The military and diplomatic radio situation in Europe at the end of the novel 1633 is a result of a unique combination of the authors' needs in the story line, the limitations imposed by the authors' choice of town to base Grantville on, and other historical accidents which left us with a wealth of some technologies and a dearth of others.
There are four important elements to the radio background of the 163x series: the environment that the planet and solar system provide due to Eric Flint choosing to start the series in the year 1632, the people of Grantville, the physical resources they have available, and the goals of their government.
From a political perspective, 1632 occurs during the Thirty Years War. From a social perspective, 1632 occurs during the "Early Modern Era." From a biographical perspective, 1632 features players who are still household names, such as Cardinal Richelieu, Galileo, King Charles the First, Oliver Cromwell, etc. It's a fascinating time and a critical point in the development of western culture. When Eric contacted me and asked that I help brief him on the possibilities for radio in 1632, it became quickly clear that from a radio specialist's perspective, Eric could not have chosen a worse time to drop a town into than 1632. Just at the beginning of the period where there are telescopic observations of the heavens, approximately simultaneous with the trial of Galileo, 1632 drops Grantville into the beginning of a time best known to science as the "Maunder Minimum."
At about the same time as Galileo published his description of his construction of the Dutch invention of the telescope, natural philosophers throughout Europe began noting that the sun had imperfections, "spots" on it. This was far easier to watch with a lens, since you could project an image of the sun onto a white sheet, and observe it without destroying your eyes. The novelty led several natural philosophers to begin a program of noting the sunspots on a regular basis. Therefore, we have an excellent European record of the number of sunspots starting with Galileo's first such observation in 1610.
This notion of the imperfection of the sun would have come as no great surprise to the court astronomers of China and Korea. In the court logs of the observations of those staff astronomers, there are sunspot records made with the naked eye going back another millennium and a half. Using those records, we can trace the sunspot number from about 28 bce, using a reasonable relationship between the capabilities of naked-eye astronomers and those using projections and lenses.
For all of this two thousand year period of recorded observations, the number of sunspots on the surface of the sun has varied in an eleven-year cycle. As of this writing, in 2003, we are near the falling side of the peak of the current cycle with sunspots near the historic high of over 200. This extreme activity has resulted in spectacular auroras being seen as far south as 30 degrees north (Oklahoma City). At the other end of the measure, the lows have had sunspot numbers in the low teens to the mid-20s. The "average" low is between 20 and 30.
For reasons that no one understands, starting in about 1610, the number of sunspots plummeted. By 1632, which should have been a peak year, the sunspots were down to the mid-teens, and by 1640, had dropped to zero. (There is an anomalous high data point in 1639.) The 11-year cycle did continue, with peaks as high as 8 or 9 between 1645 and 1700. Then, again for reasons that no one understands, starting in 1710, the numbers went back up, and have continued quite regularly for the last three hundred years. This is not a "lack of observations" artifact, since the court observations in China and Korea correlate quite well with the western records. This is real.
Recent work by observational astronomers using a combination of new techniques by really really smart people on type G2V stars like our sun have figured out a way to measure the sunspot number of a star even though we cannot "image" the star. This work indicates that G2 stars may typically spend as much as 20% of their time in this "quiescent" mode. It could start again tomorrow. No one has any models for why it happens, or what causes it, or why it stopped. It's all quite confusing.
So what, you say? Well, it turns out that the number of sunspots is very highly correlated with the thickness of the upper layers of the ionosphere. There are several "layers" in the upper atmosphere, which get ionized for different reasons. These are labeled, from the inside out: D, E, F and "topside."
It turns out that the number of sunspots is very highly correlated with ability of the atmosphere to reflect radio waves back to the earth. There are several "layers" in the upper atmosphere, which get ionized for different reasons and have different effects on radio waves.
The layers are caused each day by the action of solar X-rays, ultraviolet light, and charged particles streaming out from the sun on the earth's upper atmosphere. This is the same action that splits O2 apart and gets the free oxygen that can combine into O3, to form the "ozone" layer. Ionization increases in the sunlit atmosphere and decreases on the shadowed side. Although the Sun is the largest contributor toward the ionization, cosmic rays make a small contribution. Any atmospheric disturbance effects the distribution of the ionization. These ionization layers form every morning at sunrise, thicken throughout the day, and then begin to fade at sunset. The combination of their chemistry and their electrical properties causes them to absorb and reflect radio waves. The amount of the ionization in each layer controls the absorption and reflection of radio waves. High frequency radio waves are absorbed by the weakly ionized D region.
Further out, the topside and F2 layers are ionized not only by UV light, but also by the action of the solar wind on the outer layers of the earth's atmosphere and its interaction with the earth's magnetic fields. During periods when there are lots of sunspots, the sun puts out a lot of particles, and these ionization layers are quite thick and robust. Without the solar action, during sunspot minima, the F2 layers are thinner and weaker.
The thicker and more robust the outer layers are, the shorter the wavelength they can refract or reflect. During sunspot maxima, the maximum usable frequency (MUF) can get as high as 30 or even 50 MHz (six meters). That is, 30 MHz signals can bounce right off the ionosphere, or be trapped between two upper layers and ducted around the world before breaking out and coming down most anywhere. That's how CB radio "skip" works, when folks listening to the radio in their cars on the highway in Kansas hear the chat between boats working the shrimps in the gulf of Mexico. Normally a CB radio is good for 5 miles, but when the sunspots are high, all bets are off.
During a normal sunspot minimum, when the sunspot count is down around 20 or 30, the MUF stays up around 14 MHz for at least part of the day, and seldom goes below 7 Mhz.
Frequency and wavelength are related. The higher the MUF, the shorter the wavelength and the smaller the antenna that is needed to send and receive radio signals. In general, one wants to use as short a wavelength as possible, because the higher the frequency, the smaller the antenna needed. A 30 MHz transmitter uses a "natural" antenna that is only three meters long. But a 7 MHz transmitter uses a natural antenna that is about twenty meters long. Thus, the higher the MUF, the more convenient it is to build radio installations. Most Hams therefore work the 20-meter bands, and the 40-meter bands are not uncommon. But it's the rare Ham who works 80 or 160 meters, since the natural antenna for 80 meters is 40 meters long, and 80 meters long for the lowest common Ham band of 160 meters.
However, remember the missing sunspots? During the Maunder Minimum, during the period that Eric has set the 1632 series in the middle of, the F2 layers of the ionosphere go away to a great extent. Of course, there is always some solar wind, some extreme UV, and some ionization by solar X-rays and cosmic rays. Thus there will be some ionization and some reflection. But for the purposes of the story, the tech team and the authors have decided that the MUF keeps dropping and dropping toward the lowest usable frequency (LUF) until, by the year 1640, to do long-distance communications without relays you would need to be using 2 MHz for much of the day, and can get up to 4 MHz only late at night.
And remember that the D layer absorbs the radio waves, so the low MUF means that you have little if any ability to do long distance communication during the day at all. The absorption of the layers defines a lowest usable frequency, an LUF. It is possible for the LUF to be higher than the MUF. Then, nothing much reflects.
No one really knows what the effect of the Maunder Minimum was on the radio characteristics of the atmosphere. Some contributors have suggested that the poor ionosphere is balanced by the low amount of interference due to the low number of radios on the air. Nevertheless, based on some reasonable guesses, the tech team and the authors have decided that for the purposes of the 163x stories short wave above 80 meters is pretty much useless from 1630 to 1710.
As a result of the long wavelengths, the radio installations in 1632 universe end up using very large antennas. The most common antenna for a diplomatic mission will be an 80M inverted V two-element beam installed this way:
Take a piece of wire, forty meters long, and cut it in the middle. Put a glass insulator in the center of it, and hook another piece of wire to each of those twenty-meter-long pieces. The "hookup" wires are held apart every few inches by a hunk of glass or plastic or wood, like a little ladder two inches wide. This ladder leads back to the transmitter. Meanwhile, take your center insulator and haul it up to the top of a tower as high as you can get. One hundred and fifty feet is really a good height. Attach the glass insulator to the tower, and then draw a line on the ground, in the direction of the city you want to talk to the most. Stretch each of the twenty-meter-long legs away from the tower at 60 degrees up from vertical, 30 degrees down from horizontal, and perpendicular to the line you drew (crossing it). Then hook the end of each wire to a rope with another glass insulator, and pull the ropes taut so that the wire is as straight as you can get it.
Now, remember how you drew a line towards the radio you want to reach, that you want to "beam" at? Build another tower, 20 feet back away from your destination, on that line. Now, do the exact same thing with another piece of wire on that tower. (You do not need hookup wires on this one.)
So, two 150-foot towers, two 40-meter long hunks of wire, suspended in the air, and lots of rope. If you want to use 1.7 MHz (160 meters) instead of the 3.5 MHz we designed this for, double all the numbers above. (Well, you can keep the tower height the same, but taller is better.)
Repeat this, as often as necessary to build a beam pointing at each city you want to talk to. A big central diplomatic radio installation will have a cluster of these beams pointing in a variety of directions and will require a clear level space a quarter of a mile on a side.
You begin see the problem. . . .
As the characters in the series approach 1640, the electronic situation in the atmosphere worsens. The MUF drops towards 1.7 MHz, and the antennas and such get bigger as above, and harder to build. It's not fun. That's why Gayle and Jeff kept muttering about the bad timing of the radio situation in 1633. From the perspective of a Ham, they were dropped straight into hell.
What can be done about it? Several things:
1) You use a lot of power to overcome the fact that not much bounces.
2) You experiment to find the best frequencies available and use them.
3) You build good antennas.
4) You send your messages at the right time of day (generally a window about four hours long starting at sunset called the "gray line").
5) You set up relays, i.e., you send the message as far as you can, and then relay it. Thus, in 1633 the mission in Amsterdam relays to London and to Scotland.
6) You maximize the use of the power you have, by using CW (Morse code) instead of voice. Voice requires far better signals than CW does.
Very awkward, yes. But that's the situation until the newly emerging society can get satellites back up, which will be a long time yet—in fact, at least as long as the year 1700, which is about the same time that the short-wave bands will reopen.
In short, no matter how you slice it, long-distance radio communications will be a very different thing in the 1632 universe than what we've experienced in our own timeline. And as tube production comes on line, and high power radios go into production around the world, bandwidth for long distance communications will be a precious and rare resource. The pressure to build cables across the ocean will be even higher in the 1632 universe than it is in ours.
In addition to the physical world around them, the radio situation in Grantville is shaped by the technological world they brought with them. What radio technology does Grantville posses? What just won't work? Let's examine each of the common up-time radio technologies and consider its place in Grantville after the Ring of Fire. When Eric began writing 1632 he did a very clever thing. He decided that with a few exceptions which he has carefully limited, Grantville is based on the real-world town of Mannington, West Virginia. In general, and with a few specific exceptions (the main one being the power plant), it's safe to assume that if something was in Mannington in late 1999 or early 2000, it's in Grantville; and if something was not in Mannington then, it is not in Grantville. That presumption drives the following discussion.
There is not a Radio Shack store in town, there is no electronics store, there is no radio dealer of any kind. Some CB radios will be available at a few stores. There is one TV repair shop.
Sadly, while there was a cell phone antenna and cell in Mannington and thus, in Grantville (an analogue one—no CDMA or TDMA digital cells were operating in Mannington in late '99 or early '00), the cell was not linked to the local phone switch. It was operated by a different company. And while one of the short stories from the Ring of Fire anthology explains that there is an excellent phone tech in town, he's not a cell phone guy. It may be possible eventually to cross connect that cell to the phone system, but in the first two years, no one has had any success at it. The manuals for the cell weren't in town, no one knows the computer passwords, and the cell was not set up for autonomous operation. The cell phones themselves are useless without the cell being attached to a billing and authorization computer system and to a phone switch. For all practical purposes, you may regard cell phones as a source for small high energy density rechargeable batteries and other electronics parts, but not as radios.
Pre-Ring of Fire handheld and base station commercial FM radios were used by the coal mine, by the electric company, the police, the school district, the city water department, etc., etc. The presumption of the 1632 authors is that these radios remain dedicated to their pre-RoF use. One radio from each incompatible frequency set was placed in the Grantville emergency Operations Center to provide cross\network links.
CB radios are featured in 1632 because they were owned by Mike Stearns and his friends, as well as many other residents of Grantville. CB radios are common in the U.S., particularly among rural populations prior to the wide spread of cell towers. They provided unlicensed, free, simple radio communications for a variety of purposes. It was automatic that the Stearns administration began to use the CBs to coordinate the new military actions that Grantville found itself engaged in. By the end of 1632, CB radios are primarily used by the military for tactical coordination.
CB radios operate at 21 MHz (11 meters) and are well above the MUF described above. Without relays, they are good for one to five miles on level open ground. The signals are blocked by hills or mountains. CB radios in airplanes, or situated on mountain tops can generally talk about 20 miles line of sight. Of course, we can relay over-and-over and go any distance.
Four types of Pre-RoF CB radios exist:
1) Children's toy walkie talkies. These are useful for small-area crowd control type operations. They would have been gathered up where possible and parsed out as needed—except some kids refused to give them over and . . . it's a free countrylet. There are probably twenty to a hundred total in the town.
2) "Base" stations designed to operate off the 110V mains. There are probably between twenty and forty in the Ring of Fire area.
3) "Walkie-talkies" that are "full power" 5-watt mobiles, generally with cigarette lighter power take-offs for use in cars when not using internal batteries. This is the most common style radio produced in the last six years. We estimate that there are one to two hundred of this and other high-powered mobiles (see type 4) in the RoF.
4) High-power mobiles, 5-watt mobile radios designed for use in cars. These and the high-powered walkie-talkies exist in two sub-types:
a. AM only. Older CB radios only supported AM modulation.
b. Single Side Band capable. SSB gives you basically double the range for the same power. Newer CB radios have a switch that allows them to run SSB.
SSB radios have a second advantage in addition to range. They can not be overheard with a crystal radio. AM radios can be eavesdropped on with 17th century built radios. SSB radios have built-in signals security. SSB signals are not understandable without a BFO (Beat Frequency Oscillator) capable receiver, and so SSB is secure except against stolen radios capable of tuning into the 27 MHz band. Having said that, stealing a CB is a possibility, but they also need to steal a battery charger, a generator, a set of batteries, and so on. The on-ship radios for the air force and the on-ship radios for the navy are the newer SSB models.
Managing radio outside of Grantville for tactical use by the military is non-trivial. Batteries die, there are no power lines to plug chargers into. Cars with cigarette lighter outlets don't exist. If you and your army buddies go outside the RoF and you want radios to chat among yourself for battle coordination, you have to figure out how to power them. This is tricky.
First, just forget solar power; we have no supply of solar cells in Grantville and cannot make any. The Lindsey publications book "Make your own working solar cell" aside, the copper oxide cells that are described produce so little power that a CB radio would require the entire roof of a house papered with them. High output solar cells are many decades in Grantville's future. Wind, water, steam, and cranks are how we must power electronics outside Grantville.
If someone manages to steal an up-time radio, even if they steal a set of batteries and a generator, they will still need to have a person with pretty good electronics knowledge to manage the care and maintenance of that radio and battery and generator. Destroying radios and batteries is just as likely as charging them if you are not very careful.
For those taking radios away from Grantville and from Gustavus Adolphus' Europe, away from steam engines and windmills, the radio heads looked to Australia's native genius Alfred Traeger for a hint. We'll be taking a page from Traeger's book. Traeger was tasked with the problem of providing radios for the Royal Australian Flying Doctor Service, providing medical service throughout the vast Australian outback. No electrical generators existed. No batteries existed. Few if any of the outback stations had electric motors or lights. Traeger developed a small, lightweight generator with a set of pedals attached that could be screwed down to the floor of a wooden building in front of the table that the radio was set on. No batteries were needed. When you wanted to run the radio, you sat down and pedaled, and the radio ran. This was a major benefit.
Battery management is difficult. A car battery lasts about three thousand charge cycles. Even with careful use, the best will die within the next six years. Once we've used up the supply of car batteries, we will be down to wet cells of some sort. Danielle cells, or hand-built lead-acid cells with much lower efficiency than what we brought along with us can be made. Danielle cells (wet cells) were used to power the first radios and telegraphs and telephones. They are well documented and simple to make, once Grantville begins importing and refining zinc, but they have transport and reliability problems. The Traeger pedals solve the problem. Anywhere we can take a radio, we can take a six-pound pedal generator. That's not to say that our fixed installations won't also have batteries, and windmills and steam generators. They will. But the first choice is the Traeger pedals.
Hand-held radios will slowly become man-portable and then fixed base operation as the supply of rechargeable batteries declines and Grantville lacks the tech base to make new compact batteries for them. Over the course of the first few years down-time, the battery to run a walkie talkie turns from a few C cells into a couple of three-gallon buckets of blue goo and sulphuric acid.
There will also be a small number of FRS (Family Radio Service) 49 Mhz handhelds which are FM. Gayle used one pair in 1633 to chat with Oliver Cromwell in his dungeon. Range is very limited (less than one mile). Plus, see the battery problem above. Less than 20 FRS radios exist in the RoF, since in 1999 they were not yet popular.
You can't talk about Ham Radios without talking about Hams. The 1632 authors are blessed with a good selection of people in Grantville who know about radios, who build, operate, and collect radios as a hobby, and who have the material needed to set up a functioning communications system for the new United States (which, by the end of 1633, is now the United States of Europe).
In late 1999, there were eighteen amateur radio operators in Mannington, and thus in Grantville. There are three Extra class (the highest), two Advanced class Hams, five General class and one Tech-plus. All those have shown Morse code proficiency. There are five Technician class Hams who have shown general class knowledge of radio operation and design. There are two Novices. One of the Extra class Hams is female.
The FCC database does not give information on original date of issue of licenses, but a number of those licensed have licenses dating back ten years, which is the expiration period. Two of the three "extras" must have studied and tested together, because their call signs are sequential.
These individuals—not them, of course, but the characters who reflect their skills in the 1632 universe—have a large variety of radios available. Several of those have been sent out with the various diplomatic missions along with antennas and antenna parts to London, to Amsterdam, and (in the upcoming novel 1634: The Galileo Affair) to Venice. As follows:
Julie and Alex Mackay have a portable Radio Shack DX-398 and a supply of six-volt lantern batteries to power it. This is a middle range portable transister radio, designed for the mobile short wave listener. It weighs less than three pounds.
Gayle Mason has three FRS handhelds described above, a Radio Shack DX-394 receiver, and a hand-built CW transmitter and amplifier powered by a set of Traeger pedals. She has an isotron 80b antenna which she hangs out the window of the tower to use. An isotron is a very odd antenna. It looks like a six-sided aluminum box with a coil suspended in the middle. It is about 32 inches tall, 16 inches wide and 15 inches deep. It is very very different from typical "wire" antennas and is refered to by the Grantville away teams as "modern art."
Rebecca Stearns and her mission were supplied with the best radios of any team in 1633, which makes sense, as she is Mike Stearns' wife. (And, leaving aside nepotism, her Holland mission is likely to bear the brunt of the relaying work for all the diplomatic missions.)
Becky has a Kenwood TS520 transceiver. It is simple to operate, plug and play, 12 V ready, 160M to 10M all band transmitter, SSB, CW, AM capable of operating at either 20 watts or 100 watts. It will "punch through" to Grantville with no problem. In the same box integrated is an excellent receiver, better than the one sent with Gayle for our purposes. Original cost was around $600. Good stuff, two revisions back from the current state of the art. It's bulletproof. It pulls 20 amps at 12V for power, exactly on target for our power budget. It was chosen from the radios available in Grantville because its tube finals will tolerate poorly matched antennas better than an all-solid-state radio would. The Holland team also has an isotron 80b antenna and wire to make a big "beam" antenna if they get a place and the time.
Radios have been assigned to the mission headed for Venice also, but as of the time this article was written those stories had not been published and a discussion of their capabilities would give away story elements currently not for publication.
Meanwhile, as of 1633, large antenna installations are in place in Grantville, Magdeburg and Luebeck with up-time designed and built "Ham" radios for long-distance use. Due to the Maunder Minimum and the sunspot issues, long distance communications is done via Morse code at 3.5 MHz, and sometimes at 1.2 MHz.
Grantville will be building more "Ham" style radios for use by the army, the diplomatic corps, and the banking system. Using recycled parts, and arranging a relay network, Grantville can build between one hundred and several hundred CW (Morse code) radios for this purpose until they get tubes on line.
It is expected that Grantville can start tube production sometime in the late 1630s or early 1640s. (Radio tubes are very hard to make. The characters will have to reinvent a few industries to make tubes. Radio tubes are not light bulbs. They are much harder to make than light bulbs.)
Using these down-time-built but up-time-parts radios, Grantville and the USE can have world-wide communications as soon as they can train operators and send them out. The limiting factor on building down-time-built radios is the availability of high power transistors and tubes salvaged from radios and old TVs. It is unclear how many such high-power parts will be available. Transistors have a "top frequency" beyond which they become mostly useless. In order to build high-powered radio transmitters, the techs will need high-power high-frequency transistors and/or tubes. The salvaging of power supplies of dead equipment will be a booming business for a while. Every tube will be cherished.
If Grantville was really good at putting its junk into the dump—which, alas, was not within the Ring of Fire and remained behind in the old universe—then there will be substantially fewer high-power radios built, and spark-gap radios will become far more important than is described here.
Strategic radio, long-distance diplomatic and military communications will be CW-only (Morse code). This is due to the Maunder Minimum.
Additionally, it is presumed that we are not transmitting CW in clear, and that either one-time-pad ciphers generated off the computer screens, or reasonably sophisticated codes beyond manual cracking will be used.
However, the number of up-time parts is limited. What can they do, until they get to building down-time tubes, to make new down-time radios?
The obvious answer is "spark" radios. Spark existed long before tubes did, and they can and will build spark transmitters and crystal radios.
Details about the design and operation of spark transmitters and crystal radios will have to wait for another article. Spark transmitters and crystal radio receivers can be built with 17th century ("down-time") resources.
1632 and 1633 depict the existence of TV in Grantville. No commercial radio or TV broadcast facility existed in Mannington in 1999/2000, so it does not exist in Grantville at the time of the RoF. The high school had a TV production studio, but no transmitter. No one had a commercial TV or radio transmitter.
The TV "broadcasts" that Rebecca Stearns gave in 1632, and which continue in 1633, are not "over the air" but are rather "cablecast." A link was made from the TV studio in the high school to the "head end" of the cable TV system in Grantville, and shows and movies were distributed over the cable system. There was no "transmitter," no tower, and no antennas were needed.
The people participating in the 1632 Tech Manual conference in Baen's Bar discussed for a long time how to resolve the lack of a commercial radio station in Grantville. The FCC antenna tower database made it clear that no appropriate towers existed in Grantville for an AM radio station. While it would have been possible to build an FM radio station simply enough, you can not hear an FM station on a crystal radio. Since the authors of the 1632 series wanted a supply of down-time radios to be available to listen to the broadcasts of the Voice of America, it was necessary to figure out how to build a radio station.
Gayle Mason's Ham radio station could be rebuilt to provide a modestly powered AM radio transmitter, but what to use for an antenna? A natural antenna for an AM radio station is 140 feet tall. The folks in Grantville did not have such a tower, nor did they have the free steel to build one. The available steel was going into the ironclad ships and into railroad track.
Additionally, the government of the new U.S. wished to conceal its ability to talk to its remote diplomatic staff as long as possible. After months of discussion on Baen's Bar by the "Barflies," the concept of the Great Stone Radio Tower was born. Many European cathedral towers exceeded the height needed for the Voice of America transmitter tower. By building a stone antenna tower (and running copper wires down the outside to act as the active antenna elements), Grantville solved both the technical problem of building the tower, and the political problem of distracting the French and the English from the ability of Grantville to talk to its diplomats. Somehow the idea that long-distance radio requires huge massive antennas became commonplace.
By early 1634, the Voice of America will be on the air with a transmitter rebuilt from Gayle Mason's high powered Ham radio transmitter, and the Great Stone Radio Tower. Prior to the Great Stone Radio Tower's construction, the Voice of America was on the air with a variety of makeshift antennas.
The Barflies have long discussed, but no "official" author has yet mentioned, the idea that Gustavus Adolphus will not be satisfied with the Voice of America and will push for a second AM broadcast radio station to promote the concord of his nation and his faith. The Barflies refer to Gustav's station as the Voice of Luther.
The Voice of Luther will go on the air in late 1634 or early 1635 using an all-down-time built transmitter using the same style transmitter as the first broadcast AM radio station. The details of the construction of a Fessenden Alternator are beyond the scope of this article, but suffice it to say that operating this station will involve speaking into a microphone directly inserted into the feed line from the transmitter to the antenna while it is carrying up to 10,000 watts of power. This is very dangerous. Operating broadcast radio stations in 1632 is not for the faint of heart. A wrong move will result in a fried DJ.
The technical and historic background in the 1632 series is the result of the work of a huge number of participants in the "1632 Tech Manual" conference at the Baen's Bar website.
This article attempts to summarize information from two sources: the background briefing documents prepared for Eric Flint and David Weber, and the collective wisdom of the Baen Barflies. The mistakes, of course, are my own.
The combination of people, material, and environment presented by 1632 results in a rich playing field for people who want to work on alternate history. Certainly I have enjoyed the experience. I strongly invite any of you interested to join us. There is still a lot of work to do.
NASA site on sunspot numbers:
http://science.msfc.nasa.gov/ssl/pad/solar/sunspots.htm
Visual Large Sunspot record:
http://alpha.uni-sw.gwdg.de/~wittmann/awittmann-Dateien/navbar-Dateien/Largespotscatalog.pdf
Extra Solar sunspots:
http://www.ucar.edu/communications/lasers/sun/stars.html
http://www.owlnet.rice.edu/~echollet/solcon.html
For more than you want to know about the Ionosphere see:
http://www.ngdc.noaa.gov/stp/IONO/home.html
Isotron antennas:
http://www.rayfield.net/isotron/
The Traeger pedal radio:
http://www.antiqueradio.com/traeger_pedal_07-99.html