Monthly Archives: September 2018

1948 One Tube CW Transmitter

1948SepRadioCraftThis schematic was sent in to the September 1948 issue of Radio Craft (the last issue published under that name) by one Robert Fink of Cleveland, Ohio.  The circuit was probably a bit on the chirpy side, and the output filtering probably isn’t adequate by modern spectral purity standards, but it probably got the job done.  It put out about 20 watts on 80 or 40 using a single 1614 beam power pentode (plus a type 80 full wave rectifier.)

Tuning was accomplished by plugging an ammeter into the key socket and tuning for maximum current of 80-90 mA.



Wood Burning USB Charger

We recently featured a 1958 Soviet kerosene powered radio and lamented the fact that similar products are not available today.  It turns out, however, that we were wrong.

LufoFirst, a Facebook comment to our original post alerted us to the Lufo lamp, shown here.  This is a kerosene lantern, apparently developed as part of a UN project to provide radio receivers for Africa.  The heat from the lamp operates a Peltier effect device which powers the built-in AM FM radio.

These don’t appear to be manufactured currently, but they are reportedly available in Europe if you look hard enough.

There is, however, one device on the market currently, and it doesn’t even require kerosene!  At Amazon, you can purchase a wood-powered USB charger that uses the same principle. You can then charge your phone using sticks gathered from your yard.

The USB charger appears to be a bit of an afterthought, but also appears to be fully functional. It appears that the Peltier device power supply is intended mostly to power an internal fan that increases the efficiency of the stove. But it also provides usable power, which is available from the USB socket.

The stove also includes an internal 2600 mAh lithium-ion battery to store the charge. According to the Amazon reviews, the stove itself works extremely well.  According to one review, the stove will boil a pint of water in about four minutes, which is quite good for a stove burning nothing but small twigs.   The stove is useful for charging a phone or other device. The fan speed appears to be a trade-off. With the fan on high speed, the stove runs most efficiently, but it also uses most of the current that is produced. It appears that the best compromise for generating electricity is to run the fan on low speed.

For the do it yourselfer, it seems that producing a similar device should be relatively easy and inexpensive.  The Peltier elements are readily available on Amazon.  You can also order direct from China with free shipping at this link.  They’re normally intended for use in applications such as 12-volt coolers, where an electric current is run through the device, where it produces a difference in temperature between the hot side of the device and the cold side.  But this is a case where the physics works the same with a minus sign in front of the equation:  If you generate a difference in temperature, this will cause electric current to flow.

You’ll probably need more than one, and you’ll probably have to experiment with wiring them in series (to increase voltage) and parallel (to increase current) to get sufficient power.  You’ll also need some kind of heat sink mounted on the cold side.  The device will have maximum output when the temperature difference between the two sides is greatest.  So you need to get one side as hot as possible while keeping the other side of the thin device as cool as possible.

Once you have sufficient voltage and current, you can hook the output to a 12 volt USB charger.  Even if you don’t have a full 12 volts, most such chargers are little more than a voltage regulator, so as long as your output is more than 5 volts, you should have a fully functional USB power connection.

To use your new power supply to listen to the radio, you could add the small portable shown here.  When batteries are available, you can use standard AAA batteries.  During the day, you can run it with the built-in solar cell.  And at night, you can plug it in to your wood burning charger with its USB port.

Of course, most of our readers will want to listen to shortwave, and will probably opt for this inexpensive USB-powered receiver  which tunes AM, FM, and 4.75-21.85 MHz shortwave.

In addition to being useful for camping or emergencies, such a project would be excellent for a science fair project.



SWLing Hurricane Florence

HWNlogoIf you have a shortwave receiver (or even if you don’t), here are some frequencies you can keep in mind for tuning in to information about Hurricane Florence.  Modern news media do an admirable job of getting the information out, but there’s something to be said for being able to tune in first-hand reports directly.

The best option is the Hurricane Watch Net (HWN), a group of amateur radio operators who will be on the air more or less continuously during the storm, taking reports from stations in the affected areas.  Since most hams are able to get on the air without commercial power, this is often the first source of reports from damaged areas.

HWN formed informally during Hurricane Betsy in 1965, and now becomes active any time a hurricane approaches populated areas.

You can tune in to HWN on  14.325 MHz Upper Sideband (USB).  An alternate frequency, which will be more active during the evening hours, is 7.268 MHz, Lower Sideband (LSB).  Conditions on 20 Meters (14 MHz) have been poor in recent days, so it’s likely that there will be more reliance on the 7.268 MHz frequency.

Health and welfare messages from those affected by the hurricane will be heard on the Salvation Army Team Emergency Radio Network (SATERN), which will meet on 14.265 MHz USB.

If you have a shortwave receiver, you’ll want to tune to these frequencies for live updates.  Even if you don’t own a receiver, there are many connected to the web, and you can listen online.  Simply go WebSDR.org, find a receiver in North America, and tune to these frequencies.

For updated information about amateur radio involvement in the hurricane response, please check the ARRL news page.

You can also listen to live streams of many NOAA weather stations at this link.



Hurricane Shopping List

Storm forecast as of Monday afternoon. NOAA image.

Storm forecast as of Monday afternoon. NOAA image.

Yesterday, we posted some products that may make your life easier if your area is hit by Hurricane Florence, which is approaching the Mid-Atlantic states. We provided Amazon links to purchase some of the items, since in most cases, there was still time to order online and have your purchases delivered well before dangerous conditions hit your area. If it’s not already, it will soon be too late to order online and wait for items to be delivered.

But if past experience is a guide, local stores don’t get mobbed until the last minute. There are probably already crowds, but they are still manageable.

Update:  In some inland areas, it might still be possible to take advantage of the advice given on this page for online ordering.  But as early as Tuesday, some Walmart stores in the Carolinas, particularly in the Charleston area, already closed.  Before ordering, check the status of your store at this link.  Even if online ordering is no longer available, this page will give you some ideas of hurricane supplies you might have forgotten.

And to remove much of the stress, you can still order items online at Walmart, and then pick them up at your local store a few hours later. You’ll probably still have some gaps where you’ll need to go to the store and find an item or two. But if you go to Walmart.com and select items with  “free pickup today,” you’ll be able to save yourself a lot of time.

In some areas, you can use this service for all grocery items. But almost all Walmart stores offer this service for most items, including the non-perishable items you’ll need to weather the storm. To make things easier for you, we have the following shopping list of the most common items you might need. Simply click on the link, and if it’s what you need, you can place it in your cart. If you need to look for additional items, or if one particular brand name is out of stock, you can search for it on the Walmart site.

When you’re finished, simply check out as usual, but make sure you select pickup today, and pick the most convenient store. Within a few hours, you’ll get an e-mail or text telling you that your items are ready. You just go to the store with photo ID and pick up your items from the online counter, which is usually at the front of the store.

Your individual preferences will vary, but here’s a selection of many of the items you might need to weather the storm. If the link says that the item is already out of stock, you should still be able to search for different brands of the same product.

 

Note:  This page contains affiliate links, meaning that if you order after clicking on the links, this site will receive a small commission.



Hurricane Preparations

Hurricane forecast as of _____. NOAA image.

Hurricane forecast as of 5:00 PM Sunday. NOAA image.

With Hurricane Florence bearing down on the Eastern Seaboard, it’s a good time to think about whether you need to top off your hurricane supplies. Even if you’re in a possibly affected area, as of this writing (Sunday evening), there’s probably still time to make a leisurely trip to the store to find everything you need conveniently on the shelf. There’s probably still even time to order on Amazon and have the things you might need delivered. If you wait until the warnings for your area go into effect, the stores will probably be mobbed with anxious last-minute shoppers, and the shelves will be bare of the supplies you need.

So if you live near the Atlantic Coast, you should think about this today. And even if you live elsewhere, it’s a good reminder to make sure you’re ready for unexpected disasters.

Here are links to some previous posts of reminders of things you’ve forgotten.  A comprehensive list of supplies is available at other sites, such as the National Hurricane Center.

Water

Having bottled water on hand is always a good idea if you know that a storm is coming.  Your tap water might be interrupted or become unsafe to drink.  But you can also store tap water, both for drinking and cooking, and also for other purposes such as cleaning.  You probably already have all of the containers you need, but if you need more, they’re still readily available.  I have more information at this link, both for suggestions on what to use that you already have, and also other containers you might consider buying.

If your water goes off, being able to take a shower can be a priceless luxury.  If you wait, it will be too late.  But if you act now, you can get an inexpensive solar shower, which I have described on this link.

You’ll probably want to use some of that water to make a cup of coffee.  You probably already own everything you need, but you might want to invest in a gadget that will make the process easier.  You can read all about it at my How To Make Coffee Without Electricity page.

Communications

The main topic of this blog is radio, and we often discuss how to communicate during an emergency.  For a detailed look at the problem, visit my Emergency Communications Primer.  At a minimum, you’ll want an AM-FM radio such as the one shown here, along with plenty of batteries.  Even if you have cellular service, cell towers often have very limited backup power, so if you’re counting on your phone as your only communications device, you might be disappointed.  A portable radio will give you access to information.

And even if cellular service is available, it won’t do you any good if you don’t have power to charge your phone.  At a minimum, you should have a car charger so that you can go out to the car to charge it up.  But another good option is  the USB charger shown here, which allows a cell phone or other USB device to be charged with AA alkaline batteries.

And speaking of battery operated devices, don’t forget to get some flashlights and batteries.  You don’t need anything fancy.  Just get a few inexpensive flashlights like this one along with plenty of extra batteries.

For information on running 120 volt appliances with the 12 volts from your car (and the limitations of this approach), please visit my power inverter page.

Food and Cooking

There’s no need to buy a bunch of expensive “survival” food prior to a hurricane.  Instead, you should simply stock up on the foods your family normally eats, with a focus on things that don’t require refrigeration and require minimal preparation.  If you buy things that you normally eat, then there’s no additional expense.  If there’s no hurricane, you simply use them up in your normal meals.  If you do want to do a bit more planning, please visit my Food Storage page for more ideas.

If your power goes out, you might not be able to cook, and having an inexpensive camp stove such as the one shown here could be a luxury that’s the envy of your neighbors.  I have more discussion of camp stoves at my coffee page.

Shopping Hints

If you’ve waited too long and it’s too late to order online, you still might consider taking advantage of Walmart‘s option to purchase online and pick up at a local store.  You’ll save time hunting down the things you need, you’ll know before you go to the store that the items are in stock, and you won’t need to wait in the checkout line.  You simply place your order online, select the option to pick it up today at a local store, and then go to the online counter to pick up your order.  If people are fighting over the last bottle of water, you’ll have the satisfaction of knowing that yours is behind the counter waiting for you with your name on it.

If you take my advice, you’ll have everything you need well before the storm hits your area.  But in case you didn’t, and you need batteries at the last minute, you can find them at a toy store.  Supermarkets will be crowded, department stores will be crowded, and they’ll all be out of batteries.  But nobody buys toys before a hurricane, and they have plenty of batteries.  So if that’s the item you need at the last minute, you’ll avoid the crowds by going to the closest toy store.

Hurricane History

Once you have your preparations in place, you might like to read about other hurricanes of the past.  Here are some links to other posts on this site:

Note:  This page contains affiliate links, meaning that if you order after clicking on the links, this site will receive a small commission.



Courtney’s Radio Service, Stratford, Conn., 1943

 

1943SepRadioRetailingShown on the cover of Radio Retailing Today 75 years ago this month, September 1943, is Mrs. Wallace Courtney, the wife of the owner of Courtney’s Radio Service in Stratford, Conn. When a representative of the magazine entered the shop, he was greeted by Mrs. Courtney, who was busily engaged in her work of servicing radios. When the reporter asked about the set she was working on, she reported that the rectifier was intermittently glowing red hot. After some poking around, she found a high voltage lead with frayed insulation that had been shorting out against the chasis.

1943Aug30BC2Mr. Courtney was working in a war plant installing radios in airplanes, and left the shop in the able hands of his wife, who juggled the business with caring for the couple’s twelve-year-old son, who was said to be earning good marks. It was her quiet, pleasant voice that answered the phone when customers called. She wasn’t able to make service calls, but when customers brought in a set, she would get it repaired as fast as humanly possible.

According to the magazine, Mrs. Courtney was “typical of a lot of American wives and mothers, who without any fuss or furore, have stepped calmly into their men’s places for the duration in whatever capacities the jobs may call for.” She ran the shop during the day, and in the evening helped her husband work out any repair problems in whatever hours he could spare.



1968 Instant Battery

1968SepEE1Sixty years ago, the September 1968 issue of Electronics Illustrated carried a review of this interesting product, an emergency battery.

Batteries have a finite shelf life, so to extend it, this dry cell was sold dry. In its dormant state, it had a guaranteed shelf life of five years. When needed, you added the electrolyte, which could be any water-based liquid. In the test, the magazine used window washer fluid, but almost any liquid could be used, such as soda, or what the magazine euphemistically called “second hand beer.” After activation, the battery was good for 72 hours.

The battery was available for $5.95 from the Globe Battery Division of Globe-Union, Inc., Milwaukee. A matching lantern was available for $10.95.

Since modern alkaline batteries have a long shelf life, it’s probably not necessary to have this battery today. The best modern equivalent is probably the one shown here, which allows a cell phone or other USB device to be charged with four AA alkaline batteries.

Another option for emergency charging is s standard 12 volt USB charger.  Even if the car battery is unavailable, in most cases, these chargers consist of little more than a voltage regulator, so if they’re hooked to any source of more than five volts, they can be used in an emergency.  So if you desperately need to charge your phone, you can use one of these adapters, along with four flashlight batteries or a 9-volt battery, as demonstrated in this video:

For another emergency battery that can be made using household goods, see our earlier post.



1960 Soviet Nuclear War Planning

Vanov4
Vanov1Shown here are some eerie images of how the Soviet Union envisioned the Battle for the Fulda Gap would take place.  In the event of war between NATO and the Warsaw Pact, it’s likely that Soviet tanks would rumble through the gap on their way to Frankfurt.  And it’s just as likely that they would have been met by the use of atomic weapons to delay their advance.  As can be seen here, the Soviet tanks were expecting the atomic blasts, and planned to dig in to continue the tank battle.

Vanov2The images here are taken from a 1960 book entitled Поражающее
действие ядерного взрыва (The damaging effect of a nuclear explosion) by A.I. Vanov and G.I. Rybkin, one in the series Popular scientific library of the military publishing house published by the Soviet Defense Ministry.

Vanov3Despite the word “popular” in the series title, the book appears to be a quite scholarly look at the effects of nuclear weapons.  In fact, the book contains numerous footnotes, including frequent citations of the definitive U.S. Government treatise on the subject, the Effects of Nuclear Weapons, as shown here in the bibliography:

Vanov5

Vanov6



NBC Radio, Canton Island Eclipse Coverage, 1937

1938Sep5LifeThis picture appeared in an RCA advertisement in Life magazine 80 years ago today, September 5, 1938. It shows NBC engineers Marvyn Adams and W.R. Brown along with NBC announcer George Hicks broadcasting live from Canton Island (sometimes spelled Kanton) in the South Pacific.

1937 Eclipse from Canton Island. Wikipedia image.

They were on the island as part of a joint expedition by the U.S. Navy and the  National Geographic Society for the solar eclipse of June 8, 1937.  The NBC eclipse coverage was transmitted from this “ultra-high frequency transmitter” to the USS Avocet anchored at the island, and from there to the RCA station at Point Reyes, California, where it went by wire to the NBC Blue Network.

According to the ad, the island would possibly “play an important role in transpacific air transport service,” a prophecy which proved true, as the island served as a stop for PanAm’s Pacific Clipper service to New Zealand, which ran from 1940 until the war, and then again from 1946.

The Navy-National Geographic expedition, in addition to observing the eclipse, placed a monument on the island to bolster the U.S. claim to sovereignty over the island. This was disputed by the British, who also had a ship anchored for the eclipse. Reportedly, the British ship, the HMS Wellington, fired a shot across the bow of the USS Avocet, which reciprocated. The two commanders called a truce pending further instructions from their command, and the two parties observed the eclipse together.

During the war, the U.S. Navy built a 6230 foot airstrip on the island, which was defended by as many as 1200 combat forces, but was never attacked by Japan.  The island now forms part of the Republic of Kiribati.  As of 2010, it had a population of 24.

The island was most recently in the news that year after a yacht stopped en route from Honolulu to Fiji and discovered that the islanders were desperately short of food, an expected supply ship never having arrived.  The islanders had been living on fish and coconuts for several months, and the yacht owner used his satellite phone to contact the U.K. Coast Guard, which contacted the U.S. Coast Guard to arrange relief supplies.



Transatlantic TV DX: 1958

1958SepRadioElecYesterday, we showed a regenerative preamplifier from 1968, designed by Hartland B. Smith, W8VVD, currently licensed as W8QX.  We promised that we would bring you another article by this prolific writer which appeared ten years earlier, in the September 1958 issue of Radio Electronics.

Smith begins the 1958 article by pointing out that he had been a licensed ham for 18 years and had his share of exciting DX contacts, but that he could “honestly say that none of these gave me quite as much a thrill as when I first saw an indentifiable transmission directly from London on the screen of my own TV set.”

And as shown by these pictures, that’s exactly what he did. The winter of 1957-58 was at the peak of the greatest solar maximum in recorded history, meaning that the maximum usable frequency (MUF) was frequently going above 40 MHz. This opened the possibility of pulling in Transatlantic TV signals, which is exactly what Smith set out to do.

Receiving the audio of British and French television signals was a relatively simple matter. The London and Belfast stations were on 41.50 MHz, and Caen, France, was on 41.25 MHz. Armed with nothing more than a prewar FM receiver, he was easily able to hear the audio. (Indeed, it wasn’t uncommon for American hams to listen to British TV audio on their six meter receivers.)

But being able to watch the video posed a much greater challenge. European TV used both different frequencies and different standards from American TV, so an American TV could not be used without some modification. So Smith set out to make the modifications. He focused on trying to pull in the powerful London station, which transmitted on 45 MHz with 200 kilowatts. The French station’s video was on 52.4 MHz, which was likely to be above the MUF even if the audio were booming in.

The first relatively modest challenge was the frequency, which was lower than that tuned by American sets. This was accomplished with a simple converter consisting of a single 12AT7 tube. With an oscillator frequency of either 33 or 123 MHz, this would bring the British signal to American channel 5, which was unused in his area. The antenna consisted of a two-element beam in the attic for video, with a folded dipole for the audio receiver.

Lisajous pattern on scope showing equal frequencies. Wikipedia image.

Tuning in the signal was one thing, but getting a visible picture required that the set be modified internally. The first issue was the horizontal sweep frequency, which was 15,750 Hz in the American set, but 10,125 Hz on the British signal. He did this by using an audio oscillator to produce the required 10,125 Hz signal, and feeding this and the horizontal oscillator into a scope. He then adjusted the horizontal and added components until the frequencies matched, as shown by a circular lisajous pattern on the scope.

The British vertical frequency of 50 Hz was deemed close enough to the American 60 Hz to not require any modification.

The final problem was that the video carrier in Britain was opposite of that used in the U.S. To correct this, he modified the video detector by reversing the cathode and plate.

With the modifications made, it was just a matter of listening on 41 MHz and waiting for the audio of the European signals to appear. This meant that the band was open, and it was time to turn on the video receiver.

This was a fairly elaborate process. The first step was to turn on the converter, and adjust the converter frequency until the “familiar out-of-sync zig-zag lines denoting a video carrier” appeared on the screen. (Anyone who watched TV in the 1970’s or earlier knows exactly what he means. If you’re too young to remember, click here for an example.)  At that point, the vertical hold would stop the picture from moving vertically, and then the horizontal hold control was adjusted (which might require some internal adjustment to make sure the control was in range). As he put it, “TV dx tuning is an art that is a little hard to describe on paper. It is best learned by experiment.”

He pointed out that picture quality would never be perfect. For one thing, there would almost always be multipath interference, since signals through the ionosphere might travel numerous paths. He noted that the ghosting problem might sometimes be acute. During one televised tennis match, he reported seeing at least 30 players batting 15 balls back and forth. But occasionally, the ionosphere would settle down momentarily, resulting in the identifiable images shown here.