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.

Road Hog

Our world is awash in technologies that in some way touch upon, or originate with, ham radio. Whether it is wireless internet, or GPS, many of our technologies owe something to ham radio. In fact, when it comes to RF devices, you would be hard pressed to find something that didn’t have its start with amateur radio. However, not all devices are alike, and people have become more dependent upon some than should be the case. GPS is one of them.

GPS is short for Global Positioning System, and has its origin in APRS, or Amateur Packet Reporting System, which borrowed from military doppler shift tracking during the era of Sputnik. Initially, it was intended as a tool to help emergency responders, and also had some use with various radio clubs for Field Day use. However, if there is a technology, it can be commercialized, and APRS was quickly commercialized into GPS, with the first handheld commercial unit being the Magellen NAV 1000.

Now, why would a blog that is, supposedly, dedicated to tube radios talk about GPS? That is a fair question, and worthy of a good answer. The honest answer is that people have become too dependent upon GPS devices, to the point in which they ignore road signs and many don’t even know how to read a proper map any more. It is sad that recent Boy Scout handbooks now address the subject of using a GPS for direction finding, and just barely mention the use of a proper map and compass. However, it gets much worse.

Along the Puyallup River, there is a bridge located at 66th Avenue. It is a small bridge with a single lane in either direction. This bridge was built in 1931, and is still in service today. However, as farm land has given way to warehouse space, there has been a very dangerous trend of truck drivers using this bridge for crossing from Levee Road on the Fife side of the Puyallup River to access River Road (Highway 167) on the Puyallup side of the river. So dangerous is this trend that Pierce County had an ordinance prohibiting any vehicle with a trailer longer than twenty eight feet on the bridge, and there are cameras on the bridge to record offenders.

However, even with signs posted warning of the ordinance, many truck drivers still take the risk of crossing this bridge. Why? Because their GPS device is telling them that the bridge is best route. I have seen, and nearly been part of, many near collision events due to truck drivers taking this bridge. I have also seen many an instance in which drivers get stuck on the bridge, all because their truck was too high, and they were following the advice of the GPS, all the while, ignoring the warning signs.

I won’t lie, I do use the built-in GPS that my Boost Mobile device comes with, but only when I am trying to get someplace that isn’t necessarily on a map, and there are no obvious road signs directing me to the place I am going. Otherwise, I still use paper maps for many places that I want to go, along with road signs. I also use Google Maps to print directions that I can follow. I don’t rely upon the GPS device, especially because you can’t always get it to recalculate your route when roads are closed or traffic is otherwise interrupted.

GPS may be helpful, but when one relies too much upon it, all it is does is become little than an electronic leash, telling you where to go. If you are a truck driver, and mindlessly following the instructions it gives you, it may well be that you are putting others at risk and have now become a Road Hog. Please disconnect from the GPS and double check the map, and read the road signs. Over dependence on GPS is a form of distracted driving, and it puts us all at risk.

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.

Alien Ham

Exoplanets are trending currently. Why? Recently NASA discovered an exoplanet orbiting a star in the Proxima Centauri system. This planet orbits within the “habitable zone”, and is named (by us) as Proxima B. However, because of its rapid rotation around its star, roughly twelve days to complete an orbit, and the fact that while it is withing the “habitable zone”, it is believed to receive 400 times the X-ray energy from its “sun” than we receive from ours. To that end, it is likely that it is comparable to either Mercury or Venus, both of which are barren and devoid of life.

Why do I bring this up? Humanity has been looking for extraterrestrial life for decades. One would think that it is only a matter of time until we find something, right? Maybe not.

2016 marked the 100th anniversary of the W7DK/W7OS Radio Club of Tacoma. This is the single oldest, continuous, ARRL affiliated radio club in the whole of the United States. This is a big deal when you consider that  on 23 December 1900, Reginald A. Fessenden became the first person to send an audio single via wireless transmission , and that  he made the first commercial broadcast on Christmas Eve of 1906. This means that radio has been a known medium of communications for 116 years, and that there are some earlier experiments that predate these two events.

What does this have to do with aliens? Plenty, if you don’t mind some pretty extreme mathematics. It really has to do with how far radio waves really carry, and they really do carry quite some distance.

I’m going to go ahead and be generous. That is to say that I’m going to ignore the first 16 years of radio transmissions, at least for the moment. Those first sixteen years really are important, but I want to make things easy, at least to start with.

A radio wave travels at the speed of light, which is roughly 186,200 miles per second. This works out to 11,172,000 miles per minute. That, in turn, works out to 670,320,000 miles per hour. In the course of twenty four hours, a radio signal will travel 16,087,680,000 miles. This is nearly four times the distance between the Earth and Pluto. In a month, that signal will have traveled over 482,630,400,000 miles. That means a radio signal will travel, in one year, a distance of 5,876,025,120,000 miles. In a century, that distance is clearly seen as being 500,876,025,120,000 miles. This doesn’t account for those first sixteen years, which adds another 94,016,401,920,000 miles to the overall total.

All that looks impressive, but meaningless, until you start to look at a list of all the potential exoplanets that are thought to exist in the habitable zone. About a quarter of those planets are less than fifty light years from Earth, and some are even closer than that. To date, we have not received an authenticated signal back from any of these supposedly closer exoplanets. Let that sink in for a second.

Over the years, we’ve seen numerous UFO sightings, some going back as far as 1697, though the first fully credited sighting was in 1947 near Mount Rainier, in Washington state. Yet, despite these supposed sightings, we have no hard evidence that extraterrestrials exist, aside from various conspiracy theorist drivel, much of which is easily debunked. Even the “WOW signal” from 1977 has now been attributed to a passing comet, a theory that may very well be tested soon, which only further depletes the potential pool of evidence for extraterrestrial life, and only leaves the flimsiest of evidence, and that being the previously mentioned stuff that is easily debunked.

What does this mean? Ultimately, it means that in all of decades of searching for extraterrestrials, we have found nothing. Furthermore, with at least six exoplanets existing within 56 light years of earth, if they had a level of technological development equal or greater than that of our own (most people seem to seek extraterrestrials with a greater level of technological development for some reason), then we should have already heard something from them, something that would have already put our world into technological overdrive, as we rapidly built a deployed our first hyper-light drive systems. However, no such signal has been shown to exist, and most claimed signals have either been debunked, or have been relegated to suspected pranks by unscrupulous individuals with questionable motives.

Radio has been around for over a century. If there were an extraterrestrial race with a level of technology equal to or greater than our own, we would likely have heard back from them, and it would have been impossible for any government to block such a communication. I know some will believe that I am wrong, and I accept that, but I am firmly convinced that radio, and the lack of an authentic signal from an extraterrestrial race that off of the Earth has heard, is sufficient evidence to suggest we are alone in the universe. This is observational science, and radio is all about what we can observe. If I can be proven wrong, by a personal radio greeting by an extraterrestrial, and they can prove it, I will admit to it, before committing suicide.

 

It Varies

Radio technology is ever changing. Whether that is good or bad is really up to the individual. I like to think that change can be good if it serves a purpose. However, I am often opposed to change just for the sake of change. That includes unnecessary changes in technology.

Many old timers remember the days of the big dial on the VFO (Variable Frequency Oscillator). This dial, or knob, was connected to a genuine variable capacitor. As you turned the knob/dial, the capacitance within the capacitor would change. This change in capacitance corresponds to a subsequent change in the frequency the radio was tuned to, thus it would vary accordingly. This is why we called it a VFO. Today, many so-called “VFO’s” are really just optoisolator circuits, meaning that when you turn that know, it simply changes where light hits a photo-conductor.

Want to know whether or not your radio is using a real VFO or an optoisolator? Turn the dial while the radio is off, and then turn it on. If the frequency is unchanged, it is an optoisolator. If it changes, it is a real VFO.

What about volume control? Pretty much the same thing. However, in older radios, volume is handled by a potentiometer (basically a variable resistor). As the resistance is decreased, the volume in your speakers increase. Just like the VFO, many modern radios also use an optoisolator for volume control. Thus, it should be obvious that the same test would apply. To know if it is a real potentiometer, or an optoisolator, turn off the radio, spin the knob, and then turn it on. A change in volume should indicate that it is the real deal.

There is something I should say about optoisolators versus a genuine variable capacitor, or potentiometer, and how they work. Maybe it will be obvious to some of the older guys, but many young guys might not get it. There is a definitive difference in how an optoisolator feels versus either the VFO, or a potentiometer. With an optoisolator, you can feel something to the effect of clicking. With both the VFO and potentiometer, there is a certain level of positive resistance when turning the knob that controls them. Optoisolators don’t have that resistance. Thus, you should be able to tell, based entirely upon feel, if your radio has the real deal, or just a digital fake.

Maybe it is just me, but I prefer the real deal. Yes, it does take up more physical space, but it is less likely to fail. Perhaps that is the true beauty of older radios, they aren’t as likely to fail, as they are not reliant upon computer parts. Yes, I am being a bit of a curmudgeon, but sometimes I have to.

Changes in radio technology can be good. I don’t necessarily mind an HT using digital circuitry. However, for a good base station, I’d prefer a genuine VFO and potentiometer, as an optoisolator just won’t cut it. Digital does have a place in the ham shack, but does it really need to be part of the radio? I would like to think not. However, I leave that to the discernment of the reader.