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Showing posts with label minimalist radio. Show all posts
Showing posts with label minimalist radio. Show all posts

Friday, June 10, 2022

SolderSmoke FDIM Interview: Adam K6ARK and his 2.6 gram Mini-Pixie SMD Transceiver


I've not bee a big fan of the super-simple Pixie transceiver, but Adam K6ARK could make me a believer. 

Our correspondent Bob Crane W8SX interviewed Adam at FDIM.  You can listen to the interview here: http://soldersmoke.com/2022 K6ARK.mp3

The video above shows Adam's tiny Pixie in action in the California desert.  His rig is about the size of a postage stamp and weighs about 2.6 grams. FB Adam. 

Adam did a lot better with his Pixie than I did with my far larger and more complicated SST transceiver. He also did better than I did on 40 when I was using my ET-2 (two FET) transceiver. 

I liked how Adam recorded in the field the CW from his rig, I also liked his key (!) and his EFHW antenna and "tuner."  Adam's ability to cope with no CW sidetone was also admirable.  

Adam's YouTube channel is here: https://www.youtube.com/c/K6ARKPortableRadio

Thanks to Adam and to Bob Crane.  

Wednesday, November 17, 2021

SolderSmoke Podcast #234: PSSST, KWM-1, VHF Woes, Mighty Midget, TinySA, 17-12 Dual-Bander Advice Needed. MAILBAG


SolderSmoke Podcast #234 is available: 


Roots of SolderSmoke: The "Click and Clack" of ham radio? 
Influences: Jean Shepherd, CarTalk, Shortwave stations.
Steve "Snort Rosin" Smith WB6TNL?  No. Steve "Aching Sinus" Smith WA6SOC  

Pete's Bench:
PSSST Super Simple SSB -- 7 Transistors. Switching IF Module: 
PSST Details:  https://www.n6qw.com/PSSST_20.html
DC RX.
KWM-1 Resurrection "Shame Shelf".
How to make things work:
(Why the T/R diodes in the BITX 20 amplifiers?)
National Receiver.

Bill's Bench
Farhan's Talk to RSGB got me thinking of VHF 2 meter AM.
2 meter Benton Harbor lunchbox madness. SuperRegens Super Strange.
I broke my Maplin AF Sig Gen in the process. Fixed it.
Playing with MMMRX again. Put in 6 kHz ceramic filter. Sounds great SSB and AM.
Swept IF with noise, TinySA, and NanoVNA. Need better noise gen.
Mod to listen with TinySA (on blog).
Thinking of 17 meter /12 meter Dual-Bander IF around 21.4, VFO around 3.41 Mhz. Thoughts?
Sweeping double half lattice filter from Swan 240.  UGLY.  

MAILBAG:
--- ROOTS OF MAILBAG: Radio Moscow, Havana Cuba, HCJB, others.
-- Thomas K4SWL of the SWL Post: Could have been worse! Stairbag?
-- MY NOVICE LOG -- Heard back from ex-WN2RTH ex-WN2FLK ex-WB2RKK.
-- Drew N7DA worked Wes W7ZOI in Sweepstakes. FB.
-- Peter VK2EMU The movie Frequency and the Magic of Heathkits. Good, but not that good!
-- Thomas KK6AHT! Our old friend. Minima! Now has a young son! FB
-- Chuck WA7ZZE Saw QST profile. Sympathizes with Two-er trouble.
-- Tim M0CZP. Spell corrector. Vatican Diodes. Infallible!
-- Ramakrishnan VU3RDD Working on a NORCAL and a noise cancellation arrangement.
-- Skip NC9O said I was 40 Hz off on 17. But he had a reason to KNOW!
-- Steve K9NVD Glad he's a listener.  
-- Bob KY3R Novice Nostalgia. Should he use 75 watt bulb for dummy load? Yes! 
-- Todd K7TFC Video about why solder smoke goes into the face.
-- Anthony VU3JVX  Homebrew Antuino. I ask for help in moving freq to 450 kHz.
-- Jack NG2E Building Pete's DC RX.
-- Scott WA9WFA HBR-13 and MMMRX.
-- Stephen 2E0FXZ also got a FT-101 VFO.
-- Bob K7ZB on the air with 56 mW and a big antenna.
-- Dean AC9JQ Retired.
-- Allan WA9IRS Right to Repair update.
-- Farhan Invited us to Lamakaan ARC, Dec 11 or 12. Will be on QO100 Satellite Live! 
-- Many suggestions about my Apollo 11 Time Capsule. Still looking for ideas.

Happy Thanksgiving to all who celebrate this holiday!

Saturday, July 18, 2020

Overcoming the Complexity of the Michigan Mighty Mite: Walter's Sunrise Net Special


From Walter KA4KXX
June 21, 2020

Michigan Mighty-Mite:  Why So Complicated?

The April 2020 issue of QRP Quarterly magazine featured an article by Bob Rosier K4OCE which included a schematic for a “Ten Minute Transmitter” by G4RAW (SK), which apparently first appeared in SPRAT 82 in 1996. 
It is even simpler than the Michigan Mighty Mite, so this transmitter can truly be built on a solderless breadboard in about 15 minutes, because a complex coil is not required.  
The only tuning needed was for me to establish the correct value of the output series capacitor. 
This rig allowed me to check-in to the Sunrise Net (see details in blue text on my QRZ page) today on my very first attempt, and landed me a 549 signal report from 250 miles away.
The first photo shows the transmitter connected to a Transmit/Receive Switch mounted in an Altoids box. In the Transmit position the antenna is disconnected from my 1979 Heathkit HR-1680 receiver, which then coincidentally supplies a sidetone at an ideal volume level.  That little black pushbutton which can be seen in the second photo serves as my key, and works just fine for a five-minute daily QNI on the Sunrise Net.
Of course, part of the secret is having a crystal exactly on the Net frequency, and I have a few left, free to whomever in the Eastern U.S. is interested in building one of these simple Sunrise Net Special Transmitters and participating in our Net. 


Thursday, May 28, 2020

Tribal Wisdom from KE3IJ


Lots of homebrew wisdom on OM Rick's web site.  Excerpts: 

----------------
Why am I not on the air as much as I'm tinkering with toy radio circuits? Well, if some of the hams reading this don't mind my saying so, the manners of many of the people using the bands these days leaves so much to be desired that I often find more pleasure in futzing around with "minimal" QRP [low-power] ham-band transmitters and receivers, as well as good-old AM broadcast receivers, than in getting on the air anymore. 

So I've found a certain twisted fascination with trying to build the simplest pieces of junk possible, and seeing what I can pick up with them. I usually start by drawing a rough schematic on paper, then tack-soldering a haywire "spider-web" of components, as a 'first pass,' and then I rebuild the circuit more neatly once its design is finalized.

It still amazes me that we can connect some modified "rocks and sticks" together (that's basically what copper wire, silicon transistors, etc. really are, when you think about it) and hear voices and music magically appear out of nowhere...
-------------

He has many regen circuits.   And his Drake 2-B dial skirt looks just like mine.  

Visit Rick's site:  http://ke3ij.com/radios.htm


Wednesday, March 18, 2020

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: 






Monday, February 17, 2020

K6RRE's One Tube Rig Project


Mike will send us more info later... 

Sunday, December 15, 2019

Hangin' it up (the ET-2)


My ET-2 minimalist QRP CW adventure is (for now) officially over.   I have taken the rig - festooned with the callsigns of all the stations I contacted -- and have put it up on the wall.  This may be a new form of art.  I think I am the first radio amateur to do this.  I think it is pretty cool. 

Here are the stats:   I made 20 contacts with the rig. I had it on the air from 12 October 2019 to 7 December 2019.    Seventeen of the contacts were the result of my posting pleas for help on the SKCC Sked page and/or the Summit DX page.  Three of the contacts were completely random. One station -- W1PID -- provided four of the contacts.  Thanks Jim. 

My power out was usually around 100 milliwatts.  I used either a 40 meter coax fed dipole or a 135 foot doublet fed with window line. 

My best distances were Wisconsin and Georgia. 

Crystal control was the real limiting factor.  100 milliwatts didn't seem to be much of an impediment. The most amazing thing about this rig is the N0WVA regen receiver.  It took a lot of peaking and tweaking, and it took some skill to operate. but once I got it going it was an amazingly good receiver.  Really Amazing for just ONE J-310 FET. 

The last contact was really nice.  I was calling CQ and AA8OZ came back.  He was in a cabin on a trip with some scouts.  He too was on a wire antenna.  He was one of those guys who said WOW! when I told him about the rig.  We had a nice long conversation on 40.  It was a great way to wrap up the ET-2 adventure. 

Thanks to all who helped me make contacts and for all those who tried to work me. Thanks to N0WVA for the regen inspiration. And thanks to Glen Yingling W2UW (SK) for the ET-1 idea. 

The rig is standing by.  On the wall.  Perhaps it will return to service, maybe during solar max. 




Friday, December 6, 2019

My QRPp Signal Arrived in Utah -- 100 mW, 1950 miles, 26 db Above the Noise!


So yesterday morning I was calling CQ on 40 meters with my ET2 two-transistor 100 mW rig.  Later, I took a look at the Reverse Beacon Network (RBN).  Among the East Coast skimmer stations that regularly pick me up I saw an  outlier:   WA7LNW in Utah.  He's 1950 miles from me. And the RBN reported that his receiver had me at 26 db above the noise.  

Here is a screen shot of the RBN report.  Note the time: 1234 UTC.  Around sunrise here -- so gray line conditions.   



But the really BIG factor explaining that 26db s/n ratio is WA7LNW's location: 

"Realtime spots are being received at this location and uploaded to the Reverse Beacon Network."

"CW Skimmer antenna is located on cliff edge overlooking the Virgin River Valley, 1,200 ft. below."

We reported on the WA7LNW RBN station back in 2013:  https://soldersmoke.blogspot.com/2013/03/edgy-skimmer-antenna.html

Check out Jack's QRZ.com page: 

RBN is an important resource for QRPers and homebrewers.  Three cheers for Jack and all the skimmer stations.  Thank you all.  

Tuesday, December 3, 2019

ET-2 Contact #18 W4FOA -- RANDOM, UNSCHEDULED, AND NOT SPOTTED (Video)



On December 1, 2019,  my 100 milliwatt signal flew more than 500 miles to reach Tony W4FOA in Chickamauga, Georgia. And -- icing on the cake -- this was a random contact.   Tony just heard my CQ on 7038 kHz -- he had not been alerted to my CQ by any spotting site or by the SKCC Sked page.  I made a quick video of my side of the contact (above). 

In a follow-up e-mail Tony explained how my CQ sounded to him: 


"I was just listening on the 40 meter band and having been a QRP'er for 50+ years, I tend to notice the weaker stations, thus explains my calling you.  Also, your signal had that little "sound" of "yesteryear" when signals were not all pure, hi.  Had it not been for the QSB and QRN we could have had a long chat despite the weak signal from your QRPp.  Over the years I have QRP DXCC, 2 way QRPARCI WAS, and my best DX was two QSO's with 2 different VK7 stations on 40 when I was running 1 watt.  I've had a lot of different QRP rigs and still have some home brew stuff plus a couple of HW8s, HW9, Elecraft K2, etc..."  

From Tony's QRZ.com page, we learn more about his ham radio activities (note his homebrew rigs and his obvious affection for the Drake 2B and 2BQ) 

First licensed as WN4FOA in April 1954. Other calls held include EL2AD, 7Q7AA, PY1ZBA. Prefer to work CW but I do work some SSB, primarily DX-related. Enjoy chasing DX on all HF bands. Have 9BDXCC and I now have worked and confirmed all of the current DXCC countries . I enjoy QRP operation and currently use an Elecraft K2 (#2213),Ameco AC-1, Kenwood TS-130V SW-40, DC-40, HW-8 (2), Heathkit HW-9 Deluxe (WARC) PSA-9 HFT-9B SP-99 HM-9 HD-420 VLF, MFJ 40T and MFJ 40V VFO,  and a homebrew 6AG7/6L6 or a 6C4/5763  etc. I also enjoy operating boatanchor gear which includes a Johnson Viking Adventurer, Viking Challenger,  an Eico 720 and an Eico 723 with a HG-10B VFO and a Heath AT-1 and a Drake 2NT. Recently added a neat Lysco 600 transmitter and a Knight Kit T-60, Johnson Viking II, and a Ten Tec 544.  Boatanchor receivers include a Hallicrafters SX-100, SX-110, SX-71, Drake R4C and the incredible Drake 2B/2BQ combo. Recently added a Kenwood TS-830S, VFO-240, AT-230 and SP-230.


Tony W4FOA
Thanks a lot Tony.  73

Sunday, December 1, 2019

ET-2 Contact #16 -- Pete, KD2OMV, Builder of a 6T9er (with video)



Yesterday I had my  first contact using the ET-2's improved receiver.  I had watched the video of N0WVA's receiver and I realized that more sensitivity was possible.  So I tried to replicate his LC ratio. I think that helped a lot.  Today I posted a plea for help on the SKCC Sked page and then called CQ on 40.  I was answered by Pete, KD2OMV who was so loud that I had to take the headphones off my ears!  He was booming in, all the way from upstate New York. The receiver was running off a somewhat depleted 9 volt battery.   I made a quick video (above).  I'm just holding the I-phone up to the headphone, while also trying to copy the incoming CW. 

This was a really great contact.  Pete has a wonderful knack story.   He was licensed as a kid but never made a contact.  As an adult he found his old box of parts for a 6T9er in his parents house. So he builds it and uses the homebrew rig to make his first ham radio contact.  FB Pete. Thanks for the contact OM.  I wrote your call on the ET-2. 


Pete KD2OMV

Monday, November 25, 2019

SolderSmoke Podcast #215 Regen Madness, KWM-4, Paesano, Mailbag

Latest N2CQR version of N0WVA's Regen
SolderSmoke Podcast #215 is available. 

25 November 2019

http://soldersmoke.com/soldersmoke215.mp3

Happy Thanksgiving! 
Transit of Mercury
Book Reviews 

Bill's Minimalist Adventures:
-- 15 Contacts with the ET-2 
-- Ethical issues:  Is spotting yourself OK?  OK to use TWO FETs? 
-- Using Reverse Beacon Network
-- How to keep receiver on the right frequency
-- N0WVA's receiver sounded better, so I built a second N0WVA receiver
-- Regens reach back to Edwin Howard Armstrong's 1912-1923 breakthrough
-- Regens are fun, but they are not good projects for new builders. 

-- Pull out those Michigan Mighty Mites and listen for yourself via on-line SDR receivers.

Pete's Projects: 
"WHEN YOU KNOW STUFF YOU CAN DO STUFF!"
-- Left Coast SSB -- "The Paesano" -- To be featured in December 2019 SPRAT. 
-- Pete's KWM-4 on The Collins Collectors Net
-- Pete builds an N0WVA regen -- just in time for Sweepstakes CW Saturday! 
-- Arduino IDE Library trouble
-- uBITX 6.0? Fake News? 

No more BITX40 Modules.  Long Live BITX40 HOMEBREW! 

BITX-101.   Intriguing but on second thought, no.   

MAILBAG

Steve Silverman:  Lexicon:  "Audible Modes." 
Felipe CU2BD   Old buddy from the Azores
Michael Rainey AA1TJ:  Come back Mike!  The ionosphere needs you! 
Jack Welch  AI4SV is in 5G land  (Cyprus, not the cell phone thing). 
Walter AC4IM is at the San Vito Solar Observatory in Italy.  DO SOMETHING WALTER! 
Kostas SV3ORA has an amazing homebrew web site.  Thanks Kostas! 
Mike KC6SAX -- How to deal with the frustration of HB projects that don't work. 
Paul KL7FLR -- Pete is 7 Hz high. 
Keith W3ISZ  sent his photo of the Transit of Mercury.  

PLEASE USE THE AMAZON SEARCH BOX ON THE SOLDERSMOKE BLOG PAGE WHEN DOING YOUR CHRISTMAS SHOPPING. 

PLEASE SUBSCRIBE TO THE SOLDERSMOKE CHANNEL ON YOUTUBE. 


N2CQR's ET-2 with callsign Tattoos 

Thursday, November 21, 2019

Notes and Video on Doug N0WVA's Amazing Single Transistor Regenerative Receiver



When I had trouble getting the regen receiver in W2UW's ET-1 circuit to work, I turned to the internet and -- through AA7EE's site -- found the circuit of Doug N0WVA.   This circuit has completely changed my attitude toward regen receivers.   I have been exchanging e-mails with Doug -- below is a compilation of the info and regen-wisdom that he has shared.  More to follow... Thanks Doug. 
From Doug N0WVA: 

I came up with the diode after exploring ways to ditch the source r/c combo. The thinking was the closer I could get the source to ground the less voltage/capacitance fluctuations the gate would see.  Also I hated seeing everyone using .01 bypass to avoid audio oscillations and also losing audio gain. 

 The green LED works good but even better is directly grounding the source. Then feed a small negative bias through the gate leak resistor , adjustable via a potentiometer.  

On video, the audio is taken straight from the radio shack headphones that are connected to the audio transformer. The headphones are held directly to the phones case ( no hole for the microphone seen on the phone)  

The variometer is  made with I think a 1.25 inch pill bottle and the tickler inside is around an inch in diameter pill bottle. I used a pharmaceutical syringe's outside tube for a shaft. The tickler form has a couple holes cut for the shaft to pass through, it is a friction fit, more like slits cut and the rod pushed through. I used the soldering iron to melt round holes on the actual outside coil form for the shaft to turn on. On the back of the shaft is a small screw that goes through the outside coil form and screws into the syringe center hole that holds it in place. The tickler is one turn, I think, and routed through the inside of the shaft via small holes melted with the soldering iron.

A couple tweeks to mention is instead of a resistor in the gate, use a choke for less noise, makes a big difference, especially if you listen to AM.  Also I have been using a gimmick for the gate cap.  Just maybe a #36 enamel wire wrapped around  the hot tank lead 5 or 6 times and then I remove turns till the thing stops oscillating, then add a turn. This helps cut down even more on strong signal pulling. 

I have always been on a quest for more performance out of the least parts. This design was about as far as it could go, I think....

I have never done any real sensitivity tests on the regen, so you have gone farther than me already. One thing was noticed though is the gate resistor does add a lot of noise, especially noticeable just under oscillation in AM detection mode.  So I took a one meg 1/4 watt resistor and wound as many turns of #38 wire on as I could, probably around 80 turns, then subbed it out for the gate leak.  This dramatically improved the noise level just under oscillation. This was with a simple antenna band noise test. I think it also improved the noise under oscillating conditions. 

Adding extra antenna coupling will probably help a lot, but, there is a point where we start getting too much strong signal pulling.  The strong external bias battery trick will also improve this, although at the cost of extra parts.

Tuesday, November 12, 2019

Listen to the ET-2's Minimalist Regen Receiver



I'm guessing that most of you have never listened to a regen receiver that uses only one transistor.  So in these videos I've tried to capture the experience.  The audio that you hear from the receiver is from a small I-phone microphone taped to the one of the headphones on my DLR WWII headphones.  So you are hearing it just as I hear it -- with no additional amplification. 

Here is N0WVA's schematic.  When I tune the "regeneration" control I am turning the knob on the variometer.  The broad or "bandset" tuning control is essentially N0WVA's 25 pf cap.  My fine tuning control (the one that I use the most in the video) is the equivalent of the smaller cap in parallel with the larger tuning cap. 


I had trouble shooting the video for this post -- taping the mic to the headphone turned out to be a bit difficult.  So I ended up with a few extra (and imperfect) videos.  I include them here for anyone who might want to listen some more to a single transistor regen.  (I have a few more -- let me know if you'd like to see them!)



In the next one, at the end I throw the switch to transmit allowing you to hear what "sidetone" sounds like on the ET-2

Monday, November 11, 2019

SV3ORA's Amazing Homebrew Web Site

Kostas Giannopoulos has  a lot of really great homebrew information on his QRP web site.  It is reminiscent of the JF1OZL site. Check it out:  http://www.qrp.gr/index.htm 

For an example that his apropos of recent ET-2 discussions, Kostas has an extensive page with  many, many versions of his hyper-minimalist rig:  


Link to this project: http://qrp.gr/allbandtrx/

Thanks to Kostas for putting together such a great site.  And I really like the name of the site: Discrete Electronics.  FB. 

Saturday, November 9, 2019

SPRAT, the FETer, DLR headphones, and recent QSOs on the ET-2


Yesterday we had QSO #13 on the ET-2.  This was with Jim W1PID.  In an earlier contact Jim told me I had some chirp.  I fiddled with the coupling cap and the bias pot and am now T9!  These days, chirp is an endearing, nostalgic problem to have.  Thanks for the report and QSOs Jim! 

Contact #9 was with Fred K9SO.  He is in Wisconsin and QRZ.com put our distance at 633 miles.  That is our DX record so far.  Not bad for 92 milliwatts to a dipole on 40 meters. 

Most of my contacts come as a result of pleas for assistance on DX Summit or the SKCC Sked page.   But I did make one "random" contact: Contact #6 with N2VGA.  He just heard my CQ and gave me a call.  FB. 

I checked to see if OM Glen Yingling W2UW -- the guy who started all this with his ET-1 -- is still around.  He became a silent key in 2012.  But his ideas live on... 

SPRAT 137 (Winter 2008/09) has a great article by QRP hero G3XBM.  Roger built a version of the ET-1.  His was for 80 meters and he called it the FETer.   FB.   I was struck by his estimate of the sensitivity of the ET-1 receiver: -100 dbm.   I measured the N0WVA receiver (the one that I am using) has having a minimum discernible signal of -93 dbm.  Pretty close.  We may be at the limit of what you can expect from a single transistor receiver. 

SPRAT 137 had something else that really resonated with me.  G3YVF had an article on a minimalist rig using only one 6V6 tube.  Geoff opened the article with this warning "Don't try this unless you have a set of balanced armature type DLR 'phones as they are really sensitive."  I have a collection of old headphones that I picked up at hamfests in London years ago.  When building the ET-2, I checked all the old phones for sensitivity.  A set marked DLR was the most sensitive.  So Geoff's observation had been independently confirmed.   QRP Quarterly had an article comparing the sensitivities of old headphones -- we should dig that article up.   

SPRAT #137 is a reminder of what a great resource SPRAT -- The Journal of the GQRP Club -- really is.  As we say on SolderSmoke, if you are not a SPRAT subscriber you are just wrong!  Here is how to join GQRP and subscribe to SPRAT: http://www.gqrp.com/join.htm

Thursday, November 7, 2019

The ET-2 with Callsign Tattoos


Slots are still available! 
Get your callsign on the ET-2!

This rig will probably soon turn into wall art here at SolderSmoke HQ.  With this in mind I have started writing on the wooden base of the rig the callsigns of all stations worked. So far we have 10.   There is space for more.  

Frequency is 7038.6 kHz.    I usually try for contacts around 1430 UTC (0930 Eastern) and again at around 2130 UTC (1630 Eastern).  I post messages asking (pleading!) for assistance on the DX Summit site and on the SKCC Sked board.  

If you are within reasonable range for a signal in the 100 milliwatt range (antenna is either 40 meter NVIS dipole or a doublet) please keep an eye on the DX Summit and/or SKCC sites and maybe try to have a contact.  

Background on the rig here: 





Wednesday, November 6, 2019

Contact #10 with the ET-2 -- Perry K9NZ



Perry K9NZ was contact #10 with my ET-2 QRPp rig.   I found the above on his QRZ page.  Beautiful sentiments.  Most of us have similar stories, and similar feelings about ham radio. FB Perry.  

Saturday, November 2, 2019

SolderSmoke Podcast #214 is FINALLY out!



WE ARE WORKING TO IMPROVE THE AUDIO QUALITY.  IN THE FIRST RELEASE OF THIS PODCAST SOME OF THE AUDIO WAS KIND OF MUFFLED.  I TRIED TO FIX IT THIS MORNING AND I THINK I MADE SOME IMPROVEMENTS.  THE IMPROVED AUDIO IS NOW AT THE LINK BELOW.  


4 November 2019 (shockingly late!)

http://soldersmoke.com/soldersmoke214.mp3

The visit of Farhan to Northern Virginia
"I heard this guy from Southern California on 20..."
Fire Report from Pete

Pete's Bench Report
"When you know stuff, you can do stuff!" 
The CRAP rigs 
Old Boatanchors -- the Swan 120  with SUPER STABLE ANALOG VFO! 
Ten Tec rigs dial cord replaced with Chinese digi sig counter 
Pete's 500 mW encounter with a QRO curmudgeon
The ZL2BMI Challenge has Pete building crystal filters
The Left Coast Loafer CW rig 

Bill's Bench Report

ET-2 Refinements
N0WVA's Regen Receiver 
Going from ET-1 to ET-2
J-310s vice MPF-102
100 mW from a single J-310
Receiver kind of deaf -103 dbm MDS
10 contacts so far in 9 states 
THREE contacts yesterday.
Worked Wisconsin - 633 miles on 92 mW 
We are at sunspot minimum. 
"Rage, rage against the dying of the light." 
Simplicity is the real reason for CW 

IDEA:  Get those Michigan Might Mites on the air! 
Use Reverse Beacon Network to see if you are getting out 
Use SDR receivers to make contacts

MAILBAG
DL1AJG
KC6SAX
W9VNE
KA4KXX
N0WVA
Zl2BMI
AJ6BD  











Friday, October 25, 2019

Minimalist Masochism at Solar Minima -- But More Contacts with the ET-2

Dylan Thoams
  "Rage, rage against the dying of the light" 

I thought of that line from Dylan Thomas's poem when I read on G3XBM's web site that we are kind of at the very bottom of the solar cycle.  Roger wrote on 22 October: "Solar flux is 64 and the SSN 0. A=5 and K=0. As far as I am aware this is the lowest solar flux this solar minimum."   

I also thought of this as I pounded brass (Indian brass!) in an effort to make a few more contacts with my ET-2 two transistor rig.  Obviously venturing forth on 40 meters with just TWO transistors (one for transmit and one for receive) and crystal control AT SOLAR MINIMA is not for the faint of heart.  It is almost a Dylan-esque act of defiance. 

I have had to resort to please for help on the DX Summit, the SolderSmoke blog and the SKCC Schedule page.  Fortunately for me, the brotherhood has sprung to my support.  

W1PID (who gave me contact #3) also gave me contact #4 on 21 October. 

W4KAC in Hickory NC was contact #5.  This was on 22 October.  This was the only marginal contact so far.  He was running 5 W into an end fed half wave. 

Yesterday was a big day for the ET-2. I had two solid contacts: 

#6 was N2VGA in New York UPDATE:  Larry N2VGA confirmed by e-mail that this was a "random" contact -- not the result of my on-line pleas for assistance.  He just heard my CQ and responded.  FB.  

#7 was K4CML in Newport News, Va.  He switched to QRP himself at 2.5 watts for a nice 2X QRP contact. 

Looking at my Rigol 'scope, I now think I'm putting out about 150 milliwatts.  Not bad for a single J310.  I may have to invest in a heat sink.

40 seems most cooperative in the morning (around 0930 local) and again in the afternoon (around 1630 local). 

Thanks to all who have helped.  I will try to make a few more. 
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column