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Friday, May 17, 2024
Band Imaging Rigs (Receivers and Transceivers) -- Video from WA7MLH
Wednesday, May 31, 2023
Farhan VU2ESE FDIM Interview (#6) by Bob Crane W8SX: VHF Rig, sBITX, and Good News on Raspberry Pi 4
Here us Bob's interview with Farhan:
http://soldersmoke.com/VU2ESE23.mp3
Wednesday, October 13, 2021
SolderSmoke Podcast #233: PIMP, Boatanchors, Novices, MMM, Heathkits, DC Receivers, Mailbag
SolderSmoke Podcast #233 is available.
http://soldersmoke.com/soldersmoke233.mp3
Travelogue: Cape Cod. SST. Marconi Site.
The WFSRA: The World Friendship Society of Radio Amateurs.
Pete's Bench:
The Pimp.
The NCX rig.
The Collins.
The many DC receivers built worldwide.
The parts shortages are real! Several key radios on hold. Si5351 sub.
Talk to G-QRP convention
Bill's Bench:
FT-8. Not for me. I tried it.
Novice Station Rebuild.
Globe V-10 VFO Deluxe.
Selenium rectifier removal CONTROVERSY?
Not crazy about my Novice station. Not crazy about CW.
Mate for the Mighty Midget. Again.
Mike W6MAB -- Detector problems LTSPICE Check
One more mod for MMM RX. Ceramic filter at 455.
Dropped screw inside tubular cap on Millen 61455 transformer.
Talk to the Vienna Wireless Society
Thinking of a Moxon or a Hex beam.
BOOK REVIEW Chuck Penson WA7ZZE New Heathkit Book. http://wa7zze.com
Mailbag
-- New SPRAT is out! Hooray!
-- Todd K7TFC sent me copy of Shopcraft as Soulcraft. FB.
-- Dean KK4DAS building an EI9GQ 16 W amp. FB.
-- Jack NG2E Getting close on Pete's DC receiver.
-- JF1OZL's website is BACK!
-- Tony K3DY sent link to cool books.
-- Sheldon VK2XZS thinking of building a phasing receiver.
-- Peter VK2EMU has joined the WFSRA. FB!
-- Ned KH7JJ from Honolulu spotted the Sideband Myth in the AWA video.
-- Chris M0LGX looking at the ET-2, asks about the variometer.
-- Pete Eaton Nov 64 anti HB rant in november 1964 QST. Wow.
-- Josh Lambert Hurley spreading FMLA stickers in the UK. FB
-- Stephen VE6STA getting ready to melt solder.
-- Got a great picture of Rogier PA1ZZ back on Bonaire.
-- Farhan reading the manual of Hans's new digital rig.
-- Paul G0OER wonders if FMLA getting ready to move on 5 meters.
Saturday, August 21, 2021
W2EWL's "Cheap and Easy SSB" Rig -- And The LSB/USB Convention Myth
In March 1956 Tony Vitale published in QST an article about a "Cheap and Easy" SSB transmitter that he had built around the VFO in an ARC-5 Command Set transmitter. Vitale added a 9 MHz crystal-controlled oscillator, and around this built a simple phasing generator that produced SSB at 9 MHz. He then made excellent use of the ARC-5's stable 5 - 5.5 MHz VFO. His rig covered both 75 meters and 20 meters. Here is the article:
Because it used the 9 and 5 frequency scheme, over the years many, many hams have come to think that Vitale's rig is the source of the current "LSB below 10 MHz, USB above 10 MHz." This is wrong. An example of this error popped up on YouTube just this week (the video is otherwise excellent):
Monday, July 26, 2021
QST Repeatedly Got Sideband Inversion Wrong
It kind of pains me to do this. These articles are from a long time ago, and the author is an esteemed Silent Key, but the myth about the origins of the USB/LSB convention is still out there, and as a homebrewer of SSB gear I feel obligated to point out these examples of the error that that myth is based on.
Last Friday, Pete WB9FLW and I were talking about homebrewing SSB rigs. I recommended a series of QST articles by Doug DeMaw. "Beginner's Bench: The Principles and Building of SSB Gear" started in QST in September 1985. There were at least five parts -- it continued until January 1986. (Links to the series appear below.) I hadn't looked at these articles in years, but when I did, a big mistake jumped right out at me: In the first installment, on page 19, Doug makes the same mistake that he made in his Design Notebook:
"Now comes the conversion section of our SSB generator. We must move (heterodyne) the 9-MHz SSB signal to 3.75-4.0 MHz. Our balanced mixer works just as it does in a receiver. That is, we inject the mixer with two frequencies (9 MHz and 5 MHz) to produce a sum or a difference output frequency (9 - 5 = 4 MHz, or 9 +5 = 14 MHz) If we are to generate 75 meter SSB energy, we must chose the difference frequency. We could build an 20-meter SSB transmitter by selecting the sum of the mixer frequencies. The RF amplifiers and filter (FL2) that follow would then have to be designed for 14-MHz operation. In fact, many early two-band homemade SSB transmitters were built for for 75 and 20 meters in order to use this convenient frequency arrangement. The use of upper sideband on 20 meters and lower sideband on 75 meters may be the result of this frequency arrangement (the sidebands become inverted when switching from the difference to the sum frequency.) "
Those last two sentences are incorrect. They repeat the "Myth," or the "Urban Legend" about the origins of the LSB/USB convention. Contrary to what many hams now believe, with 9 MHz filter and a 5.2 MHz BFO it takes more than just switching from sum frequency to difference frequency to invert one of the sidebands.
There are two conditions needed for sideband inversion to take place:
1) You have to be taking the difference product (DeMaw got that right)
2) The unmodulated (VFO or LO) signal must be larger than the modulated signal. (DeMaw and the ARRL obviously missed that part. Repeatedly.)
This is another way of stating the simple, accurate and useful Hallas Rule: Sideband inversion only occurs when you are subtracting the signal with modulation FROM the signal without modulation.
For DeMaw's claim to be correct, one of the SSB signals going into the balanced mixer would have to invert, and the other would have to not invert. Let's see if that happens: He has the sideband signal being generated at 9 MHz and the VFO running around 5 MHz.
9 - 5 = 4 But we are not subtracting the modulated signal FROM the unmodulated signal. SO NO INVERSION
9 + 5 = 14 We are not subtracting at all. SO NO INVERSION.
Thursday, July 22, 2021
The Unicorn! A 75 LSB /20 USB Receiver (That Can't Work)
Thursday, June 17, 2021
The Stubborn Myth about USB and LSB
It has been repeated so often and for so long that many of us have come to believe it. I myself believed it for a while. Like many myths, it has a ring of truth to it. And it is a simple, convenient explanation for a complex question:
Why do ham single sideband operators use LSB below 10 MHz, but USB above 10 MHz?
Here is the standard (but WRONG) answer:
In the early days of SSB, hams discovered that with a 9 MHz SSB generator and a VFO running around 5.2 MHz, they could easily reach both 75 meters and 20 meters (True). And because of sideband inversion, a 9 MHz LSB signal would emerge from the mixer as an LSB signal (True), while the 20 meter signal would emerge -- because of sideband inversion -- as a USB signal (FALSE!) That sideband inversion for the 20 meter signal explains, they claim, the LSB/USB convention we use to this day.
Why this explanation is wrong:
There is a very simple rule to determine if sideband inversion is taking place: If you are subtracting the signal with the modulation FROM the signal without the modulation (the LO or VFO) you will have sideband inversion. If not, you will NOT have sideband inversion.
So, you just have to ask yourself: For either 20 or 75 are we SUBTRACTNG the Modulated signal (9 MHz) from the unmodulated signal (5.2 MHz)?
For 75 meters we have: 9 MHz - 5.2 MHz = 3.8 MHz NO. We are not subtracting the modulated signal from the unmodulated signal. There will NOT be sideband inversion.
For 20 meters we have 9 MHz + 5.2 MHz = 14.2 MHz. NO. No subtraction here. No sideband inversion.
So it is just arithmetically impossible for there to be the kind of happy, easy, and convenient USB/LSB situation described so persistently by the myth.
---------------------------------
We discussed this several times on the podcast and in the blog:
https://soldersmoke.blogspot.com/2015/05/sideband-inversion.html
https://soldersmoke.blogspot.com/2012/05/usblsb-urban-legend-debunked.html
This myth shows up all over the place:
We see the myth here:
http://n4trb.com/AmateurRadio/Why%20The%20Sideband%20Convention%20-%20formatted.pdf
Here the web site owner warns that this is "highly controversial." Really? Arithmetic?
The myth is very old. Here is a clip from a 1966 issue of "73" magazine:
https://worldradiohistory.com/
Finally, to my disappointment, I found the myth being circulated by the ARRL, in the 2002 ARRL Handbook page 12.3:
Saturday, August 29, 2015
Adam Savage (Myth Busters) Interviews Andy Weir (Author of "The Martian")
I liked this interview a lot, and I am sure SolderSmoke listeners will like it too.
Weir admits to NOT having the Knack, but Mark Watney clearly does have it.
Also, check this out: http://www.cannonade.net/mars.php#map
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
Friday, March 15, 2013
Kludge: Rube-Goldberg Heath-Robinson Ad-Hockery
Wow! "Ad-hockery... verging on being a crock." That sounds like my building technique! I thank Kevin for sending this, but I admit to now being more confused than ever.
Bill:
A snippet from my kluge research. This was a word I learned from my dad who told me he had heard it first used in the 1930s. Here is where I find a divergent meaning with the new word kludge which I have often heard pronounced as rhyming with sludge. I was asked why I pronounced it with the d as silent. I asked why I should pronounce a letter which was not even in the word. Thus my introduction to the new word kludge which means something very different than what I had learned from my father. While a kluge is something clever a kludge is an ad hoc and usually buggy hack.
I found a little supporting evidence for the etymological timeline. To whit:
programming trick intended to solve a particular nasty case in an
expedient, if not clear, manner. Often used to repair bugs. Often
complex assortment of cams, belts, and linkages to both power and
Mr. Brandtjen's history of the device and his allegation that it was a
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
Wednesday, June 20, 2012
SolderSmoke Book Review: "The Day We Found the Universe"
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
Sunday, November 6, 2011
Tony Sale and the Re-Building of Colossus
http://mathdl.maa.org/mathDL/?pa=mathNews&sa=view&newsId=1195
Amazing info on Tony Sale's work here:
http://www.codesandciphers.org.uk/lorenz/index.htm
I got a kick out of this bit:
One reason for wanting to get Colossus working in 1996 was that for far too long the Americans have got away with the myth that the ENIAC was the first large-scale electronic digital calculator in the world. It was not, but they got away with it because Colossus was kept secret until the 1970s. As 1996 was the 50th anniversary o the switch-on of ENIAC I made sure that Colossus was rebuilt and working in Bletchley Park, just as it was in 1944.
There has been a stunned silence from across the water!
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20
Tuesday, January 18, 2011
Rouges Gallery: Three Possible SolderSmoke mics
At first, I thought the re-done Turner would win out. Then I thought the computer mic would keep its job. But then -- surprisingly -- the D-104 started to sound REAL good. The D-104 was especially good at keeping AC hum out of the signal -- that was a problem with the other two.
I found that I could get a very nice-sounding audio by running the D-104 audio through some EQ to knock down the little bit of hum that it did pick up, and to put about 30 db of attenuation on my now infamous SSSS whistles. I also used Audacity's noise remover.
So, the next SolderSmoke may come to you via an Astatic D-104. Kind of appropriate, don't you think? What do you guys think? Maybe I should post an audio sample to get some expert opinion before I chrome lollipop #130...