Monthly Archives: August 2021

1941 Optical Communicator

1941AugPS1Eighty years ago, this well dressed gentleman was sending a message through this light beam transmitter, as described in the August 1941 issue of Popular Science.

The magazine was a bit prophetic, since there was more experimentation with the idea after Pearl Harbor. When hams were ordered off the air for the duration of the war, optical communications was one of the ways they continued to practice their hobby (along with carrier current communications.)

The idea is simplicity itself, and it’s an idea that I independently invented as a youngster 30 years later, and I know others did as well. The light beam of a flashlight is modulated with an audio signal by wiring the light in series with the secondary of a transformer. The primary of the transformer is wired with a buzzer and key to send Morse code. When I did the same thing, I hooked the transformer primary to the output of a transistor radio or other audio amplifier, allowing voice signals to be sent.

The receiver is an audio amplifier, with a photoelectric tube hooked to the input. In my later experiments, I used a solar cell hooked directly to the input of an amplifier, which didn’t seem to mind the small DC voltage.

The student looking for an interesting project for a science fair could easily duplicate this experiment with modern equipment, at very low cost.  It’s an easy demonstration of a communications device dependent only upon light.

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1936 Deroyla Radio

7PghPressThis ad appeared in the Pittsburgh Press 85 years ago today, August 7, 1936, and it raises some interesting questions. It’s for the store of one S.H. DeRoy, 408 Smithfield Street, Pittsburgh.
It implores customers not to be confused by stores of a similar name, and points out that there is but one location for the S.H. DeRoy store. There was a picture of S.H. DeRoy in the window, and you were supposed to look for that before going in.

It appears that other relatives of S.H. DeRoy might have been operating their own competing stores, hence the warnings. This case from the U.S. Tax Court reveals that S.H. had been in partnership with his brother and father running a jewelry business, but the partnership went bankrupt in 1930. Another brother acquired the assets, formed a new corporation, and attempted to continue the business. But by 1937, it too had become insolvent. While it’s hard to tell for sure, it’s likely that other family members were in competition, hence the warnings.

According to the court decision, the company was primarily in the retail jewelry business, and it appears that much of their business was frames for eyeglasses.  In 1936, S.H. apparently branched out into radio, with the model shown here.  The court opinion notes that the jewelry was sold on credit, and the radio was as well, since you could take it home for only 25 cents per week, or buy it for $9.95 cash.

Despite the insistence on not being misled by similar names, it’s interesting to see the brand name of the radio being sold. This set, described only as receiving both longwave and shortwave, bears the brand name of Deroyla. That makes perfect sense, since it’s being sold by DeRoy. But it’s also suspiciously similar to Detrola, which was a major brand name at the time. The only other Deroyla radio I’ve been able to find is this ebay listing, which is for a model with a similar description by somewhat different front panel layout.



1941 Soviet Crystal Set

1941AugRadioFrontIn August 1941, the Germans were busy invading the Soviet Union, but they would have realize the futility if they had known that the Soviets were quite undaunted, and were busy putting together crystal sets. As you can see from the August 1941 issue of Радиофронт (Radio Front) magazine, that is exactly what they were doing. The diagram shown above is clearly a crystal set, and most of the parts appear to be homemade. Despite what the Germans could throw at them, the Soviets were still able to pull in the stronger stations thanks to simple receivers such as this one.

As you can see from the diagrams below, the tuning was accomplished with a variometer, using two spiderweb-style coils hinged together. And as long as they could find a suitable mineral, the Soviets could easily put together the detector shown below.

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5 August 1921: First Baseball Broadcast

Forbes Field exterior.jpg

Forbes Field. Wikipedia image.

One hundred years ago today, August 5, 1921, the Pittsburgh Pirates beat the Philadelphia Phillies 8-5 at Pittsburgh, as duly recorded by the next morning’s newspapers. While nothing remarkable happened during the game, it was a landmark event, since it was the first time that a baseball game was broadcast by radio.

Harold Arlin provided the play by play over KDKA, which had just received its commercial license. He sat in a converted box seat at Forbes Field and spoke into a microphone that he described as looking like a tomato can lined with felt.

Hams:  To commemorate the event, KD3KA will be operating a special event station on August 7 and offering a commemorative QSL card.  Details are available at the ARRL website.



1960 NEAR Test, Charlotte, MI

1961AugPE1We’ve previously written about the NEAR system, which was a system envisioned to alert the American public to a nuclear attack. It relied upon a 240 Hz signal superimposed upon the power lines. This signal was picked up by an ingenious electromechanical receiver in the home, and sounded a loud buzzer in the event of an alert. We previously described how the receiver worked, and the August 1960 issue of Popular Electronics, from which the pictures above were taken, explains the equally simple method used to transmit the signal. In the schematic at right, at the utility substation, to send the alert, switch S1 is opened. The rectifier sends a flow of DC1961AugPE2 pulses through the transformer secondaries, generating a signal at the fourth harmonic of the power line frequency. This signal averaged about 2-3 volts, meaning it would not interfere with regular power transmission.

On that October day, the alarm originated at a radar station in the Arctic, from which it was relayed to NORAD headquarters in Colorado Springs, CO. An officer there pushed the button to activate the NEAR system, resulting in the alarm being sounded almost immediately in Charlotte, MI.

That morning, seniors at the high school, the Charlotte Class of 1961, had inflated weather balloons and distributed them around town. When the devices buzzed in each home, homeowners were to release the balloon on a tether. Back at the courthouse, the students were in the tower of the courthouse counting balloons.

References



1931 Grocery Prices

1931Aug3WashStarFor a snapshot of what groceries cost in the 1930s, here the ad for A&P stores that appeared 90 years ago today, August 3, 1931 in the Washington Evening Star.  (You can click on the image to see the full size version.)  The prices look like bargains, but there has been a lot of inflation in 90 years. According to this inflation calculator, one dollar in 1931 is the equivalent of $17.87 in 2021 dollars.

So the one pound loaf of bread for a nickel is the equivalent of 89 cents today, which is about what one would expect to pay. But if you want to butter your bread, it’s two pounds for 59 cents, which works out to about $5.28 per pound. And eggs start at 29 cents a dozen, but that’s over $5 in today’s money.

Frankfurters are 30 cents a pound, but that is over $5 today. Depending on the brand, coffee ranged from 19 cents to 29 cents per pound. That’s relatively inexpensive, since it’s the equivalent of $3.33 to $5.09.

What item do you think is the best bargain? Feel free to leave a comment below.



Taking the Radio on Vacation: 1921

1921AugSciInvFor the amateur radio enthusiast a hundred years ago, summer vacation didn’t mean a vacation from radio, and the August 1921 issue of Science and Invention contained some pointers on bringing the station along. Even if the method of getting there was canoe or motorcycle, the station shown here would prove very suitable. The transmitter-receiver combo is built into a compact case, with extra storage room for extra tubes, pencil, log, and whatever else was needed.

The kite antenna proved most suitable, and for much ordinary work, just a wire tossed over a tree would prove adequate.

A century later, the same general concepts apply, but the equipment looks a little different.  For some ideas, see some of our earlier posts about outdoor operating.



How to Use USPS General Delivery

generaldeliveryOccasionally, we need to write about very simple concepts, because we have discovered that those simple concepts are at risk of being lost to the ages. For example, you can find on our website instructions on how to make coffee without electricity.

Another simple concept that many people apparently don’t know about is the concept of General Delivery.  Did you know that you can receive a letter or package by snail mail, even if you don’t have your own address?  You can, and you can do it at almost any Post Office in the United States, or indeed, in the world?

I mailed the letter shown above to myself, but it didn’t come to my home or business.  I picked it up at the Post Office in another state where I don’t live, and have no connection.  I did this by mailing it to myself at “General Delivery.”  I waited a few days, and then picked it up at the Post Office in the town to which I sent it.

Why You Might Need General Delivery

MovingImageHHSdotGOVThere are many reasons why someone may need to take advantage of the General Delivery service.  When I asked the postal clerk, she said that the most common reason was people who were temporarily between addresses and had to receive mail.  For example, someone might move out of one apartment but can’t move into their new home for a few days.  In the meantime, they might stay in a hotel or stay with friends.  If they don’t know exactly where they are going to be staying, but need to receive mail during this time, they can receive mail by General Delivery.

NPSRVphotoGeneral Delivery is also useful for people who are traveling.  For example, many full-time RV’ers take advantage of General Delivery.  If you live in an RV, you probably have a permanent address set up somewhere.  But if you decide to order something on Amazon, you will want it sent to you on the road.  If you know exactly where you will be staying, sometimes you can have it sent to the campground or motel.  But if you don’t know exactly where you will be staying, you can take advantage of General Delivery.

NPSApTrphotoGeneral Delivery can also be part of an outdoor experience.  For example, hikers hiking a long distance, such as thru-hikers on the Appalachian Trail can arrange to have supplies such as food and clothing mailed to them at towns along the trail.

One way to send money to a stranded traveler is to send them a Postal Money Order via General Delivery.  They can usually cash the money order right at the Post Office.  (For more information on money orders, see my Money Order Basics page.)

If you are ever relocated due to a natural disaster or emergency, General Delivery could be an important way to stay in touch.  If you are displaced, you can ask friends to send you needed items or even money by General Delivery to the closest Post Office.  After a disaster, the Post Office is often one of the first services to re-emerge.  And in outlying areas away from the disaster, it will probably continue to operate without interruption.  If you are forced to relocate, then General Delivery can provide you with a needed mailing address.

There might be situations where someone needs to receive mail without the knowledge of their roommates or nosy neighbors.  If so, they can arrange to have the item sent by General Delivery.  Or, there might be situations where a service is provided only to persons with an address in a certain ZIP code.  A General Delivery address might provide that ZIP code.  Finally, General Delivery provides a method for homeless persons to receive mail.

In short, any time you need to receive mail but don’t have an address, you can use a General Delivery address.

How and When To Send General Delivery

Practically anything that can be sent by mail can be sent to General Delivery.  It can be a letter or a package.  To make sure you get it, you’ll need to make sure that the sender follows these instructions carefully.

First of all, they need to figure out when to mail it.  There might be exceptions, but you can generally plan on the Post Office holding the item for about two weeks.  If they send the item too late, then it won’t arrive in time.  But if they send it too early, then it might be returned to the sender before you pick it up.

In my example above, I mailed the letter from Minneapolis, MN, on a Monday.  I went to the Post Office to pick it up on Thursday, but it hadn’t arrived.  I went back a week later (a total of 10 days after mailing) and it was there.  I would recommend planning on it taking about one week, so have them mail it one week before you plan to pick it up.

If the timing is more critical, then it might be best to send the item by Priority Mail or Express Mail.  If you mail early enough in the day, then Express Mail is almost always delivered the next day, almost anywhere in the country.

Finding a Post Office

Next, you need to decide on the Post Office at which you will get the letter.  Most Post Offices offer General Delivery, but not all of them do.  There are exceptions, but in large cities and their suburbs, General Delivery is available only at the main downtown Post Office.  For example, I live in the Minneapolis-St. Paul area.  In Minneapolis and suburbs, the ZIP codes begin with 554.  In St. Paul and suburbs, the ZIP codes start with 551.  In those suburbs with 551 and 554 ZIP codes, General Delivery is available only at the downtown Post Office.  You can’t get general delivery at the neighborhood Post Office.  This is true in other cities as well.  For example, in Chicago, in any area with a 606 ZIP code, the only place to get General Delivery is the main downtown Post Office.

If you live or work downtown, this is great.  But going downtown isn’t particularly convenient for many people these days, so if you are in an urban area, the most convenient place to get General Delivery might be an outlying suburb.  In general, if the first three digits of the ZIP code are not the same as the main city Post Office, then that Post Office will have General Delivery service.  So in the Minneapolis-St. Paul area, most of these outlying suburbs have a ZIP code starting with 550.  In general, all of these post offices offer general delivery.  Since I had to drive a few miles anyway, I decided to send my experimental General Delivery letter to another state, to Hudson, Wisconsin, ZIP code 54016.

In general, small town Post Offices will have General Delivery available.  If you are sending something to a larger city, then you will need to check more carefully on which post office to use.

There are exceptions to all of these rules, so before deciding on a Post Office to use, you should look it up on the USPS website.  From the main page, select “Find USPS Locations” from the menu.  Then, click on the Post Office you are interested in.  The hours will be listed.  For larger towns, it will be open about 9:00-5:00 Monday through Friday, and Saturday mornings.  Almost all Post Offices will be closed on Sunday.  In small towns, the hours might be much more limited, such as just a couple of hours in the morning.  So before selecting a Post Office, be sure to check that you will be in that town at a time when the Post Office is open.

generaldelivery2Then, scroll down to “Services at this Location.”  If General Delivery is offered, it will be shown on this list.  If it’s not listed, you’ll need to pick another Post Office.

After confirming that the Post Office offers General Delivery service, scroll to the top of the page, where you will see thegeneraldelivery3 address of the Post Office.  The street address is shown.  You’ll obviously need this information later, so that you can find the Post Office to get your letter.  The person sending the letter, however, will not need the street address.  Instead, they will need the City, State, and first five digits of the ZIP code (but not the last four).  So in this example, they will need:  HUDSON, WI 54016

Addressing the Letter

Once you have found a Post Office where you can get your item, the sender can address the letter or package.  The letter should be addressed with your full name.   You will need to show identification when you pick up the letter, so make sure the letter is addressed to your real name, and not a nickname.  The second line of the address should be:  GENERAL DELIVERY.  The third line of the address should be the City, State, and ZIP code.  The nine-digit zip code for General Delivery always ends in -9999.  So they should include this after the five digit ZIP.  So in the example above, the ZIP code is 54016-9999.

Here’s an example of the address.  You are sending a letter to John Q. Public, and he will pick it up at the main Post Office in New York City at 421 8th Avenue:

John Q. Public
General Delivery
New York, NY  10001-9999

Make sure the sender includes their return address.  If something goes wrong, the letter will be returned to them.  Of course, they should make sure to include enough postage, which they can calculate online.  If it’s a small item they’re sending, the postage for a letter of up to one ounce is 63 cents (as of April 2023), or one “Forever” stamp.  (For information on how to buy stamps, see our Buying Stamps During Quarantine page.)

Picking Up Your Item

After you have given enough time for your letter or package to arrive, you simply go to the Post Office to which it was sent.  Just tell the clerk that you are expecting a General Delivery letter or package.  They’ll go to the back room, and if it’s arrived, they will bring it out.  You will need to show identification.  When I picked up my letter, my out-of-state driver’s license was all I needed for ID.

General Delivery in Other Countries

The instructions on this page are specific to the United States, but most other countries offer the same service.  So if you are traveling in another country and need to receive mail, you can probably take advantage of this service there.  In most other countries, the service is called “Poste Restante”

Other Alternatives

The USPS is not the only way to send items if you don’t have a permanent address.  Private delivery services such as UPS and FedEx allow you to pick up packages at fixed locations.  However, USPS is still the least expensive.  You can send a letter anywhere in the United States for only 55 cents.

And keep in mind that if you are buying an item from Amazon, another alternative is to have it sent to one of their lockers  located all over the country.

The USPS official information about General Delivery can be found on their website.

 

 



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