For Book: Shortwave Radio Questions

[ncbill]

At the start, he's going to "pick up" a big-ass diesel generator. He recognizes that fuel will go bad (looks like diesel, gasoline, and kerosene all go bad). He'll add fuel stabilizer, which should make the diesel last for more than five years. That is, he'll go to a gas station, estimate how much diesel fuel is in the underground tank, and dump in stabilizer. He'll calculate how much he will need per year (he used the be the president's accountant, so he's good with numbers).

Or, he might find a house with a working solar power system.

Commercial/government sites would likely have trailer-mounted diesel gensets designed for extended operation.

Find a home with well/septic & wire up a transfer switch w/ generator inlet to the home's panel and they've got all the comforts of home.

 

[TromboneAl]

Okay, the Morse code will be a bit of a stretch, but it could be fun. There will be someone trying to contact others, and maybe I can find a way for her to have to resort to Morse code. I'd say she can only find a transceiver that can only be used for code, but that's not likely.

BTW, I built a transmitter that would have used Morse code in the 80s (and got a limited license), but I never got it to work.

Al, Is this guy moving fast because there are other dangers on the way? Would he have time to spend figuring out the equipment? What kind of communication equipment would a firehouse or airport have available? For some reason this pandemic reminds me of a book that my mom was reading a long time ago. I can remember small pieces of the story. Most of the world population died, woman that survived the virus had long hair and cut it to be more practical, her son survived but they were in separate areas of the U.S., he joined up with someone else (or a group, don't remember), he shoots her from behind from a long distance and doesn't realize it's her. The end! Do you know the book? I'm sure you can tell what it is from my great description. lol


Al, How many books have you written now?

Initially he has all the time in the world. That is, at first he decides to just enjoy the situation, not try to find others or save the human species. Then he finds a baby, and it changes his perspective. Then he gets an intriguing message over the shortwave.

Firehouse, airport, or military base. Good ideas.

I don't recognize that book. I'll see if someone on the Kindle site recognizes it from your tidbits. I just finished Earth Abides*, which I recommend. I first read it forty years ago.

This will be my fifteenth book. Each one was going to be my last. Love/Hate.

*That site is a library with a lot of books that you can borrow for 14 days.

 

[TromboneAl]

Commercial/government sites would likely have trailer-mounted diesel gensets designed for extended operation.

Find a home with well/septic & wire up a transfer switch w/ generator inlet to the home's panel and they've got all the comforts of home.

It's in. Thanks.

 

[braumeister]

Firehouse, airport, or military base. Good ideas.

Around here, many of the more affluent counties have a central disaster preparedness facility with every kind of communications apparatus and other needs to get through a crisis.

As a ham radio operator, I used to be a small part of the effort and got to tour a couple of these buildings. Lots of resources and maybe worth considering.

 

[LOL!]

Nowadays, we use a Garmin InReach Mini to send text messages via satellite. But one needs to pay for a satellite plan. One would be able to figure out the Garmin InReach without a manual. They could also just press the blue SOS button. The InReach has a USB-cable rechargeable battery like a cell phone does.

 

[TromboneAl]

Trying to make the Morse code thing work ...

Wouldn't a Morse code message get through better/go farther? That is, aren't there conditions (e.g. extreme range) under which a code signal could be understood while a voice message couldn't?

 

[ERD50]

Trying to make the Morse code thing work ...

Wouldn't a Morse code message get through better/go farther? That is, aren't there conditions (e.g. extreme range) under which a code signal could be understood while a voice message couldn't?

Yes, that is one of the reasons it is still used.

All you need to be able to do is hear the presence or absence of the 'beep', you don't need to be able to make out the nuances of a vocal sound.

I bet if you googled Morse code and "signal to noise ratio" you'd come up with some technical comparisons.


edit/clarify: The signal (voice versus beep) wouldn't actually "get through better/go farther", but in a weak reception area, the receiving party could make out the beeps in the noise, when voice would be difficult/impossible to reliably make out. But the actual signal is essentially the same. It's the interpretation ability of the signal that changes.

-ERD50

 

[TromboneAl]

A discussion at https://ham.stackexchange.com/questions/135/why-is-morse-code-still-in-use mostly says Morse is used because it's fun. But there's this:

"The advantage? Efficiency! You get to put all of that power of your rig into a very small bandwidth, whereas voice modes need to spread the power out much more (for example, SSB uses roughly 2.8kHz of bandwidth)."

This is a clear example wanting something in a book, and searching for a way to justify it.

 

[ERD50]

That also makes sense that the energy could be put into a smaller bandwidth, so therefore more efficient.

I'm not a ham, so I'm not sure how that works out in practice. Is a transmitter optimized for Morse code versus voice? Can the transmitter bandwidth be changed depending on if you are using voice or Morse code? Is this something an non-tech person could figure out?

-ERD50

 

[Col. Klink]

If you go to a longer wavelength, like the ham allotted frequencies on the 20 or 40 meter band, you can actually get worldwide coverage as the signal bounces around / along the ionosphere. Boy, that takes me back to my first ham test as a kid. You could also have this guy fabricate his own simple dipole antenna. Literally a long string of wire cut to the corresponding length for the frequency (band) he wants to uses.

I remember how p.o ed my dad was one day when he got home from work and my buddy and I had strung a dipole along the length of the roof of our home and then out to a telephone poll at the corner of the lot. I think it was about 66ft.

OTOH, you might be able to add some spice to the book if he locates an old CB radio. Then, he powers it up and at the other end is the reincarnation of Jackie Gleason as Sheriff Buford T. Justice!

 

[ncbill]

Nowadays, we use a Garmin InReach Mini to send text messages via satellite. But one needs to pay for a satellite plan. One would be able to figure out the Garmin InReach without a manual. They could also just press the blue SOS button. The InReach has a USB-cable rechargeable battery like a cell phone does.

Have you seen this for the iPhone? (Android later this year)

https://satpaq.com

Pre-pay for messages, no need for a monthly plan.

 

[braumeister]

Nowadays, we use a Garmin InReach Mini to send text messages via satellite. But one needs to pay for a satellite plan. One would be able to figure out the Garmin InReach without a manual. They could also just press the blue SOS button. The InReach has a USB-cable rechargeable battery like a cell phone does.

InReach is a good system and I've used it myself to stay in contact with DW when I've been camping or hiking in remote areas.

But it relies on a connection between the satellites and their ground station, which then forwards the information via the internet to the recipient. In a doomsday scenario, that would probably break down pretty quickly.

 

[TromboneAl]

At some point, I think I'll have him scanning through the frequencies, and hear a transmission from the ISS. The astronauts will be saying, essentially, (1) "Can anyone down there hear us?" and (2) "if you aren't familiar with the radio equipment, do this to respond ..."

Is that reasonable?

For part (2), would they just assume that all listeners would know their way around the transceiver? If not, what instructions would they give?

To get a feeling for this, I'm trying to understand this manual. It would be a hard slog, but perhaps he could do it. A lot of jargon:

"PSK31 Operation
Two dedicated PSK31 modes are available, one each for USB-side and LSB-side injection. For BPSK work, the injection does not matter, but for QPSK the two working stations must use the same sideband."

The problem is that with (almost) no one transmitting, it will be hard for him to figure out whether anything is working.

 

[TromboneAl]

It might be more interesting if he re-invent the wheel, and decodes it by himself.

Just from movies, I think many people would know that SOS is either . . . - - - . . . , or - - - . . . - - - . Then they might figure on their own that the most common letters are the shortest, "E" is ".", "S" is more common than "O", so "S" would be the ". . . " and "O" the "- - - ", etc

-ERD50 ( . .-. -.. ..... ----- ) https://morsecode.scphillips.com/translator.html

I may pursue this. If someone would enjoy solving a puzzle, below is the message that he will receive. Instead of the Morse "letters," I've substituted letters from the alphabet.

The protagonist knows SOS, so, in this example you know that "U" decodes to "S" and "E" decrypts to "O." He also knows that "E" is the most common letter in the English alphabet, but that's all. He doesn't have any books on cryptography available, but he has solved problems like this as a kid.

The automatic decoders on the internet don't have any trouble with this, of course.

There's a trick involved, and I'm curious as to whether any of you will come up with it.

Here's the message:

somu mu z qguuzlg vef ztgr heengf ztgr cogx iep lgs somu qguuzlg ytgzug le se sog uqmsouexmzx mxusmspsmex zs qzfitzxd zwg uc czuomxlsex db

 

[braumeister]

At some point, I think I'll have him scanning through the frequencies, and hear a transmission from the ISS. The astronauts will be saying, essentially, (1) "Can anyone down there hear us?" and (2) "if you aren't familiar with the radio equipment, do this to respond ..."

Is that reasonable?

No, sorry.
For one thing, transmitting to the ISS would require a highly directional signal aimed exactly at where the station was going to be when the signal reached it. Without the proper data, it's unlikely in the extreme.

Another issue is that the signal would likely have to have circular polarization to be successful, and you need a somewhat specialized antenna for that.

Finally, the controls on modern (or even old) transceivers need quite a bit of knowledge (theory and manual instructions) and practice before they can be manipulated with success. The astronauts would probably not be familiar with even the commonest ones.

I've been a ham for nearly 40 years, so I have a little experience.

 

[TromboneAl]

I trust you, but I want to understand. The ISS is about 250 miles up, line of sight. Why couldn't they get a signal when they are in the right place?

I got my idea from here: Contact the ISS - ARISS

Some ISS crew members make random, unscheduled, amateur radio voice contacts with earth-bound radio amateurs, often called "hams". They can make radio contacts during their breaks, pre-sleep time and before and after mealtime. Astronauts have contacted thousands of hams around the world.​

--------------

>Finally, the controls on modern (or even old) transceivers need quite a bit of knowledge (theory and manual instructions) and practice before they can be manipulated with success.

So, if I were to go into a ham operator's house (with power), I would probably not be able to get his/her radio working?

How about if I found a book like this:

Thanks for the help.

PS Was it you who said you're willing to believe one impossible thing when reading a fiction book? I've always remembered that and kept it in mind when writing.

 

[braumeister]

I trust you, but I want to understand. The ISS is about 250 miles up, line of sight. Why couldn't they get a signal when they are in the right place?
PS Was it you who said you're willing to believe one impossible thing when reading a fiction book? I've always remembered that and kept it in mind when writing.

Sorry, you're right. I was thinking of satellites. There's no question that you could contact them. But even the ISS would be tricky. For one thing you would have to be on the same frequency they were listening on, and if they were desperate to contact anyone, they would be trying all over the bands. It would be pure chance to have them listening on the same frequency you were transmitting on.

Yes, that was me. I'm happy to believe one impossible thing in a science fiction story, but when they start multiplying I'm gone.

 

[ERD50]

Sorry, you're right. I was thinking of satellites. There's no question that you could contact them. But even the ISS would be tricky. For one thing you would have to be on the same frequency they were listening on, and if they were desperate to contact anyone, they would be trying all over the bands. It would be pure chance to have them listening on the same frequency you were transmitting on.

Yes, that was me. I'm happy to believe one impossible thing in a science fiction story, but when they start multiplying I'm gone.

Plus, the ISS is only overhead for a few minutes out of their 90 minute orbit. So contact time is limited. Looking at data from www.heavens-above.com roughly 6 minutes out of a 92 minute orbit?

-ERD50

 

[TromboneAl]

Plus, the ISS is only overhead for a few minutes out of their 90 minute orbit. So contact time is limited.
-ERD50

Yes, and sometimes the orbit doesn't take it over a particular location for a while. I've watched it pass overhead multiple times (https://spotthestation.nasa.gov/).

I will have the protag monitoring shortwave transmissions. He'll hear the transmission either due to luck or due to a lot of monitoring.

Are there scanners in shortwaves that will seek transmissions at many frequencies??

 

[TromboneAl]

I thought you guys would be interested in seeing how your ideas are getting incorporated into the book. With your permissions, I'll be including your real or screen names in the acknowledgments.

Current idea:

The main character passes a house with antennas and realizes that maybe he can find others via radio. He goes in, powers up the house and the radios, but they are too complicated for him. He can't find manuals or a book on amateur radio tech.

He figures out how to listen, however. He scan the dials and he hears a Morse code message. He doesn't know the frequency of different letters in English, but he determines it empirically by laboriously counting the frequency of letters in a long passage (the trick I referred to above). Then he decodes the message.

Then, or later on, he hears a transmission from the ISS, but is unable to respond.

Later, at a bookstore, he discovers the Ham Radio for Dummies book. He studies for a long time, and at the next ham radio house he finds, he's able to both receive and transmit.​

Reasonable?

 

[TromboneAl]

Congrats to Braumeister for solving the puzzle, above.

I'm quite sure this is the shortwave receiver that we had in our house when I was a kid (late 1950s):

Amazing what you can find on the internet!

 

[Peter]

He figures out how to listen, however. He scan the dials and he hears a Morse code message. He doesn't know the frequency of different letters in English, but he determines it empirically by laboriously counting the frequency of letters in a long passage (the trick I referred to above). Then he decodes the message.

​

I don't think this is realistically possible. If you don't know morse code, it would be very difficult to pick out 26 different long/short combinations from a message that someone's sending. Especially if it was being sent at any realistic speed.

​

 

[braumeister]

I don't think this is realistically possible. If you don't know morse code, it would be very difficult to pick out 26 different long/short combinations from a message that someone's sending. Especially if it was being sent at any realistic speed.

Yes, I was going to point this out as well. Someone even reasonably proficient at communicating via Morse code (hams call it CW) would be sending it far faster than a non-expert could capture by listening. When I passed my last ham license exam, the requirement was at least 20 words per minute, and I knew plenty of hams who routinely had on-air conversations at 35-40 words per minute, a few at much faster speeds. No machines to help them, either.

You could probably get around this by having the sender be a novice to it as well, sort of like a "hunt & peck" one-finger typist.

 

[Peter]

Now if he happened to have this on his phone, he'd be all set!

Although the example is pretty slow. I could read it OK even after 50+ years since I passed my test in the UK.

 

[TromboneAl]

Got it. I tried to write down this conversation, and failed:

I'll fix it one or more of these ways:

1. The sender sent it slowly, knowing that the receiver might not know Morse.

2. The message is going to be repeated continuously. Alex (the main character) will try over and over, and eventually get the message.

3. Alex will record the message and either have a way to slow it down.

4. Alex will record the message and start and stop the replay so he can get down a few letters at a time.

I used trick #4 and was able to get "RETURNED FMP. C." from the start of that video above.

I used trick #3 and got "BEACH,FLIN30?30FTTBRAVEM/HANDNWBAT" from the conversation further on.