Pete N6QW and Steve G0FUW Talk to RSGB About Homebrew (Video)

Wow, what an unexpected treat!  Here we can watch Pete N6QW and Steve G0FUW talk to the Radio Society of Great Britain about homebrew radio.  Steve talks about kits and scratch-built rigs.  I really liked seeing his early rigs and his description of how building these rigs helped him become a more advanced homebrewer.  I also liked his mention of George Dobbs as a guiding light in the QRP and homebrew world. 

Pete focuses on SDR and provides a really great description of this approach to homebrew.  I was struck with how great it is that, after a lifetime of HDR building, Pete is willing to embrace this new technology. He talks about it as part of "a learning journey."  As always, he sets the example for us all.   

Thanks to Pete, Steve, and RSGB. 

KLH Model Twenty-One II -- Is My Speaker Dried Out?

A few years back Rogier PA1ZZ very kindly sent me a box of electronics parts.  Included was an FM table-top radio with a nice walnut case.  Thanks Rogier! 

I hadn't looked at the receiver in years, but this week I dusted it off and looked it up on the internet.  Turns out that it is kind of famous.  It was produced by the KLH company.  The K stood for Henry Kloss, one of the giants of Hi-Fi audio gear.  Henry appears in the picture below. 

I got the receiver working, but it sounds awful.  It sounds much better with an external speaker, which is disappointing because the internal speaker was the main attraction of this receiver. It even has a little badge on the front panel trumpeting(!) its "Acoustic Suspension Loudspeaker."

I'm wondering if the problem is in fact the speaker.  The cone looks intact, but it seems very dried out.  It has been more than 50 years...  What do you guys think?  Picture above.  Any other suggestions on what to do with this thing, or how to make it sound better? 

Some KLH history:  

https://klhaudio.com/history

https://antiqueradio.org/KLHModelTwentyOne21FMRadio.htm

KLH receiver with pillow

The Dream of a Shortwave Fiend

 

Thanks to Mark Rowley and Jeff Murray for posting this magazine cover on Facebook.

A Parachute that Flies Home Autonomously

 

Too often ham radio bloggers and podcasters tend to focus their efforts on the projects of, well, older guys like us.  I think it is a good idea to direct attention toward young innovators, the next generations of people who are working on interesting new projects using new technology.  

Yohan Hadji is definitely one of these young innovators.  He is 16 years-old and is working to develop a system that would guide the parachutes of descending balloon payloads to designated safe landing areas.  Having spent a lot of time chasing the parachutes of Estes rockets, and after having to PERSONALLY guide my own parachute to a safe landing area (sometimes without success),  Yohan's project caught my attention.  

The videos above describe the project.  

A Hack-A-Day article provides good background: 

https://hackaday.com/2021/01/07/gps-guided-parachutes-for-high-altitude-balloons/#more-454705

And finally, if you want to support Yohan's work, he has a GoFundMe site: 

https://gofund.me/c0ae8d1f

The Amazing Rigs of WA3TFS

There are a lot of great ideas and circuits on WA3TFS's page.   He spans the SDR-HDR divide.   He makes great use of simple SDR dongles.  Check out his QRZ page and the web site that describes his projects in more detail: 

https://www.qrz.com/db/WA3TFS

https://044640f.netsolhost.com/

An End to the HDR - SDR Conflict? Kevin AA7YQ Combines the Best of Both Worlds

We've had some pretty amazing contact with Kevin AA7YQ over the years.  Kevin and I originally bonded due to our common experience with parachutes  (he was smoke-jumper, I jumped while in the army).  Kevin once used a parachute to insulate a QRSS beacon.   And one day, while thinking about SolderSmoke during a drive through Montana, Kevin turned on his rig only to hear... ME!  He caught one of my infrequent CW contacts. TRGHS.  

Now we hear that OM Kevin may be poised to end the HDR-SDR civil war that has for so long been dividing our great podcast.  Can Kevin's new rig heal our wounds and allow us to enjoy the beauty of SDR waterfalls while not forsaking the joy of hardware defined rigs?   Kevin will soon launch a blog describing his effort at rig-building. See below for a preview.  Stay tuned.  

Kevin wrote: 

I am currently working on a new rig design.  It is a hybrid HDR(Hardware defined)/SDR radio that incorporates some classic superhet design along with some of the more useful features of SDR.  I have found that pure SDR is really not that enjoyable for me.  I love using GNU radio to mock up and test design concepts, but SDR basically dilutes the “magic” of radio to nothing more than software and touchscreens, stuff we use every day all day.  Its not the Ham Radio I grew up with as a kid and was fascinated by.  On the other hand, I have always fought temperature drift, large variable capacitors minimal tuning range, and associated with classic VFO and VXO designs.  In fact, in 1997, for my senior capstone design in EE at Montana State University, I designed a 20m superhet that used a DDS LO.  At the time DDS was cutting edge technology I used an AD7008JP50.  I had to beg and plead with ADI to get a couple samples for my design, since they exceeded my self-funded college student project budget. 😊  But that’s another story.  SDR has made me grow extremely fond of the waterfall display.  I love having the visual “situational awareness”  of what is going on in a moderate bandwidth outside of the spot I am tuned to. I also am a big fan of digital filtering and modification-ability that comes with boot-loadable microcontroller designs.  So this design includes most of the real highlights of SDR but does not take the fun out of designing,  building, and operating a HDR.

Anyhow, this design is a big goal of mine to complete and build in 2021.  I am not retired yet so I still have to balance, work, family, and tinkering time, but I am very excited about this project.  I have “noodled” this design to the point of what I have achieved full-on “analysis paralysis”.  That is, I keep designing and redesigning, optimizing, and figuring to the point where after months of thought, I have nothing to show for it 😊.  So my New Years goal for 2021 is to make “good enough” rather than “perfect” design decisions and move forward.  I will keep you posted on the design and possibly start a blog so I can get some peer review input from the greater RF Design/Homebrew community on my project.  I’ll keep you informed on my progress.

Glowing Numerals for the Lafayette HA-600A (With Jeweled Movements)

 

I really like this receiver.  I have strong sentimental ties: it was my first SW receiver.  But the frequency readout situation was kind of rough -- depending on where you put the Main Tuning cap, your Band Spread dial could be WAY off.  

China to the rescue!  Specifically the very nice San Jian PLJ-6 frequency counter boards.  I have used these in several projects.  I like them a lot. I get mine on e-bay.  They are very cheap.  Here is the manual with specs: 

https://www.mpja.com/download/35057tebasic%20manual.pdf

As I did with my BITX20, I put mine in an Altoids-sized box.  I got to use my Goxawee rotary tool with circular metal blade to cut the rectangular hole.  Hopefully future efforts will yield neater results, but the flying sparks were fun;  they made me feel like one of those car-part  "fabricators" on cable TV. 

To tap the VFO frequency, I just put a bit of small coax at the point where the 10 pf cap from the VFO circuit enters the first mixer.  I ran this cable to the unused "Tape Recorder" jack on the back of the Lafayette -- this connects to the input of the counter.  I attached 11 volts from the power supply to an unused terminal on the accessory jack of the Lafayette -- this powers the counter.

Having a counter on the VFO proved very illuminating -- in more ways than one.  I measured the Center Frequency (CF) of my IF to be at 456 kHz.  I set the PLJ-6 to display the VFO frequency MINUS 465 kHz.   For AM broadcast signals, this worked fine:  I'd tune the signal for peak S-meter reading.  This meant that the carried was right at the CF.  

For SSB, things were a bit different.  I set the BFO knob  to be RIGHT AT 465 kHz when the dot is in the center position.  With the BFO there, I could tune in SSB signals.  The suppressed carrier would be right at the center of the IF passband, with the audio information above or below the suppressed  carrier frequency.  But it didn't sound good this way -- it sounded better if I would tune an LSB signal 2 kHz down from the center, then adjust the BFO down about 2 kHz.  This put most of the the audio in the peak portion of the IF filter(s) curve.  Doing it this way means that I have to remember that the number displayed on the PLJ-6 is 2 kHz down from the actual suppressed carrier frequency of the transmitting station.  I can live with that.  

I am going to leave the Lafayette on the corner of my workbench so that I can easily tune in hams  and SW broadcast stations.  Having modified the product detector and added the digital frequency readout makes listening to this receiver even more pleasing.  The jeweled movements are as smooth as ever. 

So 2021 is off to a good start on my workbench.  HNY to all!  

So Many Wonderful Things on W7ZOI's Site

 

There he is.  Wes Hayward, W7ZOI in 1957.  I had never seen this picture before.  I found it on Wes's recently updated "shackviews" web page: http://w7zoi.net/shackviews.html . 

There are so  many treasures on that page, and on all the other portions of Wes's site.

Some highlights for me: 

-- Wes's description of the station in the above picture. 

-- On his page about Doug DeMaw, Wes mentions that after Doug edited Wes's 1968 article about direct conversion receivers, Doug built some himself, experimenting with different product detector circuits. Having used Doug's mixer circuit in many of my rigs, and having recently experimented with different product detectors for my HA-600A, I kind of felt like Doug was watching over my shoulder, guiding me along as I experimented. 

-- Wes's use of a digital Rigol oscilloscope.  Makes me feel better about giving up on my Tek 465. 

-- The page about Farhan's visit to Wes, and the awesome gathering of homebrew Titans that ensued... 

-- Wes's meeting with Chuck Adams.  

Thanks Wes.  Happy New Year and best of luck in 2021!  

Ross Hull and Clinton DeSoto -- Ham Radio and R/C Planes

Rogier PA1ZZ sent me a video that linked Ross Hull and Clinton DeSoto to the development of today's killer drones.  While it looks like that is quite a stretch (I'm sure Rogier would agree), the involvement of these two radio guys in the early development of radio-controlled planes is very interesting.  

An article, “Radio Control of Model Aircraft,” by Ross A. Hull and Roland B. Bourne, was the first to describe in detail a working radio system suitable for model aircraft.  They wrote: “Most hams are usually far from being one-hobby men and one discovers, almost invariably, an interest in the other sciences and the crafts. A common interest in ham radio, aeronautics, model building, and photography is almost the rule. We happen to be built that way and our interest in aircraft led us, this summer, to take an active interest in this problem of radio control.” (QST, October, 1937) 

More here: 

https://jmrc.tripod.com/fa/days/days_2.htm

And here: 

 https://ethw.org/Ross_A._Hull

Listen to this! The Kearsarge Mountain Transmission System -- Winter Test Transmission -- 9670 kHz

This is a bit mysterious, but I think that is part of the allure.  Last week reports began to surface on reddit about a shortwave test transmission from a group called the Kearsarge Mountain Transmission System.  Kearsarge Mountain is in New Hampshire. Thomas K4SWL over at the SWLing Post Blog posted a link to a SoundCloud recording of the transmission:     

https://soundcloud.com/user-25048993/kmts-winter-test-transmission-9670-khz-17122020

I don't really know much about the origins of this recording, but -- like Thomas -- I really like it.  It is EXACTLY what you need to have playing in the background as you work on some piece of radio gear.  Trust me on this:  If you are a radio person, you WILL like this.   Have a listen at the link above. 

Here are some excerpts from the reddit posts on this: 

Notice of a KTMS winter test transmission beaming to Europe/USA on 9670 kHz at 2300 UTC on 17.12.2020. This transmission will consist of interval jingles, engineer test signals, rare re-media mixes of cult radio favorites, strange tones, and vox. Thank you for your continued attention as the KTMS crew continue working to bring the SWL community unique transmissions.

Our aim as the programmers of the KTMS Test Transmission is to entertain, edify and get SWLs excited about the possibilities inherent in radio. The crew of KTMS consists of amateur radio operators, community and college radio aficionados, antique radio restorationists, low budget radio astronomers looking for alien life and in general people who love the hobby of radio in all its many faceted aspects.

People who put their own funds towards creating radio on the shortwaves are helping to keep the shortwaves interesting and alive and bringing programming that is original and idiosyncratic to a medium that is often otherwise overrun by nationalists, spies, and fundamentalist preachers. They also help to keep shortwave stations on the air -something that ain’t so cheap. Rather, our view, is that by injecting some creative energy into a project such as our KTMS Winter Test Transmission we are giving back to the SWLing community by 1) creating a show for any listeners who happen to catch it, 2) giving the listeners a mystery that doesn’t revolve around numbers, 3) to do our part to keep the airwaves a little less stodgy.

We view this Test Transmission as an exercise in conviviality, surreality, and genuine love of all things radio and shortwave. 2020 has been such a serious minded year we aim to lighten that load with a bit of old fashioned fun.

For anyone who wishes to enjoy a nice winter evening around your set or online SDR we welcome you to get warm with us around the glowing tubes.

Thanks to all who tune in, and until then 73s.

Observations from the Mars 2020 Opposition

 

These are some of the drawings that I made during the Mars 2020 opposition. I would go out to my back porch with my 6 inch Dobsonian Newtonian telescope.  I would look closely at Mars, making mental note of what I was seeing. Then I would go to the shack and immediately draw what I'd seen. I would then look for relatively recent images of Mars made by people with more experience and better equipment, and I'd compare my drawings with their images -- this enabled me to understand what I was seeing.  Also useful was the Mars Profiler of Sky and Telescope magazine -- you just plug in the date and time and it displays the part of Mars that is facing us. 

I was especially pleased with the drawing and image above because I'd been reading a lot about the Hellas impact crater in Kim Stanley Robinson's Mars Trilogy.   (SCP should be SPC = Southern Polar Cap.)  

I came to think of this as the "M of Mars."  I think it is just Mare Cimmerium, Mare Hesperia, and Mare Tyrrhenum. 

bcastropics.com made this illustration of how Mars's apparent size has changed

The Parkes Radio Telescope Picks Up a Possible "Wow" Signal from Proxima Centauri (maybe)

An article about SETI and our favorite dish.  From Scientific American:  

https://www.scientificamerican.com/article/alien-hunters-discover-mysterious-signal-from-proxima-centauri/