VE7SL's Beautiful Single Tube Transmitter and Single Tube Regen Receiver

Just stunning, in their simplicity and beauty.  Really amazing work.  Kind of reminiscent of my ET-2, but with tubes, and much nicer construction.  More details here: 

RECEIVER: https://qsl.net/ve7sl/neophyte.html

TRANSMITTER: https://qsl.net/ve7sl/neotx.html?fbclid=IwAR3cM6tSRjyTsNouHWVz_buuzz4C9O-IwQbdZM5dekkle69ZW7-JBQcHTVI

Three cheers for Steve VE7SL!  I've been linking to his blog for several years, but somehow I missed this magnificent red rig.   

Steve's online notebook: https://www.qsl.net/ve7sl/

Steve's blog: http://ve7sl.blogspot.com/

Video: N2CQR Talks About Homebrew SSB with The Vienna Wireless Society's Makers Group

It must have been great to have been a ham during the heyday of homebrew gear.  Imagine walking into your local club and finding a dozen or so people who share your passion for melting solder and homebrewing your own equipment.  Well, I got a taste of that thanks to the Vienna Wireless Society's Makers Group.  Led by Dean KK4DAS, this group of intrepid radio amateurs has built versions of Pete Juliano's Simple SSB transceiver.  They are finalizing the rigs; many are already finished.  And I could tell from the questions and the discussion that I was talking to a bunch of guys who knew which end of the soldering iron to grab.  It was really wonderful to talk to people who had gone through the experience of building an SSB transceiver, who knew from personal experience that it is not as easy as it seems. And I could tell from the questions that many of these guys are already thinking of their next projects, of how to put to use the experience they gained building Pete's SSB rig. 

Dean asked me to talk to the group about my recently completed "Mythbuster" rig.  This was a good topic for the group because my rig is similar enough to the Simple SSB that they could relate to it, but different enough that it could give them ideas about how they might do things differently next time. 

I really enjoyed this session.  I'm glad that VWS captured it on video.  I think SolderSmoke listeners and readers will like watching this video.  

Thanks to Dean KK4DAS and the VWS Makers group for hosting me.  And thanks to Jacek KW4EP for helping with the video. 

Here is the Vienna Wireless Society's YouTube Channel: 

https://www.youtube.com/c/ViennaWirelessSociety

Great News for Homebrewers: JF1OZL's Amazing Web Site is Back!

I was very happy to read this morning (on the G-QRP e-mail list) that the amazingly useful web site of Homebrew Hero Kazuhiro Sunamora has been resurrected after too many years in 404 status. 

Here it is:

https://www.qrp-ja.net/jf1ozl/index.html 

There is a LOT of tribal knowledge and lot of great ideas on his site.  Kazuhiro-san has apparently quit wireless, but is climbing mountains near his home.  We hope is doing well and that he will someday return to radio (perhaps for the peak of cycle 25).  

We last posted about him back in 2011.  In the comments to that post you can see the sad news about the demise of his web site (which is now back on the web): 

http://soldersmoke.blogspot.com/2011/12/homebrew-hero-kazuhiro-sunamura-jf1ozl.html

JF1OZL's bio: 

My name is Kazuhiro Sunamura. I am a 50 year old mechanical engineer, born in 1956. I am not an engineer in electronics. I have been interested in electricity and radio from the age of ten. For the last ten years, I have been active on my ham radio station JF10ZL. I have also written articles about my some of my radio projects in Japanese for the Japanese CQ Magazine. Now I have decided to get onto the internet and will take the opportunity of showing you my equipment and ideas. Please have a look at my schematics. I will be very happy if this material helps you with your own radio projects. I am a member of the J.A.R.L. affiliated Tsuchiura Club, the local ham club in my home town.

Some Initial Thoughts on FT-8

 -- This is really interesting technology.  Three cheers for Joe Taylor and colleagues.  This mode would obviously be very useful for fast, weak signal contacts as are needed on meteor scatter or EME. 

-- FT-8 does give you the chance to work DX that would have been difficult on other modes. 

-- Chinese hams showing up on FT-8 -- more than other modes. 

-- I think FT-8 is good for hams who just want to have a lot of "contacts." It is definitely not for the rag-chewer. 

--  I find it it kind of cold and antisocial.  More like a computer game than ham radio. A bit like sending  short text messages on a cell phone. 

--  I think FT-8 contacts are in some ways more meaningless than a "59!" contest exchange -- unless you look, you don't even know the report you got,  nor do you know the report you sent. 

--  For me it is more impersonal than CW.  But at least we let the technology decode the characters instead of having to memorize dot and dash sounds.  In a phone contact you can hear the other person's laugh.  In a CW QSO, you hear him key "HI HI."  FT-8?  No laughter at all. 

-- With PSK Reporter, FT-8 gives you a good feel for how propagation changes during the day. But it is kind of like 2-way WSPR.  As with WSPR, it is -- at first -- fascinating, but then it loses its charm. Yes, everyday you are heard in Belgium. 

-- It seems to be getting kind of crowded.  The passband for FT-8 contacts is often full, and it is hard to find an open space.

-- There is little opportunity for the homebrewer.  I hooked it up to my homebrew transceivers and had a small bit of fun using a 2N3904 as a switch triggered by the RTS signal for T/R.  But that's about it. 

-- I get the sense that the ham himself is not really needed in FT-8.  This mode seems like it could easily be automated or run by an AI.  Just tell it to go out there, make a lot of contacts and log them.  Maybe prioritize the DX you "need."  Has this already been done? 

--  After a session with FT-8, I had a really nice 17 meter ragchew SSB QSO.  That SSB contact left me happy.  The FT-8 session was a bit like spending time on social media or a video game.  It left me edgy.  FT-8 made me appreciate phone even more.

But hey, to each his own.  A lot of people really like FT-8.  I hope they have fun. 

Opening up an Apollo Command Module Microwave Radio System

So much radio goodness in this video.  The enthusiasm of the narrator is unmistakable, and entirely justified. 

A number of things struck me: 

-- Nice shout out to our beloved Parkes Radio Telescope, of  "The Dish" fame. 

-- I like how the French narrator takes some friendly jabs at out use of "archaic British measuring units," and his skillful use of American slang" "Let's open up these bad boys!" 

-- Wow, they filled the radio cases with Nitrogen!  That will definitely save you  money on De-Oxit! 

-- When they opened up the boxes, the construction looked very similar to what I found inside my HP-8640B frequency generator.   

-- Collins built some of this stuff.  

-- 11.6 watts to transmit the TV signal from the moon. 

-- PLL.  

-- A tube type amplifier.  

--- Lots of SMA connectors, but many BNCs also, right? 

-- Finally, and this is really amazing:  THEY HAD A MORSE KEY WITH THEM, JUST IN CASE. 

Thanks a lot to Bob, KD4EBM for sending this to us.  There will be more episodes.  These guys intend to fire up the equipment. 

Much SSB Tribal Knowledge in Bill Orr's 1959 Handbook

 

There is a lot of really excellent information and tribal knowledge in the 1959 issue of Bill Orr's Radio Handbook.  I was especially taken by Chapter 17 (SSB) and Chapter 28 (Low Power Transmitters and Exciters).  

Looking at the 1959 SSB rigs, I don't see any information that points to the origin of the LSB/USB convention.  Most of these rigs -- especially the phasing rigs -- include provisions for switching to either sideband.  

Check out the "Glove Compartment Sideband Exciter." 

Here is the link to the Orr book: 

http://www.rsp-italy.it/Electronics/Books/_contents/radio/The%20radio%20handbook%2015th%20-%20William%20I%20Orr%20-%201959.pdf

Thanks to Tony K3DY for sending us the link that led us to this book.  There are many other great books there: http://www.rsp-italy.it/Electronics/Books/indexhtm 

SolderSmoke Goes FT-8 (Briefly, I Think)

 

Idle hands are the devil's workshop my friends.  I was home alone this week, and kind of ran out of things to do.  I started thinking about all those signals on the FT-8 frequencies that I'd hear when the rest of the band was vacant. You know how it is:  One thing leads to another.  I remembered that Rogier  PA1ZZ had sent me some interface boards.  Soon I was downloading WSJTX.  Then I bought a USB-Serial converter from Bezos.  

I hit a major bump in the road when I managed to destroy the little optocoupler that the interface board used for T/R switching.  No big deal though -- Pete has a simpler T/R circuit that worked fine: 

I even made it a bit simpler -- instead of putting an SPDT relay on the Collector of the 2N3904, I just ran a lead to the PTT terminal on my BITX mic input connector.   This terminal just takes one side of the BITX TR relay to ground on transmit.  With Pete's circuit, the RTS signal from the computer causes the 2N3904 to conduct, in effect grounding the BITX T/R relay. Bob is your uncle.  Building this little circuit was fun. 

I used the 600-600 Ohm  AF transformers on Rogier's interface board.  I scrounged up the appropriate connectors and soon I was on 17 meter FT-8.  After about an hour of casual operating (mouse clicking, really) I'd worked HC1HC, HI8CJG, DK4RL, J69DS, F5NBQ, PT2ADM, 8P6ET, KP4JRS, XE2YWH, F4DIA, EA4R, CO3DK, and HI3MRV.    All this while no SSB signals were heard on the band. I was running about 50 watts to my 75 meter doublet tuned to 17. 

The amount of DX you can work is impressive, but I don't know if I'll stick with this mode.  It kind of reminds me of 2-way WSPR.  I find myself wanting to TALK to the DX stations.   FT-8 doesn't let you do that.  But hey, I am not alone in trying out FT-8.  In fact, one of the very first calls that I saw on my screen was the very familiar KB1GMX.  That is Allison, a true radio genius.  That's a good sign.  So maybe I'll have to give FT-8 more of a chance. 

The HBR-13C Receiver and the Poetic License of Homebrewers

I've been hanging out on 17 meters with my homebrew VXO-controlled BITX transceiver.  The antenna is my 75 meter doublet fed with window line through a homebrew tuner made from dead ( I swear) DX-40s and DX-60s. I can tune it up just fine on 17 meters, but I realize I probably have lots of nulls and lobes in the radiation pattern.  Apparently one of the lobes is over my old stomping grounds in Panama.  Almost everyday I talk to either HP9SAM or HP3SS. 

Robby, HP3SS, is using SDR gear now, but he was a real homebrewer back in the day.  Years ago he built an HBR-13C receiver. That's quite an achievement. 

Robby -- formerly VY2SS -- told me that he sold his HBR-13C to none other than Joe Walsh, the rockstar from The Eagles.  FB. 

As I was talking to Robby yesterday, I came across this wonderful web page about the receiver: 

https://sparcradio.ca/wp-content/uploads/2015/12/Restoring-a-HBR-13-Amateur-Receiver.pdf

Robby told me that his receiver looked almost exactly like the one on the SPARC site, but he didn't recognize the small box with what looked like a speaker on the chassis.  I told him that my guess was that this was a crystal calibrator in an oven. 

I also told Robby that I feel an affinity with the HBR project, not just because I like homebrew superhets, but also because my call in the UK was M0HBR.  

There are some great quotes in the SPARC pdf: 

The SPARC page led me to the amazing website of Kees K5BCQ: 

https://www.qsl.net/k5bcq/HBR/hbr.html

Here is Kees's QRZ page: 

https://www.qsl.net/k5bcq/

Drake 2-B Advertisement

A thing of beauty. 

So Where DID the LSB/USB Convention Come From?

-- Bottom line:   I still don't know why ham radio adopted as a convention LSB below 10 MHz and USB above 10 MHz.  There are several theories. but so far there is no convincing explanation in favor of any one of them. And almost all of the people involved are probably Silent Keys by now; this makes it more difficult to gather first-hand information. 

-- I'm not even sure when the convention began to be observed in ham radio. Many of the early SSB books and articles make no mention of it. We don't see it in early ARRL Handbooks. The first mention of it that I found was in the 1965 issue of the ARRL's "Single Sideband for the Radio Amateur" page 8. This article claims that adding a provision for selectable sidebands would "add appreciably to the cost of the equipment. " It went on to say that,  "For this and other reasons there has been a species of standardization on the particular sideband used in the various amateur bands. Nearly all operations in the 3.5 and 7 Mc. phone sub-allocation is on lower sideband, while the upper sideband is used on 14, 21, and 28 Mc."  

-- We know that the informal convention was being followed as early as 1958.  Jim N2EY reports that in 1958, the manual for the Central Electronics 20A shows that LSB was the "sideband most commonly used" on 75, with USB preferred on 20:

-- Some cite a 1959 ITU recommendation on commercial multiplexed radiotelephony as the reason for the convention.  But I don't think this obscure and long-ago ruling explains the convention.  If this were the case, we'd  see follow-up FCC regulation, and at least some discussion of the ITU recommendation in the amateur radio literature.  But we see none of this.  And, as noted above, by 1958 hams were ALREADY -- on their own -- opting to use LSB on 75 and USB on 20.   The 1965 ARRL SSB book refers not to some hard-and-fast rule, but rather to  "a species of standardization" on LSB and SSB.  That ARRL book said nothing of the 1959 ITU recommendation. 

-- There is a widely held belief that this practice originated in the design of a rig that had a 5.2 MHz VFO and a 9 MHz filter.  According to this theory such a rig -- due to sideband inversion -- would produce LSB on 75 meters and USB on 20.  But, as we have demonstrated, this doesn't work, so this theory has to be discounted. 

-- Early SSB activity seems to have been concentrated on 75 meters, and there was a competition for space with AM stations.   SSB operators appear to have used the very upper band edge as their gathering spot.  Using LSB allowed them to operate very close to the upper band edge -- a lot closer than AM stations could go.  This may explain why LSB became the preferred SSB mode on 75.  But how do we explain USB on 20 and above?  That remains a mystery. 

-- It is important to remember that in the early days of SSB, for most hams there were only two important phone bands: 75 meters and 20 meters.  40 meters was CW only until 1952, and even after that was crowded with shortwave broadcast stations.   So a design that allowed for both 75 and 20 was twice as good as a monoband design. 

-- Early on there were designs and parts for phasing rigs.  You could take that ARC-5 VFO at 5 MHz, build a phasing generator around it, and then mix it with a 9 MHz to get on either band.  But with just a simple switch, this kind of rig could operate on USB or LSB on either band.  So the early popularity of this kid of rig does not explain the convention. 

-- There were a lot of surplus 5 MHz ARC-5 VFOs available. There were also FT-243 and FT-241 surplus crystals at both 5 MHz and 9 MHz that could be made into filters.  Later in the 1950s, 9 MHz commercial crystal filters became available.  If you used a 9 MHz filter with a 5 MHz VFO, there would be no sideband inversion in your rig.  If the SSB generator was putting out LSB on 9 MHz, you'd be on LSB on both bands.  So if there was a desire to have LSB on 75, why not just also have LSB on 20? 

-- But if you built a 5.2 MHz filter and a 9 MHz VFO,  you could have LSB on 75 and USB on 20 without having to shift the carrier oscillator frequency.  This would save you the trouble and expense of moving the carrier oscillator/BFO to the other side of the passband.  This desire to economize and simplify may explain why we ended up with LSB on 75 and USB on 20.  But this still begs the question: Why the desire for USB on 20?  

-- Both the manufacturers and the hams wanted there to be sideband standardization.  With monoband rigs, the manufacturers would be able to cut costs by building for only one sideband.  Hams also wanted to cut costs, and they did not want to have to figure out which sideband a station was on when trying to tune him in. 

-- By 1962-1963  Swan and Heathkit were selling mono-band SSB transceivers that used the "conventional" sidebands:  The rigs for 75 and 40 meters were on LSB while the 20 meter rigs were on USB.  There were no provisions for switching to the other sideband. This seems to have reinforced the practice of observing the convention.   (Heath later added sideband switching to the HW monobanders -- in view of the growing observation of the convention, they may have been better off sticking with their original design. Does anyone know why they did this?)  But again, why USB on 20 and above? 

--  In 1963, Swan, by then in Oceanside California, came out with the Swan 240.   Swan used a filter centered at 5174.5 kc. The VFO ran from 8953 kc to 9193 kc on 75 and 20.  The VFO ran from 12222 to 12493 on 40.  This gave the buyer 75 and 40 on LSB, and 20 USB with only one carrier oscillator frequency. (Swan offered a mod that allowed hams to install an additional, switchable carrier oscillator frequency.  I luckily acquired one such modified rig.)  But again, there is an explanation for LSB on 75, but why USB on 20 and above?

This is an important part of ham radio history.   There should be a clear answer.  We need to find it.   If anyone has any good info on this, please let me know.  

Simple SSB Success in Northern Virginia -- "The Radio Does Not Build Itself...."

Dean KK4DAS and the Vienna Wireless Society (VWS) Builders Group have had some remarkable success with Pete Juliano's Simple SSB design.  Sixteen of the rigs have reached the point where the receivers are fully functional.  Eight more have gone the final (!) stretch and have the full transceivers working.  This week Dean and two other VWS builders met up on 40 meters for the world's first multi-SSSB QSO (see Dean's video in the link below). 

https://kk4das.blogspot.com/2021/09/simplessb-three-way-qso.html

Here's Dean's presentation to the club describing the project and Pete's rig: 

https://docs.google.com/presentation/d/1eUFEO3mZNrwdwaZnyPzr5G6ooozxFoU7/edit?usp=sharing&ouid=100787991139259592659&rtpof=true&sd=true

As Pete says, "The radio does not build itself..."   Indeed it doesn't!  The VWS builders made these rigs.   FB! 

Visiting the Site of Marconi's Wireless Station at Wellfleet, Massachusetts

 

We were in Boston and the Cape Cod area this week.  We stopped off at the Marconi Wireless site at Wellfleet, Mass.   

This is from the National Park Service web site: 

Spanning the Ocean

For Marconi the ‘great thing’ was to transmit wireless signals across the Atlantic. He built stations at Poldhu, England, Glace Bay, Nova Scotia, and South Wellfleet, Massachusetts. At this stage of wireless technology relatively long electromagnetic waves were used as signals. Transmitting great distances, therefore, required great sensitivity of receivers and tremendous power. Originally, huge rings of masts were installed to support the needed antennas. When storms destroyed them, they were replaced by sets of four wooden towers, 210 feet in height. Power requirements were tremendous. Keroseneburning engines produced 2,200 volts. When fed to a Tesla transformer, the voltage was stepped up to 25,000 volts – the energy needed to transmit longwave signals so far. It was from the Glace Bay station that the first successful two-way transatlantic wireless test message was sent on December 17, 1902.

 

The original wireless array.

Impacting Lives

January 18, 1903 the first public two-way wireless communication between Europe and America occurred. With elation, communiques from President Theodore Roosevelt and King Edward VII were translated into international Morse code at the South Wellfleet and English stations, respectively, and were broadcast.

Ocean-going vessels quickly adopted Marconi apparatus to receive news broadcasts, and soon ship-to-shore transmittals were a major operation. Business and social messages could be sent for fifty cents a word. The South Wellfleet station became the lead North American facility for this function. The station’s effectiveness was limited however, so broadcasts were made between 10 pm and 2 am when atmospheric conditions were best.

This brought little enthusiasm from local residents, who endured the sounds of the crashing spark from the great three-foot rotor supplied with 30,000 watts. The sound of the spark could be heard four miles downwind from the station. Eventually, the novelty of wireless telegraphy waned. However, the need for communication at sea remained high. Effective communication resulted in numerous sea rescues, culminating in the Carpathia’s wireless-aided rescue of over 700 people from the Titanic in 1912.

For fifteen years the South Wellfleet sparkgap transmitter continued in commercial use. Skilled telegraphers sent out messages at the rate of 17 words a minute, and station CC (Cape Cod) served in effect as the first “Voice of America.”

https://www.nps.gov/caco/learn/historyculture/marconi.htm

SST -- QRP On The Beach

Up in a beach house on Cape Cod Bay in Massachusetts, I put the SST on 20 meters using an End-fed Half Wave antenna and QRP-guys tuner.  Conditions were pretty bad, with solar storms causing disturbances in propagation, but I did manage to get picked up by RBN skimmers in Iceland, Germany and Italy (see below).  And I had one nice QRP-QRP contact with DK4AN.

I was having trouble getting out until I used the oar to raise the central portion of the half wave antenna -- that's where the current is. 

Thanks again to Bob KD4EBM for sending me the SST.  

Cosmic Rays, Bit Flips, and Computer Vulnerability

Here is a very interesting video about a problem that many of us have been blissfully unaware. 

You can see the role played by the solar cycle.  This is the subject of some on-going research by the folks who put out the SpaceWeather.com web site.  They have been flying balloons to measure high altitude cosmic rays: 

I've been meaning to build a cloud chamber for a long time.  I recently discovered that my local 

supermarket sells dry ice... 

Thanks to Dave, K8WPE for alerting us to this video.  

1BCG -- 1921 Transatlantic Test and the Upcoming 100th Anniversary

In December 2021 we will reach the 100th Anniversary of the famous Transatlantic Test that marked the first crossing of the Atlantic by radio amateurs.  The video above provides a really excellent description of the momentous event. A few things struck me: 

-- Even then they struggled with amplifiers that wanted to oscillate. 

-- Armstrong should have gotten more credit for the transmitter design.  After all, it was his regenerative system that gave rise to the kind of oscillators that allowed for CW (vice spark) and that formed the basis of the MOPA transmitter that these fellows used. 

-- The info on the Superhet receiver used by Paul Godley in Scotland was really interesting:  It used   "resistance-coupled amplifiers without transformers," similar to what we have today in Farhan's BITX transceivers. 

-- Wow, Harold Beverage himself! And his antenna was used at the Scotland receiving station. 

-- "It was a miracle that no one got mixed up with the high voltage."  Indeed.  

The Antique Wireless Association has built a replica of the 1921 transmitter.  The video below shows it being tested. 

 

The 1BCG website announces that: 

On December 11, 2021 the American Radio Relay League, The Radio Club of America and the Antique Wireless Association will recreate these historic transmissions on 160 meters near the same location that was used in 1921, using a replica transmitter constructed by volunteers at the Antique Wireless Association. This special event is your opportunity to relive a historic moment in amateur radio history.

The operating schedule and frequency for the 1BCG Transatlantic Tests Special Event has not been established.

Additional details will be posted here when they are available.

http://1bcg.org/1BCG/

A Public Service Announcement

 

Only YOU can prevent reverse polarity accidents! 

Thank you Jeff Murray.

SSB History -- The Tucker Tin 2 (and 3) with a 1961 Recording. Hallicrafters FPM-200 Video by W9RAN

There is so much important SSB history in this video from Bob Nichols, W9RAN.  I liked all of it,  but the on-the-air recording of a 1961 transmission from a Tucker Tin 3 was really amazing.  Check it out. 

Here is the 2014 SolderSmoke blog post about the Tucker Tin 2. You can see the 1961 schematic here: 

https://soldersmoke.blogspot.com/2014/09/kiwi-lunchbox-sideband-tucker-tin-two.html

As you can see this is a very simple phasing-type SSB rig.  The SSB generator is crystal controlled at the operating frequency.  

Thanks to Bob W9RAN, and thanks to Peter Parker VK3YE for posting about this video on the SolderSmoke Facebook Page. 

 

The Chatham Islands

Kintsugi -- A Japanese Philosophy for the Owners of Imperfect Rigs

 On Sun, Aug 29, 2021 at 4:05 PM Bob Scott wrote:

Hi Bill:

   After listening to the latest Soldersmoke I thought you might find the Japanese concept of "kintsugi" (literally "golden joinery") interesting.  

 

    From Wikipedia:  https://en.wikipedia.org/wiki/Kintsugi#Philosophy

       As a philosophy, kintsugi is similar to the Japanese philosophy of wabi-sabi, an embracing of the flawed or imperfect.[11][12] Japanese aesthetics values marks of wear from the use of an object. This can be seen as a rationale for keeping an object around even after it has broken and as a justification of kintsugi itself, highlighting the cracks and repairs as simply an event in the life of an object rather than allowing its service to end at the time of its damage or breakage, and can be seen as a variant of the adage "Waste not, want not".[13]

  Kintsugi can relate to the Japanese philosophy of mushin (無心, "no mind"), which encompasses the concepts of non-attachment, acceptance of change, and fate as aspects of human life.[14]
 

  Not only is there no attempt to hide the damage, but the repair is literally illuminated... a kind of physical expression of the spirit of mushin....Mushin is often literally translated as "no mind," but carries connotations of fully existing within the moment, of non-attachment, of equanimity amid changing conditions. ...The vicissitudes of existence over time, to which all humans are susceptible, could not be clearer than in the breaks, the knocks, and the shattering to which ceramic ware too is subject. This poignancy or aesthetic of existence has been known in Japan as mono no aware, a compassionate sensitivity, or perhaps identification with, [things] outside oneself.

 — Christy Bartlett, Flickwerk: The Aesthetics of Mended Japanese Ceramics

73,

  Bob KD4EBM

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

I shared Bob's Kintsugi message with David, WA1LBP.  David was one of the few radio amateurs in the ranks of the Foreign Service.  He was in Okinawa during the early 1990s, when I was in Santo Domingo.  For a time we both wrote columns in the "73 International" section of Wayne Green's magazine -- this made us "Hambassadors."  David is a real scholar of difficult Asian languages.  During my last years in government service I would sometimes cross paths with David at lunch time on the National Mall in Washington -- he'd be out there with a colleague, studying ancient Chinese poetry. 

Here are David's thoughts on this: 

Thanks,  Hambassador Bill.

In Buddhism, muxin (in Chinese wuxin) is about freeing oneself from troubling thoughts, distractions, and selfishness and so attaining a calmness that is very aware of all that goes on at the same time.  I suppose once free from distractions one can be more alert.  So maybe not literally no mind but no-selfish-obsessed-mind

Amazing what one can find online. A distraction too I suppose!

https://plato.stanford.edu/entries/buddhism-chan/

Chan embraced this account of nonduality and Buddha-nature, but distinctively used it to qualify the meaning of Buddhist practice and the personal ideal of the bodhisattva. In the Platform Sutra attributed to Huineng, he insists that

meditation is the embodiment (ti) of wisdom, and wisdom is the functioning (yong) of meditation.

The point of Chan is to see one’s own “original nature” (benxing, 本性) and realize “authentic heartmind” (zhenxin, 眞心), and in doing so the dualities of thought and reality, of passion and enlightenment, and of the impure and pure all dissolve. Then,

true suchness (zhenru, 真如) is the embodied structure (ti) of thinking, while thinking is the functioning (yong) of true suchness. (Platform Sutra, 13–17)

To see our own original nature is to see that true suchness and thinking are as intimately related as the bodily structure of a horse and its customary activities. Just as the bodily structure of the horse establishes the conditions of possibility for grazing and galloping, it is only the proven evolutionary advantage of grazing and galloping in horse-like ways that have made this bodily structure possible. True suchness or ultimate reality is not a preexistent something “out there” that can be grasped intellectually or accessed through some mystical vision; it can only be enacted.

Huangbo Yixun (d. 850) describes this as demonstrating no-“mind” (wuxin, 無心) or freedom from conceptual impositions that would define or limit reality. But this is not a lapse into mental blankness or indiscriminate presence. Realizing no-“mind” restores our originally whole mind (yixin, 一心) that Huangbo qualifies as the “silent bond” (moqi, 默契) of “conducting oneself as all Buddhas have” (in Taishō shinshō daizūkyu, Vol.48, 2012.380b to 383c). Significantly, the term “qi” originally referred to notches or tally marks on a strip of bamboo that record the terms of a trade agreement and the bonding that Huangbo invokes is thus one of mutually entrusted obligation and responsibility. True suchness consists in the personification of the bodhisattva ideal of realizing liberating forms of relationality. Ultimate reality consists in enacting the morally-inflected nonduality of wisdom and compassion.

David 

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

I remember that it was George Dobbs, G3RJV who introduced us to the concept of Wabi sabi:

https://soldersmoke.blogspot.com/2010/04/homebrew-hero-george-dobbs-g3rjv.html

This philosophical embrace of imperfection and repair is very appealing to me.  I am surrounded by old radios that bear the marks of wear, tear and repair.  My homebrew radios are filled with imperfections (especially in the cabinetry).   But Kintsugi tells me this is all OK.  I accept it. 

Thanks Bob.  Thanks Hambassador David. And thanks to George Dobbs. 

No More Automatic E-mails from the SolderSmoke Blog

Blogspot and Feedburner tell me that as of the end of August 2021, they will no longer be sending automatic e-mails to those who have subscribed to e-mail alerts for blog postings.  

I believe you can still subscribe to the blog. But no more e-mailed alerts. 

Please let me know if this loss of automatic e-mails will cause major disruptions for you. 

soldersmoke@yahoo.com

Adding Automatic Gain Control to the Termination Insensitive Amplifier

 

Earlier this month Paul VK3HN had a very interesting blog post about adding Automatic Gain Control to Termination Insensitive Amplifiers (TIAs).  

Termination Insensitivity is especially important in bidirectional rigs.  The shape of the crystal filter bandpass response is very dependent on the impedances presented at both ends of the filter.  In bidirectional rigs you are changing the signal path direction through the filter when you go from transmit to receive.  If the amplifiers at either end of the filter have impedances that vary depending on what is on the input or output of either stage, you will have great difficulty keeping the bandpass identical as you move from transmit to receive.  Termination Insensitive Amplifiers let you do just that -- they stay at one fixed input or output impedance (usually 50 ohms) independent of what is attached to the other end of the amplifier circuit.  This greatly simplifies impedance matching at the ends of the crystal filter. 

When I started building BITX rigs, I asked Farhan about the impedance matching problem.  He advised me to use TIAs on both ends of the filter and pointed me to a great 2009 article by Wes Hayward and Bob Kopski.  Using the information from that article, I built my DIGI-TIA transceiver, and I have used TIAs in almost all of the rigs I have built since that project.   

In his August 2021 blog post, Paul wanted to add Automatic Gain Control to the TIAs. He came up with a way to do this, but we worried that his circuit would have an impact on the impedance of the amplifiers. 

Yesterday, Wes Hayward W7ZOI posted on his web site a TIA circuit that lets us do it all:  Termination Insensitivity with Automatic Gain Control: 

http://w7zoi.net/tia+agc.pdf

I now find myself tempted to rebuild one of the TIA stages in my Mythbuster transceiver, adding the AGC circuitry from Wes's design. 

Thanks to Paul VK3HN for the blog post on this subject. And thanks to Wes Hayward for the TIA AGC design.  It is a real privilege to have direct input from Wes on questions like this.