Ham Radio / Off-grid communication

Jotch said:
The 5 most disliked Amateur Operators on 7200 have been called:
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My local repeater is slowly turning into 7200.

Its great for me as it's in LOS of my house and about 5 minutes walk away, so it comes blasting through no matter the conditions. There has been a huge uptick in activity recently as more and more people are going mobile thanks to cheap Chinesium handhelds. Its the most popular repeater in the area because of it's location, so theres activity on there almost 24/7. Consequently there is a lot of shit talking on there.

This morning there was a guy calling out on CW for about two hours. In fairness he wasn't being a dick about it, but before he gave up he had a response that came in right in the back of the box that simply said "F U NIGGER". It ain't much, but it had me laughing for a solid five minutes.
 

►I'M RETARDED HOW DO I JS8CALL? (and other digital modes)
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JS8call is an open source program that enables Ham radio operators to communicate around the world on the HF bands, even with extremely low power (fractions of a watt) and poor propagation conditions.

JS8call takes data, such as text, and modulates it into sound. That sound is then transmitted over the air and up to the ionosphere from a radio connected to a computer running the software.
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JS8call is based on a digital mode called FT8. FT8 is a "weak signal mode", meaning that it takes next to nothing to get a signal out and can even be received lower then the noise floor.

These signals can then be decoded by other users with JS8call allowing them to receive the text you transmit.

One drawback is JS8call is quite slow. However, it can be used quite effectively for transmitting text such as bulletins, signal reports, and for short conversations.



Getting started
​
1. Rig
To operate JS8call you will first need to setup an HF capable station. You will need a radio that covers the HF bands, ideally from 80 meters to 10 meters.

A good starter HF rig is something like the Xiegu G90. It has 20 watts of transmit power, a built in tuner, and only costs around $400 USD. Other options include the Yaesu FT-891, which has a full 100 watts of transmit (TX) power for around $700 USD.

To operate digital modes, you will need a soundcard and a audio cable for your radio. For example, the Xiegu G90 uses a DIN connector on the back for sound in and out. My personal setup is a cable like this connected to a USB soundcard.
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For the G90, you will also need a cable connected to the radio for CAT control. CAT control just means allowing software on your computer to control the radio, such as keying it to transmit, the frequency it's on, etc.

Some radios like the Xiegu X6100 and ICOM-7300 also have built in soundcards, meaning that you typically just need one cable to plug them into them for both CAT control and audio in/out.

For more detailed info you can search "your rig + digital mode setup". There are also hardware options available like the Digirig.


2. Frequency selection & antenna
The two bands primarily used for long distance communications on HF are 20 meters ( 14.000 MHz to 14.350 MHz ) and 40 meters ( 7.0 MHz to 7.3 MHz ). The @KFALL group and KiwiFarms bulletin for example uses 7.096 MHz under the 40 meter band.

20 meters is generally open during daytime and 40 meters opens up at night, after the sun sets.
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newplot.webp

Here we can see an example of propagation conditions from the East to West coast in the US using the VOACAP modelling tool. The chart on the left shows reliability over the time of day.

We will want an antenna that covers both of these bands. Most antennas are simply a length of wire cut to a specific resonant frequency. Some examples of easy to build antennas that can get you on the air fast are:

The Rybakov Antenna (easiest to DIY for beginners)
(PreserveTube)


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Random wire verticals

(PreserveTube)

My own setup for rapid mobile deployment is a random wire with a 12 meter Spiderbeam fiberglass pole. I either guy it to the ground or use a drive on flag pole mast if I have access to my vehicle
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(If you decide to go with this setup, just make sure the opening is the right diameter and has enough clearance)


There are many options for antennas and other people in this thread might have some ideas too. When selecting an antenna, it's important to chose one that best fits your operating parameters:
- Mobile or permanent
- Space constraints
etc

Once you have your rig, computer with data cables, and antenna, you are ready to get on the air.

3. Install & Configure JS8call

JS8call is straightforward to setup and install, with Mac, Linux, and Windows support. On Windows there is a executable and for Linux distros it can be installed through 99% of package managers.

Once it's installed, open the program up. You will be greeted by the configuration screen.

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The first tab we see is our station info. You can specify your callsign here, or specify your "callsign" here. All it is looking for is a value that matches the callsign format. For now, I will put AE1XYZ.

Next is our maidenhead, or our grid square. This is a 4 or 6 character value that has our location. This is optional. If you want to specify this, you can find your grid square using a site like https://www.levinecentral.com/ham/grid_square.php

Finally, our callsign group. If you want to participate in the Kiwi Bulletin, we are using the callsign @KFALL. The "@" in JS8call designates a group.

We do (in most cases) want to participate in the @ALLCALL group, so leave that unchecked. The @ALLCALL group is as the name suggests.

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We can leave the station messages their defaults for now.

Next, go up to the "Radio" tab. This is where we configure our rig. On the backend JS8call uses Hamlib for keying the radio and CAT control.

Select your rig up at the top. Next set the serial port and the baud rate. To find the baud rate you can search for it online, or sometimes it's configured from the radio itself.
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With the rig selected, the serial port specified, and baud rate, hit "Test CAT". If it shows up in green, that means you are good to go.

Next, go to "Rig Options". Select "CAT" for PTT Method
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Then hit "Test PTT". If it's greyed out make sure to press "Test CAT" first. You should see your radio key up. Once you are done, hit "Test PTT" again and it should go from red to grey, unkeying the radio.

Finally, we configure "Audio".

Head over to the audio tab and select your input and output device. Find the USB audio device connected to your rig and set it for the input and output device.
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For me, on LINUX ™️ I'm just using "default". On Windows and Mac select whichever shows up as your sound device.

WE ARE NOW DONE AND READY TO GET ON THE AIR!

These settings can be accessed any time under File -> Settings

The JS8call UI is very simple to use. In the top input, incoming messages are displayed, and the bottom input is for outgoing messages.
Beneath that is the waterfall, for viewing our signals as they come in through our soundcard.

Screenshot from 2025-09-13 23-02-18.webp

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Sending HELLO :) to @ALLCALL. To send, hit "SEND". It shows us how long this transmission will take (20 seconds) using the default speed mode. You can find all speeds under the "MODE" tab

Playing around in the software for 5 minutes should get you familiar with it. A complete guide to the software written by the developer, KN4CRD has also been attached as a PDF.

And that's pretty much should cover all of the basics. Once you are familiar with JS8call, you are also familiar with just about every other packet software out there, including the FreeDV modem written for the KiwiNode (setup is near identical).

If there is anything I'm missing or if there are any other questions let me know.

Other helpful links:
► Part 1 - Simple intro to off-grid comms
► Part 2 - Intro to HF
► SDR Buyers Guide
► KiwiFarms over HF radio with Reticulum and NomadNet
 

Attachments

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Are there any other nets as exciting as 7200?
 
Jotch said:
Are there any other nets as exciting as 7200?
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14.313, though less active in recent years as 7200

also somewhat related is the 43 meter band. If you are into SWL’ing you can find all sorts of fun pirate broadcasts in North America from 6.4 MHz to 6.9 https://www.hfunderground.com/board/index.php/board,3.0.html

A few years ago I found a station that just played Johnny Rebel. 6960, I have the recording somewhere.
 
Onillius said:
I'm also looking into ways to get encryption without calling it encryption since the FCC Title 47 § 97.113(a)(4) prohibits the use of it, and since I want widespread use I need to find a workaround or some some rule that makes it exempt from the FCC regulations.
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One way to avoid this is to call it scrambling - pick some common, fast and modern encryption algorithm and some trivial, public key like all-zeros. Then when you really want to encrypt it, use a random key (at that point you are under FCC reg's, but who cares). You can use the standard key exchange protocols over the plain-text (scrambled) link to define some standard (but not assosciated with the original protocol) way to do the key exchange, like in SSL.

Just to remind you that this sounds like a mesh network, and with no hierarchical control it behaves like an ALOHA style net, so while the theoretical link speed is in the 30's of mbps, once you start hitting some link saturation the collisions rapidly decrease the real transfer speed. Wikipedia has a whole page about ALOHA networks and the design considerations for maximum transfer speeds.
 
Anyone down for another test of the JS8call Kiwi Bulletin on 10/04 at 0200 UTC, (2100 CST, 2200 EST)?

Duration: 1 hr

Primary:
7.065 USB
Backup
7.116 USB

This time it might be a good idea to focus on QSOs with signal reports, then followed by a test transmission of the bulletin.
 
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The Real Slim Shady said:
One way to avoid this is to call it scrambling - pick some common, fast and modern encryption algorithm and some trivial, public key like all-zeros. Then when you really want to encrypt it, use a random key (at that point you are under FCC reg's, but who cares). You can use the standard key exchange protocols over the plain-text (scrambled) link to define some standard (but not assosciated with the original protocol) way to do the key exchange, like in SSL.

Just to remind you that this sounds like a mesh network, and with no hierarchical control it behaves like an ALOHA style net, so while the theoretical link speed is in the 30's of mbps, once you start hitting some link saturation the collisions rapidly decrease the real transfer speed. Wikipedia has a whole page about ALOHA networks and the design considerations for maximum transfer speeds.
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An issue is it says we’re forbidden to transmit “messages encoded for the purpose of obscuring their meaning” not specifically “encryption”, so “scrambling” is obscuring etc etc. packet can be sent in clear so in the unlikely event of prosecution you'd have to explain why you are using a cypher, as it serves no purpose other than obscuring a message, publishing a key in a public place likely wouldn’t cut it. A really broad interpretation could be talking in clear voice but in a secret code known only unto the speakers also being verboten.

The only exemptions off the top of my head are sat telecommand and repeater controls etc.

This has come up a lot over the years. You have to explain this to the judge, not convince other hams at the end of the day.
 
I won't be able to listen in to this transmission but I wish you the best!
 
temeluchus said:
An issue is it says we’re forbidden to transmit “messages encoded for the purpose of obscuring their meaning” not specifically “encryption”, so “scrambling” is obscuring etc etc. packet can be sent in clear so in the unlikely event of prosecution you'd have to explain why you are using a cypher, as it serves no purpose other than obscuring a message, publishing a key in a public place likely wouldn’t cut it. A really broad interpretation could be talking in clear voice but in a secret code known only unto the speakers also being verboten.

The only exemptions off the top of my head are sat telecommand and repeater controls etc.

This has come up a lot over the years. You have to explain this to the judge, not convince other hams at the end of the day.
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law in the United States is established by precedent,

zero FCC enforcement actions exist for 47 CFR Part 97. All FCC enforcement actions governing the Ham radio spectrum are publicly available here. digital voice modes like C4FM (Yaesu Fusion) which are proprietary, commercial, and patented could be argued that they fall under the "no obscuring message" rule. they can't be received by the general public and can only be decoded with other C4FM radios.

also there are people who scream the nigger word everyday on 7200 WITH their real government issued callsign and literally nothing happens.

The FCC rules governing "encryption" on the Ham radio bands were drafted during a time before the Internet and are a relic of the Cold War era.

btw did you know torrenting movies is illegal? You wouldn't download a car, would you?


 
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888Flux said:
law in the United States is established by precedent,

zero FCC enforcement actions exist for 47 CFR Part 97. All FCC enforcement actions governing the Ham radio spectrum are publicly available here. digital voice modes like C4FM (Yaesu Fusion) which are proprietary, commercial, and patented could be argued that they fall under the "no obscuring message" rule. they can't be received by the general public and can only be decoded with other C4FM radios.

also there are people who scream the nigger word everyday on 7200 WITH their real government issued callsign and literally nothing happens.

The FCC rules governing "encryption" on the Ham radio bands were drafted during a time before the Internet and are a relic of the Cold War era.

btw did you know torrenting movies is illegal? You wouldn't download a car, would you?


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It would be funny if a farmer ends up setting the precedent, I always had a hunch the mesh and feng brigade might be the straw that breaks the camels back, we’ll see.

I was really just making the point that part 97 explicitly forbids “obfuscation”. Im not anyones mother and you do what you want to do.

Deregulation of ham radio may be pretty limited as it’s governed by international treaty and mostly defined by the itu. Its already one of the least regulated spaces in the spectrum to begin with. The dumb sub bands should go. Only the US seems to do that, for whatever retarded reason.

That is one of the upsides of us being mostly being ignored is we get away with a lot. One way to preserve that in the long term is to not poke the bear too much. The sheer freedom we get for the minimal effort of the piss easy tests (if you cant pass extra, you’re braindead) is pretty astounding.
 
temeluchus said:
It would be funny if a farmer ends up setting the precedent, I always had a hunch the mesh and feng brigade might be the straw that breaks the camels back, we’ll see.
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please forgive my autistic ramblings, but software encryption itself was considered an armament and subject to export controls the same likes of a guided missile or fighter jet up until Bernstein v United States set the precedent thas source code of software was protected under the 1st Amendment

https://www.eff.org/deeplinks/2015/04/remembering-case-established-code-speech (archive)
 
Just below the 40 meter band there is a segment allocated to unlicensed ISM use under CFR Part 18
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There appear to be no power limits or other guidelines. The only drawback is potential for manmade noise from diathermy machines and induction furnaces.


Given how close this is to 40 meters, it likely shares the same propagation characteristics and could be very interesting for doing unkosher stuff generally prohibited on the amateur radio bands such as encryption. Anyone know anything more about this?
 
temeluchus said:
it serves no purpose other than obscuring a message, publishing a key in a public place likely wouldn’t cut it.
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That's not entirely true. Plenty of digital modems include a scrambler or other pseudorandom encoding in order to improve noise rejection and keep decoders from losing sync from a long series of ones or zeroes. The requirement on all of those is that they're documented and the specifications are published before it's used on the air.

There's actually a good bit of beef about the VARA modems on that last point, since the documentation published about them is insufficient for someone to build a compatible decoder and the guy who wrote it is charging money for the thing.
 
Thanks for keeping the KF builtin goin, @888Flux
I'd like to test 20m propagation this upcoming weekend. Sorry for just goin dark the last two weeks, work got nuts and made me uninstall the starlink mini i had there till this audit was over. Should have internet again starting this coming week and have time to keep working on this. If 20m works well, then that'll be great, if 40m still seems like the best option I'll finally finish my 40m dipole or take up the challenge and make a 160m loop.

On another note, I've been looking at these sparkplug antennas, and I'm intrigued. I still want to make a coil loaded mini-whip too, but that'll wait till after we can get this JS8Call figured out.
 
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