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Showing posts with label CW. Show all posts
Showing posts with label CW. Show all posts

Friday, June 13, 2025

Britain's Secret Listeners


Today Hack-A-Day has an unsually good report on Britain's Voluntary Interceptors. I was especially touched by the story of the guy who provided reports while still bedridden from devastating wounds received in World War I. 

https://hackaday.com/2025/06/12/crowdsourcing-sigint-ham-radio-at-war/#more-786810

I've had the video on the SolderSmoke blog several times.  It is so good that it warrants inclusion yet again: 

https://www.youtube.com/watch?v=RwbzV2Jx5Qo&t=228s

That regen looks a lot like the one I bought at the Kempton Park rally (London) so long ago.  I still have it.  And those headphones found in the old "radar" station look a lot like some that I have in my shack today.   And of course there is that HRO dial.  I build a whole receiver around that gem from Armand WA1UQO.  

I thought the comments on the ability to detect the nationality of the enemy operator from his Morse Code "fist" (sending style) was very interesting.  

Three cheers for the Voluntary Interceptors!  


Saturday, June 7, 2025

A FIRST! K1OA Contact with N2CQR -- All Homebrew with SolderSmoke Direct Conversion Receivers on Both Ends

At around 0630 EDT on June 7, 2025 I heard K1OA calling CQ on 7030 kHz CW. This was exactly where I had a crystal.  I called him, but he didn't hear me.  I sent him an e-mail.  We tried again -- he heard me calling him and I heard him responding by calling me, but I don't think we succeeded in exchanging signal reports. It was close, but no cigar.  

I had to walk the dog. Scott and I agreed to meet on 7030 kHz at 0730 EDT.  Arggh.  There was a QSO there.  I thought we might have to try to change frequency, but this would have been tough because both of us were crystal controlled on transmit.   Fortunately, the contact on 7030 kHz wrapped up.   Scott called me, I responded, and we were able to exchange signal reports.  I was so excited that I almost forgot to hit the record button on my phone.   But I caught the last minute or so.  See above.  

This was really something.  This really goes to prove what Dean and I have been saying all along:  this receiver is not a toy!  It can be used for real ham radio contacts.  And now we have had these receivers on both ends of a contact.  For transmit, Scott was using a KA4KXX transmitter with about 3 watts output.  I was on my Tuna Tin 2 at about half a watt output.   

Thanks Scott! And thank you Walter!  

Friday, June 6, 2025

A Tale of "Ten Minute Transmitters" and "Tuna Tin Twos": N2CQR Goes Back to CW QRP!

Inspired by K1OA and KA4KXX, I put the SolderSmoke DC receiver to work on the CW portion of 40 meters. At first I used a very (perhaps overly) simple "Ten Minute" transmitter. On June 4, 2025 I worked N2WJW in New Jersey. But the transmitter drifted as it got hot. So I switched to the more robust Tuna Tin 2 (TWO transistors!) and worked W2XS in NY and N9FGC in Indiana on June 5. With both transmitters I was "rock bound" -- crystal controlled. Power out was always less than 200 milliwatts. Antenna was a low to the ground dipole. The receiver was powered by our beloved 9V battery. The transmitter had a second 9V battery. Some observations: First, even if you CAN hear other signals, the different tones allow your brain to seperate them out (this has long been known to CW operators, but might not be readily apparent to newcomers). So even if the DC receiver is broad in frequency response and even though it IS also receiving the other side of zero beat, you can make CW contacts (unless, of course, another station is on a frequency that produces exactly the same tone as the one you are trying to work), even at very low power . Second, you don't always really have to be right on the other station's frequency. Here's why: If he is looking he can see you in his waterfall! So that SDR waterfall is now a friend to crystal-controlled HDR operators. Who would have thought? Above is a picture of the my station with the Ten Minute transmitter. See the notes I wrote on the QSO with N2WJW.

Ten Minute Transmitter (the gray thing is a CW key)

Direct Conversion Receiver

Tuna Tin 2 that replaced the Ten Minute Transmitter
Note battery and crystal

Saturday, May 31, 2025

Not a Toy! K1OA Making Contacts with the SolderSmoke Direct Conversion Receiver and a KA4KXX Transmitter

This goes to prove what we have been saying all along:  this receiver is not a toy!  It is capable of operating as part of a real 2-way ham radio station. Hall of Fame member Scott K1OA has paired his receiver up with a Merry Christmas transmitter designed by Walter KA4KXX and has been making CW contacts with it (see above).  Walter supplied the crystal and many of the needed parts.  Scott has already worked WA9RNE, N4HAY and W3RJ, and has tried making contact with Walter but no luck yet. He has gotten RBN reports from Germany and New Zealand. All that with just 3 watts.

This is not the first time this receiver has been out to use.   I made one contact with it using a "Ten Minute" QRPp transmitter that I had intended only to use for test purposes: 

https://soldersmoke.blogspot.com/2023/02/first-qso-with-high-school-receiver-100.html 

HoF member Aaron ZL1AUN used his receiver with an SSB transmitter to make contact using his receiver:

https://soldersmoke.blogspot.com/2025/02/soldersmoke-direct-conversion-receiver_23.html  We understand Aaron's article about the receiver has been published in "Break-In" magazine -- we hope to get a copy (electronic would be fine!) 

And who can forget HoF member Nate KA1MUQ who turned his "frying pan"  direct conversion receiver into a double sideband transceiver and used it to make phone contact with Idaho from California: 

https://soldersmoke.blogspot.com/2025/03/nate-ka1muq-turns-his-frying-pan-dc.html 

If anyone is aware of other contacts made using this receiver, please let me know.  

Thursday, April 24, 2025

The Copasteic Flow Blog -- German UHF Mobile CW Through a Geostationary Satellite, Agent Sonya's Homebrewing, More

It is always good to be reminded that someone out there is listening and reading,  especially when it is nice folks like Hamilton and his family. These are the people who built the TouCans rig that was (is?) suspended above San Francisco at the center of a dipole antenna.  

Following posts on the SolderSmoke blog, Hamilton has been monitoring the CW activites of a German ham who sends UHF CW signals through the sunroof of his car to the QO-100 satellite in geostationary orbit.  See above.  Very cool.  Listen live to the satellite here: 

https://eshail.batc.org.uk/nb/

Also cool is Hamilton's analysis of Agent Sonya's ability to homebrew a 1930s era CW station that could be used to communiate with Moscow Center.  Hamilton believes she could do it.  I have my doubts.  But the discussion is a lot of fun. 

Check our their blog: 

https://copaseticflow.blogspot.com/

Thanks to Hamilton and his kids! 

Thursday, March 6, 2025

Honorable Mention: Bruce KC1FSZ's SolderSmoke Direct Conversion Receiver ON A PRINTED CIRCUIT BOARD


This is obviously not the style of construction that we would recommend for new builders.  Thus the "Honorable Mention" category.  But Bruce is not a new builder -- in fact he has been a friend of the SolderSmoke podcast for many years: https://soldersmoke.blogspot.com/search?q=KC1FSZ   When Bruce sent us the above video and a report on his build of the SolderSmoke Direct Conversion Receiver,  we thought it was so cool that we wanted to share it with the community. Be sure to go to Bruce's GitHub page for more details: https://github.com/brucemack/kc1fsz-tjdcr


Bruce writes: My unauthorized modification is in the construction realm.  I've built Bill/Dean's original circuit in a compact form on a commercial PCB. This was a good chance to practice with KiCad, Chinese PCB fabs, and SMD soldering. Huge thanks to Scott KQ4AOP for making me the PTO form! The rig works great.  Thanks to Bill/Dean for leading such a successful/educational build project.

Hi Bill:

I had refrained from any postings of my work because the "purity" of my build may be called into question and I didn't want to create further distractions from your efforts. HIHI.  If you scroll down this page you'll get an idea of what I've been up to: https://github.com/brucemack/kc1fsz-tjdcr.

I also see that you've switched away from the Schottky diodes which I have not done, so I'll make that change to see how it impacts performance.

Moving fully into the realm of unauthorized deviations, I've been experimenting with the simple "frequency offset" feature shown in SSDRA on page 218. Hanging that simple circuit from the high side of C2 seems to provide the hook needed for a simple companion CW transmitter module. Joking aside, I'd never built an analog VFO before the TJDRC project, nor did I ever learn CW, so it's been quite interesting to try to create a sister board that stays true to the TJDCR ethos but can still make legit contacts.

Thanks for all the work you guys are doing to educate the rest of us,

Bruce KC1FSZ



Dean and Bill:

What you guys have done with this project is truly amazing. I didn't build the rig in the "original wave," but I recently made one just for fun.  I finally got around to looking at your Discord this weekend and was completely amazed...  And Dean's tutorial videos are surely headed for YouTube platinum status!

Congrats and 73s,

Bruce MacKinnon KC1FSZ, Wellesley, MA

Bruce:  There are several builders on Discord who would be very interested in your CW transmitter module. 

Thanks Bruce!  Congratulations!  73  Bill  Hi7/N2CQR

Saturday, March 1, 2025

Ken W4KAC's Wonderful SolderSmoke Direct Conversion Receiver -- with a Leaf Blower Tuning Dial


Ken W4KAC tells me that the tuning knob that he used to minimize hand-capacitance effects on his PTO started out as a gear in a leaf  blower.  I commented that the engineers who designed that gear surely never thought that it would someday be used in a homebrew direct conversion receiver.   

Ken lamented the polemical nature of the SSB discussion captured in the above video, but the clip does give a good demo of the SSB capabilities of Ken's receiver. And the video gives some nice close-ups of the receiver itself.  

Ken is a CW guy, and he has already homebrewed a QRP CW transmitter that he hope to pair-up with the receiver.  Here it is: 


Ken reports 160 mW output with a 377 mile reception report on the Reverse Beacon Network.  I made a contact with something similar: https://soldersmoke.blogspot.com/2023/02/first-qso-with-high-school-receiver-100.html

Ken wrote about the importance of persistence: 

Good morning. Just wanted to say, don't give up if your receiver is not quite right. Mine was working, I even posted a video here. When building the AF amp from the transformer end back, the Q4 stage was fine. I added Q3 and had a "motor-boating" oscillation when I applied a signal. I tore it all off the board and started over. I still had the problem, so being stubborn I continued on and kept adding more filter caps to quiet it down all I could. The receiver worked and sounded pretty good during the day when I copied WA4FAT and others. That evening was a different story when the band was working well and very full of signals. Very strong stations were ok, but I was getting lots of "hash" and noise other than normal band noise. FT8 was breaking through weakly all over the band along with other unidentified stuff. Yesterday morning I grabbed a new piece of copper clad and built and entirely new AF amp. It tested properly all through the build. Instead of installing that board I decided to find the problem with the original. I "thought" I had used new transistors when I rebuilt it the first time. Turns out I had probably put the original Q3 back, because replacing it cured the problem. I had an entirely different receiver last night. A pleasure to listen to. Don't give up like I did at first!!

Ken went the extra mile by building a SECOND Direct Conversion receiver.  So he may soon get TWO Hall of Fame credits.  Here is the second one that Ken built: 

Thanks Ken!  

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

For more information on how you too can build the receiver: 

Join the discussion - SolderSmoke Discord Server:

https://discord.gg/Fu6B7yGxx2

 

Documentation on Hackaday:

https://hackaday.io/project/190327-high-schoolers-build-a-radio-receiver

 

SolderSmoke YouTube channel:

Wednesday, January 1, 2025

Happy New Year from the Dominican Republic! SKN from HI7/N2CQR


As you guys know, here at SolderSmoke we are all about tradition.  Things like homebrewing, thermatrons,  crystal radios,  April 1, and even (at least once a year), MORSE CODE.   This morning was the morning for morse.  Straight Key Night my friends.  I got on the air with a QMX transceiver that my friend Bob had given me, and with a Sankar VU3XVR key that Farhan gave me a few years ago.  It all worked great.  First contact was with DF0W, then in quick succession WA3KCP, K3CQR, and K4DY.  All 5W 20 meter CW with a 1/4 wave vertical.  TRGHS. FB. HNY!

2 days of RBN spots, QMX barefoot to vertical at HI7/N2CQR
December 31, 2024 -- January 1, 2025 

Tuesday, December 24, 2024

So Many Great Pictures, So Much Radio History

 

I make it a point to go back to Wes W7ZOI's web site every once in a while.  That is always a good idea. This time I found myself looking at the page that described Farhan's 2017 visit.  Wow, just look at the guys at that table. 

-- Wes W7ZOI.  The man who launched the solid state direct-conversion receiver revolution.  Author of SSDRA and EMRFD.  And so much more. 

-- Roger KA7EXM.  Son of Wes.  The guy who developed the receiver for the Ugly Weekender transmitter.  

-- Rick KK7B.   The guru of phasing type direct-conversion single signal receivers.  

-- Roy W7EL.  Father of EZNEC antenna modeling software. And the optimized QRP transceiver, with the diplexer that we are using (perhaps improperly) in our high school direct conversion receiver project. 

-- Jeff WA7MLH.  Builder of so many of the great projects in SSDRA.  Made me feel good about gear that looked a bit rough.  

-- Farhan VU2ESE.  Creator of the BITX20, the BITX 40 Module, the uBITX, the sBITX and so much more. 

Just scroll through the site.  You will see Rick there with his Classic 40 phasing receiver.  Roy with his  Optimized transceiver.  Roger with the Ugly Weekender transceiver. 

Finally, the morse key that Farhan gave to each of the participants.  Farhan gave me one of these too.  I will try to use it from the Dominican Republic on Straight Key Night. 

Check out the site: 

https://w7zoi.net/Farhan-visit.html

Monday, December 9, 2024

Listening to 40 meters on the DC Receiver -- And I Heard a Distinguished Homebrewer!


I made the video above to show postential builders how useful our Direct Conversion receiver really is.  Late in the video (starting at 11:17), I heard a station calling CQ.  It was N4QR.  A check of QRZ.com shows it was Bob Null.  Here is picture from Bob's QRZ page: 


Check out the old general coverage receiver and -- wait for it -- the homebrew thermatron transmitter.  TRGHS. 

Google led me to this amazing video by Stever N4LQ that describes a book that N4QR put together on how to build thermatron transmitters from Junkbox/Hamfest parts: 


Steve N4LQ is in contact with Bob N4QR and asked him which transmitter he was using when I heard him.  Bob said he thinks it was his 30 watt 807 final transmitter. 


Thanks Bob. and thanks Steve!


Thursday, September 19, 2024

AG5VG's Homebrew 20 meter Superhet (with a CW rig Coming) (Video)

 Michael AG5VG finished this receiver last weekend.  He hopes to build a CW transmitter using an output of the Si5351.  Obviously I defer to Pete on that one.  Good going Michael.  I think it sounds great and looks even better.  

Monday, September 16, 2024

"QRP Classics" The Book that Got Me Started in Homebrew


A question this morning from Scott KQ4AOP caused me to Google this old book    On page 59 I found the article about my first transmitter.  Someone has put a copy of the entire book on the interenet.  Here it is: 

https://ham.v4.si/books/QRP%20Classics%20-%20The%20Best%20QRP%20Projects%20from%20QST%20and%20the%20ARRL%20Handbook.pdf


Friday, September 6, 2024

Ham Radio in the 1970s (and earlier, with some cool Jazz). What favorite rigs do you see?


Rogier PA1ZZ sent me this today.  I think I may have seen pieces of it before, but this restoration 
is really nice.  But ham radio seems to have been a lot cooler in California.  I don't remember it being so socially advantageous on the East Coast.   See Dilbert cartoon below. 

So many memories: 

-- The video opens with someone working on a QF-1 Q multipliers.  We have destroyed so many of these relics, in pursuit of the variable capacitors (which turn out to be not so good). 

-- A Drake 2-B on Field Day. 

-- An HT-37 in a shack.

--What looks like an HW-32a in a mobile rig. 

-- Maybe an HW-101. 

--  A BC-348. 

-- The ATV station with lots of homebrew gear was very cool. 

-- I also liked the single THERMATRON homebrew CW rig made from an old TV.  FB. 

-- The CW used in the video was all pretty good.  There was a lot of chirp.  This, of course, adds character to a signal.  FB.

After the video, they take a walk down memory lane, looking at ham radio magazines with some cool jazz playing in the background.  I saw a Swan 240 and a D-104.  The debauchery of the 1970s was evident on the magazine covers.  Even QST seemed to be caught up in this.  Check out the August 1975 cover of QST.  

Anyway, this video was a lot of fun.  Thanks Rogier!  

What favorite rigs do you see?   Make note of them in the comments. 


This video and the Dilbert cartoon reminded me of a discussion we had many years ago about THE KNACK: 

Thursday, May 16, 2024

A Light-beam QSO in Hollandia, Christmas 1944


This old QST article caught my eye, largely because my father was also in Hollandia on that  Christmas day in 1944.  He was in the Navy hospital there, recovering from wounds received in the battle of Leyte gulf (in the Philippines).   Hollandia, also known at Humbolt Bay, is now Jayapura, Indonesia. The picture above shows the harbor in 1944.  Rod Newkirk W9BRD went on to write QST's inspirtional "How's DX?" column for many years. 
----------------- 
From S/Sgt. R. H. Newkirk, W9BRD, "Christmas, 1944" QST, January 1946, pages 25 and 102.

Christmas, 1944


In a wartime world the singular and exclusive camaraderie that exists in the hobby of amateur radio results in so many unexpected and coincidental meetings between good friends, who have previously never seen each other, as to make such happenstance fairly commonplace. But I boast a tale in which time, place and circumstance combined to cause a similar occurrence to be most extraordinary.

The Liberty ship El Segundo Ruiz Belvis lay at anchor in the murky waters of Humbolt Bay, New Guinea, on a tepid tropical night in '44. In the absence of the moon, the Dipper and the Southern Cross scintillated bewitchingly. On the shore, the lights of the army base of Hollandia burned steadily in contrast to the varipowered signal blinkers which intermittently pieced the opaque darkness throughout the harbor. The latter were visual communication between ships and shore plus an admixture of ship-to-ship chatter, official and otherwise. There was an underlying tense tinge to the atmosphere and the stillness was broken only by the sharp staccato of the Belvis' blinker shutters as the signalman transacted port business with the powerful land station.

This was rendezvous. Our Liberty, with scores of army personnel aboard, had here become a unit in the formation of a huge convoy. Crammed into holds, on hatches and into every available nook and cranny of the steel deck, we were Leyte-bound. Stifled, sweaty and hungry on our two meals per day, we wore out deck after deck of pinochle cards and read every available piece of literature over and over again. It was almost a month since we had left Sansapor, scene of our last operation. We were exuberant in the knowledge that we were soon to leave New Guinea.

Christmas was but a few days away and we had had no mail for weeks. Men leaned languidly on the rail and thought of home while others dreamed of the same in their cramped quarters. The circumstances certainly made this Yuletide one to be long remembered. Nevertheless, all that would feature this day for us would be a possible piece of priceless turkey added to the usual dehydrated viands. Just another dragging equatorial day to be piled atop hundreds of others like it.

It was ten o'clock. I was wide awake; only my eyes were tired. Presently, I found myself detachedly reading the blinkers which poked their focused fingers indiscriminately about the bay. My quarters, in the cab of a 399, were on the port rail amidships and afforded a good view across the water. I became absorbed in various bits of chatter between nearby vessels. It struck me that QRM was quite heavy tonight—a sort of an optical 80 meters. I saw one of the lights sign off with a "73." This was interesting as among the host of merchant marine signalmen, hams are spread pretty thinly. I seized my M-1 torch and focused an insipid beam in the direction of that ship. I sent CQ CQ CQ K. A ham call sign is a cumbersome thing to handle with a blinker. Furthermore, I had no faith in the DX powers of my 3-volt flashlight bulb. I was therefore elated when a bright interrogatory sign beamed forth, aimed obviously in my direction. Contact! True, it was outside the hambands, but band divisions in the microwave region are indefinite anyway.

I was still dubious as to whether my man was an amateur. Rather than complicate matters immediately, at this speed of 8 words per minute, I began in the language of the layman: HELLO PAL WHERE YOU FROM? K. Back in an agreeably rhythmic style came: R TULSA OKLA NAME IS HAL K. The given name and place struck a subconscious inner chord vaguely. Next, I blinked: GE HAL IM ROD FROM CHGO K. There was a pause. He reoriented his beam to compensate for tidal drift and then startled me with: W9BRD DE W5EGA K.

The night quickly took on an exhilarant aspect as we lapsed into ham vernacular, spiced with many Morse slaps on the back. Hal Frank was no other than an old c.w. crony of mine. We had heckled each other on 80, 40 and 20 a countless number of times in the prewar days. In memory I was hearing again that beautiful swing and T9X sledge-hammer signal off his three-element rotary. We discovered mutual ham friends and we exchanged much welcome information and recounted bygone days. He was quite amazed to learn that I was behind a mere GI flashlight (with low batteries at that). The QSO continued far into the night—the next and the next.

We seemed destined to rot in our anchorage. The convoy movement was postponed from day to day. However, this Christmas season took on a much different aspect for me as arrangements were made and, at 0900 Christmas Day, my friend, Wilbur Kuure, W9YNY, and I debarked unsteadily down the ladder and made our way across an undulating swell to the Liberty ship Chittenden. There, we met Lt. Hal Frank, W5EGA, personally, for the first time. We all agreed that it was quite a small and bizarre world that December 25th.

Verbal reminiscences cluttered the air within W5EGA's exceedingly neat cabin for several hours. Shelves in his quarters were lined with excellent reading material including many late QSTs. Compared to our situation aboard the Belvis, Kuure and I thought this a bit of heaven.

We were thoroughly acquainted by the time we appeared in the officers' mess. As the cuisine took shape before us and disappeared into our eager gullets, my army pal and I felt somewhat sorry for our less fortunate buddies on the home ship. But such is life. We had, in nautical terms, a "Little Roundhouse," consisting of a generous helping of everything on the menu. We swept our plates clean to Hal's amusement. I remember, most distinctly, the dessert of apple pie and ice cream.

Nightfall found Kuure and me "back to earth" on the Belvis after a most delightful Christmas Day. According to plan, we blinked a "goodnight and thank you" to W5EGA through the twilight. That was our last QSO of that series. Not long after that we weighed anchor and headed for our next stop on the long road back home. Our holiday was over, a new year had begun and there was still a war to be won.


From S/Sgt. R. H. Newkirk, W9BRD, "Christmas, 1944" QST, January 1946, pages 25 and 102.

Saturday, May 11, 2024

Helge SM/LA6NCA Activates Colorburst Liberation Army in Sweden!


FB Helge.   This is really cool.  I didn't realize until I saw the schematic at the end that he was on 3579 kHz -- that is the old color-burst frequency, and now the frequency of the Color-burst Liberation Army. 

It was challenging to do this without sidetone.  But there appears to be a bit of room left in the matchbox -- could he squeeze in a few more components for a rudimentay sidetone?  Maybe just a piezo buzzer across the key? 
VIVA EL CBLA! 

Saturday, May 4, 2024

W4YWA's Homebrew Rig on 20 Meters

 

Ed W4YWA is far too modest -- he has built a very FB homewbrew transmitter.  Congratulations Ed.  I think your original plan to use a Web SDR receiver will work, if you and the other station are just willing to pause for an additional second or two to let the internet catch up with the real world.  Also, you might find some Web SDRs that have less latency than other.  You could used a little SW receiver or a simple buzzer for your sidetone ( I think sidetone is your most pressing latency concern.)   My suggestion is to try to get a few contacts using the Web SDR (perhaps via schedule -- try the DX Summit or the SKCC web page to set some up). Then build yourself a simple Direct Conversion receiver to use with this rig.  You don't have to try to build a VFO at 14 MHz (that can be difficult) -- you could build one at 7 MHz (use the circuit from our High School receiver project) and pair it up with a "Subharmonic Mixer" so that you can tune the 20 meter band.  Please keep us posted on your progress. 

Ed writes: 

Home-Brew Fun and Failures 


I’m not much of an amateur radio operator, but I enjoy the electronics, self leaning, and the home brewing aspects of our hobby. Here’s an account of a recent effort. While trying to re-learn CW, I discovered web-based SDR sites with waterfall displays, all kinds of filtering and better performance than any of my vintage station receivers. So, I start thinking….. if I had a little transmitter and a simple antenna, along with internet access, I’d have a capable station to take on vacations to the beach. Yes I know, there are web based amateur radio stations, but remember the operative words here are: “Home Brew.” After pinging the Google machine, I came up with a two-stage 1-1/2 watt transmitter sometimes refereed to as the “Universal QRP transmitter,” or the “Little Joe Transmitter.” There’s lots of variations of this circuit but it is essentially a Colpits crystal oscillator coupled to a class-C PA. I chose 20 meters because I didn’t want to hire an arborist to string my antenna. My design modifications included a transistor switch that keys both the oscillator and PA, a VXO circuit, power transistor protection, and a 5-th order Chebychev low pass filter.

Notice the (do I dare say, good looking?) enclosure. In a former life, it was a SD card reader from a defunct PC. FYI, gutted CD/DVR drive cases also make fine enclosures for your home brew projects. I opted for a “foil side up – without holes” for my PCB design. All the parts are soldered down on the lands - no PCB holes. I wanted to change parts without having to do open heart surgery. Functional placement was also important to me. I took more time than I’d like to admit to organize the circuit layout as I did, but I’m glad I did.


When all was said and done, it was time to power it up and….. and …. nothing! Not a single function worked! I won’t bore you with the debug stories that took forever, but the only part I didn’t have in my junk box was the PA transistor. I got 10 of them for $5 off the Internets and they all failed to deliver. I could only get a few tenths of a watt from my design. In a fit of desperation, I un-soldered a PA transistor from an old CB radio and it immediately gave me 1.8 watts of pure CW ! ! ! ! Happy dance, happy dance! But, save your accolades. There were lots of other problems; they were my problems not component issues. For example, before you design your own RF filter be sure you understand cutoff frequencies. They are not the same for every filter design. I suggest Paul Harden’s NA5N site to learn about PA output filters. My first few filter attempts had the transmit frequency well down on the attenuation curve. I was attenuating my own signal ! So, after weeks of “why don’t the damn thing work,” I got a clean signal. Whoo-Hoo!


Now it was time to unshackle the dummy load and see where I can be heard. And, Oh boy… I’m beaming into Pennsylvania, Georgia and Northern VA, all from an inverted V on a tripod mounted paint stick, held apart with two tent stakes. But then, reality took over. My grandioso plans for using the web-based SDRs as a station receiver (and the side tone oscillator for my transmitter) didn’t account for the latency delays of the SDR software. If you ever listened talk radio and the host says, “Turn your radio off – the delay will make you sound like a ….” you know what I’m talking about. You would think that someone who over thinks everything, would have foreseen this issue before spending countless hours of breathing solder fumes? Humility and eating crow are my better traits. But not to worry, I’m not ready to give up. Stay tuned for more adventures of Home-Brew Fun and Failures. 

73s W4YWA

Wednesday, May 1, 2024

KE5HPY Builds a QRP Transmitter

 

FB Chuck, very cool.  Please send us more reports on this rig.  
Chuck has been on the blog many times, with many projects: 
73  Bill 
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Bill/Pete:

 

Thought you would appreciate a recent project inspired by the fabulous EMRFD.  This started as a test bed W7ZOI universal tx to evaluate my stock of RF BJTs and employ some FT-243s in the shack.  That was interesting by itself but the 16-32 dBm output (choice of device really matters!) did not reach the intended targets using my 40m dipole.  So, add a W7EL RF PA and a nifty, clean 7W emerges after damping output from Q2.  The final is pleasantly efficient and needs only a modest heatsink to survive key down for 60 seconds.  KFS then reported S7-9.  Success.  Time to box it up and go XTO, add a meter output at 30dB down and an RF driven LED indicator.  Left room to add an ATtiny85 CQ keyer but ran out of time.  Had to move house and knock down my 40-6m antennas.  That was the most painful part of moving.  So this rig sits while I find a new place to hang antennas.  Eventually, the TX will get a RX mate when it is possible to box up a 40m DC RX with Si5751 and OLED display. Am still trying to solve how to mount an OLED display cleanly in an aluminum box. First, I have to reconstruct my workbench.

 

Keep up your good work, and that is no April Fool’s joke. 

 

73,

 

Chuck KE5HPY


Sunday, April 21, 2024

The War of the Worlds -- In CW -- By Chuck Adams AA7FO


This is for CW fans, or for those wishing to improve their CW skills.  You can now listen to the entire H.G. Wells book in CW, thanks to Chuck Adams, AA7FO. 

This seems very timely becasue my son and I are watching the NETFLIX version of "The Three Body Problem" by Cixin Liu.   This deals with an entirely different war of the worlds.  

Check out Chuck's CW version of the book.  Thanks Chuck! 

https://www.aa7fo.com/war-of-the-worlds.html

Sunday, April 7, 2024

Another CW Contact with the SupeRX/TX 40 (Video)


I changed the crystal in the transmitter.  I got a different rock from Mouser and am now on 7030.  

Wednesday April 3, 2024. On 40 meters in the afternoon with Mike KM4KY in North Carolina.

Thursday, April 4, 2024

MXM SupeRX/TX 40 Rig Info

 

My SupeRX/TX 40 -- now on 7030 kHz

Click on schematics for a better view





Article on MXM Industries of Smithville,Texas:  



Click on images for a better view

Click on images for a better view


Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column