The entire United States amateur radio community are relative late comers to using or even understanding what LoRa is.
Black & White: What is LoRa?
Amateur radio or "ham" radio people usually love to talk about history and sometimes forget to look forward.
LoRa actually has some roots going back to the German radio company Telefunken and the underlying thinking of LoRa as a general concept was even described in part of a 1903 US patent by Nikola Tesla.
During World War II, both the Axis and Allied powers experimented with "frequency hopping spread spectrum".
The smart minds of the day such as
Leonard Danilewicz,
Willem Broertjes and actress
Hedy Lamarr being just a few to read about to learn the history of spread spectrum communication to help level up when it comes to learning about LoRa and technology like it.
While frequency hopping spread spectrum or FCSS can be useful for both data or voice transmissions, only "chirp spread spectrum" or CSS is useful for sending short bursts of data over multiple frequencies.
This is one reason why the "maker" community has adopted LoRa because they generally care more about actionable use cases versus "talking for the sake of talking", which is what a lot of "ham radio" people enjoy most.
LoRa is not meant for voice transmission and it even requires some fancy manipulation to get it functioning for basic "chat" sort of communication.
The good news is that the HVDN team and our HASviolet project went a few more steps where others gave up when it comes to use case exploration.
The lack of voice communication via LoRa does not matter much for non-amateur radio users as other electronics hobbyists are more interested in using LoRa to relay sensor data or control the status of different devices, like a gate, mailbox or even as a
fault indicator for a 3-D printer. But, not all amateur radio people use voice to communicate so this is ok.
The "Continuous Wave" or CW mode for short involves Morse Code and is still highly practiced within the amateur ranks today.
Even much newer modes like WSPR, JT-65, JS-8CALL and PSK31 are some other choices with different use cases, but all really only focus on chat functions and not anything more use case driven beyond that. This now starts to make some amateur radio and maker people not very different from each other, aside possibly from age.
How to send LoRa: Straight key optional
CSS also not only helps obscure messages as Hedy Lamarr exploited in her work more than 70 years ago with torpedoes and the US Navy, but also helps increase transmission range and control of torpedoes.
While encryption on amateur radio spectrum is not permitted, LoRa is easily demystified once you know how to look for the signals and decode them. This makes LoRa and CW not really that far different from one another.
An amateur radio person may known Morse Code and a maker will not. Conversely, a maker may know how to probe packets and reassemble messages where someone who lives only in the ham radio world will not.
Perhaps the shared merit of LoRa and CW as "DX" or "Long Distance" communication capabilities is worth exploring within amateur radio, but with value added use cases for a change beyond making contact for the sake of it.
This is where both communities can share and learn different skill sets and what HASviolet is all about.
LoRa implements CSS mostly in a default configuration which takes up about 250 kHz of spectrum,
but can be easily modified by changing the spread and bandwidth settings, which may be advantageous for certain applications.
This may sound crazy compared to sub 2 kHz wide CW signals, but LoRa can offer so much more.
What makes LoRa unique compared to other "spread spectrum" methods of transmission is that it is focused on relative narrow band use cases and thus better suited for sub-GHz spectrum use.
Comparatively, Bluetooth and Wi-Fi are also spread spectrum based, but use much wider bandwidth and would be troublesome to be used at frequencies such as 433 and 868 MHz as well as 900 to 928 MHz. Since Bluetooth and Wi-Fi live at 2.4 GHz and above, this is a non issue since the higher you go in frequency, the shorter they travel when not including "Line Of Sight" communications.
The HASviolet project's goal is to utilize LoRa in the 900 to 928 MHz band also known as 33cm and to take advantage of the different characteristics this unique mode offers.
And because how well LoRa works very far into the "noise floor" the communication distance when thought about as a function of transmit power, range and antenna size becomes pretty interesting.
There are ways to shrink the bandwidth which LoRa uses for single channel communication and will also be explored via the HASviolet project too at a sub 6 kHz levels and possibly even further with correct precision timing.
LoRa: Made better with fruit?
One major challenge with LoRa is that it uses proprietary modulation offered by Semtech and is not considered an "open source" mode like what NB IoT uses, which is a competing wireless standard along with SIGFOX as popular "Internet of Things" type of applications that commercial and maker enthusiasts are using.
A company started in 2005 by Lady Ada (Limor Fried) called
Adafruit Industries helps the educational "STEM" and maker communities through open source development of fully functional and semi-complete products which incorporate components made by company like Semtech.
The modern electronic hobbyist or "maker" can easily purchase what Limor and her team creates and use them in any number of projects, just like our HVDN HASviolet project.
And there is one thing that the "ham radio" community really loves, and it is anything that involves "low cost". LoRa easily becomes a low cost way to experiment with something very fun.
A side benefit beyond cost is that it makes a perfect platform to start the "ham radio" crowd to essentially start to "level up" on some areas of interest that the maker crowd has already zoomed far ahead on. Some of these include things to do with "Raspberry Pi", "ESP32", "MicroPython", "IoT"
Full integrated Semtech LoRa chips such as the SX1276, SX1272 and SX1261 can all be generally had on preconfigured breakout boards for under $10 USD, so lets dive into what each community can learn from each other in upcoming articles.
So what is HASviolet?
When the HVDN HASviolet team came up with an idea to make something which the maker and amateur radio community could use together, they started thinking about how to highlight underused spectrum where licensed and unlicensed users may overlap.
Originally, the amateur 50-54 MHz "6m" band and its nearby unlicensed 49 MHz spectrum was thought to be a good starting point due to the ability to easily design something that could use the popular Raspberry Pi with an add on RF filter board.
This proved pretty quickly even after discussion with other amateur radio enthusiasts as far away as Arizona and Germany to not be a path to start down first as others have done it, but failed to get a lot of interest.
Instead, it became clear that going much higher in frequency would still offer what the HVDN team was looking for.
We would like to introduce you to the HVDN backed HASviolet project, our journey and lots of great documentation to inspire others to come along for the ride using violet shared spectrum.
If you want to learn something cool involving hardware, antenna or software, we think you will like what you are about to find.
HASviolet Team
- Joe Apuzzo N1JTA - General Do'er & HASviolet HW Certification Guy
- Steve Bossert K2GOG - Antenna & RF Design Lead & UI/UX Hamster
- Joe Cupano NE2Z - Core Software Developer & Git Hub Jedi Master
HASviolet General Details
