Early on, Bruce Perens, K6BP, amateur radio and open source advocate voiced concerns about D-Star’s use of a proprietary vocoder. Asking; does it really fit into the spirit of the hobby? Bruce makes a strong argument that an Open Source vocoder needs to be developed. The codec2 development started in 2009, when David Rowe, VK5DGR stepped up to the challenge.
While the Codec 2 development was and is good, here we are 2020, and sadly there hasn’t been a lot of work in my opinion, for a drop in replacement for VHF/UHF radios. Presently that seems to best match up to FreeDV’s 2400B mode. Most of the work has been for HF applications. Or at the very least, Codec2/FreeDV hasn't been adopted by VHF/UHF manufacture like many would have hoped.
The bad part is Bruce brought an awareness to the AMBE patents that probably would have otherwise not have been thought about much by fellow hams. So the bad part is Bruce created a stigma. And it was further improperly (in my opinion) used as a sly marketing tool by some of the ham manufactures of the AMBE DV Sticks.
And from what I have seen, there are still hams out there that think the AMBE patents surrounding D-Star are still an issue. (they aren't, they expired in 2017) And more than likely the the big-bad-boogie-man is gonna come nab you if you meddle with trying to create your own open source AMBE, or using something that has someone else’s non-licensed AMBE, etc.
Facts of the matter are;
When you buy consumer electronics and other things that might have technology under the cover that might be covered by patents, does it impact your buying decision? Likely not. However, truth be told since the majority of electronic things are manufactured in China, it’s not uncommon for there to be cloned (improperly/unlicensed/bootleg - whatever you want to call it) intellectual property under the cover. (If you don’t believe me, go look at the Indusic chip in your Chinese DMR handheld, then go look at DVSI’s note on their website)
Second, non-commercial/research usage of patented technology is, and always has been covered by exceptions on the definition of "patent infringement”. By our very definition, ham radio is all about non-commercial, experimental and research activities.
Have you ever heard of anyone actually successful at litigation, if the defendant never made any money off your patent? No, and no one is coming to your local court to instigate that fruitless endeavor against you.
And if you are still biting your damn nails, remember that; Bruce told us that there is prior art from David Rowe that would likely invalidate the AMBE patents, and that DVSI used the AMBE codec in commerce before some of their patent applications, potentially invalidating their own patents.
Let’s look back:
Patents have been around longer than ham radio. In radios formative years there were a lot of patents, and since that time, have obviously expired.
I have been trying to research how those patents impacted ham radio operators. Back then, then pretty much had to build everything from scratch. Nowadays, if a new thing is patented related to radio (perhaps something like LoRA), hams generally are buying something from a supplier to use that mode or technique. This pretty much moves any possible legal concerns off the individual hams shoulders and on to that of the supplier. (These days it’s America’s (and the worlds) convenient way of evading legal repercussions).
So I have been combing the archives of QST magazine and other sources trying to understand if anyone seemed concerned that back then, when things like the Hartley oscillator were under patent. I haven’t found one mention of concern.
If you were a ham messing around with SSB in the 1930's the Hartley patent might have been a problem. But there wasn't a lot of specialized parts back then rather than general purpose components.
However, it does appear that you had to pay RCA for certain parts necessary to build a transmitter with then, current technology as they held the patents and were the only source/supplier.
I tend to think a patent on a circuit design (as opposed to a component) would be easy enough for an amateur to copy without much worry of being sued for infringement.
Truth be told, I have a tough time understanding radio circuits with solid state components and tubes, so its hard to imagine what was possible then.
With "Single Sideband for the Radio Amateur" published in 1954 it would seem things were pretty wide open by that time. The forward to that says the first QST mention of single sideband was in 1948, at which time the Hartley patent would have been expired.
However, in more recent years (post print media), I personally do recall some possible patent issues;
Satoshi’s D-Star GMSK node adapter and his supposed patented pseudo real time monitor circuit? There were clones of this circuit initially.
The ZUM Hotspot? Some say jumbo/china spot was an improper clone of Jim, KI6ZUM’s design. But it actually seems to have been released with an Open Hardware license?
I feel these patent concerns have been over amplified for the individual ham/end user. They are valid concerns and something to ponder when it comes to the ability and impact of smaller businesses being able to feed the needs of the ham community. Like I pointed out, if you are making money then you do need to pay attention to this sort of thing as litigation becomes a potential real thing.
Fortunately, much of the innovation in ham radio is now is purely in the form of software, which is much easier to mass-produce than hardware.