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Monday, April 15, 2024
A QRP Quiz Question
Monday, April 8, 2024
The Doug DeMaw Article that got me into Homebrew Double-Sideband
Sunday, April 7, 2024
Another CW Contact with the SupeRX/TX 40 (Video)
Thursday, April 4, 2024
MXM SupeRX/TX 40 Rig Info
Click on schematics for a better view
Friday, March 29, 2024
A QRP CW Contact (Video) with the Winterfest MXM SupeRX/TX 40 (1 Watt, Crystal Controlled Transmitter)
I picked this transceiver up at Winterfest for one dollar. 40 meters. Superhet receiver with 455 kc ceramic filter and 2 NE602s. Crystal controlled one watt transmitter on 7039.5 kc. I emailed Jeff KA2BKG and asked him to slide up a bit to my freq. I am glad he did. Thanks Jeff.
Wednesday, March 27, 2024
KD0FNR's Amazing San Francisco TouCans Rig -- A Rockmite and a Tuna Topper in a Pineapple Can Mounted on the Dipole in a Shopping Bag
This post has a definite San Francisco vibe.
Hamilton KD0FNR appeared on the SolderSmoke blog way back in 2011. Perhaps he should join forces with N6ASD who lives quite close to him in SF, and seems to share radio interests. Also in their area is the esteemed Bay Areas blogger and homebrewer Dave AA7EE ; Dave recently sounded the CBLA alarm, alerting us to the presence of an intruder on 3579 kHz. In the process, Dave mentioned the Pt. Reyes Web SDR, the presence of which came as welcome news to Hamilton. Finally, Dave and Hamilton mention the KPH Web SDR, which brings to mind Dick Dillman W6AWO who has been on the SolderSmoke blog several times.
Hamilton and his kids have their rig (a Rockmite and a Tuna Topper in a Dole Pineapple can) mounted at the feedpoint of their dipole (in the red shopping bag above). They link to it via WiFi and Bluetooth. FB. Thomas Witherspoon has a nice presentation (by KD0FNR) of the TouCans project on his blog: https://qrper.com/2023/12/field-radio-kit-gallery-kd0fnrs-rockmite-20-and-tuna-topper/
Hamilton KD0FNR writes:
At the moment, the kids whose dad I am, better known as the gang—12, 10, and 8 year-old Diaze, Mota, and Tawnse.. all internet aliases—are big into 20 meters QRP CW with Project TouCans, a Rockmite coupled to a Tuna Topper. The radio and the amp that popped us out of QRPp to plain-old QRP are both housed in a Dole Pineapple can with a tuna can as a cover and antenna mount. The whole rig is still very much mounted in our half-wave dipole!
Project TouCans consists of a Rockmite feeding a 5 Watt Tuna Topper, all of which is housed in our dipole antenna. The Rockmite has a single crystal bandpass filter on it's rx input. That makes it a pretty wide reciever which is fine, but it's particularly sensitive to its tx frequencies, 14075.5 and 14058 kHz AND—for some reason I have yet to understand—10459 kHz. By watching the SDRs that now—thanks Dave—envelope us here at our home QTH in San Francisco, we can see the frequencies of incoming signals. That information keeps me from responding to 14059 kHz signals in vain.
And now, the headphone repeater: TouCans is completely wireless with respect to the ground. That means there's no power line, no feedline, no keyer lines and no headphone line. Keyer controls are handled via wifi to a Raspberry Pi Pico-W on the rig while audio is brought back to my headphones via Bluetooth. Power is provided by a USB-C battery pack that lives in the rig which is mounted above us in the antenna. (Yes, all of this is becuase I thought feedlines matches and baluns were too mystical and hard to understand years ago. Yes, this has probably all been more work than a balun. Yes, I am still totally enamored of my original design decision. :) ) Anyway, the bluetooth range is about 50 feet and the wifi range is shorter than that. The short of it is—pun not intended—that I can't quite use the rig while I'm in my office. But, I can send CQ to the rig every half minute or so via a memory keyer, then turn on the SDR in my office, and then sprint a bit closer to the rig when someone calls back. (It helps that houses in SF are a bit tiny.) So, SDRs are kinda an integral part of our QTH setup and it's awesome to learn about a new—to us—one! Thanks again!Monday, March 11, 2024
Radio Items Picked-up at VWS Winterfest 2024 Hamfest
-- Behind the MXM there is a nice box marked "Diode Detector" I opened it up and there is just a solid state diode and a 50 ohm resistor to ground. Box may be useful.
-- I got a couple of books: "Weekend Projects" 1979 from ARRL, and "A History of QST -- Volume 1 Amateur Radio Technology 1915 - 2013" 2013 from ARRL.
-- On top of the Weekend Projects book you see a "Crystal Holder" from Gross Radio of New York City. W1UJR has some good history on this company: https://w1ujr.com/written-word/gross-radio-company-circa-1931/ This device seem to be intended to hold in place a raw piece of quartz! Cool.
-- To the right of the books there is a serious-looking VFO. One dollar! Deal! It is a CB VFO, but the markings say it puts out 5.44 to 5.99 MHz. So it should be useful. The dual speed dial is very nice.
-- Above the VFO is a nice step attenuator from the "Arrow Antenna" company of Loveland Colorado.
-- Further to the right are some Electric Radio and Antique Wireless Association magazines that Armand WA1UQO gave me. Really nice. The AWA mags have a very thoughtful piece (warts and all) on Jean Shepherd. And the ER pile has an article by Scott WA9WFA that mentions my work on the Mate for the Mighty Midget receiver. Thanks again Armand!
-- I also got some ADE6+ surface mount mixers. The price was right!
Thanks to VWS for putting on this great hamfest!
Wednesday, February 14, 2024
We Get Mail! Red Poster? Really a Tapestry from Ecuador
Listener Tobias was laid up yesterday, following the extraction of wisdom teeth. (This seems like an appropriate follow-up to our talk in SolderSmoke Podcast #250 of sBITX "wisdom files" to correct FFT "hallucinations.") Tobias does not appear to have been hallucinating, but he was having trouble seeing what he thought to be a "red poster" in my shack.
In fact, what he was seeing was a red tapestry from Ecuador that was sent to me by Galo Constante HC1GC way back in 1993. I was in the Dominican Republic, running my first ever real homebrew transmitter. Here is an article about this project: https://www.gadgeteer.us/TXHB.HTM I think Galo was also QRP homebrew. My log shows that I worked him eight times from the DR.
Mitad del Mundo = Middle of the World (a reference to the equator).
Here is the QSL I got from Galo:
Sunday, January 14, 2024
QRP Trigger Warning! 500 kW from WLW (great video)
Thursday, November 30, 2023
AA9IL's Sputnik Tube, Altoids Tin Transmitter
Tuesday, October 10, 2023
A Low-Power (QRP) Contact from Australia to Spain (with video from both sides!)
Wednesday, September 27, 2023
Ciprian YO6DXE Puts the Michigan Mighty Mite on AM! (video)
Saturday, June 17, 2023
Sam WN5C Builds a Michigan Mighty Mite and Takes it to Lake Thunderbird
Thursday, June 1, 2023
George Heron N2APB talks about Coherent CW at FDIM: Interview #7 by Bob Crane W8SX
It was great to hear George's voice again. I was a big fan of his "Chat with the Designers" podcast. And it was great to see that Pete Eaton WB9FLW (an old friend of SolderSmoke) was also involved in this presentation.
At FDIM George was talking about Coherent CW. Now, my views on CW have been made quite clear, but I am going to deliberately avoid snide comments about how Coherent CW might be a contradiction in terms. Thank you. I think this is something that Pete N6QW and I can agree on.
Nevertheless, this is all technically interesting. This reminds me of what happens with WSPR. But I wasn't quite sure what George was getting at with his discussion of the phase of the incoming signal -- I can see the need to get the receivers' narrow filter exactly on the transmitting station's frequency, but why the phase?
Here is Bob Crane's interview with George:
http://soldersmoke.com/N2APB23.mp3
And here are a couple of things with background info on CCW.
https://www.sigidwiki.com/wiki/Coherent_CW
http://www.arrl.org/files/file/Technology/tis/info/pdf/7509026.pdf
Thanks George, thanks Pete, and thanks Bob.
Monday, May 29, 2023
Eric Schwartz WA6HHQ of Elecraft -- FDIM Interview #4 by Bob Crane W8SX (audio)
It was really cool that our correspondent at FDIM caught up with Eric Schwartz WA6HHQ of Elecraft. Some highlights from the interview:
-- Eric met Wayne Burdick through the NORCAL 40 (Wayne had designed it, and Eric was writing articles about it). That was a very influential rig -- it was the basis for a book and a CALTECH course by David Rutledge.
-- Elecraft has a strong QRP element in its DNA.
-- The K2 is "Heathkit style" and offers the builder the opportunity to understand the rig at the component level.
-- Eric says that using something you built yourself is worth at least 10db.
Here is Bob's interview with Eric:
http://soldersmoke.com/WA6HHQ23.mp3
Thanks Eric and thanks Bob.
Wednesday, April 26, 2023
Retro QRP Rigs of the 1960's, 70's, and 80's -- Video by Mike WU2D
Friday, April 7, 2023
More Info on the Cuban Jaguey Solid State DSB Transceiver
Continuing our search for information the Cuban "Jaguey" DSB rig, Trevor Woods pointed me to Dick Pascoe's QRP column in the (below) July 1998 issue of Ham Radio Today. I think the first SPRAT article about Eric Sears' ZL2BMI DSB rig was in SPRAT 83 in the summer of 1995. This fits well with the sequence described below by Arnie Coro CO2KK.
I am still looking for a schematic and pictures of the Jaguey rig: If you can help in this, please let me know.
Sunday, February 26, 2023
First QSO with the High-School Receiver -- 100 mW to Dipole. (with videos) -- Homebrew to Homebrew!
This little contact is a reminder of the fun that can come from using simple, homebrew, QRP gear. It is really amazing that the very first contact with this receiver was with another homebrew station. This all reminds Dean and me of something we have been telling the students: the little DC receiver they are building is not a toy -- it is capable of being used in real, long-distance contacts.
Sunday, January 15, 2023
Working Walter KA4KXX from Hispaniola
Walter KA4KXX in Orlando has been a prolific builder of rigs for many years, and has been a great friend of SolderSmoke: Here are some of the SolderSmoke podcasts and blog posts in which Walter's solder melting was mentioned: https://soldersmoke.blogspot.com/search?q=KA4KXX
As we approach the end of our current stay in the Dominican Republic, I could not miss out on the chance to work Walter with his homebrew rigs. Even though the space weather was stormy, and my dipole was droopy, we arranged to meet up on the high end of the 20 meter CW band this morning. See the results in the video above. A solid QSO with Walter. He says it is HB2HB, but truth be told I was on a uBITX that was built more by Farhan than by me. But this was a great contact. Walter started with a 50W rig, then switched to his 3 watt rig with a DC receiver. FB
Here is the e-mail I received from Walter after the QSO:
Dear Bill: