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Saturday, February 4, 2023
To Re-Cap or Not to Re-Cap -- Curious Marc on the Electrolytic Controversy in Ham Radio
Friday, February 3, 2023
CuriousMarc (AJ6JV) Goes to a Hamfest
Checking Into the Vienna Wireless Pow-Wow Net after 23 Years!
Thursday, February 2, 2023
Direct Conversion Receiver Bandscan -- 40 Meters early on a Thursday Morning -- With W1AW/4
Wednesday, February 1, 2023
Hammarlund HQ-100 Misidentified in 1963 FCC Film
Oh the indignity! It appears at 7 minutes 16 seconds in this FCC film. It is clearly an HQ-100, but the FCC subtitles identify it at an HQ-110. It is clearly an HQ-100 ( the model without the clock).
https://www.youtube.com/watch?v=LzPIOfpKkRM
As the owner and operator of what must be one of the few remaining HQ-100s, I feel obligated to defend the reputation of this fine piece of shortwave gear.
How many of you have HQ-100s?
Tuesday, January 31, 2023
Curious Marc's Lab and Workshop
Sunday, January 29, 2023
Rick N3FJZ Builds the Mixer for the High School Direct Conversion Receiver
Saturday, January 28, 2023
Hugo Gernsback -- Was he Like Wayne Green?
Friday, January 27, 2023
N3FJZ Builds PTO for High School DC Receiver
Thursday, January 26, 2023
"The Electrical Experimenter" -- A Treasure Trove of Inspiration
Oh this is really phenomenal. Nick "the Vic" M0NTV is on the mend from some routine surgery. While mending he found this 1915 issue of Hugo Gernsback's "The Electrical Experimenter." I just spent a few minutes quickly going through it and I can see that this is a treasure trove that could keep us -- the modern day electrical experimenters -- busy for a long time.
-- We see Signor Marconi in Italian military uniform (I never saw that before).
-- There is mention of successful DX reception of the station in Arlington Va. (just down the road from me).
-- There is a an article about the radio station of T.O.M -- Hiram Percy Maxim.
-- There are detailed maps of Mars, complete with the canals.
And there is a lot more.
Above all, I think what stands out from this magazine is the homebrew spirit, the notion that we can and should build our rigs ourselves, and seek to understand them.
Below is the whole magazine. Please take a look and use the comment section below to point us to passages of interest to the electrical experimenters of today.
Thanks Nick. Your e-mail came during a discouraging period filled with a few "tales of woe." The magazine really lifted my spirits.
Here it is:
Tuesday, January 24, 2023
Update on High School Direct Conversion Receiver Project + .asc File
So far, in response to my recent request for testing, no one has stepped up to build the DC receiver Dean KK4DAS and I are testing out. We did get a couple of comments explaining why guys are opting not to help, but so far no other builders are actually melting solder in response to our recent request.
So Dean and I decided to each build second versions of the receiver. That will bring the total finished build population to 4. I finished my second version yesterday. Picture above. It works great.
One change: The emitter resistor on the final AF amp was too low in value. The transistor and the transformer were getting hot. I switched from 10 ohms to 100 ohms and the problem disappeared. I have made the change on the LTSpice Schematic. Here is the .asc file (I hope!) :
http://soldersmoke.com/DCRX.asc
Dean posted the .asc file (and some other info) here:
If you have trouble accessing that file, please let me know and I will try to e-mail it to you. In any case the schematic appears here:
https://soldersmoke.blogspot.com/2023/01/a-call-for-builders-please-help-us-test.html
You will notice that this Spice schematic actually works! The PTO turns on, and I put a simulated RF signal at the antenna port. Audio appears at the output.
Time is getting very tight. Dean and I will begin presenting this project to the high school students on February 2. So it is not too late to help. But helping is, of course, strictly voluntary -- if you are reluctant to build this thing, DON'T!
Saturday, January 21, 2023
My HI7/N2CQR QSL Card
A Call for Builders! Please help us Test this Receiver! Please Build this Receiver!
This is the Direct Conversion receiver that Dean and I have built. We plan to have students at a local high school build it, starting in early February. We would like to have some others build it, to make sure that the design is re-producible without problems.
Please build this receiver! But we ask that you build it exactly as per the schematic above and below. Innovation can come later -- for now we just want to make sure this thing works, that there are no errors in the schematic, and that it can be built by the students with minimum woe. Thanks in advance!
Dean or others with 3D printers may be able to supply the plastic form for the PTO inductor.
We know of one other builder, but he is having some trouble. We would like to confirm that this design is sound.
-------------------
Here is a larger image of the schematic (click for a full view):
Friday, January 20, 2023
Open Circuits: The Inner Beauty of Electronic Components
I was not going to buy this book. But then, Elisa and I were in a book store and there it was. I decided to take a look. I opened it to a random page: 2N3904. TRGHS. Sold.
It is really interesting.
You can order yours through the Amazon Search block in the right side column of the blog.
Tuesday, January 17, 2023
SolderSmoke Re-Play: Goggle EMBRACES Morse Code: Gmail Tap
A True Measure of a Jean Shepherd Fan: Did You Fly One of His Ornithopters?
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:
Working Vienna Wireless Society member (KA4CDN) from Hispaniola
Thursday, January 12, 2023
On Ten Meters with a uBITX from the Eastern Tip of Hispaniola
Tuesday, January 10, 2023
SolderSmoke Re-Play: Shep tries to build a Heising Modulator -- Shep on Parasitics and Troubleshooting: "That way madness lies"
You guys really have to listen to this. This is culturally important.
In this 1965 radio broadcast, Jean Shepherd describes his teenage struggles with parasitics and other technical problems in his homebrew 160 meter transmitter.
He describes the sound of parasitics on a signal, saying that they sound as if the signal is being attacked by "debauched erotic locusts."
He really nails it in describing the scornful, dismissive tone that many hams use in telling their fellow radio amateur that there are problems with his signal. ( I have recently been on the receiving end of this kind of treatment.)
He observes that no one is more worried, "than a man who has built something and can't get it to work." Indeed.
During a date with a girl from his high school, he is so obviously preoccupied with his transmitter trouble that she tells him that something is wrong with him and that his mother "should take him to a doctor."
And he describes the joy that comes when you figure out the problem and get the thing to work.
The REALLY good stuff begins at about the 25 minute point.
http://ia310115.us.archive.org/2/items/JeanShepherd1965Pt1/1965_01_29_Ham_Radio.mp3
Shep was quoting from King Lear: "O, that way madness lies; let me shun that; No more of that." In other words: "BASTA!"
EXCELSIOR!
Monday, January 9, 2023
Other Workshops: Building a Flying 21:1 Scale Airbus A-380
Arnie Coro CO2KK -- Homebrew Hero -- Silent Key
I was sorry to read this morning of the passing of Homebrew Hero Arnie Coro CO2KK. As we see in one of the obits, Arnie got his start in radio at age 12, with the gift from his father of a chunk of galena, a coil, and some headphones.
Here are some of the SolderSmoke posts about Arnie:
https://soldersmoke.blogspot.com/search?q=CO2KK
He will be missed.
Sunday, January 8, 2023
Wednesday, January 4, 2023
Dilbert Knack Video: Who was the "Doctor"?
Sunday, January 1, 2023
Happy New Year and Straight Key Night from HI7/N2CQR
Saturday, December 31, 2022
EI0CL as Heard on a uBITX in the Dominican Republic
27 December 2022: My old friend Mike EI0CL:
Wednesday, December 28, 2022
Tuesday, December 27, 2022
Monday, December 26, 2022
A Blast from the Past: TR on Homebrewing (sort of)
"It is not the critic who counts; not the ham who points out how the homebrewer stumbles, or where the builder of rigs could have built them better. The credit belongs to the ham who is actually at the workbench, whose hands are scarred by solder and metal and glue; who strives valiantly; who errs, whose amp oscillates again and again, because there is no effort without error and shortcoming; but who does actually strive to build his rigs; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of homebrew achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid operators who neither know victory nor defeat.”
Sunday, December 25, 2022
Some Direct Conversion Receiver History
Here is the article by Wes Hayward and Dick Bingham that started it all:
https://worldradiohistory.com/Archive-DX/QST/60s/QST-1968-11.pdf
page 15
Here's a discussion by Wes of the original project:
https://www.n5dux.com/ham/files/pdf/Direct%20Conversion%20Receivers%20History%20-%20W7ZOI.pdf
Here is an article about DC receiver in phasing rigs by Gary Breed K9AY:
https://worldradiohistory.com/Archive-DX/QST/80s/QST-1988-01.pdf
page 16
Roy Lewallen W7EL's Optimized transceiver (with a direct conversion receiver):
https://worldradiohistory.com/Archive-DX/QST/80s/QST-1980-08.pdf
page 14
Jerry KI4IO on Building a DC Receiver
https://groups.io/g/qrptech/message/17
Michael Black wrote on March 5, 2014 at 3:54 PM
Isn't it a bit dated?
When "direct conversion" receivers came along in 1968 (the concept existed before, just not the name), it was to build simple receivers. They took over from regens (which of course for the purpose of CW and SSB, were "direct conversion"), and kind of bumped simple superheterodyne receivers out of the magazines.
And they were easy to build, so long as the meaning of the dots were standard, but good performance was elusive. Endless articles about better mixers or more front end selectivity, and still the same basic results The Heathkit HW-7 comes along, and endless mods to that, but still no perfection.
Slowly the move was back to simple superhets, especially with some of the early seventies ICs intended for radio, and then ladder filters came along (actually they came early at least by 1974 from the UK and/or France, but while they got mention in North America early-ish, it took some years before the KVG filters were pushed aside and ladder filters got the spotlight).
And then wham, in the mid-eighties someone caught on. The problem with direct conversion receivers wasn't the mixer (well not once it was a balanced mixer) or lack of front-end selectivity, it was the matter of properly terminating the mixer. The problems that had been there all along were gone. And direct conversion receivers started their climb to being complicated receivers.
I guess it was that receiver by Gary Breed in QST circa 1986 with diode balanced mixers and termination that changed things. A new concept, but not really, I remember an article in QST in 1974 where a DBM diode mixer for VHF was properly terminated, and yet the concept went no further until a decade later.
Actually, I think there is a tiny bit about mixer termination in "Solid State Design for the Radio Amateur" but it never went so far as to say "this is what we need".
Or perhaps that tiny transceiver by Roy Llewellyn in QST was the first, I cant' remember. It certainly used a diode mixer with termination for the receiver.
And that set the stage for Rick Campbell's various receivers, all counting on termination of the mixer.
The ideas can often be there, but not applied because technology doesn't allow it yet, or just not looking that far beyond this month's construction article.
Michael
Saturday, December 17, 2022
Kludge. Rhymes with Fudge. On PBS!
At about 12:26 in this video, David Brooks uses the word "kludge" on the Public Broadcasting System. He pronounces it CORRECTLY! (But then he and the host question whether it is a real word.)