As another powerful hurricane approaches Florida, many mutual aid organizations are doubtless bracing for impact and poised to help residents recover in the aftermath.
It is predicted that Hurricane Milton will make landfall in as little as a few hours from this post.
Given the rather large role that radio continues to play throughout recovery from Hurricane Helene, some might be interested in listening to the Hurricane Watch Net on the 20 and 40 meter bands.
The Net will Activate Tuesday at 5:00 PM EDT (2100 UTC) on 14.325.00 MHz (USB) and 7.268.00 MHz (LSB)
If you do not have an HF or shortwave radio, you can tune in via a web SDR.
If you do have an HF transceiver and you are not in an affected area, it is important that we LISTEN for information that could be useful to mutual aid disaster relief and recovery efforts.
Florida also has an interesting statewide linked repeater system called SARnet, which also has a Broadcastify stream.
We post this information in the sincere hope that it will be useful for those affected by these hurricanes, and at least educational for those who are not directly impacted.
Solar generators are great disaster preparedness tools that are worth getting if you can afford them. But they have a few problems.
They’re expensive.
They’re hard to modify. They lock you into a particular set of features that’s hard to expand on without buying a dozen different adapters, or taking the whole thing apart to cannibalize parts, and re-building the whole thing into a configuration you actually want with a lot of probably pretty sub-standard components. This is because they’re made by capitalists who will often cut corners to give you the cheapest (for them) version of the very expensive thing you think you’re paying for.
They lack creativity.
If you can’t afford one of the myriad battery boxes you see advertised all over the place like Jackery and EcoFlow, building one yourself can save you some money. To be honest, even the components for DIY projects are getting so expensive that sometimes you save more money by buying something pre-manufactured. And I’m not even talking about “if you factor in the time you spend building it”. That’s just how fucked the supply chains are.
But DIYing a battery box offers a couple of advantages that the manufactured ones don’t.
Less money all at once: You are able to spend money on one or two component at a time, rather than surrendering your whole paycheck to Jeff Bezos.
Modular: You can configure these components in any way you want. You can add and remove parts, or you can easily cannibalize the whole thing later on if you need parts for a more pressing project.
Repairable: If you know how to build it, you know how to fix it.
Ice fishermen have been building battery boxes similar to these for a long time. There are some significant differences in the end products because they’re built for different purposes. But if you want to build your own battery box, they might be a good source of information for you.
TOOLS USED
drill
step drill bit
Oscillating tool / box knife
wrenches/pliers
Ratcheting wire crimpers
Ratcheting PowerPole crimpers
Automatic wire strippers
THE BATTERY
The most important component of the battery box is obviously the battery. Lithium Iron Phosphate (LiFePo4 or LFP) has pretty quickly supplanted Lead-Acid batteries and pretty much all other battery chemistries in the realm of amateur radio. The advantages of LiFePo4 over lead-acid are many:
3X higher energy density,
more charge/discharge cycles,
you can actually completely discharge a LiFePo4 battery without damaging the cells, unlike a lead-acid battery which can be damaged if discharged to below 20%,
pretty constant voltage,
no hydrogen gas or other fumes
not made of literally brain-destroying lead or bone-melting acid.
And if you wonder why we didn’t choose Lithium Ion or Lithium Polymer batteries for this build, it’s because even though LiIon and LiPo are a little cheaper and have a higher energy density, LiFePo4 has a major advantage when it comes to safety: This type of battery does not catch fire nearly as easily as liIon or LiPo batteries.
Tesla Cybertruck on fire
A 100 Ah LiFePo4 battery is about the size of a car battery, but weighs only about 9kG (20Lbs). Unfortunately, there are about a thousand different brands of LiFePo4 batteries and only a few of them have “good” reputations, which are far more expensive than the other unknown brands. Long story short, quality control is kind of a crap-shoot on this stuff if you’re trying to save money, but the good news is that due to the LiFePo4 battery chemistry being very safe, your house (probably) won’t catch fire if it fails. But don’t worry, we’re going to take other precautions as well.
BTW, you can also build your own LiFePo4 battery from individual cells and a BMS, but that’s a whole other very deep topic, and something we haven’t tried yet.
In any case, we weren’t about to spend $900 on a fucking battery. We found a 100 Ah battery from a company called WattCycle for about $165. There weren’t a lot of reviews, but you can’t trust reviews anyway due to enshittification. There were no reports of explosions and it seemed like a decent price.
This battery can allegedly handle a maximum continuous discharge current of 100 Amps, which means it could discharge 100 amps for about 1 hour before the battery dies.
(Or 50 amps for 2 hours, 25 Amps for 4 hours, 12.5 Amps for 8 hours, 1 Amp for 100 hours, etc. If you don’t know what the Amp-hour rating on a battery means, now you know.)
We don’t really trust that statement, because that would mean that the wires going from the cells to the lugs would be at least 4 AWG copper wire, which is kind of expensive. We suspect that the people who made this battery are a little “smarter” with their money than they are with their mouths.
But it doesn’t matter, since we don’t expect to pull even half of that from this battery at any one time, and all connections will be fused anyway.
We’re using 12 AWG copper wire for most connections to the battery. 12 AWG wire can handle a maximum current of 20 Amps. And since none of these circuits should really pull any more than 15 Amps, that fits well within the 80% Rule. Our panel has 5 switches, and there’s another switch for the 20V circuit as well. Assuming each circuit would be On and pulling their maximum current of 15 Amps (a pretty unlikely scenario), that means that the maximum possible load we could put on the battery is 90 Amps which is ~allegedly~ well within the 100A spec for this battery. Furthermore, some of these circuits will actually have 10 or even 5 Amp fuses, so really we should be pretty safe.
Because of that potential 90 Amp total load, we actually need to use much larger wire to connect directly from the positive terminal of the battery to the 100 Amp cutoff switch, to the fuse block, and then to the negative side of the battery.
The battery’s BMS does have over-current protection, but it’s apparently programmed to quite a high current so we’re better off relying on our fused circuits. In theory, the BMS could be re-programmed, but it’s locked inside the plastic case and we don’t want to compromise any waterproofing that may provide.
The battery has high-temperature and low-temperature protection as well, because running the battery outside the -20°C to 60°C (-4°F to 140°F) range can cause damage to the cells.
BATTERY MONITORING
It’s important to have an idea of the battery’s state of charge, how much load is on it, and how much longer it can run. There are a lot of battery monitors out there. Mainly there are types that use a shunt, and there are types that use a hall sensor. Some even have Bluetooth built in so you can monitor the battery from your phone, but who needs another app.
We chose a pretty cheap shunt-type battery monitor. There are instructions on the back that show you how to wire it up to a battery.
VERY IMPORTANT about these types of battery monitors: The battery monitor should be fully charged when you wire it up, otherwise the monitor will just assume that it’s fully charged when it’s not, and that could create problems and confusion down the road.
Another important point about these shunts, at least with a battery as large as the one we’re using, is that it took a VERY long time for it to “learn” what the capacity of the battery was. It needs to stay connected while it slowly counts how many miliAmp Hours the connected battery has.
THE SOLAR CHARGE CONTROLLER
Solar Charge Controller
A solar charge controller is a device that sits between the solar panel and the battery and makes sure that the battery doesn’t get overcharged and that current flows only from the solar panel to the battery, and not the other way around.
There are two main types of solar charge controllers: PWM and MPPT.
PWM stands for “Pulse Width Modulation”. PWM charge controllers tend to be cheaper than MPPT, but they’re less efficient and they have a tendency to generate RF interference. Think of PWM as a switch that automatically turns off and on extremely fast in order to prevent too much power from getting to the battery and overcharging it.
MPPT stands for “Maximum Power Point Tracking”. These are much more efficient charge controllers that, generally speaking, generate less RF interference, but they tend to be more expensive.
There are exceptions to the RF interference. The PWM charge controllers sold by Bioenno have been shown to not create RFI, while the opposite is true of some of the cheaper MPPT controllers that are available. I myself have bought a 2-pack of PWM controllers, one of which created interference, the other of which did not.
The box we’ve chosen is a Bauer modular rolling toolbox from Harbor Freight.
You can and should use whatever kind of container you want, but we think that due to their relative weather resistance, these modular stackable toolboxes – of which there are many brands, none of which are compatible with each other, of course – hold the potential to expand into a mobile modular system for different purposes such as ham radio, computer networking, or even a cooking station for a squat, encampment, or commune.
But if modularity and weather resistance is not something you need, you could easily build a similar system into a plastic tote, an old suitcase, or a wooden box. It’s up to you. Other types of containers would certainly fit better on a bike trailer than what we’ve chosen here.
“PANEL MOUNT” EVERYTHING
This is a “5 Gang ON OFF Toggle 12V Car Switch Panel Dual USB Socket Charger…” yadda yadda etc. according to the online listing.
The trick to finding all the little ports you want on the outside of the box is to search “panel mount” or “chassis mount” in front of everything you need. Panel mount USB C, Panel mount Power Poles, Panel mount switches, Panel mount battery monitor, etc.
If you’re in a situation where you can’t have things delivered to you, look for an RV or boating supply store you can get to. They should have a lot of this stuff.
We bought most of these components on AliExpress. We know people have feelings about that sort of thing, but it’s the same place Amazon buys it from before they double the price.
WIRE AND FUSES
We went with 12 AWG silicone-jacketed copper wire for all the connections from the fuse box to all the connectors and devices. The maximum current rating for this wire is 20 Amps, which according to the 80% rule means we should really stay under 15 Amps for each circuit anyway.
We used 4 AWG copper wire for the main circuit between the battery, cutoff switch, and fuse block.
The 4 AWG ring terminals had to be filed down so that they would fit on the cutoff switch.
There are several tools for crimping large gauge cables like this. The best is probably a hammer crimp tool, but one of us already had a table vise so we used that instead.
If you are wiring two or more batteries together, you should definitely use at least 4 AWG wire or possibly even 1/0 welding cable in the shortest lengths possible between the batteries.
If you are wiring two or more batteries together, you should definitely use at least 4 AWG wire or possibly even 1/0 welding cable in the shortest lengths possible between the batteries.
The manual for our battery actually lists 12AWG wire as having an ampacity of 25 Amps. This may be true in most situations, but given that most sources say the ampactiy of 12AWG copper wire at 60 C is 20 Amps and we don’t really know how hot it might get inside this box, it’s just safer to go with the lower estimates.
Using wire that is too thin in any of these circuits creates a fire hazard!
So the “hot” side of each circuit will have a 15 Amp (or lower) fuse going directly to the positive side of the battery. It’s really a good idea to also fuse the negative side of each circuit as well, but 99% of problems that could cause a fuse to blow will occur on the positive side of the power source.
A mini-rant about Copper-Clad Aluminum (CCA) wire
TL;DR, Use pure copper wire if you can. Don’t use CCA wire if you don’t have to. If you do have to use it, use thicker wire than you think you need.
There was a short period of time in the 1970s in the so-called “US” when buildings were being built with copper-clad aluminum electrical wiring due to being cheaper than pure copper wire. The practice was generally abandoned after it became apparent that CCA wire tended to get much hotter than pure copper wire, creating a fire hazard. But it’s not like this was made illegal or anything. In fact, CCA wire is being used again in some newly-constructed homes, saving future slumlords literally TENS of dollars per McMansion.
CCA wire is also available online to regular people working on their DIY electronics projects, and it’s not always obvious what you’re getting. There is some math you can do to figure out what gauge of CCA wire should be used safely for a given current, but as far as we can tell it’s based on a combination of rules-of-thumb and straight up guessing the ratio of the copper-aluminum composition which doesn’t seem to be standardized. So it’s best to just look carefully and make sure you’re using pure copper wire.
THE INVERTER
We’re using a 500 watt “pure sine wave” inverter. This actually isn’t a very good inverter, but we really should only use the inverter as a last resort anyway.
The reason to avoid using an inverter as much as possible is because generally speaking, at least 10% of the energy is lost in the conversion (or inversion, as it were) from DC to AC. That might not sound like a lot, but when you consider that most of the small appliances we use on a daily basis actually convert the Alternating Current coming out of the wall into Direct Current, you’re basically simulating that same process by converting the DC of the battery to AC, and adding a whole new layer of inefficiency by turning that current back into DC so your device can use it. It’s an enormous waste of energy for most applications, but sometimes you have to do it.
This could be the difference between running a CPAP machine for one night or running it for 3 nights by using a DC-DC converter, so it’s important to think about this stuff.
The inverter came with its own 12 AWG wire and two 45 Amp fuses, so we ran this directly to the battery and ran a panel mount 120V AC receptacle to the front of the box.
Buck-Boost converter and a pair of blue and black Power Pole connectors mounted into the plastic box.
Due to the relative inefficiency of AC inverters, and an abundance of DC devices that require voltages other than 12V or 5V, we decided to do something we haven’t seen on other battery boxes. We’ve added a constant-current (CC) constant-voltage (CV) buck-boost converter. This is an adjustable DC-DC converter that can step the voltage up or down from 12V and supply it to a device at a specified current.
Mostly this is for laptops and power tool batteries which require about 20V DC.
There are a lot of guides out there on how to convert older hardware to be compatible with USB C and therefore be able to automatically negotiate voltage between source and load, but it’s a hell of a lot easier and cheaper just to snip off the cables that go to each of these devices and put Power Poles on them. In order to hopefully avoid confusion, we used blue Power Pole connectors on the positive side of the 20V leads, so that they are different from the red leads of the more common 12V connection.
The first thing we did was decide where the main switch panel would go. We laid it on the front of the box and marked the holes for all the switches with a pencil. Using a stepped drill bit, we cut the holes for the switches.An oscillating tool was used to cut an opening for the battery monitor, but a box cutter can also be used.cut a piece of scrap plywood to fit on the back side of the box, and pre-drill holes so that it could be bolted on later. Lay out the fuse box, solar charge controller, and inverter, and mount them to the plywood.
A group 24 battery tray was adhered to the bottom center of the box, and the battery was placed inside.
inside of the boxcompleted solar generator
Aside from a lot of wire cutting, terminal crimping, and making sure the wires all go to the right places, that’s pretty much it! We would provide wiring diagrams, but they would probably just be more confusing than helpful, both for author and audience. Even though it looks like a mess in there, this stuff is not too hard to figure out once you’re sitting in front of it.
In the realm of amateur radio, good programming software is clutch. If you’ve ever spent hours tediously manually entering frequencies, offsets, and repeater codes, you know tools like CHIRP and RepeaterBook are essential. If you haven’t used these tools, check out some YouTube vids for CHIRP!
CHIRP supports a large variety of radios and is multi-platform, free, open-source software. If you can use it, you definitely should. It allows you to pull saved memories from your radio, import / export lists of entries, and pull from RepeaterBook to snag all the repeaters in your area (with slick filters for the band, mode, etc). So for example if we want all the 2 meter and 70cm repeaters using either FM or D-star within 20 miles of Atlanta, GA, we can pull that list and throw it on our mobile radio in seconds instead of spending error-prone hours of adding these manually on my rig.
So… good programming software for radios: clutch! The happy path? Dope. But not everything goes this smoothly; enter the cycle of frustration…
One of our members recently acquired an ICOM IC-7100. It’s a beloved options since it is dubbed an “all-band” transceiver. In addition to the HF bands, it also supports VHF/UHF and it has two SO-239 coax ports on the back so you can have both your HF and VHF/UHF antennas connected to the same radio. This “all-band” option is relatively rare and it makes for a great “shack-in-a-box” as some of the ham nerds refer to them. (We put all-band in quotes cause it supports all of the common amateur radio bands, but not literally all of them)
When our comrade excitedly began setting up their rig, it became rapidly apparent that CHIRP wasn’t going to happen. While support has been added for the 7100, there were some errors, missing fields, no way to work with multiple memory banks, etc. Of course within the open-source world, one should file a bug, give detailed steps of the issue and how to reproduce. We want tools like CHIRP to continue to grow and improve. But our friend was impatiently looking to other more immediate options to get on the air stat.
After some searching, multiple sources were pointing to RT Systems software for the 7100. Some YouTube videos showed a nice interface and pretty comprehensive support for all major settings / memory management. The downsides:
costs money
proprietary software (source code is not open)
not general purpose (separate software for each radio for some reason?)
does not support Linux
The last one was the real show stopper, but that was not gonna deter our automation-hungry anarcho ham. They took a gamble, threw down $25, snagged that disgusting .exe file, and crossed fingers. Running via wine was the first step. Misc errors, would kinda launch, then crash. Apparently the RT Systems devs said running this way is not possible. Next stop was VirtualBox (to run windows in a virtual machine and install on there). This worked! Well, the program installed and opened. The next problem seemed to be the usb connection to the radio was recognized on linux but not the Windows VM. After some fiddling, the key resolution was to:
1) install the Virtualbox extension pack (unsure if this step is actually essential)
2) determine device location of the usb radio connection (this is possible using CHIRP; download data from radio on there and the device file will look something like /dev/ttyUSB0)
3) Edit VM serial device settings. Choose COM1 for port num, port mode: Host device, port/file path: /dev/ttyUSB0 (or whatever you determined from step 2)
Now when you start the windows VM and launch the RT Systems software, make sure to select the appropriate port in the Comm port setup under the “Communication” menu setting. And then we can properly sync to/from radio!
So, in conclusion, proprietary windows-only software sucks. It is unfortunately quite common in the ham radio programming software ecosystem. As anarchists we vociferously advocate for free, multi-platform, open-source software, but sometimes compromises are inevitable when you’re impatient and just want to get repeaters on your goddamn radio. We hope this helps anyone facing similar frustrations!
This is somewhat less of an activist-oriented post, because shit would honestly have to be pretty fucking dire in the world for CW (we’ll get into why we call it that in a bit) to actually be practically useful. Not that such situations are impossible, and of course it’s worth thinking about and imagining, but we just don’t find them terribly likely. For a lot of people, Morse Code scratches an itch on a part of our brains that loves learning languages and sending secret codes. Anyhow, Morse code is cool and fun.
Hams call it CW, which stands for Continuous Wave. That’s because rather than modulating in response to the oscillations of a human voice or multiple tones of a digital signal, it uses one continuous tone generated by an oscillator. The oscillator is either On or Off. The circuit is either open or closed. The differences in the amounts of time the radio transmits is what creates the language.
And yes, it is a language. A relatively unique one, too because it’s neither a written language, nor a spoken one. It is sent by the hand, but also it is meant to be heard and experienced in time, not seen as dots and dashes on a piece of paper.
Each combination of fist, key, and radio system has a “voice” which is as distinct as a human voice, and can be picked out among a pileup of other voices.
It is not exactly binary, even though it is regarded as the first digital mode. If anything, it’s Ternary. The “dits” and “dahs” are not equivalent to zeros and ones, because the gaps in between the tones are just as important as the tones themselves. For example “dah dit dah dit … dah dah dit dah” is “CQ” which is basically a way of saying “is anyone out there?” But if you change the timing to say “dah dit … dah dit … dah dah … dit dah” it says “NNMA” which probably doesn’t mean anything to anyone.
Computers aren’t very good at decoding CW. CW decoders do exist and are quite common, but they require a certain set of conditions in order to work properly. They expect tones in a certain range, a clear strong signal without any interference, and a very regular cadence. When CW is sent by a real human (especially with a straight key) on the real airwaves, using low power, a computer is of very little help. The human ear is much better at decoding this than a computer.
As far as radio communication goes, CW is the most efficient mode there is, by many standards.
Bandwidth: CW uses the smallest amount of bandwidth. Usually only about 500 Hz. Compare that to the typical 2400 Hz bandwidth of an SSB phone transmission.
Signal to noise: some “low signal” digital signals such as FT8 can be decoded by computer when it’s so deep into the noise that it can’t even be heard by the human ear. However, a skilled CW operator can decode CW that sounds exactly like static. That’s not easy to do with the human voice, and computers are not good at decoding messy CW.
Efficiency: You can probably squeeze more miles per watt out of CW than any other mode. Moreso, the equipment can be extremely small and lightweight.
0.3 watt CW transceiver inside an Altoids tin, made by Adam K6ARK https://reflector.sota.org.uk/t/worlds-smallest-sota-station/20825/45 watt QCX Mini CW Transceiver from QRP-Labs http://shop.qrp-labs.com/qcxmini
A word about keys
There are several different types of CW keys, but most people either use a “straight key” or an “iambic paddle”. The straight key is the one most people are visually familiar with.
J-38 straight key
The straight key produces “dits” and “dahs” by pressing down the key for shorter or longer periods of time.
Back when Morse Code was still a primary mode of long-distance communication, telegraphers – especially postal workers – primarily used straight keys. Prolonged use of straight keys caused a repetitive stress injury known as “glass arm”. To prevent this from happening, keys were made which relied on a side-to-side motion such as semi-automatic keys called “bugs” and then iambic paddles.
Most modern radios have circuitry inside them which allow you to set the sending speed, so the duration of the “dits” and “dahs”. This enables the use of iambic paddles.
Search for “stainless steel iambic paddle” and you’ll find these all over the place for about $50. They’re pretty good.
Iambic paddles are pretty good. One of the paddles is “dit” and the other is “dah”. You can press them at the same time send “dit dah” or “dah dit” depending upon which paddle was pressed first. Very convenient. They allow you to send well formed characters very easily.
The dis/advantage of straight keys is that they almost force you to send slower. You also have to be very conscious of how long your dits and dahs are. On the air you can often tell when you’re talking to someone using a straight key because they can lean on the “dah” for what seems like an eternity once you get into the groove. The sounds may not be consistent relative to each other. A consistent and legible operator is said to have a “good fist”. The irregularity of the straight key may or may not be desired.
How to learn the Code:
The most important things to do are listening to and sending CW.
There are three main methods of teaching CW which are generally accepted: Koch, Farnsworth, and Instant Character Recognition (ICR). They’re all slightly different and tedious to explain, but we thought we’d point that out as they are terms you might come across.
Many tools exist to help people learn Morse code. Below is a non-exhaustive list of some options that are out there.
Morse Mania is an app for Android and iPhone. It’s good at teaching letters using the Koch method, but they want you to pay for numbers and punctuation. Rather than paying for software, you may want to move on to Morse Trainer (Android) which is open source and also uses the Koch method, but in a slightly different way. There are many different mobile applications
Learn from people: The Long Island CW Club and CW Academy are two groups that meet online and teach CW in different ways. Participation in both of these groups pretty much requires that you have both a Key and either a dedicated oscillator or a radio with a practice mode.
Long Island CW Club has regular Zoom meetings where people practice sending back and forth. There is no curriculum. You just show up to whichever meetings are convenient for you. There is a membership fee for LICW.
CW Academy is free, but it’s more structured. Students sign up for an 8 week long course consisting of two one-hour Zoom meetings per week.
How NOT to learn the Code:
Most skilled operators will advise that you NOT try to learn it visually. CW is an audible language, not a written one. Do NOT rely on a sheet of paper with the alphabet as a list of dots and dashes. The reason is basically that when you memorize the symbols in a visual way, you will always try and decode using a visual reference to each corresponding symbol, which is much slower than hearing the sound of each symbol.
Conclusion
So, while CW may not be particularly useful in the day-to-day, consider some of the information above. CW rigs are small and light. They don’t require computers or other equipment. The transmissions are very narrow-banded. CW signals can get out in very poor band conditions, when almost no other signal can. It’s a great emergency mode, and just another great skill to have.
Hurricane Sandy’s blackout and the streets of lower Manhattan –Dan Nguyen
It didn’t take long after the attacks on the power substations in Moore county, North Carolina for the old Civil Defense guys in the ham radio community to start ranting about the “Shit Hitting The Fan” in their email lists. Talking about how State emergency response groups are woefully unprepared or – more to their point – disconnected from the ham radio community.
While we disagree with the statist approach to their solutions, they’re not wrong about the problems. If power, Internet, and cellphone systems all go out, that leaves people vulnerable. Elderly people, people with disabilities, people living with food insecurity, etc. You know, the working class.
Prior to 9/11, the number one threat to national security in the eyes of United States government was not from Islamic Extremists, nor “Illegal Aliens”, nor “The Chinese”, but from American white supremacists. The anti-Black racism, homophobia, xenophobia, and hatred of poor people that existed before 9/11 never went away. Instead, it was redirected towards a War on terror, a War on Drugs, and a War on “Illegal Immigration”. The hatred was focused on external perceived threats to cishet white male Christian hegemony. So now, there are power substations being attacked, likely by white supremacists.
In the case of Moore county, North Carolina there’s a possibility that the ideological target was the local LGBTQ+ community due to a drag show that was happening at exactly the same time. The physical target, however, was anyone who uses electricity. While the motivation for the attack in Moore County is yet to be confirmed, the plausibility of terrorist attacks on critical infrastructure targeted at marginalized communities in both the present and future is very real. Regardless, the effect is the same.
Due to the known fact that many police and their ilk are either fascists or simply sick bastards in their own right, it should be understood that state-based solutions to communications outages are neither tenable, nor necessarily desirable for many people.
With that said, it may be obvious to us that having a ham radio base station at the local police department monitoring for emergency traffic may not be so desirable. What may not be obvious is that police departments tend notto want people calling them over the radio either.
So what is to be done? The short, very general answer – and probably the most important – is to build dual power in the form of networks of solidarity and mutual aid. But here are a few ideas.
What already exists? NCPACKET, APRS, solar panels, batteries, flashlights, candles, heaters. What should we build? As always, build community, bases of knowledge, networks of mutual aid and solidarity. What does that look like? Queering ham radio and building Community mesh networks.
Pick up some FRS, MURS, GMRS or CB radios for your friends and neighbors. Come up with a comms plan and practice.
The Narrow Band Emergency Messaging System is probably one of the easier digital systems to implement. In its simplest form, all you need is your radio and an Android device running AndFLmsg. Simply type your message in the app, hold your radio up to the phone speaker and press the PTT button while the encoded message plays over the speaker. This method is called “audio coupling”.
The downside of audio coupling is that it makes a lot of audible noise in your local environment. The sound is pretty annoying, too. It’s also possible for environmental noise to interfere with a good copy, although some of the modes used with NBEMS are fairly robust against noisy environments.
There are a few ways to solve this, but they all involve either more equipment, more capable radios, or both.
If you’re using a Baofeng UV-5R or similar HT, you could use an audio interface cable such as the BTECH APRS-K1. This cable is usually used for APRS, but it does work for AndFLmsg. One end plugs into the Kenwood connector socket on the radio, and the other connects into your phone with a 3.5mm TRRS connector. If your phone does not have a 3.5mm audio jack, it may be possible to use a USB-C to 3.5mm adapter, but it seems like a lot of people have trouble with this. Besides, that’s a lot of cables and connectors at that point.
Speaking of a lot of cables, you could also use a sound card interface such as the Digirig Mobile, the Wolphi Link, the AIOC, or possibly the EasyDigi if you want a more DIY option. It’s similar to the APRS cable, except that it’s more modular and can be used between various devices and radios, provided you have the right cables to go between them.
The downside to the BTECH APRS K-1 cable is that you either still have to manually push the PTT button, or you have to put the radio into VOX mode. This means that the PTT is triggered by audio rather than by pressing the button. This can cause the beginnings of messages to be cut off, or (in my experience) cause the radio to overheat and kill the battery, or it may completely fail to trigger the PTT at all. The other issue – and Baofeng radios are notorious for this – is that the VOX circuit may be quite laggy, which might cause the first part of a message to be cut off. To overcome this, it may be a good idea to start a message with some junk data, such as a bunch of zeros or just jumbled letters, in order to give the VOX circuit the split second it needs to activate the PTT.
Audio interfaces such as the Digirig shouldn’t give you this problem, as they are able to send the RTS signal to the radio, which activates the PTT much like a radio with built-in CAT control would be able to do.
As of this writing, it seems that the Mobilinkd TNC3 does not work with AndFLmsg.
AndFLmsg is based on a more feature rich suite of free and open source programs called FLdigi. AndFLmsg basically consists of FLmsg and FLwrap. The full desktop version can be a little more complicated to set up, but FLmsg and AndFLmsg are capable of talking to each other.
Sending text
The first thing AndFlmsg shows you is a simple screen that looks like a chat interface. A mostly empty screen with a text field at the bottom where you type the message to be sent. For quick, informal messages that need to be sent from one person to another, this is perfectly acceptable.
However, AndFlmsg also supports forms. These are pre-formatted XML files, often made for particular organizational purposes. The most common form is the ICS-213 “General Message” form. (It is also possible to create custom forms, but that’s beyond the scope of this post.)
It takes about 3 minutes to send the text of John Brown’s last speech using a mode called MT63-2000L. With the BPSK31 mode, it takes almost 11 minutes to send the same text. AndFlmsg supports dozens of different modes that have varying levels of robustness, and transmit at various speeds. You’ll want to research the different modes and decide which is most appropriate for your group in any given situation. Take into consideration the length of the messages you’re likely to be sending back and forth, how long you can sit in one place waiting for a message to be transmitted, as well as both audible and RF interference in your local environment that you’ll have to deal with.
Sending images
To send and image in AndFlmsg, go to the Compose View and scroll down to select the “picture.html” form. Fill out the form, and attach your picture. Tap “save to outbox” and it will take you to the Outbox view. Select your message, and then tap “TX OVER RADIO”. The encoded message will begin to transmit.
When sending images which contain text using AndFlmsg, we have observed that rotating the image 90° so that the text is vertical makes the decoded transmission 100% more legible. However, sending images with text should probably not be your primary purpose for using this system. It could be useful to send images of injuries, an area affected by flood or fire, the face of a missing person, maps, or aerial photographs for instance – in other words, things which can only be effectively expressed through images. It took more than 3 minutes to send the black and white images above.
Sending text is bound to be faster, more efficient, and less prone to error than sending images, at least in most cases we can think of.
Edit: another application has become available, quite similar in concept and usage to AndFlmsg, called Rattlegram (on Google Play Store or wherever you get your APKs). It uses a method called Coded Orthogonal Frequency Division Multiplexing (OFDM), which makes it quite fast. However, as far as we can tell, it is only possible to send text (and emojis!) not forms, images, or files.
You ever email someone about something really important? Why? You know they’re not going to read that, right? The signal to noise ratio of email is so unbelievably low that the vast majority of people rarely if ever check their inbox. Text messaging is how you generally get a hold of someone quickly.
But if you’re in a situation in which, as we’ve proposed before, your local area is cut off from cell phone and internet access – and worse yet, you are out of range of an APRS digipeater, meaning SMSGTE is inaccessible- there is yet another way for you to send an SMS text message using ham radio, this time using HF and Winlink.
It’s possible that you have accidentally stumbled across a feature provided by your cell carrier. Your phone number has an email address associated with it.
Most likely it’s something like 555012345@tmomail.com or whatever domain your carrier uses. Here’s an incomplete list.
It may go without saying that you need to know the recipient’s cell carrier ahead of time in order for the message to be sent. It is necessary to plan ahead a little.
When you send an email to an address like this, the email shows up as an SMS message for the recipient. The recipient can then reply to the message as if it was a normal SMS text message.
But there may be a hitch. When you *receive* a message from a phone number, it may not be a plaintext message. Some cell providers format the messages with HTML and attach a few images and logos just to be jerks. When you’re using a 1200 Baud connection over VHF, or even 300 Baud over HF, it is difficult to overstate how LONG it takes to download these unnecessary attachments, not to mention the poorly formatted HTML message. It can take so long to receive these messages that the connection to the RMS gateway being used may time out to relieve congestion. This system is for emergency use, after all.
For this reason, it would be best to primarily use this as a one-way communication technique, e.g. to notify your loved ones, affinity groups, journalists or lawyers of what’s happening.
It would be a good idea to append such a message with something like “Due to low bandwidth conditions, please do not reply via SMS. Send an email from [known, accepted email address] instead.”
The email address must be in the “accept” list.
To add an email address to your Winlink “accept” list, send an email message to that address via Winlink ahead of time, or send your message to the contact’s known email address at the same time. Keep in mind that it may take several minutes to send an email. Sending the same email to 2 addresses doubles that time because you’re sending the same message twice.
If you need to send a message to several people, it may be possible to set up an email list. This saves your radio from sending the same message several times over at 300 or 1200 Baud. Riseup.net runs a good email listserv. You do not need a riseup.net account to use it.
We know that police and the State can shut down cell towers at any time, basically by asking the telecom companies nicely to “pretty please turn the tower off because there’s an emergency”. We also know that not every protest takes place in an urban setting with cell and Internet service on every block. At pipeline protests, railway blockades, and forest occupations, cell service can be anywhere from spotty to non-existent.
Burning cell tower
With ham radio and APRS, it is possible to get a message out to people who need to know what’s happening when you’re in the digital dark. The best part about this technique is that the people you contact basically don’t need to know *anything* about ham radio.
You need:
1. a valid call sign (sorry pirates, sometimes that’s just how it goes.) (UPDATE: I actually tried setting up APRSdroid with a fake call sign, and NOT entering an APRS-IS password, and it seems to have worked fine. I did not transmit over RF. Tired old reminder that illegal things are illegal, own risk, etc.)
2. a device with Internet access, and a device capable of sending and receiving SMS text messages.
3. Important phone numbers. National Lawyers Guild, outside support team, a friendly reporter, your mom, etc. You’ll be adding these as “aliases” later on.
4. a VHF radio with APRS capability. This can be:
-A Baofeng or other basic HT, an Android phone or tablet with APRSdroid installed, and an APRS cable or AIOC.
-A Baofeng or other basic HT, Android phone with APRSdroid installed, and a Modem/TNC such as the Mobilinkd. (There are options for iOS, but I don’t know what they are)
-A VHF transceiver with APRS built in, such as the Yaesu FT-3DR, the Yaesu FTM-400, or the Radioddity GD-AT10G.
How to get set up
1. Get APRS working. You can start with APRSdroid using the APRS-IS service in order to avoid transmitting your phone number on the air for no reason, and for the sake of using a stable Internet connection rather than RF. It’s up to you. However, once this process is all done, MAKE SURE you can actually send and receive packets VIA YOUR RADIO (not the Internet. [I made this mistake.])
2. Send a message (any message) to the “SMS gateway” service by entering in the callsign SMSGTE. The message format should be “@5551611312 some message”. Use your phone number, or a number you don’t mind being associated with you for a while. You have to do this at least once.
(Note that you can actually stop here and use the SMSGTE service without registering, but the following steps will add a little tiny bit of privacy, at least against anyone within RF range listening to APRS traffic, or watching a site like https://aprs.fi. And by itself, this is still useful. If a comrade really needs to get a message to their partner or family member for example, you could let them borrow your device, type in the phone number and message and hit ‘send’. They do have to know the number, or be able to find it in their contacts.)
3. Go to https://SMSGTE.org and create an account. Follow their instructions, as part of the registration process involves sending at least one APRS message.
4. At the top of the page, go to ‘User Tools’ and ‘Alias Manager’. You should see an empty list with “Name, Number, SSID” at the top. SSID isn’t necessary, but will make it easier to manage multiple conversations in your chosen APRS interface.
Example entries:
Alias
Number
SSID
NLG
5551611312
LG
MyCrew
6667654321
MC
Mom
5551234567
MA
TeenVogue
1234567890
TV
Doing all this allows you to save contacts and conversations as distinct message threads. So when you want to send a message to the NLG phone number, you can send it in one of two ways:
With just the Alias,
Callsign: SMSGTE
Message: @NLG My name is X, we're at Y, some of my friends have been arrested. Please send help.
or with the SSID
Callsign: SMSGTE-LG
Message: My name is X, we're at Y, some of my friends have been arrested. Please send help.
Receiving SMS messages via APRS.
When someone receives a text message from the SMSGTE service, it will look like
@[CALLSIGN-7] message
If the person you sent the message to wants to reply, they *must* begin the message with your callsign and SSID such as “@[CALLSIGN-7]” otherwise it will just go straight to the SMSGTE number and never be transmitted back to you.
@[CALLSIGN-7] reply
Pros and Cons
1. APRS is basically GPS. Even though the “P” stands for “Packet”, it’s often referred to as the “Automated Position Reporting System”. As such, most APRS devices periodically beacon out your GPS location while it’s running. This includes APRSdroid. Radios with APRS built in may be set up differently and have different options. To mitigate privacy concerns, APRSdroid has a GPS ambiguity setting, which in my experience has abstracted my position by as much as 34 miles from my actual location. so that’s…something. Location beaconing can also be set to manual.
2. APRS would be good for coordinating logistics that are legal, like water, food, first aid, legal observers, and media. It is extremely important to understand that these messages are sent in the clear, and over the airwaves, AND over the Internet, AND through unencrypted SMS messages. So this is very much a technique to use when the grid is down and you have an emergency.
3. APRS being useful is still reliant on beacons that are run by volunteers. There is no guarantee that wherever you go, there will be an APRS Igate that’s running and within RF range. Remember that getting your antenna as high up as possible will help you get out farther. Raise your radio up over your head, stand on top of a car, climb a tree. Do whatever you have to to get the signal out.
4. If you are within RF range of an APRS beacon, it’s possible that you will be able to *send* SMS messages, but not receive them. Unfortunately some Igates only *receive* and do not transmit.
5. while SMSGTE is automated, it is also a *service* that is run by *human* *volunteers* who can forget to pay the phone, server, or electric bill, or trip over a power cord, or get struck by lightning or any number of other things, just like anybody else. This service is correspondingly vulnerable. It’s pretty robust, but it’s not bulletproof. Hardly anything is. https://SMSGTE.org has a donation link near the top of the page.
Videos about SMSGTE:
Videos about APRS more generally
UPDATE #1 (11/13/2023): The FCC is at it again. The SMSGTE service has been shut down for over 6 months. From smsgte.org:
“The SMSGTE service us currently offline. New regulations put into place in the US, Canada and other jurisdictions along with some recent abuse of the service to send SPAM have forced me to shut the service down. I am currently searching for a solution to restore service. If there is a club or HAM organization interested in assisting, one that is a legally registered business or non-profit, please contact me.”
As such, we will leave this post up for posterity, and will update it either when the service comes back online, or when a solution arises. In the meantime, consider our later post on how to Send text messages via email – over ham radio as a sort of workaround.
UPDATE #2 (12/18/23): A solution has arisen. http://aprs.wiki/SMS/ This system works pretty much the same as SMSGTE, the difference is that people have to enter their phone numbers to opt in ahead of time to receive messages. When the number is entered, they will receive the following message:
“You have opted-in to the APRS to SMS Gateway Service. To opt-out, reply STOP. To opt-in again, reply START. See http://aprs.wiki/SMS/ for more information.”
It is also possible to create aliases using the SMS service. However, so far it is only possible to do this from the APRS network itself, not the webpage.
Before the bombs started dropping on Ukraine, I was trying to write something about the ban on ham radio there. Now I’ll do the same thing, but not try to be clever or funny about it. I don’t know that this information will be particularly useful to the people of Ukraine *right now*, but it might come in handy for any of us later on.
There are essentially two ways a ban on ham radio can be enforced.
1. Jamming: basically, jamming is the deliberate interference of a radio signal by transmitting on the same frequency as the target signal, usually at a higher power. So, if you are transmitting at 5 watts, a 6 watt signal on the same frequency would drown you out. Or even a 1 watt transmitter if it is very close to the receiver. This is especially easy on FM due to a phenomenon called the “capture effect”.
We saw the use of jamming a few months ago when the Cuban government used powerful transmitters to block signals on the 40 meter band which is used for long distance communication.
2. RF direction finding: in movies and TV shows they often call this “triangulation” and it’s a real thing. If you’re on VHF/UHF your antenna most likely transmits in an omnidirectional radiation pattern, meaning your signal travels roughly the same distance in any direction. The signal is strongest at the source – near the antenna – and gets weaker as you get farther away. An attacker can find the source of your signal by the use of one or more *directional* antennas. These are antennas that have a more focused RF radiation pattern for both transmission and *reception*. Two common types of directional antennas are the Yagi-Uda antenna (featuring a large pole with a handful of smaller perpendicular bars) and the more well known satellite dish. The attacker would sweep an area, swinging the antenna in different directions to find out where the signal is strongest.
An attacker can, of course, jam a signal using these directional antennas. However, they may be just as likely to send someone over tofind the source of the transmissionand shut it down themselves.
Solution/circumvention
VHF/UHF
If an attacker is jamming theseline-of-sight radio frequencies, you are probably a bit stuck.
Assuming the jammer is only working on a narrow portion of the spectrum, you can try switching to a different frequency. Coordinate with your affinity group beforehand to select contingency frequencies.
If the attacker is jamming on a huge chunk of frequency space, your only options are to switch to higher power, or switch to a different band.
HF
It might be possible to get a signal out using different modes of operation such as CW (Morse Code) or weak signal digital modes such as JS8Call. The narrow-banded nature and other properties of CW make it easy for human ears to pick out of the noise and decipher. Weak signal digital modes like JS8Call can be decoded deep into the noise floor.
Neither of these options are *guaranteed* to be immune to jamming. It’ll depend on the situation. The only way to try is by experimentation.
NVIS
Near Vertical Incidence Skywave propagation is a technique for HF radio comms that involves *lowering* your antenna, generally to between 1/4 and 1/10 of a wavelength off the ground.
Diagram comparing NVIS propagation to “DX” or normal skywave propagation.
To clarify: under normal circumstances, the ideal height of an HF antenna should be 1/2 wavelength above the ground. So if you’re on the 40 meter band (~7MHz), set it 20 meters up. 20 meter band (~14MHz), 10 meters up, etc. Antenna science is complicated, and there are many exceptions to this, but it’s a general rule of thumb. This allows your signal to radiate *outward* toward the horizon as much as possible, where it can reflect off the ionosphere once again beyond the horizon.
If you’re doing NVIS on 40 meters, you would want a *horizontal* dipole between 4 meters and 10 meters off the ground. For 20 meter NVIS, you would want your antenna to be between 2 meters and 5 meters off the ground.
By setting your antenna *lower* to the ground, you do the opposite. You are trying to make sure that as much energy as possible is directed skyward. Hence “Near Vertical Incidence Skywave”. This technique gets your signal
out farther than line-of-sight (VHF/UHF), but for shorter distances than normal HF propagation. It can also be used to get a signal over mountainous, or possibly militarized, terrain.
Direction finding is also more difficult with NVIS because in a way, you are using the earth as part of a directional antenna, which means an attacker’s *directional* antenna is going to have a tough time figuring out which direction a signal is coming from, as you no longer have an omnidirectional signal.
