Tezukuri and Chappy Happy -- Amazing Videos on Homebrew Radio (from Japan?) - Another 40 Meter Direct Conversion Receiver

So around the time we were building 40 meter direct conversion receivers, someone else was doing something similar.  His product (above) is a lot nicer than ours.  He has an S-meter and a digital frequency readout.  But like ours, his is built on a wooden board.  FB OM.  

If you want to see what a direct conversion receiver can do, watch his video (above). 

I was really amazed to see him use a modified VFO from a Kenwood TS-820.  Not long ago Pete N6QW spotted one of these on e-bay and recommended that I buy it.  As with the Yaesu FT-101 VFOs, we bought it for the gears and reduction drives but ended up with the entire VFO circuit.  I now have one on my shelf, ready to go.  TRGHS. 

We are not sure who Chappy Happy is, but "Tezukuri" means "hand-made" in Japanese. The writing in the video descriptions are in Japanese, then Chinese. 

Here is the YouTube channel.  Amazing stuff here:  https://www.youtube.com/@chappyhappy3675  He is clearly a ham.  He even works on an old S-38.  Who is this guy? 

Fernando's Rigs -- Vintage Ham Radio Receivers

Thanks to Rogier PA1ZZ for sending me this YouTube link.  It is a truly wonderful channel from Spain. Not only the Collins Gold Dust Twins, but also lots of great (and not-so-great!) older receivers.  SP-600s, S-38s,  Rhode and Schwartz rigs, lots of great stuff.  Go to the "Videos" link and enjoy the Thermatron goodness.   Thanks Rogier!  And thanks Fernando! 

 https://www.youtube.com/@jonglei

Progress Report Video on the SolderSmoke Shack South

The new shack is coming together in HI7 land.   I will need a shelf for the test gear -- I am looking for something thatcan sit on the main workbench -- the wall behind the bench is drywall and won't support any weight.   I will have to get some plywood to protect the nice woodwork. I have melted some solder already -- I had to fix the little magnifying lamp -- it felt good to get back in the game.  

The AM radio station that was providing background music was from just across the Mona passage -- they were in Cabo Rojo, Puerto Rico.   My S38-E shows the frequency as being a bit above 700 kHz, but as with most things S38-E, this readout is suspect.  Can anyone tell me the call sign of this station?  

I have been using the homebrew 15-10 rig, but only in receive mode so far.  

I am also doing some VHF scanning, using a Realistic Pro-36 scanner that Bob KD4EBM gave me.  So far I am picking up aircraft approaching Santo Domingo from the East.  I have the maritime calling freq also programmed in and hope to hear some ships at sea.  Thanks Bob. 

Dino asked about astronomy.   As you can see in the video, the Orion telescope is ready to go, but we are in rainy season here, so the skies aren't too great right now.  They will be better in the winter. 

Hurricane Beryl is approaching, but current projections are for it to pass to our south on Tuesday. The eye of the storm is not expected to hit this island.   

From the Last Whole Earth Catalog (1971) -- Short Waves -- Part 1

Click on image for a better look

Having recently returned from San Francisco, it seemed somehow appropriate for me to take a look into the Last Whole Earth Catalog  (1971).   I picked a copy of this book up some time ago.  There is some radio stuff in it, a lot of it on shortwave listening.  Above is one article. I'll post more in the days ahead. 

It was around 1973 that I gave my cousin's husband Mike an S38-E shortwave receiver.  It is a wonder that he survived.  He did report electrical shocks.  

Working On My Old Hammarlund HQ-100 (Part 1)

I like this old receiver, with all its shortcomings.  I picked it up in the Dominican Republic in 1993 or 1994.  I've been using it on AM with my K2ZA DX-100.   It needed some contact cleaner, and I took the opportunity to work on a few of the circuits that were getting kind of decrepit. 

I came to a new understanding of -- and appreciation for -- the Q-multiplier.

While of similar vintage, this receiver is MUCH nicer than the Hallicrafters S-38E: 

S-38E 1957-61 $54.95 5 tubes.  AC/DC, kind of flimsy. 

HQ-100 1956-60 $169  10 or 11 tubes.  Power supply,  regulator,  much sturdier construction

You get what you pay for.   

 In Part II I'll show you how this thing sounds and what it is like to use it for SWL, CW, SSB and AM. 

Level UP EE Lab Builds a Superhet Receiver

I was really glad to have stumbled across Darren's YouTube channel: 

(46) Level UP EE Lab - YouTube

Heck, he has an S-38E on the shelf above his bench.  He is clearly one of us.  What is his callsign?  

This morning I watched the first and last of his 10 videos on his superhet receiver project.  Very cool.  Lots of good info in there.  And there is something for everyone:  Arduinos and Si5351s, along with a lot of standard analog circuitry.  The first episode appears above. 

The variable bandwidth filter looks very interesting. And there was a nice shout-out to Charlie Morris and one to Hans Summers. 

I really like his effort in episode 10 to measure Minimum Discernible Signal using commonly available test gear.  This helped me in my effort to get more rigorous and serious about receiver performance measurement.    

Darren has many other excellent projects on his YouTube channel.  My Hammarlund HQ-100 receiver started giving me trouble this week, and I was debating whether or not to fix the old thing.  Darren's channel provided the inspiration I needed.  It will be fixed!   

Please subscribe to Darren's channel.  And spread the word about his videos.  We definitely want him to make a lot more.  

Thanks Darren! 

Mike WU2D Looks at the "Dream" SW Receivers of the 1960s and 70s (Video)

Wow, I really liked Mike's walk down memory lane. I saw several of my own dream receivers: 

S-38E.  Indeed, this little monster did add some danger to your life.  AKA "The Widow Maker," I gave one to my cousin's husband so he could listen to what the commies on Radio Moscow were saying.  He later told me that the receiver had given him a shock.  I now have TWO S-38Es in my shack (two more than I really need).  I have installed isolation transformers in both of them, so they have lost the one element (danger!) that made them attractive.  

HA-600A. I got this one for Christmas in 1972.  The A model is MUCH better than the plain vanilla HA-600.  I recently got another HA-600A and found serious deficiencies in the Product Detector.  Has anyone else noticed these problems?  BACKGROUND INFO AND A PLEA FOR MORE INFO HERE: https://soldersmoke.blogspot.com/search?q=HA-600A+Product+Detector

HQ-100.  Got one in the Dominican Republic.  Fixed it up, repairing damages caused by radio life in the tropics.  Disabled the goofy audio amplifier circuitry.  I now wonder if this receiver might benefit from the insertion of a 455 kc ceramic filter. 

NC190.  Wow "Cosmic Blue"  Perhaps this was an early influence that led to "Juliano Blue?" 

HQ-180.  "18 tubes and almost as many knobs!"  FB!  

HRO-500.  Love the dial. 

Transoceanic.  Never had one, but built a BFO for the Transoceanic that W8NSA took with him to SE Asia during the war. 

R-390A.  I don't have a crane for the workbench.  

Thanks Mike -- that was a lot of fun.  

Meet Your New Soviet Neighbor -- With Hallicrafters

 

Thanks to Jeff Murray for alerting us to this.  It is obviously from World War II.   If the new neighbors had S-38s, well, that might help explain why things didn't go so well.  

Twenty-nine S-38s on Craig's List

This is almost like a nightmare.  I guess it could be worse -- they could all be E models. 

https://boston.craigslist.org/gbs/ele/d/arlington-twenty-nine-29-variouss/7188621508.html

Thanks to Jim W3BH for alerting us to this, uh, opportunity. 

SolderSmoke Podcast #220 -- S-38Es, AD9833s, Pete's Phasing Rig, FT-8

Java on the S-38E Tuning Dial

SolderSmoke Podcast #220 is available

http://soldersmoke.com/soldersmoke220.mp3

Hunkered Down.  StayInTheShack:  SITS!  Flatten the Curve!  It is working.

Teaching English again – via Zoom.  Kids completing the school year remotely.  

BILL'S BENCH

-- Finishing up on the S-38Es.

  

-- I wrote up my alignment, isolation and dial string experiences.

-- SWL  WRMI Radio Miami International on 39 meters 9.4-9.9 MHz.  Rock and Roll.

-- S-38E work is causing me some serious legal problems.  They are threatening to take down our sites and our podcast.   Google has put a CEASE AND DESIST ORDER on my blog:   Check it out http://soldersmoke.com/CEASEANDDESIST.JPG

--S-38E caused me to want to get my HRO dial receiver on the SW broadcast bands with a good AM detector.  

-- Next up: Hayseed Hamfest cap for my Drake 2-B.  And I have an idea on how to easily broaden it for AM:  Tap the 455 kc output on the Q multiplier jack.  455 AM detector to audio amp. 

SHAMELESS COMMERCE DIVISION

PETE’S BENCH

AD9833

Phasing Rig Project

.

DEAN’S PROJECT – Step by step.  Trouble shooting.  Understanding.  Receiver triumph.  FB.

MAILBAG

Jack 5B/AI4SV doing well in Cyprus

Daniel SA7DER listens during commute in Sweeden.

Peter VK2EMU building a 6 meter amp.  With Tubes

Jim WA8ZHN  says there are still 7751 Novices on the books.   FB.

Mike WB2BLJ modding his BITX – having a lot of fun.

Fred KC5RT – Great idea on isolation transformer in my S-38E.  

Jerry Palsson: S-38C's curves vs. S-38E's exotic places.  Java. 

Krakatoa East of Java

The Year of Living Dangerously

Anonymous mail:  FT-8 DX -- Are these contacts legitimate? See below. 

Dear Bill and Pete: 

I've been meaning to share with you something that has come to my attention by a rather circuitous route. 

As you guys know, I've been involved in the software/IT side of ham radio for many years. I've watched many digital modes come and go.  I've always enjoyed my work, but lately I've seen something that makes me uneasy. 

I'm sure you guys have heard of the fantastic DX that is being worked by many guys using FT-8.  It seems like all they need to work Jakarta is a couple of watts to a wet noodle. Shazam!  Contact! 

Well, I learned something that calls into some question the legitimacy of many of these contacts....  

As i understand it, certain manufacturers, in cahoots with a major American ham radio organization (that happens to be very dependent on ad revenue from that manufacturer), have secretly set up a system that combines the internet and ham radio. 

Here is how it works:  Suppose Joe Ham gets on FT-8 on 40 meters.  He puts out a call using his QRP transmitter and the aforementioned wet noodle.  No way that signal is going to Jakarta, right?  Well, it will with a bit of help.  

The system has SDR transceivers  and great antennas set up at strategic points around the world -- these are really great locations -- think mountain tops near the coastlines, always with high speed internet T5 connections. I think this is part of the whole “contest superstation for on-line lease” business model.  

One of these stations picks up Joe Ham's FT-8 call. Sometimes it will just re-transmit it, sometimes is will send it to a counterpart station on the other side of the globe.  Bingo, Joe Ham's signal is suddenly in Jakarta.  A station there enthusiastically responds, and that signal goes back with the same kind of repeater/ internet assist.  This is all done out of the reach of the FCC.  They are usig overseas locations,  some of them in Mexico.

Of course they have to be careful not to "facilitate" these kinds of contacts during times in which the bands are obviously dead,  That's why 40 is so useful for this system.  Obviously they can't keep this kind of thing secret forever -- they just want to get guys hooked on FT-8, then they can reveal the system, selling it as nothing unusual, you know, sort of akin to Echolink.  

Of course, this hasn't been made public (for obvious reasons!) but I can tell you the name of the system:   They tried to make it sound like something familiar (in this case like APRS): They call it  "Automatic Private Radio Internet Link 1."  My understanding is that when they do their “roll out” they will offer the new service to those willing to pay a subscription.

Obviously as an old-school, traditional ham, I'm troubled by all this.  What do you guys think?  I wonder what your listeners would think. 

Please don't mention my name..  But here is a site that describes the new system: 

http://www.automaticprivateradiointernetlink1.com/

Thanks and 73... 

Please let us know if you have any information on this, or have observed any unusual and suspicious success with FT-8.

Double Trouble: Notes on TWO Hallicrafters S-38E Restorations and Alignments (with videos)

Winterfest S-38E on the left, junker on the right 

I have been talking bad about the Hallicrafters S-38E receiver for several years now.  For a long time I agreed with my friend Pete Juliano in his colorful description of the receiver: "a pig with lipstick."

But as I've gotten to know the receiver better, I have come to like it.   It is very simple.  There is a certain minimalist thing that explains the attraction; it is a challenge to make the most of this very low-budget 1950's receiver.  It uses tubes, but the voltage is not really in the very lethal range.  It covers a wide range of frequencies.  Its frequency stability is fairly good.   And it sounds great on AM (scroll to the bottom to listen).  It seems to be technologically related to the Echophone EC-1 -- we have been posting about the WWII  advertisements featuring Hogarth and his (unbelievable) efforts to attract women with this receiver.  

The S-38E has a big "picture window" frequency dial, marked with exotic foreign locations (Java!).  I share with it a similar vintage with the S-38E:  IGY.  The S-38E was produced from 1957-1961.  Duck and cover my friends; the CONELRAD frequencies are marked on the dial. Working on these two receivers has kept me busy during the first few days of the COVID-19 emergency. 

I now own two of these things. I might get a third.   I thought it would be worthwhile to write up my experiences with the S-38E.  I hope this information will be of use to others who might work on this piece of gear.   

Winterfest RX on the left, junker on the right

SHOCKINGLY BAD? 

I had an S-38E as a kid.   Around 1980, I gave it to my cousin Mary's husband Mike so he could listen to shortwave broadcasts. Recently I asked him about that S-38E -- he said it had given him a nasty shock.  That was because of the "transformer-less" AC/DC power supply -- if you plugged the AC line cord in "the wrong way" you would be putting 115 V AC on the chassis.  Ouch.  

AC/DC DESTROYS AN ANTENNA COIL

I picked up an S-38E at a Vienna Wireless Winterfest a few years ago.  I think I paid ten bucks.  I didn't pay attention to the polarity of the AC plug and managed to plug it in the wrong way. Then I managed to short the antenna terminal to what turned out to be a very AC hot (115V) chassis.    This destroyed a significant portion of the antenna coil.  Smoke was released.  

ISOLATION TRANSFORMER

Not wanting to repeat the hot chassis disaster, I installed an isolation transformer.  On the junker,  I used the Triad N-49X,  available from Digikey. In retrospect I probably should have gone with the larger, 35 watt  N-51X, but Fred KC5RT provided a great suggestion that would make the smaller N-49X adequate:  Run the filaments in series DIRECTLY from the AC line, with neither side of the AC line to the chassis.  Then run the rest of the circuitry through the isolation transformer.  This would take a lot of current out of that little transformer and would likely make replacement with a larger unit unnecessary. I will try this later. Update: 2 April 2020:   I tried to run the S-38E with the filaments in series fed with AC directly from the line cord and the rest of the circuit running through the isolation transformer.  I got it working this way.  Sort of.  But AC hum was a lot louder and I found myself back in the AC/DC transformerless situation with the chassis going hot if the set is plugged in "the wrong way."  So I retreated, going back to having the whole receiver running off the isolation transformer.  The hum went back to the earlier (normal) level and the chassis would not go hot no matter how I plugged it in. 

On the Winterfest S-38E it looks like I had used a larger isolation transformer. 

I put a 500 ma fuse in the primary circuit.  On the N-48X the black lines are primary, the red are secondary.  One black line goes to the fuse, then on to the front panel on/off switch.  The other side of the switch goes to the AC line.   The other side of the AC line goes to the other black line.  Neither of the AC lines goes to chassis.  On the secondary side, one of the red lines goes to Pin 4 of V5 (rectifier); the other goes to the B- line which is Pin 3 of V3 the 12AV6 which is also connected to the volume control.  I put the isolation transformer on the top side of the chassis.  It ends up close to the speaker, and fairly close to the AF output transformer.  This raises hum concerns. 

Where I placed the isolation transformer on both my S-38Es

HUM?  

I did a test to see if my placement of the isolation transformer was adding to the hum.  I simply took the S-38E back to its original transformer-less configuration and then listened to the hum.  I noticed no difference and concluded that the isolation transformer is NOT adding to the hum. If there is a difference, I'd say that there is less hum with the isolation transformer.  (And yes, I did make sure the AC line plug was in the correct way with the old power supply configuration.) 

See what you think:  





The hum is not really a problem. You can only hear it when the volume control is turned all the way down.  As soon as you turn the volume control to the right,  band noise overwhelms the hum and you can't hear it any more.  I think this was the normal condition of this very economical receiver. 

The two receivers have different speakers.  The Winterfest speaker measures 7.6 ohms (DC) and the junker has a 3 ohm speaker (closer to that called for in the schematic). I think the 3 ohm speaker results in somewhat less hum. 


REPAIRING/REPLACING THE ANTENNA COIL

After the smoke release, I tried to re-wind the burned out portions of the antenna coil on the Winterfest S-38E, but I got tired of the project, cursed all S-38s, and sent mine to the basement/crawl space.  I would have given it away, but I was afraid that the recipient would electrocute himself.   So it sat in the basement for a couple of years.  Recently I got interested in shortwave listening again, so I pulled out the S-38E.  

On e-bay, I found and bought an S-38 antenna coil.   I put it in my S-38E, hoping that it would bring the receiver back to life. But I had a lot of trouble with the front end alignment.  I theorized that the coil I had bought was from the original model of the S-38, and perhaps the S-38E coil had different inductances.  So I went back to e-bay.  There I found a junker S-38E being sold by Mark W1MEM.  It had been owned by KA1WFY.    

At the suggestion of Scott W1NB on the AntiqueRadio forum, before installing the coil from the junker, I measured the inductances of the S-38E coil and the previously obtained S38 coil.   I was surprised to find that the values were almost identical.  That meant that my theory about coil inductance differences was incorrect.  But I took the S-38E coil from the junker and put it in my S-38E.  I took note of the fact that the junker did not in fact look like junk, but there it was, sitting on the floor of the workshop, having had its antenna coil extracted.  And I had in hand the old S-38 coil that I knew from testing was very close in value to the S-38E coil.  

I was kind of getting tired of S-38s at this point, and I thought about leaving work on the junker S-38 for another day (or another year, or decade), but familiarity with the innards of the rig and alignment procedures is perishable, so I decided to try to get the junker going while it as all still fresh in my mind.  I installed the isolation transformer mod on the junker and put the S-38 antenna coil in.   That is how I came to own a second S-38E. 

RF ALIGNMENT PROBLEMS

One of the problems I had was that the alignment instructions for the S-38E are very sparse.  For the front end alignment, they just tell you to put signal generator signal into the antenna terminal, put a meter or scope on the audio output then tweak the antenna and oscillator coils for max output. I had no trouble getting the oscillator on the right frequency -- for bands 2 and 3 that would be the signal frequency PLUS .455 MHz.  For Band 4 it would be signal frequency minus .455 MHz.  But I could not get the LC circuit in the front end to peak on the input frequency.   Now, if you have the peak for the input LC circuit in the wrong place, your receiver will still work (sort of) but image rejection will be even more horrible than it is designed to be.  

For example,  assume you want to tune a strong signal at 7.0 MHz.  Your VFO is at 7.455 MHz.  The difference frequency is .455 MHz.  This signal goes through the IF transformers and you hear the signal. 

But now tune down .910 MHz to 6.09 MHz.   Your VFO will be at 6.545 MHz.  7.0 - 6.455 = .455    Unless the front end LC filter blocks the strong signal at 7.0 MHz, it will also show up at 6.09 MHz on your dial.  If the S-38E is aligned properly, that front end LC circuit will track the tuned frequency.   In this case it will be peaked at 6.09 MHz and the strong signal from 7.0 MHz will not get through.  Oh happy day! That 7.0 MHz signal shows up only on one place on the dial.  All is right with the universe. 

Of course there is another image problem.  If you are tuned to 3.9 MHz, your VFO is at 4.355 MHz.  If a shortwave broadcaster fires up on 4.81 MHz, well 4.81 - 4.355 = .455   That is why I can hear "Brother Stair" raging away, seemingly at 3.9 MHz.  Even if a simple receiver like this is properly aligned, a powerful shortwave broadcast signal will often get past the puny single LC circuit in the front end.  

But what happens if the S-38E is misaligned?  What happens if that LC circuit is peaking above the desired frequency? 

Now when you tune to 6.09 MHz, the front end tuned circuit may be peaked at say 6.5 MHz.  There is only one tuned circuit in this receiver front end, so the "skirts" are quite wide.  Wide enough to let that 7.0 MHz signal through to the mixer where it mixes with the 6.545 MHz VFO output to produce a very audible output.   This is what was happening when my S-38E was misaligned.  The 40 meter ham band and the 75 meter hambands were both showing up at two places on the dial.  After alignment, this problem disappeared.   

I realized later what my problem was:  I was putting far too much faith in the accuracy of the frequency readout needle on the front panel of the S-38E.  Many of these receivers had had their dials restrung over the years, so in many cases the placement of the needle was significantly off. 

MY RF ALIGNMENT METHOD

What you really need to do is this:  At first, don't pay much attention to where the red or yellow frequency indicators are pointing.  View them as rough measures.  Put a signal generator across on the A1 antenna terminal, with ground from the sig gen going to both A2 and GND.  Then put a scope probe across the same A1 -A2/GND terminals.  On Band 2 set your sig generator to, say, 4.0 MHz.   Tune the main tuning dial UNTIL YOU SEE A BIG DIP ON THE SCOPE.  At that point your front end is tuned to 4.0 MHz.    Now, you need to set the oscillator coil to 4.455 MHz.  I used a separate general coverage receiver (Radio Shack DX-390) tuned to this frequency.   I slowly tuned the trimmer on the oscillator coil until I could hear the oscillartor on 4.455 MHz on the DX-390.  At this point the front end is in alignment.  

It might not be that easy at first.  You may need to use the LC trimmer and the oscillator trimmer to kind of "walk" the two desired frequencies close to each other.  But by doing this, I was able to get the LC circuit to peak at the frequency at which the VFO was .455 MHz above the freq at which the LC signal peaked (the desired signal frequency).  Now, you may notice that the red frequency indicator is not at 4.0 MHz exactly.

Later I decided to tackle this problem of front panel calibration.  I decided to only worry about Band 2 (1.6 -5.0 MHz) and Band 3 (4.8-14.5 MHz). 

I picked two frequencies on these two bands that would use the same position of the red tuning pointer.  (I put they yellow bandspread pointer at 0. )  I chose 9 MHz and 3.1 MHz. 

For Band 3,  at 9 MHz I set up my sig gen and scope as described above.  With the sig gen on 9 MHz,  I tuned the main tuning dial for a dip at 9 MHz.  Then, keeping the tuning cap at the same spot, I moved the red pointer to exactly 9 MHz. (I just pinched the cord to the front panel with my finger and slid the red pointer down along the cord a bit.  I then turned on my general coverage receiver, set it to 9.455 MHz and turned oscillator  trimmer H (see above) until I heard the VFO at that frequency. 

I then moved the S-38E to Band 2.  I set the sig gen to 3.1 MHz.   Leaving the main tuning cap and the red pointer exactly where they were, I tuned the antenna coil trimmer L until I saw the dip on my scope.  I then turned the general coverage receiver on to 3.555 MHz and tuned oscillator trimmer K until I heard the oscillator signal at that frequency.  

The S-38E was then aligned for RF on Bands 2 and 3 with fairly good front dial calibration.  

Here is how to tell if you've got it lined up right.  Tune to the 75 meter band on Band 2 or to the 40 meter band on band 3.   Then tune 910 kHz BELOW where you found the ham band.  Do you hear the ham chatter in that second location on the dial?  If you do, the signal strength should be significantly lower than the signal strength 910 KHz up.  If you don't hear it at all, great.  If you hear it at significantly reduced strength, that's OK too.  the S-38E has only ONE tuned circuit between the mixer and the antenna, so you can't expect really great image attenuation. But if you hear the image at the same strength (or stronger!) than the desired signal, you have placed the peak of the antenna input tuned circuit in the wrong place.  See above. Try it again.  

IF ALIGNMENT

IF alignment was relatively easy:  I put a 455 kHz signal onto the grid of V1 and my scope on pins 5 & 6 of V3.  I then peaked the four IF transformer coils.  The IF cans in he Winterfest receiver were close to .455 kHz.  The coils in the junker were quite a bit out of tune.  

RECAP

On the first S-38E I assumed that I would have to change out all the electolytics and the older tubular capacitors.  So I did.   But with the second ("junker") S-38E  my replacement capacitors from Hayseed Hamfest had not yet arrived.  So I pulled out my Variac and made a somewhat hasty effort to re-form the original caps.   It seemed to work.  No smoke was released.  Nothing exploded.  There is no horrible hum.  But I could tell that all was not quite right.   The BFO really wasn't oscillating properly.   When the capacitor kit from Hayseed Hamfest arrived, I replaced all the caps.  The receiver works great -- including the BFO.   

Recapping in process.  Hayseed electrolytic in green can..  Old tubular caps being replaced by new yellow caps.  

Recapping completed   

ALIGNMENT OF THE JUNKER

Armed with my newfound knowledge of how to align an S-38E, I applied this skill to the junker and was able to get it aligned without difficulty.  

RE-STRINGING OF DIAL CORDS

On both of these S-38-Es there were dial string problems.  Interestingly, both problems were with the BANDSPREAD dial cord, NOT with the MAIN TUNING dial strings.  I see this as evidence that these receivers were used by ham radio operators.  You don't really need the bandspread to tune AM shortwave station, or AM broadcast band stations.  But novice ham radio ops would be frantically tuning that bandspread control up and down, wearing those dial springs out.  The Bandspread dial string on my Winterfest S-38E broke while I was turning it -- I replaced it but it is not really smooth, so I may try again.  The Bandspread dial on the junker broke also.  

Broken Bandspread string from Winterfest S-38E

Approximating the size for the replacement string

My re-stringing skills were better the second time around.  Tips:  use a small file to "roughen up" the spindle on the tuning knob (just the center of the spindle, so it will grab the cord better). Before installing, rub the new dial cord with an isopropyl alcohol pad, then run the string (still a a bit wet) several times over a piece of violin rosin.  This seemed to prep the dial cord well.  

Sometimes you need a bit more tension on the string to get the tuning spindle to grip properly.  Unlike the Drake 2-B, the S-38E does not have several hooks on which to attach the spring.  Not wanting to have to start all over just to add a bit more tension on the string, I came up with an easier solution:  Just put a few twists in the string near the spring by twisting the spring (with strings attached) around a few times.  Like this:  

You also need something that allows the indicator needle to grip the dial cord.  I cut open a short piec of heat-shrink tubing, put it over the cord at the desired spot, hit it with hot air,  then put a small dab of super glue at each end of the tubing. ( See above.)  This allowed the dial pointed to grip the cord very firmly.  Because you may need to move the red pointer during dial calibration (see above) I'd recommend NOT putting the drops of glue on the cord for the red pointer -- you may need to slide the red one up or down a bit. 

TUBES

On the Winterfest S-38E, the BFO had a very rough tone, making it impossible to copy SSB or even CW.  I thought it might be a bad set of filter caps, but after I replaced them, the problem was still there.  So I then replaced the tubes (warning -- that 50CS audio amplifier is expensive).  This fixed the problem 

The junker had original Hallicrafters tubes. 

LISTEN! 

Here are some YouTube videos of the S-38Es in action: 

SolderSmoke Podcast #219 SPECIAL CORONA VIRUS CRISIS PODCAST

SolderSmoke Podcast #219 is available for download: 

http://soldersmoke.com/soldersmoke219.mp3

14 March 2020

SPECIAL CORONA VIRUS EMERGENCY EDITION

We thought it would be nice to put out a special edition of the podcast to help listeners keep up their morale during this difficult time.  So we’ll do our regular kind of show, but we’ll try to emphasize things you can do to stay busy and keep up morale while stuck at home.

BILL’S BENCH (and operating position)

--NOVICE RIG ROUNDUP.  NRR.  Continues through this weekend.  Lots of fun.  Cool rigs worked:  Jon WS1K’s "Scrounger."   Greg AA8V’s 6X2 superhet.  And WN4NRR. 

-- S-38 MANIA.  My S-38E story.   Bought parts.  Bought a junker.  Fixed the first one then used the parts to fix the junker. Now I have 2 S-38Es. 

-- Got capacitor kit from Hayseed Hamfest.  FB.

PETE’S BENCH

Hilbert Transforms

AD9833 glued onto a Nano

Teesny and Radig and ZL2CTM

PWKSCDS 

More Mint

SOME THINGS TO DO DURING COVID 19 CRISIS

Sampson Boat Company Tally-Ho videos. https://www.youtube.com/channel/UCg-_lYeV8hBnDSay7nmphUA

WebSDR  NA5B  http://na5b.com:8901/

NRR http://soldersmoke.blogspot.com/2020/03/novice-rig-round-up-march-7-march-15.html

Revive an old boatanchor

Get back into shortwave listening.

Get on the air—make some contacts! 

Take a walk.  Get some exercise.  Listen to SolderSmoke and other podcasts when you walk.

Cook something from the famous Pasta Pete web site. http://www.pastapete.com/

Help someone who needs help.

MAILBAG

QSP – What a cool magazine!  Pete and I both have articles in there.

Hot Iron – great new issue also.  Lots in there.

Tony Fishpool G4WIF  Words of Wisdom on the NanoVNA.