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Sunday, April 23, 2023
Helge LA6NCA's Altoids Tin Receiver
Tuesday, March 15, 2022
VK2BLQ's Two-Tube Regen with a SolderSmoke Dial
Monday, December 27, 2021
A Christmas Story: Mike AA1TJ Builds Receiver for 486 kHz, Listens to Fessenden Commemoration (Audio)
True to form, I began scratch-assembling my receiver yesterday afternoon just as Brian went on the air. Then again, a two-transistor regenerative radio for 486kHz isn't exactly rocket science. In any case, I was up and listening inside of a half hour.
What did I hear? Static. Just static. As a sanity test I quickly tuned down to 371KHz to find my favorite non-directional beacon, "GW," beaming in loud and clear from Kuujjuarakip.
Kuujjuarakip?
Kuujjuarakip is a tiny settlement of mostly Inuit and Cree inhabitants located up on Hudson Bay. The villages are primarily accessible by air and water so a robust radio beacon is an obvious necessity.
Satisfied that my receiver was working properly, I re-tuned to 486kHz. Back to static. On the bright side, at least there were no commercials. I continued listening intently until Vic called me to dinner. After the dishes were done I slipped back down to my underground radio shack for one last try.
I heard it right away. Beneath the static I heard a weak, out-of-tune, solo violin playing, "Oh, Holy Night." The signal strength varied wildly with ionospheric propagation. When the signal finally climbed high enough above the noise I ripped out the bipolar transistor audio amplifier stage, connecting my headphones directly to the junction field effect transistor detector output terminals. Of course the audio was far weaker now, yet I could easily follow the tune until it eventually faded away. Not bad for an estimated 15 watt ERP AM signal from a distance of 920km. And on 486kHz, no less, just a hop-skip-and a jump from the old 500kHz Maritime CW band; where countless ship radio operators went to send their last SOS.
Returning to the house, I emailed my reception report and included a short recording that I had made of it. Brian replied just after midnight; apparently, equally as stoked
"Yours’ is the best DX ever given your regen RX! Way to go! I just love it."
He went on to tell me that he was born and raised in Vermont, but he'd been working as a radio scientist down in Virginia since 1990. Told me his heart was still here in the Green Mountains and he was touched to learn his meager signal had found its way back there on Christmas Eve. All in all, a night to remember.
If you're still with me I hope you'll listen to the short NPR story in the provided link. It originally aired on the supposed 100th anniversary of this event. It's not just about radio history. It's about belief, memory and the myths we lug around in our heads. I thought it was well done.
Cheers,
Mike
Thursday, November 11, 2021
Scott WA9WFA's Beautiful HBR-13 Receiver (3 videos)
This is Scott WA9WFA's first homebrew construction project. He did an amazing job on a very complex project: a 13 tube superhet receiver. It features plug-in coils for multi-band coverage, dual conversion with IFs at 1600 kHz and 100 kHz, and several regenerative stages. Scott's construction is top notch. He tells us that he had been working on this receiver for several years, so long in fact that some of his friends began to wonder if it really existed. Well wonder no more. Retirement has provided Scott with the time to finish this project.
Wednesday, October 20, 2021
Super-Regeneration is Super-Strange
Friday, September 3, 2021
1BCG -- 1921 Transatlantic Test and the Upcoming 100th Anniversary
On December 11, 2021 the American Radio Relay League, The Radio Club of America and the Antique Wireless Association will recreate these historic transmissions on 160 meters near the same location that was used in 1921, using a replica transmitter constructed by volunteers at the Antique Wireless Association. This special event is your opportunity to relive a historic moment in amateur radio history.
The operating schedule and frequency for the 1BCG Transatlantic Tests Special Event has not been established.
Additional details will be posted here when they are available.
Wednesday, March 25, 2020
Technical Manual 11-455 -- Radio Fundamentals -- July 17, 1941
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.
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.
Thursday, May 9, 2019
Book Review: "Man of High Fidelity: Edwin Howard Armstrong" (Free Download)
I really liked the book. The author captures the technical achievements of Armstrong, while also describing vividly the world in which Armstrong lived. Being from the area, I especially liked Lessing's description of New York City and the Hudson Valley in the early years of the 20th century. This was the world of my grandparents; Lessing's book helped me understand it better.
For the radio amateur, I think the most gripping part of the book is the way Lessing describes the excitement of early radio. Armstrong was a true enthusiast for the new technology, and he was -- even as a teenager -- at the cutting edge. He was constantly striving to improve the technology, especially the receivers. Like us, he often became obsessed with his radio work, often forgoing sleep and missing family meals as he toiled away in his workshop. Lessing tells us of Armstrong's astonishment and joy, when, upon inventing the regenerative receiver, he was suddenly able to clearly receive signals from distant stations that previously had been barely discernible. Realize that when he was doing that, he was the only person on the planet who was doing it. He was the inventor. He was the first.
Lessing gives us a lot of great information about Armstrong's work as an officer in the U.S. Army Signal Corps in Paris during World War I. We learn more about how his desire to be able to detect noise from the electrical systems of enemy airplanes led him to the invention of our beloved superhet receivers. But my favorite Armstrong in WWI story involves his visit to the radio shack of the ship that was carrying him to the war. In the radio shack he found a conventional station. But he asked the operator if he happened to have one of the then new audion tubes. On the spot, Armstrong took the tube and rigged up a regenerative receiver. He and the ship's radioman then delighted in hearing stations that had never before been audible. Amazing.
I was less interested in the sad tale of Armstrong's legal patent battles, so I kind of skimmed through that. I'm also not much of an FM guy, so I'll save those portions of the book for a later date.
I think this is an important book about a significant part of radio history. It is well written. It gets almost all of the technical details right (but sorry Mr. Lessing, radio waves are not composed of electrons). The book deserves a place on the shelf of all radio history libraries. If you can't get a print copy, an online version can be downloaded here:
https://archive.org/details/in.ernet.dli.2015.189098
Thanks again to Dave W2DAB.
Friday, October 6, 2017
VE3BOF's Regens and DC Receivers
VE3BOF BENCH |
Sunday, October 16, 2016
Colin M1BUU's New Receiver Project
Thursday, October 29, 2015
Haunted by the Gong (Ooooo that's Awesome!) Donald's Knack Story
Bill:
Sunday, May 3, 2015
Drake Dongle Derring-Do -- 2B goes SDR (video)
Here I take my Drake 2B -- arguably the quintessential Hardware Defined Radio -- and connect its first Intermediate Frequency circuitry to an RTL-SDR Dongle, allowing me to digitally process, filter, and display (panoramically!) the signals being inhaled by the ancient receiver. Another cool tech twist: To get at the 455 kHz IF signal I use the "Q-Multiplier" jack on the back of the receiver. This connector was put there to allow for the use of a selectivity enhancing regenerative stage. So I'm using that connector for a similar purpose, but using technology that wasn't even being dreamed about when that Drake 2-B was being designed in 1961.
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Monday, January 19, 2015
When Your Local Oscillator Could Sink Your Ship!
Thomas KK6AHT is the intrepid radio amateur from France who moved to California and successfully built a Minima as his first homebrew project. Yesterday we got additional evidence that Thomas definitely has THE KNACK. It seems that he has been looking through really old radio magazines (clearly a symptom). He sent us this add from 1942. Yikes! Imagine getting your ship sunk because your Local Oscillator is not quite local enough!
- Today we have many many signals co-existing in the radio spectrum. During the war there was much less radio garbage and the military lit up the ether with transmissions very sparingly. But that is on the transmit side. That said the local oscillators (much like you have with the Si-570 on your Minima) used in receivers also produce RF that unless is minimized in some fashion is passed right through to the antenna and can be detected. Regenerative receivers are especially prone to this. Yes some military equipment used regenerative receivers. In fact the famous Paraset had to be constantly moved so it would not be detected.
- This receiver generated RF into the antenna was addressed by companies like Scott by shielding everything. That receiver in the photo probably weighed about a 100 pounds or more. Much attention was paid to RF bypassing and grounding. The cheap table top radios were RF generators par excellence.
- There was another approach developed in WWII to solve that problem and forms the basis of what makes work that little device sitting in your pocket. The odd part it was invented by a famous movie star. Look up Heddy Lamar in wikipedia. She and a co-inventor came up with the concept of frequency hopping and spread spectrum technology. By jumping frequencies it would be hard to pinpoint a transmitting station. That concept forms the backbone of our cellphone system
- Now the QRP part – if the RF output from a receiver local oscillator (milliwatts) can be detected from afar – then it follows QRP works!
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Saturday, January 17, 2015
Colin Finishes His BITX
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
Tuesday, September 16, 2014
Regen Receivers in Cuba
Hola amigo Bill:
I was able to pick up the podcast with excellent audio quality.
It is quite true that regenerative receivers are very much in use
even today... for example many if not all of the automobile RF
keys opening and closing the cars doors rely on a superregenerative
receiver circuit !!!
The radio that you copied at the blog works very well indeed
but it would be good idea to include a 5 kilo ohms volume
control.... Very easy to do indeed.
But let me tell you that my favorite regenerative receivers are
the classic ones, using vacuum tubes, and operating them
at voltages not higher than 50 volts... As a matter of fact many
tubes work very well at the 24 volts DC voltage level.
Using the classic Hartley circuit , there is no need for a hard to
find throttle capacitor required by the Armstrong circuit, because
the regeneration control works very well by using a potentiometer
to change the screen grid voltage of the detector.
I agree that using an RF stage ahead of the detector is always
a very good idea.... In my tubes regenerative I use a triode connected
6AK5 clone.... as a grounded grid stage....another 6AK5 clone ( the
6ZHE1P Russian tube ) is the detector and I use another 6AK5 clone
as the first audio amplifier then feeding an audio output pentode
all provided from a very simple basic 70 volts DC power supply.
BTW, using regulated DC on the filaments of the detector stage,
although a luxury by my standards is very helpful to reduce
hum .... 7805 regulator recycled from a bad motherboard, with
one 1N4007 from broken Compact Fluorescent Lightbulb inserted
in series with the regulator ground pin, produces a nice 5.7 volts
regulated DC that with a brand new tube is more than enough... with old
6ZHE1P recycled from Russian TV sets, you add another 1N4007 to obtain
6.4 volts regulated DC....
As said in the podcast, it is very important to do a very good
mechanical engineering job, place the main and bandspread tuning capacitors
away from the front panel, use isolated shafts between the capacitors
and the dial mechanism and make the front panel of a a thick steel
plate if possible.
There is a Dutch Cascode Regenerative radio that several Cuban radio
amateurs have built... it was designed with the amateur bands in mind so
the information about the tuning coils and capacitors lets you
obtain a very excellent bandspread on the ham bands.
I can send you that circuit that uses very common 12AT7-ECC81
and Russian equivalent double triodes.
Keep up the good work amigo and always tell us when the next
podcast is available. BTW it lasted for almost an hour !!!
73 and DX
Your amigo en La Habana, Cuba
Arnie Coro
CO2KK
Host of Dxers Unlimited radio hobby program
Radio Havana Cuba
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
Tuesday, September 9, 2014
"Off the Shelf" Regenerative Receiver
I call it the "Off the Shelf" Regen because the base on which it is built is scrap lumber from a recent shelf building project. Also, all the parts came out of the junk box.
6-10 MHz, AM, CW, SSB, Data. 4 transistors, no chips.
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
Saturday, August 16, 2014
SolderSmoke Podcast #164 Ancient Tribal Knowledge: Tube and Tube-like Radios
SolderSmoke Podcast #164 is available:
August 16, 2014
http://soldersmoke.com/soldersmoke164.mp3
ANCIENT TRIBAL KNOWLEDGE -- TUBE AND TUBE-LIKE RADIOS
Workbench Updates:
-- Pete's Arduino Keyer Project
-- Bill Builds (and LIKES!) a REGENERATIVE RECEIVER
-- The Joys of Regen Shortwave Listening
-- Grayson Evan's Tube (Thermatron) Book
-- Book review: "The Joy of X" (It's about math).
-- Shameless Commerce: A Plug for Bill's Book
-- Pete discusses tube projects
-- Making your own enclosures from Home Depot flashing
-- Amplitude Modulation
-- Compactrons, Nuvistors and other unusual tubes
-- BANDSWEEP: Radio Havana on Bill's new regen
Bill's Mate for the Mighty Midget Receiver
3 6U8 Tubes on a Benton Harbor Lunch Box Chassis
Nuvistor 2 meter down converter
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20