Crystal Ham Part 2

It has been a few months since I last visited this topic. Sorry about that. Family matters. However, let us look at how a crystal radio works. For those who’ve been licensed hams for any length of time, this is really simple, but for others, this borders on magic, but we can do this.

Let us start with a basic assumption. Our assumption is that we are surrounded by electromagnetic energy in a wide variety of frequencies and modulations. It doesn’t matter if it is your computer, your mobile device, or something, you are surrounded by RF generating devices, and this makes our basic assumption true. If you want to say that you are miles from civilization and thus it is impossible to be surrounded by RF energy, not only are you wrong, but I’m going to wonder how you can even read this.

This is where it gets interesting, and I will do my best to keep it simple.

A crystal radio, much like any other radio, uses an antenna to pick up an RF signal. That signal is then sent to the antenna coil. The antenna coil converts that energy into a very low level of AC current, which is then fed into either a germanium diode, or cat’s whisker detector (galena or pyrite crystal with a thin wire barely contacting it). This forces the current to flow in only one direction, and rectifies the signal. The rectified signal then either goes to the earphones, creating something you can hear, or into a variable capacitor, and giving you the ability to select what you hear, by varying the amount of energy stored between the detector and the earphone. The earphone transforms that energy into an audio signal, and for the sake of being somewhat technical, it is about 400 to 2000 Ohms.

Realistically, this is an oversimplification of the whole thing. However, for the purposes of this blog, simpler is better. I will be revisiting this topic again as I prepare for the actual build process. Next time, I will build a simple “popsicle stick” antenna for detecting RF energy. Also, I will be using an actual diode for the detector, as a cat’s whisker detector is really awesome, but a royal pain to maintain a signal with.

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Market Ham

Every year I like to attend/work the K7LED Mike and Key Radio Club flea market. I really enjoy seeing what is being sold and catching up with old friends that I don’t see often. This last year, I bought myself a new soldering tool. I also picked up an older solid state two meter transceiver (yes, I know that this blog is dedicated to tube rigs and other such things, but a tube rig would be a bit big for bicycle operations). Currently the radio doesn’t work. However, the is often the case with used gear that is found at a flea market, and that is part of what makes this hobby so wonderful. It is often great fun to repair/restore an older radio to full function. I heartily encourage that if you can attend a flea market, and particularly an amateur radio flea market, that you do so. We ham really can have fun with these. In fact, we often have more fun than a hog in a bog.

Steamed Ham

I have had a fascination with the genre of Steampunk for some time now. However, I was less than impressed with an episode of the competitive series “Steampunk’d”. Grammar issues aside, I didn’t like the episode in which a wardrobe closet was built. In the episode, there was a very painful misrepresentation of radio.

Let me explain. The two teams were required to build a wardrobe. This doesn’t both me. What bothered me was when they reach the part of the episode in which an explanation of the build is given. The team with only three people built a rather awkward room and costume. The costume had a globe valve on the front of it. The explanation given was that it was to tune to other radio channels to call for help. I should mention that the room was themed as “Royal Garrison”. Please excuse my disgust, but a water valve is NOT a VFO, or even a shoddy surrogate for one.

The simple truth of the matter is that radio may have been invented as early as 1895, and is credited to Guglielmo Marconi, the fact is that the distance for a radio signal was exceedingly short, and it was Morse Code only. In fact, the first trans-Atlantic Morse Code transmission would not be until 1901. Additionally, tuning would have been very limited, for though the variable capacitor was invented in 1893 by Dezső Korda, it’s full application wouldn’t be seen for several years after the first trans-Atlantic transmission. Add to that the first voice transmission wouldn’t be until 1906, which would be after the end of the antebellum age, and you find that voice over the radio is almost inappropriate for Steampunk.

Is there room for radio, and voice transmission, in Steampunk? Yes. However, it must be presented as an alt-history scenario, and it must not be misrepresented. When dealing with radio, even in a cosplay, it must be done responsibly. Simply put, if you don’t know and understand radio, don’t talk about it as if you do. The simple truth is, you are very likely to upset somebody who is knowledgeable, and actually has experience doing what you don’t really know or understand.

What does this mean? Realistically, it is just a rant. I really hate seeing radio misrepresented. This is precisely what happened in season 2, episode 4 of “Steampunk’d”. Additionally, not only did they misrepresent radio, they misrepresented the proper use of a globe valve. I will say that had the globe valve been used to “control the flow of plasma” to the costume’s “weapon”, I would not have taken issue with it. However, to say that it was used as a radio to call for help, I have no option but to take issue. However, I will let the reader decide for themselves.

Steampunk’d Season 1 Episode 4. The affront to radio begins at the 26 minute mark.

 

If it was up to me, I’d demand an apology from that particular team for how they misrepresented radio.

Note to critics: I have been a licensed amateur radio operator since 1998, and I have built several radios, both locked frequency and variable frequency. I have also studied the history of radio, and will be quite happy to argue that radio is more product of the diesel era than that of the steam era, as it is the diesel era in which voice transmissions and tuned circuits really belong.