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https://www.ebay.com/itm/112889227124
Data sheet here: http://www.dorji.com/docs/data/DRA818U.pdf
Just remember to add an antenna output filter: those modules emit all sorts of harmonics (just like many cheap handhelds such as Baofengs etc).
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It's not that it doesn't scale - it's just there's a reason people use letters to communicate and not postcards. People expect a modicum of privacy which ham radio, to its detriment, denies.
It also completely prevents any interesting radio experimentation. There isn't anything left on that frontier that couldn't be conflated with encryption.
I think it is worth asking why modern digital radio standards (e.g. P25, DMR, LTE, 5G) were largely developed outside the ham community. My survey level understanding is they came from the communication needs of their users and are not a natural evolution of something that hams would build, with or without encryption. When I was researching DMR, there's a lot of stuff that is unnecessarily clunky when considering the use case of a ham QSO. Conversely, the business users of DMR want more structure than what's provided with amateur-designed digital modes. With 5G, I think there are some real technical and capital barriers, i.e., very few amateurs have access to the grade of test equipment needed to engineer and experiment with systems at those frequencies.
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It's safe only because nobody cares enough about ham radio to bother skimming anything. I've been pushing for encryption for years but just posting this well get a bunch of elmers posting upset replies. It's frustrating constantly being under the thumb of a generation that will not yield to progress
FCC rules won't allow encryption. I'm not sure why the rules were made originally.
If you combine these things you end up with encrypted transmissions raising the noise floor for everyone in a band with no way to know if that noise is a transmission or actual noise. A lot of ham bands are already very noisy from natural sources, a bunch of encrypted transmissions increasing the noise floor just serves to make those bands inaccessible.
The propagation makes this problem even worse because encrypted transmissions can raise the noise floor for hams hundreds or even thousands of miles away. Even if an encrypted transmission uses a very narrow bandwidth (no worse than other digital modes) you're still monopolizing part of a very small band with a private conversation preventing others from using the shared resource.
To make matters worse encryption necessitates some form of error correction. Whether this is forward error correction, retransmission, or whatever it's necessary for a receiver to receive a correct ciphertext in order to decrypt a message. Error correction necessitates a higher duty cycle in order to send the error correcting overhead. So encrypted transmissions last longer than the equivalent unencrypted digital mode tying up limited bandwidth for a longer duration.
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Ham radio relies on self-policing within the community to ensure compliance with the rules - the biggest one being "no commercial use". The "no commercial use" rule ensures companies aren't using the limited ham radio spectrum as a workaround to getting their own dedicated license and frequency allocation. If encryption were allowed, there'd be no way for other users to verify whether traffic is commercial or not.
I always thought that encryption not being allowed was a way to discourage illegal commercial use of it. No business wants their comms in the clear with no means of verifying the sender of the message - so ham radio would be useless to them.
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I always thought that encryption not being allowed was a way to discourage illegal commercial use of it. No business wants their comms in the clear with no means of verifying the sender of the message - so ham radio would be useless to them.
But even not-for-business, I don't want someone else to be able to impersonate others, so signatures/verification still needs to be supported. Otherwise someone who's good at voice impersonations of others could wreak havok.
The exact wording is in 97.113: "No amateur station shall transmit... messages encoded for the purpose of obscuring their meaning".
I think if this interests you, you'll like the LoRa-based devices better. They're unlicensed, so you can encrypt, use it without a ham radio license, etc. LoRa is pretty proprietary which is evil and all, but the end result is good. Hackaday has some good example projects: https://hackaday.com/2020/04/25/a-lora-im-me-for-the-end-of-... https://hackaday.io/project/171790-armawatch-armachat-long-r...
Imo lora and similar protocols are a great example of the innovation fueled by the existence of the ISM bands.
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IMO that's a great way to set up a sandbox: it has built in crowd control and a mechanism to keep out flagrant abuse. Yeah, it doesn't scale to the moon, but that's the whole point: it's a proving ground, not a moon rocket.
It's not that it doesn't scale - it's just there's a reason people use letters to communicate and not postcards. People expect a modicum of privacy which ham radio, to its detriment, denies.
The sad part is that the FCC has been more interested in maintaining the status quo than actually continuing the spirit of the hobby. There is nothing experimental or ground breaking about talking to someone states away using an HF transceiver that cost $4k in analog FM. That stopped being innovative 80 years ago. There are a lot of interesting things being done with RF that are off limits to amateurs because they require a business license.
But you are talking about normal people using radio for normal conversations. That's a distinct use case. Its something worth discussing, the FCC has lagged behind there too but its not the same thing as Ham.
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IMO that's a great way to set up a sandbox: it has built in crowd control and a mechanism to keep out flagrant abuse. Yeah, it doesn't scale to the moon, but that's the whole point: it's a proving ground, not a moon rocket.
> IMO that's a great way to set up a sandbox: it has built in crowd control and a mechanism to keep out flagrant abuse. Sadly nothing is really stopping anyone from buying radios online and transmitting garbage. Sure the FCC will come knocking if someone flagrantly transmits without regard for others.
Texting via APRS has been a thing for about 20 years. It's also a fantastic way to publish both your phone number and the numbers of the people you are texting in an easy to skim format. Digital modes is one of the areas where the HN crowd could introduce significant advancements to Amateur radio (while pissing off all of the older HAMs who just want to talk about the weather on 40m).
"Texting via APRS has been a thing for about 20 years." Yes, that's true. If, by "texting", you mean either: - A handheld radio attached to a laptop with a serial cable. - One of two (three ?) models ever produced that allowed you to key in APRS with T9 typing on a number pad. Yep, it's awesome .
Actually, you can do a good amount of digital modes radio stuff using nothing more than a radio and a smartphone. For example, I myself have made a lot of contacts with people using PSK31 without a cable, using my iPhone speaker and mic near the radio handset.
Digging into how these digital modes work is interesting intellectually. It's doable to implement the signal processing to implement these modes in code. And once you have one mode well-understood, it's also doable to come up with ideas on how to improve upon them and make new modes. Lots of HN readers would be able to do both of those things, and probably enjoy it.
("Modes" here means a way to communicate information over the radio.