Category: video

Shortwave Echo Mystery on Yet Another SW Station. What is this?

A few weeks ago I noticed a strange echo on Radio China International’s signal. If you scroll down a bit you can see my YouTube recording of the problem. On one of the SWL lists, there was speculation that this problem was the result of a flaw in the RCI digital studio gear. But then a few days ago I heard it again on RCI — surely the tech-savvy Chinese would not have let this kind of problem persist for weeks.

Today I heard the same effect on a very different SW station — this one an the 24/7 fire and brimstone broadcast that appears at many points on the dial. The effect is very similar to what I heard on RCI.

So OK all your shortwave gurus: What is going on here?

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“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

Alan Wolke Looks at Diode Ring Mixers

Bill, I remember in your Soldersmoke book that you had difficulty for a long time trying to understand how a mixer created the sum and difference frequencies, and how this was accomplished in a diode ring mixer. I know that you’ve got it all sorted out now, but I thought this was a good topic for a video anyway.

Here’s my video on the subject:
https://www.youtube.com/watch?v=junuEwmQVQ8

73,
Alan
Alan: Thanks. Great stuff. Yea, I’ve been looking at the innards of mixers for a long time. In my book, I try to explain how I have come to understand the physics of the mixing action — how the use of a non-linear element causes two signals to “multiply” and how this “multiplication” results in sum and difference frequencies. I tried to go beyond the trig functions because for me the trig didn’t really explain anything.


In the book I was looking at the classic two diode mixer (beloved of Doug DeMaw!). A few years later, on the blog, I was looking at the action of the diode ring. I concluded that there is a big difference between how the diode ring works and how the two diode mixer works. RSGB provided a great diagram:



73 Bill

—–
I guess one way of describing the difference between a two diode mixer and a diode ring would be to say that the more simple mixer multiplies the signal by 0 and 1 (if it is operating in “switching mode), while the diode ring multiplies by 1 and -1.

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Video: Regenerative Receiver Project!!!

Pete Juliano and Grayson Evans are luring me back into the world of tubes and (gasp!) regen receivers.

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

Homebrew Radio Rock Video! By N6QW

Watch out MTV! There’s a new music channel in town!
Music and rigs all by Pete Juliano, under the direction of the famed Italian producer/director Giovanni Manzoni.

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

Video of Pete Juliano’s 20-40 Bilateral Rig

Wow, what a beautiful rig. Nice work Pete. Kind of eerie how we both chose the 20/40 combination after building 17 meter rigs. We’ll have to talk more about this in SolderSmoke 162. Soon!

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

Clocks, CRTs, HV supplies: Eric has The Knack!

Nice interview by Jeri Ellsworth. This fellow definitely seems to have the Knack. At the end of the video he shows a high voltage supply that he is WEARING AROUND HIS NECK!

Here’s Eric’s site: http://tubetime.us/

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

QRPp Model Planes

Michael, AA1TJ, alerted me to this very interesting hobby. The video is really beautiful.

http://floatdocumentary.com/documentary

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

Links Fixed, Podcast Version of Hamfest Presentation

Armand, WA1UQO, with BITX 17

Using Dropbox to post the video of my BITX presentation at the hamfest didn’t work out too well, so I put it on Vimeo:

https://vimeo.com/87725154

The slideshow is here: http://soldersmoke.com/winterfest.pptx

I stripped out the audio for those who would like to dispense with the video.

Audio only is here:

http://soldersmoke.com/soldersmokewinterfest.mp3

73

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

Hamfest Presentation on SolderSmoke and BITX (Video)

The Vienna Wireless Society of Northern Virginia asked me to give a talk at their 23 Feb 2014 hamfest. I spoke about homebrewing and the BITX transceivers. Click on the link below to watch the video. (Special thanks to Elisa for doing the video.)

https://vimeo.com/87725154

The Powerpoint slides are here:

http://soldersmoke.com/winterfest.pptx

For those who just want to listen podcast style, I will try to turn the audio into a podcast and will post it via the normal channels.

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

Brilliant! New “TX Factor” Ham Radio TV Show from the UK

I really enjoyed this. It is the first episode of what I hope will be a long-running series.
These guys did a great job. Excellent quality video production and very interesting subject matter. A LOT of work went into this. I liked the PSK from a smart phone on a foggy hillside (with Moroccan soup!). The Marconi stuff was wonderful. Beer barrels as 2 meter cavity resonators! Excellent Knackish-ness! And a two meter repeater in an astronomical observatory. Well done!

Thanks to Nigel and Dino for alerting me to the TX Factor.

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

How they took the iconic Apollo 8 Earthrise Photo (Amazing Video)

I was ten years old and totally obsessed with the space program. This video brought back a lot of the magic. Wow. You really have to see this one.

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

Where to send all those LM386 chips: Make them BEAM robot brains!

Over in the BITX20 yahoo group there have been some comments about the shortcomings of the widely used LM386 audio amplifier chip. Many people don’t like it because it is noisy. I don’t like it because it is a chip. (In my BITX rigs I have replaced it with a simple discrete component audio amplifier.) So this morning I was pleased to find this video on the Maker blog that presents a very good use for all those LM386 devices: We can turn them into robot brains!

Make’s video and web page on this project are both very good. One paragraph in the page kind of captures the reasons I dislike the LM386:

How It Works

The core of the “Herbie” circuit is the LM386 power amplifier chip. To simplify a bit, we can think of the chip as a “black box” with inputs and outputs that respond in predictable ways, and don’t have to completely understand what’s going on inside.

http://makezine.com/projects/sunbeam-seeker-bot/

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