Early SSB in India: Espionage, Stolen Secrets, and Kleptomania

 

Earlier this month I had stumbled across a 1964 QST article entitled "A Sideband Transceiver, VU2 Style."  I forwarded the link to Pete N6QW, Grayson KJ7UM, and to Farhan VU2ESE.  Last night Farhan sent me this insider look at early SSB in India.  It is really great.  The battle for preeminence among early SSB homebrewers in India reminds me a bit of Jean Shepherd's descriptions of homebrew radio in Hammond, Indiana.   Farhan's description of the early rigs being "all over the place, in about 3 or 4 boxes... with a whole lot of  wires running all over"  really resonated with me -- yes, even today, that is true homebrew. Thank you Farhan for sharing this with us. 

Farhan writes: 

VU2NR, Raju was a legend! Quirky, brilliant and liked to be by himself. He lived to a very old age of 100 or so. He was the first ham to get on SSB from India. Therein hangs a story of espionage, stolen secrets, cold war, politics and kleptomania. Most of the actors are now dead, so it can be told now.

I never met VU2NR, he rarely travelled. One evening at Paddy's shack, I was shooting the breeze with VU2RM, Ram, about my own SSB efforts. Ram was probably the most knowledgeable ham on SSB in India and his RM96 was widely duplicated. Paddy and Ram were trying to empty out a bottle of the Old Monk and I casually mentioned how we had to scrounge around for SSB lattice filters until Wes showed us how to build them ourselves. At that point, Ram unloaded this story to us:

VU2NR joined the Allies and worked as a radio mechanic with the RAF. After the war, he joined the ICAO (International Civil Aviation Organization) and then finally the United Nations as a comms expert, he was in Aden for a while. He understood the radios well and he became a well known homebrewer. His most brilliant work was the NR60 (it is an SSB radio built around four CA3028 kind of mixers). It was the first SSB radio that I had built (and it worked!) but we are getting ahead of ourselves.

Back in the 50s, ham shacks of India consisted of World War II surplus receivers and a self-built 807 transmitter driven by a VFO. There was a fair amount of buzz on the bands about SSB. The hams could occasionally pick up DX that was on SSB and easily resolved by the BC-348s  and the HROs but there was no way to build one. The QST was difficult to get your hands on but Raju had become a subscriber of the QST during his RAF days.

A QST sailed on a slow boat from the USA and landed up at the port on the east coast of India, Vizag and made its way to Raju's doorstep. Over weeks, he gathered parts and in the summer of 1955 he quietly came on 40 meters on SSB! This blew everyone away. Until now, one had only heard stories of SSB transmitters told by sailors of Sandra Maria Gracia after a few drinks to a bunch of hams clutching onto their 807s. It was as if Jesus had materialized!

VU2RM, Ram was not amused. He was a homebrewer with pride and honour. He could never be bested. He spent the next evening tuning on Raju's SSB up and down to note that the other sideband was missing and the carrier was gone. It sank into him that Raju had indeed beaten him to SSB. Ram worked at the Kakinada port, about 100 miles further down south on the east coast as the port radio engineer. He didn't sleep well. At 5 am, he got up, walked out and took a bus to Vizag where Raju lived. He was at Raju's door at 9 am. Raju was amused at the young guy and invited him in. They knew each other as rival homebrewers. There was tension in the air. Raju showed off his SSB transmitter in the front hall of his home. It was all over the place in about 3 or 4 boxes. There was the power supply, the PA, the ssb generator using a 2Q4 (a passive RC phasing network), a separate VFO box and a whole lot with wires running all over. In a corner was his stack of QSTs.

Raju's XYL called out for coffee and snacks (called 'Tiffin' in south Indian English) and Raju sauntered off to the kitchen to fetch his celebratory feast...

With alacrity and swiftness that only comes once in a lifetime, Ram, VU2RM, sprang to action. He darted to the QST collections, quickly found the one with the SSB transmitter on the cover, turned the pages to discover VU2NR's dog eared pages. He was staring at the circuit trying to memorize it. He realized that 2Q4's internal diagram had really odd values that he could never remember. So he did what James Bond, Bertie Wooster and Louvre thieves would have done. He rolled it up and slipped it into his pocket! (In those days, QST could be rolled and slipped into your trouser pockets, leading to wider dissemination of knowledge). He called out to Raju asking him to forget the refreshments as his bus was due back home. He legged it out and didn't stop until the bus stop. He hid around the bus yard hoping to not be caught by Raju. In the meantime, Raju, cursing the young upstart, drank both the filter coffee cups and left for work. Raju was unaware that the royal jewels were stolen.

VU2RM, Ram, started to work on his SSB radio over the next few days. He stopped going to work. At first, he figured out how to null the carrier using a twin triode modulator. Next, he fabricated the 2Q4 circuit. He sand papered lower value resistors until they read as close to the value as he could manage on his analog volt-ohm meter. He gave up on the exact capacitances and just soldered a bunch of the closest together. He had a crude 2Q4 equivalent. This, he dropped into his rat next circuit and an 'Almost' SSB signal emerged. He was probably having a sideband suppression of less than 15 dB at this point. It was suppressed and the carrier was nulled. He declared victory.

In the morning, Ram was on the band strutting off his SSB transmitter to the local gang. Graciously accepting the accolades from his fan club and extolling virtues of life on SSB to the lesser mortals. The news quickly spread over CW and AM of VU2RM as the second SSB station from India.

In the meantime, the atmosphere at VU2NR was tense. You could cut the air with a toggle switch. Raju had no idea how Ram had gotten the SSB. He carefully tuned around on his signal. He could pick up faint traces of the opposite sideband. Ram's carrier was also leaky. He decided that Ram was probably passing off his AM transmitter as a SSB. He said as much on air to his own devotees. Ram, ever watchful of his own reputation, heard this criticism and broke in, challenging Raju to prove that his was indeed not SSB. Raju's reaction was mixed. Now he wasn't sure. 

It was now Raju's turn to have a sleepless night. After his breakfast, he had had enough of confusion and he hauled his old scope and himself into the 8 am bus to Kakinada and showed up at Ram's doorstep! "Show me your radio" he said crisply.

For Ram it was his moment of crowning glory. He had brought Raju down to his shack! Raju plugged his scope into Ram's transmitter. He sniffed around the transmitter which was laid all over the table. "Where is your 2Q4?" he asked. Ram pointed to bunch of resistors and capacitors and Raju realized Ram's dog headed brilliance. He sat down, traced to the balancing pots (there would be two of them as this was a phasing transmitter). At this time, he decided to show Ram his greater prowess. He reached out to the carrier nulling pots, and tweaked them to minimum carrier (Ram was watching the oscilloscope with his mouth wide open). He told Ram that he had now fixed the carrier and then showed him how to adjust the RF phasing control for minimum by tuning to the opposite sideband on Ram's Bc 348. Having proved to Ram that he was a better homebrewer, he declared that now, Ram's transmitter was indeed SSB and not semi-AM. Raju retrieved his honor by being gracious and "mentoring" Ram.

 

They had coffee and snacks and it was time for Raju to leave, as Ram was showing Raju to the door, Raju's eye caught a QST on the shelf... he pulled it out and stared down at the QST with his own address neatly stickered on the QST's cover. He glared at Ram for a long time and turned away and left in a huff. Ram called after him down the street but Raju was gone.

VU2NR's last radio was built when he turned 90. It was the NR90 and it was built using NE612 chips. His hamming came to an abrupt end when one day his son dropped in unannounced only to find him perched on his tower of 30 feet height, fixing a fallen element of his self-made log periodic. The son was so horrified that he took away all the radios to save him from self-harm (this part of the story is unconfirmed).

 

My friend Sasi, VU2XZ, was close to him and he got the family to donate his callsign to a repeater that has been established in his memory. VU2NR lives on.

- f 

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Here is the link to the 1964 QST article.   VU2NR's article appears on page 19: 

https://www.worldradiohistory.com/INTERNATIONAL/QST/QST-1964-03.pdf

Homebrew Challenges Much Like Ours: The Direct Conversion Receiver of Wes Hayward W7ZOI and Dick Bingham W7WKR -- QST November 1968

 

https://www.worldradiohistory.com/Archive-DX/QST/60s/QST-1968-11.pdf

I was thinking about some of the challenges faced by the builders of the SolderSmoke Direct Conversion Challenge Receiver, and about how similar these challenges are to those described by Wes Hayward W7ZOI and Dick Bingham W7WKR in the November 1968 QST article that launched the direct conversion revolution among radio amateurs. You can read the full article beginning on page 15 in the link above.

Some observations and comparisons:    

--The November 1968 QST article said, "This receiver was designed for simplicity and ease of duplication, rather than ultimate performance."  Ours too! 

-- Wes's receiver has a single tuned circuit in the BP filter.  Ours has two LC circuits. 

-- Wes's mixer is also a diode ring.  He starts out using hot carrier (Shotkey) diodes, but later concludes that ordinary diodes would work just fine.  We reached a similar conclusion.  But I wonder if the ordinary diodes would work well with a low output level from the single FET VFO (see below). 

-- His oscillator uses a single MPF-102 in a Hartley configuration with no voltage regulation, and no buffer.  We have two active devices and a Zener diode.  This article makes me think we could have made our PTO even simpler.  

-- Wes's receiver has a low-pass filter between the mixer and the AF amp.  The cutoff is at around 2 kHz.  This seems quite low in frequency and may reflect a preference for CW.  It features 88 mH coils that are now quite hard to find. The goal of this filter seems to be to prevent signals from beyond the audible frequency range from overloading the AF amp.  We ended up using the diplexer from the W7EL optimized QRP rig.  I think this diplexer takes care of the problem.  

-- The W7ZOI/W7WKR receiver has no AF nor RF gain control.  When encountering a strong SSB signals, the article recommends detuning the BP filter.  I think our AF gain control, and the mod calling for an RF gain control will give the operator, well, more control and will prevent strong SSB signals from overloading the AF amplifiers.  The RF gain pot might also help prevent SW broadcast AM breathrough. 

-- One big difference between our receiver and the November 1968 QST receiver:  isolation of the VFO.  The QST article puts the VFO in an aluminum box above the chassis.  We have the PTO without any shielding right alongside the other circuits.  Builders might want to experiment with the kind of isolation recommended by the QST article.  Would this kind of isolation and shielding improve performance? 

-- Wes also obviously contended with oscillation by the AF amplifier, as did many of our builders.  The QST article contains a number of recommendations: First test the amplifier to see if you can hear noise.  If it oscillates, try increasing the value of the decoupling resistors. (Many of our builders added electolytic caps to the DC power line in the AF amp.)  The article recommends trying a .01uF cap across the output.  It also recommends keeping the output of the amplifier away from the low pass filter at the input.  Wes's design has no transformer as it makes use of high Z headphones. 

-- The QST article says that the product detector performed adequetly with an LO injection level of .6 volts peak-to-peak.  This seems quite low to me,  but perhaps this would work with hot carrier diodes in the diode ring?    This might be one good reason to use diodes that have a lower turn-on voltage -- you could get away with using a super-simple VFO even if it provides lwer voltages to the mixer.  It might be fun to experiment in this area.  

As readers can see, the challenges faced by the builders of the SolderSmoke DC receiver were very similar to those face by the builders of  the November 1968 machine.  I think all of us should find this very encouraging.  

Thanks again Wes and Dick. 

What Homebrew Looks Like (And W9BRD comment on the High School receiver project)

Clikc on the picture for a clearer view of this fantastic image

Dave Newkirk is the son of Rod Newkirk, the guy who wrote the inspirational "How's DX?" column for QST for so many years.  Dave is obviously a very prolific and proficient homebrewer himself.  I really appreciate his comment on the High School receiver project.  Thanks Dave. 

Dave wrote on QRZ.com: 

Rummaging around the net for such phrases as "TJ receiver" or variations that include AA1TJ and receiver returns no solid hits, but by following clues I found a/the article with schematic at https://hackaday.io/project/190327-high-schoolers-build-a-radio-receiver. That's a well-thought-out design that'll provide fun, fun, fun.

I think I have something like 8 homemade receivers available at the moment at W9BRD, tube-based and solid-state, regenerative and superhet. all told covering 160 through 17 meters (if I include my tube-based and solid-state converters), and about the same number of homemade transmitters. With some exceptions for particular on-air celebrations and events, commonly my entire station lineup is homemade from stem to stern, so to speak.

I've been building radio gear since 1968. Here's some recent fun:

Zed thread covering the development of a converter-plus-regenerative-tuner combo that I came to call the "Super 3-in-9":

https://forums.qrz.com/index.php?th...ceiver-using-one-9-pin-miniature-tube.897249/

Zed thread covering construction of my version of a coffee-can-based receiver/converter combo my father used for 15ish years as his main station receiver after beginning its construction in 1951ish "on a kitchen table in Hartford" while working at ARRL HQ:

https://forums.qrz.com/index.php?th...building-a-160-meter-coffee-can-regen.938709/

To which discussion our own @N2EY kindly posted the mid-1960s "How's DX?" lead in which Dad laid out his station design/configuration/construction philosophy ( https://forums.qrz.com/index.php?th...0-meter-coffee-can-regen.938709/#post-7021505 ).

To us, commercial/mil/pro gear has been and always will be various shades of inspiring to fabulous, but only with homemade gear are we home.

A little Night Radio Romance at W9BRD, featuring the BRD-160CC 160-m regenerative receiver and converter (transmitter and antenna tuner not shown). 

Mike WU2D's Video on the SimpleX Super Receiver -- Part II

 Another FB video from Mike WU2D.   

But you know,  I too find myself kind of opposed to front panel on-off switches.  I power my rigs with small DC supplies.  I just turn on the supply when I want to use one of the rigs.  I don't have or need a switch on the front panel of the rig.  

I especially liked Mike's use of the gate dip meter and, of course, the Q meter.  FB OM. 

I must say I have a preference for the first version, but only because I dislike the regenerative circuit in the second version.  I do like the newer-style coils -- I have one in the BFO of the Mate for the Mighty Midget receiver.   

Thanks Mike for the sideband inversion factoid in Part 1!   The Hallas Rule -- words to live by. 

One word of caution.  I used 6U8s on my Mate for the Mighty Midget receiver.  I had good results, but WA9WFA had a lot of trouble.  We eventually concluded that the 6U8s didn't age well.  And they were quite long in the tooth.  We found (from the tube guys) that 6EA8s aged better and were a good and easy sub for the venerable (perhaps TOO venerable) 6U8s.  I switched tubes in my rig and it did seem to work better.  BTW, this is the receiver that I use to listen to the Old Military Radio Net on Saturday mornings.  

Here is the story of our switch from 6U8s to 6EA8s: 

https://soldersmoke.blogspot.com/2022/02/6ea8s-in-mate-for-mighty-midget-and.html

SimpleX Super Superhet Receiver -- A Great Video from Mike WU2D

Here is another great video (and project) from Mike WU2D.  I'm a big fan of homebrew superhets.  And wow, Mike presents a band-imaging superhet!  Two bands for (almost) the price of one!  I have FIVE homebrew dual-band band-imaging transceivers around me.  Believe me, once you have the experience needed to build an SSB transceiver, a dual-bander is the way to go.  Five bands seems like a bit too much.  But two seems to be at the sweet spot.  

I wrote to Mike reminding him to talk about the sideband inversion problem.  This rig will invert the 75 meter signals,  but this is easily resolved by just shifting the BFO frequency.  I also pointed out that many of today's builders will be detered by the need to scrounge for parts.  Where oh where is the BOM OM? 

Thanks Mike! 

Bringing a Faulty Herring Aid 5 Receiver Into the Light -- Fixing the AF Amp Schematic Error (video)

I picked up this old homebrew receiver in March 2023 at the Vienna Wireless Society's Winterfest Hamfest.  It is a Herring Aid 5.   I was surprised to see that the builder (who was he?) got the windings on the VFO transformer right.  Later, I learned that he had also substituted MPF-102s for the original Radio Shack FETs called for in the QST article. This allowed him to overcome the PC board layout problem at Q5 (VFO).  With an MPF-102, he was able to get Q1 working by kind of shoe-horning the leads into the proper holes.  FB OM.  Whoever he was, he seemed like a really competent builder.

The Hamfest Herring Aid 5

But then I started wondering:  Did he also overcome the big problem in the audio amplifier?  You see, there is an egregious error in the QST schematic.  Between the collector of Q3 and the base of Q4 (the two AF amplifiers) they have a 10uF capacitor to ground.  That would send most of the audio to ground. This is clearly a mistake.  Not only does it not make any sense, but this cap to ground does not appear in the PC board drawing, nor in the photograph that went with the QST article.  I included this cap in my 2014 built of the Herring Aid 5, but with it, I found the receiver to be exceedingly deaf.  When I clipped that capacitor out of the circuit, my 2014 Herring Aid 5 sprang to life.  Did this hamfest Herring Aid 5 have the error capacitor?  Would it too be brought into the light by clipping one lead?  

Sadly, the erroneous third capacitor was there, and it was wired into the circuit.  The receiver worked,  but just barely.  It was very deaf.  You could not hear 40 meter band noise, and you could barely hear strong CW signals.  Builders may have thought that this was normal with such a simple receiver. 

3 10uF caps. The center one is an error.  I have clipped it out

In the video above you can see what happens when I cut the lead to the mistake capacitor.  Suddenly, you can hear band noise, and CW signals.  The receiver comes to life -- for the very first time!  

This was an error that echoed through the decades.  As far as I know there was never a published errata.  The erroneous capacitor is there in the 1977 ARRL book entitled Understanding Amateur Radio.  In 1998,  NORCAL QRP redid the Herring Aid 5.  Incredibly, THEY INCLUDED THE OFFENDING CAPACITOR in their new and improved schematic.  

NORCAL's 1998 Schematic included C14

I'm fixing up this old receiver a bit.  It was nice to have it playing 40 meter CW yesterday.  Better late than never.  

This morning I was feeling kind of guilty about paying so much attention to a receiver from 1976.  But then I opened the paper and read about the recent find of a DeLorean car.  Heck if a DeLorean from the early 80's is worthy of attention, so is a homebrew receiver from the late 1970s. 

How a Homebrewer Substituted MPF102s for the RS 2035 FETs in the Herring Aid 5 -- Who built this one? Any others out there?

The Hamfest Herring Aid 5

For background on all this, see yesterday's blog post:     https://soldersmoke.blogspot.com/2023/10/a-big-error-discovered-in-1976-qst.html

Rick WD5L noted that it was remarkable how the builder of the Herring Aid 5 that I found early in 2023 at a hamfest had built his receiver using MPF102s at Q1 and Q5.  Here is how this builder  kind of "shoe horned" MPF 102s into the QST Herring Aid 5 boards.  Pinouts for the MPF102 and the RS 2035 and the PC Board Pattern for the Herring Aid 5 appear below. 

Above  is Q5 the VFO.  You can see how he "flipped it around" to get the Drain, Gate, and source in the proper holes. You can also see how he wound the transformer for the VFO.  Looks like there was  a real battle with the soldering iron here. 

Above is Q1 (RF amp).  Again clearly an MPF 102.  But here it would not be sufficient to just flip the transistor around.  So he had to twist it and take the center lead and put it in the far right hole.  Note his markings on the board.  Looks like he made another hole for the MPF102 Gate (but he didn't really have to do this). 

DOES ANYONE KNOW WHO BUILT THIS RECEIVER?  

ARE THERE ANY OTHER HERRING AID 5s OUT THERE?

DSG

DGS! 

Click on the images for better views.

A Big Error Discovered in the 1976 QST "Herring Aid 5" Article (After 47 Years)

Click on image for a better view.  See arrows for Q1, Q5 and the parts list.

I tried as a teenager to build the Herring Aid 5 direct conversion receiver from the July 1976 issue of QST.  I could not get it to work. Important points: 1) I was attracted to the fact that this receiver used only parts available from local Radio Shack stores (I bought them) and 2) The article provided a PC board pattern (I also bought ferric chloride and etched a board). 

Looking back, I concluded that I had failed to get the VFO to oscillate.  I remember hearing signals when I tuned my HT-37 transmitter (on Cal, on 40) near the receiver.  I was very close, but I never got that Herring Aid 5 VFO to oscillate.

Thirty-eight years later I tried again to build the receiver.  Important points:  This time I used mostly junk box parts and Manhattan-style construction (no etching).  Still I could not get the VFO to work.  ZL2DEX spotted a problem -- I had wound the L6 and L7 coils with the wrong "winding sense."  I corrected this, and BOOM! the VFO sprang to life.  I assumed that I had made a similar "winding sense error" way back in 1976.  This, I thought, explained my failure to get the receiver working.  The QST article had warned that proper phasing of L6 and L7 was necessary.  I figured that I just hadn't fully understood what "proper phasing" meant.  So it was, I thought, all my fault.    

 

Here is the PC board pattern from QST.  Arrows show Q1 (DGS) and Q5 (DSG).  

But it is the same kind of FET!  Click on the image for a better view.

But then on October 17, 2023 a comment appeared on the SolderSmoke YouTube channel.  Rick WD5L had also -- back in the late 70's -- tried to build this receiver.  He recently looked closely at the recommended parts list (that we used!) and at the QST PC board pattern (that we also used). AND HE SPOTTED AN IMPORTANT ERROR IN THE QST PC BOARD PATTERN.   

Take a look at the pattern for Q5 above (see arrow).  That is the VFO FET.  A Radio Shack 2035 FET has a DGS pinout (see below).   The Gate is the center pin.  If you put this transistor into the PC board pattern above you would definitely be grounding the Gate.  There is no way the VFO would work under these circumstances.  Note too that the only other RS 2035 FET in the receiver is Q1 (the RF amplifier).  In the PC board pattern above Q1 is marked correctly as DGS.  This confirms the error in the Q5 PC board pattern.  There is no way an RS 2035 transistor can simultaneously have two different pinouts! 

Wow.  So this failure to get the VFO working may not have been my fault after all.  I may have actually gotten the transformer winding correct, but even if I did, there is no way this VFO would have worked using the part called for by QST and the PC board pattern shown above.  As a teenager I just did not know enough to spot the error or the inconsistency.  I kind put blind trust in QST.  I just couldn't get the thing to work.  

Rick searched the QST archives to see if they ever put out an errata on this.  So far, nothing. Worse yet, the scan of the PC board pattern on the QST site is very unclear and may have the pin designations on Q5 scratched out. This would make it more difficult to spot the problem.  (The image above is not from ARRL.  It is from a high quality scan of the original QST article done this week by a fellow Vienna Wireless Society member.)  Please let us know if you find any kind of errata or any acknowledgment of error.  

This is really pretty bad.  This was a project aimed at novices.  Far from encouraging homebrewing, this type of mistake is the kind of thing that would push people away from the soldering iron.  

Ironically, I may have been doomed by opting to use the QST PC board.  If I had used Manhattan-style construction (as I did in my more recent build) I would not have fallen victim to this PC board pattern error.  Also, if I had built this thing stage-by-stage (as we always now recommend) I would have more clearly realized (back in 1976) that the problem was in the VFO stage.  But I was 17 and didn't know.  I put blind faith in the QST article.  It never occurred to me that something in print could be wrong.  This realization came much later. 

There is more to talk about on this ill-fated project. In future posts I will discuss another error, this one in the AF amplifier.  And possible additional errors...  And I'll write about the 1998 resurrection of this project by NORCAL QRP and the New Jersey QRP clubs.  

Thanks to Rick WD5L for spotting the PC board error.