Don's AGC and Reverse/Forward Power and SWR  circuits, I developed another board using a separate Nano and TFT display to show day, date, time, temperature and humidity as well as showing the relative audio strength in three separate bands centered on 400 Hz, 1000 Hz and 2500 Hz.  In addition, when I put the transmitter in a 'tune' mode the power out and SWR will show on the TFT display as well.  The date, time, temperature and humidity information is updated once every minute, the audio is displayed continuously during receive and the power/swr is only displayed when the transmitter is activated.

The audio frequency analyzer is based on the MSGEQ7 microchip and it actually picks up the audio strength in 7 bands covering 63 hz to 16,000 hz.  I just display the three most likely to show up in a SSB transmission.  You can see a 'live' example near the end of the video showing a 20 meter QSO and how the audio strength by audio frequency varies over time.

This project falls into that 'frivolous but fun' category that was a challenge to design but I doubt many other hams would want to replicate it. I learned a lot and wanted to thank both of you for arduino scripts, useful circuits and lots of inspiration for getting started.  I have long admired the work both of you contribute to our hobby.

Here's the link to the YouTube video. 


73,  Gary KJ5VW

Friday, May 24, 2019

Nigerian Knack: Hope Emmanuel Frank



I hope this kid has a lot of success.  He definitely has The Knack. 

Tuesday, May 21, 2019

FDIM Interview with KI4IO -- Homebrew Direct Conversion Transceiver


I've been a big fan of Jerry's for several years.  He is the homebrew wizard of Warrenton, Va.  Warrention is just about 25 miles west of us.  Cappuccio the wonder-dog was born on a farm in Warrenton.  

I'm really glad that our ace correspondent Bob Crane W8SX caught up with Jerry at FDIM.  I liked his description of the joy of using a homebrew rig, and of the advantages of direct conversion.   Inspiring stuff!   Listen to the interview here:  

http://soldersmoke.com/KI4IO FDIM 2019.m4a


Be sure to check out the KI4IO page on QRZ.com

Monday, May 20, 2019

Woz on the air -- Age 11


We discussed Steve Wozniak's early involvment in ham radio here: 
https://soldersmoke.blogspot.com/2011/12/wozs-early-exposure-to-electronics.html

Thanks to the K9YA Telegraph for relaying this great picture. 

Sunday, May 19, 2019

FDIM Interview with Hans Summers G0UPL on QSX SDR Rig, Probable Price, Features


Wow, our ace correspondent in Dayton/Xenia Ohio, Bob Crane W8SX, did a great interview with homebrew hero Hans Summers G0UPL.  

Hans discusses the success of the QCX CW phasing rig -- more than 7,300 sold.  That's amazing.  I didn't think there were that many solder melters in the world.  

Even more amazing is his description of his QSX SSB SDR rig, which is currently in development.  Click on the link below to listen to Bob's 6 minute interview.  You will be blown away by the features and the price of the QSX.  Go Hans!  

http://soldersmoke.com/G0UPL FDIM 2019.m4a

Thanks Bob! 


Friday, May 17, 2019

Pete sent me his SBE-34



Pete is such a great guy, and such a great ham.  Earlier this week I came home to find a box in the living room.  In it was the SBE-34 that you see in the video.  Pete had been talking about this rig about 18 months ago.  

So many cool features:  The main tuning dial is dual-speed.  There is the "Geneva" band switching method.  Hybrid, with sweep tubes in the final.  All analog.  A power supply that will take 110V AC or 12V DC (internal inverter).   Collins mechanical filter at 455 kc.   Bilateral amplifier stages.  PNP Germanium transistors. 

Pete suggested that I might want to use this rig for parts.  No way!  There is real radio history and amazing innovation in this rig. Plus, it has been worked on by Pete Juliano, N6QW.  

Here is the write up from Pete's YouTube page. Note the part about how they get the BFO signal. 

Here is an example of what an IC7300 might look like some 50 years ago. It is a hybrid rig using Germanium (mostly PNP) transistors in the low level stages. So OK a couple of NPN (2N706) in several key locations such as the VFO. The driver uses a tube similar to a 12BY7 and the finals are a pair of sweep tubes, the 6GB5's. The rig operated on four bands (mostly the then phone portions) 80, 40, 20 and 15 Meters. The power out on 80-20 was 60 Watts PEP and dropped down to 50 Watts on 15 Meters. That was a real stretch. The AGC sucked as you will see in the movie and the receiver gain was a compromise --too much on the low bands and weak on the higher. This was a bilateral design -- which predates the Bitx series by some 40 years--but not the 1st.The first bilateral design was the Cosmophone - Google that one. The major selling point --a Collins mechanical filter. Also an innovation was how LSB / USB was achieved using a single crystal. It was pure magic and innovation. The basic BFO frequency of 456.38 was doubled and then doubled and tripled again. The first 2X gave you 912.76 KHz and the 2nd 2X gave you1825.52 KHz and a tripling gave you 2738.28 KHz. Mixing that back with 456.38KHz gave you 2281.9 KHz USB or LSB. The VFO operated in the 5.5 MHz range and there were heterodyne crystals to put you on the proper bands. Now that was some clever math! You can download the maintenance manual at BAMA manuals. There were some smart guys leading our ham radio efforts back in the day.

Wednesday, May 15, 2019

Stop what you are doing! Go to the Radio Garden!


This is really fantastic.  The screen display is like Google Earth, but all the green dots are local broadcast radio stations.  Put your cursor on the dot and listen to that radio station live.  And it works very well.  If there are several stations in the same town, just zoom in.  

In the course of a few minutes this morning I was listening to stations in Guatemala, Costa Rica, Getxo Spain, and Bengaluru India.  

Go to the radio garden: 






Sunday, May 12, 2019

Another Amazing SSB Rig: VK3HN's "Summit Prowler 6"



Here is another truly amazing compact SSB rig.   Paul Taylor VK3HN is a true homebrew wizard.  So many great homebrew rigs come out of Australia.   

More details: 

https://vk3hn.wordpress.com/2019/05/01/summit-prowler-6-a-pocket-sized-ssb-cw-transceiver-for-80-40-30-and-20m/

Paul's QRZ.com page: 

https://www.qrz.com/db/vk3hn

Friday, May 10, 2019

Peter DK7IH's Amazing Rigs and Blog

It has been a few years since we last mentioned Peter DK7IH.  He has continued to melt solder and to document his work on an excellent blog: https://radiotransmitter.wordpress.com/

I was especially interested in the rig pictured above.  NOTE:  NO GLOWING NUMERALS.  That rig has an analog VFO.  The blog article provides some great pointers on how to achieve thermal stability.  Also, be sure to check out his "Old School" rig.  

I've put Peter's blog in the blog listing on the right side of the SolderSmoke blog.   

Thursday, May 9, 2019

Book Review: "Man of High Fidelity: Edwin Howard Armstrong" (Free Download)

Dave W2DAB sent me this wonderful book.  He picked up a copy at a recent Columbia University lecture on E. Howard Armstrong.  Written by the notable science writer Lawrence Lessing, the book was first published in 1956.  The paperback copy that Dave sent me came out in 1969; while 50 years old, my copy is in remarkably good shape. 

I really liked the book.  The author captures the technical achievements of  Armstrong, while also describing vividly the world in which Armstrong lived.  Being from the area, I especially liked Lessing's description of New York City and the Hudson Valley in the early years of the 20th century. This was the world of my grandparents; Lessing's book helped me understand it better. 

For the radio amateur, I think the most gripping part of the book is the way Lessing describes  the excitement of early radio.  Armstrong was a true enthusiast for the new technology, and he was -- even as a teenager -- at the cutting edge.  He was constantly striving to improve the technology, especially the receivers.  Like us, he often became obsessed with his radio work, often forgoing sleep and missing family meals as he toiled away in his workshop. Lessing tells us of Armstrong's astonishment and joy, when, upon inventing the regenerative receiver, he was suddenly able to clearly receive signals from distant stations that previously had been barely discernible.  Realize that when he was doing that, he was the only person on the planet who was doing it.  He was the inventor. He was the first. 

Lessing gives us a lot of great information about Armstrong's work as an officer in the U.S. Army Signal Corps in Paris during World War I.  We learn more about how his desire to be able to detect noise from the electrical systems of enemy airplanes led him to the invention of our beloved superhet receivers.   But my favorite Armstrong in WWI story involves his visit to the radio shack of the ship that was carrying him to the war.   In the radio shack he found a conventional station.  But he asked the operator if he happened to have one of the then new audion tubes.  On the spot, Armstrong took the tube and rigged up a regenerative receiver.  He and the ship's radioman then delighted in hearing stations that had never before been audible.   Amazing.     

I was less interested in the sad tale of Armstrong's legal patent battles, so I kind of skimmed through that.  I'm also not much of an FM guy, so I'll save those portions of the book for a later date.  

I think this is an important book about a significant part of radio history.  It is well written.  It gets almost all of the technical details right (but sorry Mr. Lessing,  radio waves are not composed of electrons).  The book deserves a place on the shelf of all radio history libraries.   If you can't get a print copy, an online version can be downloaded here: 

 https://archive.org/details/in.ernet.dli.2015.189098

Thanks again to Dave W2DAB.   

Wednesday, May 8, 2019

"Want one!" F6DMQ's Remote Rig


I talked to Yves F6DMQ last night on 20 meters.  I was on my all-analog BITX20.   Yves was up in Toulouse, operating his station near Cannes via this EXTREMELY COOL remote rig.   He connects to the home station via 4G.   Check out the rest of his station here: 



Tuesday, May 7, 2019

Monday, May 6, 2019

"The Bit Player" A New Movie on Claude Shannon

The Bit Player Trailer from IEEE Information Theory Society on Vimeo.

Thanks to Bob KD4EBM for alerting us to this.  As Bob put it, Shannon definitely had The Knack.  Check out the trailer (above)  for this new movie.   It looks like the IEEE is still working on the release plan for the film.  Does anyone have info on this? 

More info on the film here: https://thebitplayer.com/

Four years ago we reported on a video about Shannon: https://soldersmoke.blogspot.com/2015/09/claude-shannon-had-knack-video.html 

Thanks Bob! 

Sunday, May 5, 2019

SSB on the QCX? Sounds pretty good here (Video)



In SolderSmoke #211 we reported on recent efforts to generate SSB from the QCX CW phasing rig -- we said that we'd heard that the effort wasn't very successful.  But today we got an e-mail from Jim W4JED pointing us to YouTube video from Guido PE1NNZ.  

I must say the signal sounds pretty good to me, and it looks good in the waterfall.  Listen for yourselves via the video above.  His is the signal on the left. 

Guido has a great write up, along with software here: 

https://github.com/threeme3/QCX-SSB 

I hope this all works out -- it would be great to get on phone with Hans Summers' amazing phasing rig. Here is a picture that hints at the potential: 


Go Guido! 



Saturday, May 4, 2019

SDR vs. HDR - Is the Superhet Dead?


Pete N6QW had this very interesting video about Software Defined Radio on his blog.  Thanks to G3WGV for putting this presentation together. 

It is very interesting, but -- for me -- it is also troubling.   I think something important is being missed in this discussion. You have to listen carefully, but if you do the thing being missed becomes apparent. 

Like many others, G3WGV asserts that very soon, 100 percent of commercial radios will be SDR.  Traditional superhet radios will be a thing of the past. 

OK, but I will make a parallel assertion:  Looking ahead, I think 100 percent of TRULY homebrewed rigs will be HDR.  

Of course, this really just comes down to how you define "homebrew."  I'm a traditionalist here.  I think of homebrewing as actually building -- from discrete components -- all the stages that send or receive radio signals.  By my definition, I don't think you can really "homebrew" an SDR radio.  Taking an ADC chip and connecting it to a computer running SDR software is not -- by my definition -- homebrew.  Even if you wrote the software yourself, writing code is not the same as wiring up all the stages that go into a superhet-style transceiver.    

There were a few lines in G3WGV's talk that seemed to confirm this difference:  The SDR radio is defined as a "server." Commercial manufacturers like SDR because they can use the same components that go into cell phones (exactly -- and people will soon have the same relationship with these "radios" that we have with their cell phones). 

I kind of grimaced when G3WGV described the two sets of users of SDR technology: the "early adopters" who are "technology enthusiasts",  and the "pragmatists" who don't care what's in the box -- they just want to talk on it.  I think "pragmatist" is a nice way of saying "appliance operator." Even the "early adopters" are pretty far from the world of traditional homebrew.  And for me that gets to the point that is being missed in all this -- this shift away from hardware is also a shift away from homebrew.   

But hey, this is a hobby.  To each is own!  Have it your way.  For myself, I plan to continue with the hardcore, radical fundamentalist, hardware-defined, discrete component, fully analog homebrew radio.  This morning I am attempting to stabilize a cap and coil VFO.  And I'm liking it.  As the world shifts to SDR, I look forward to the appearance on e-Bay of massive quantities of old forsaken HDR rigs.  We will buy them for pennies on the dollar and use the parts for new HDR Superhet rigs.  

Viva  E. Howard Armstrong!   Viva!   






Need Some Trans-Atlantic Support -- "The Impoverished Radio Experimenter"

A friend in the UK writes: 

I'm looking for volumes 2 and 4 of the "The Impoverished Radio Experimenter" pamphlets. I've searched in the UK for them - they are available but at silly money (nigh on £25.00 each). No sign of any pdf downloads, either. pdf downloads (preferred!) or purchasing at £10 and under would do me fine, if you know any sources?

Any ideas?    Thanks,  Bill 
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column