Modern usage of non-navigational radio beacons

[rnabioullin]

How useful are non-navigational radio beacons (i.e., for determining current propagation conditions and testing) nowadays, whether microwave X band, HF, ELF, sub-mm wave, etc., considering the advent of computerized propagation modeling? Is the scarcity of non-amateur radio beacons a result of there being less interest in ``exotic'' propagation modes (in favor of the current dominant practice of using microwave line-of-sight, whether terrestrially [4G, Wi-Fi, etc.] or via the artificial communications satellite) and the advent of high-quality, computerized models?

Obviously there are plenty of niches for ``exotic'' propagation modes, esp. when it concerns redundancy in times of war, and I simply cannot imagine the models being comprehensive and accurate (imagine modeling the millions of meteors daily for meteor burst communications), so there must still be niches, just for propagation.

Any insight? Thanks very much in advance.

 

[sophiecentaur]

An interesting question. Propagation is understood better and better and there is always a hunt for commercially viable channels. There is a vast amount of statistical data about the performance of channels and every Hz of spectrum is sought after by at least some organisation. Is any channel being neglected these days?
You don't mention Modulation and Coding Systems in your OP. They are at least as relevant as spectrum space and propagation. There never will be a method of accurately predicting propagation for any particular route and frequency but intelligent systems can get the best out of each situation as it arises.
Our present situation is approaching the state where all Information is just Information and can all share a common pipeline. That alters the perspective from what it was a few decades ago.
Amateur Radio will always be good fun and a great way for people to get into serious EE but the methods and systems that are available for amateurs are a bit analogous to Vinyl recording and becoming more and more marginalised from mainstream comms. (I expect a tirade of disagreement for that remark but there is quite a lot of truth in it) Please respond as loudly and fully as possible.

 

[davenn]

but the methods and systems that are available for amateurs are a bit analogous to Vinyl recording and becoming more and more marginalised from mainstream comms.

and it begins

Seriously , sophiecentaur, that is total garbage, amateur radio is still working with the latest hi tech technologies in digital comms
and always experimenting with various forms of propagation.

 

[sophiecentaur]

the latest hi tech technologies in digital comms

Isn't it true that ways of getting data about the world are more and more internet based? Almost every piece of information is carried on the same system. Amateur radio used to mimic professional radio / comms in the old days. More or less wherever you are in the World, the same sort of connection is made to anyone else in another place so where does the radio ham fit in with that model these days? I can't see that there is a realistic opportunity for a amateur to be using the internet and to be able to claim they are doing their own thing. There isn't the equivalent of winding ones own coils a modular, digital world.
What part of modern comms is accessible to amateurs in the way that the standard forms of communication used to be? Large Scale Integration is to blame for it. Equipment is more and more modular except in places where the technology is specialist and highly professional. My comment was a prediction and I really think that's the way things are going. Not sure about the time scale, though.

 

[rnabioullin]

Well, with regards to amateur radio, you are both sort of right; n.b. it's important to avoid conflating the amateur radio service, and its userbase. This service is essentially an international regulatory conduit for individual and nonprofit radio communications, allowing all sorts of modulations and encodings (virtually anything, whether analog or digital, with exception of undocumented obfuscation and crypto), propagation modes, nodes and relationships (person or computer, satellite or ground, telecommand, etc.), and bands (135.7 kHz to 250 GHz, and virtually everything in between). However, its userbase, from my superficial impression, tends to consist probably 99.999% of backward-thinking, uninnovative hobbyists failing to utilize the vast potential (typically using only HF, VHF, and UHF for ancient communication schemes, the most bizarre and egregious of which is a Morse code key, in 2017!) That being said, there certainly is a relatively-small number of individuals working on the state of the art, such as alternative internet backbones over microwave, UAV telecommand, exotic communications (e.g., meteor scatter), etc.

Anyway, this is sort of offtopic; I intended my question to be about the necessity of radio beacons, from ELF to sub-mm wave, considering the computerized propagation models that we have now. I somehow doubt that they are comprehensive and fully-accurate (e.g., as I said, imagine modeling the millions of meteors daily for meteor burst communications...)

 

[sophiecentaur]

That being said, there certainly is a relatively-small number of individuals working on the state of the art, such as alternative internet backbones over microwave, UAV telecommand, exotic communications (e.g., meteor scatter), etc.

Much respect to that small minority, too!

considering the computerized propagation models that we have now.

Those models would still need some reference beacons to calibrate them on a regular basis, I suppose.

 

[rnabioullin]

I see, makes sense---what stimulated my question is my idea of setting up an X band beacon to gain experience, before I undertake the RF work of my microwave METI project (my C band amplification array is capable of approximately 15 kW at flange, but US amateur radio regs limit it at a mere 1.5 kW), another example of an ``innovative'' use for this service.

 

[tech99]

How useful are non-navigational radio beacons (i.e., for determining current propagation conditions and testing) nowadays, whether microwave X band, HF, ELF, sub-mm wave, etc., considering the advent of computerized propagation modeling? Is the scarcity of non-amateur radio beacons a result of there being less interest in ``exotic'' propagation modes (in favor of the current dominant practice of using microwave line-of-sight, whether terrestrially [4G, Wi-Fi, etc.] or via the artificial communications satellite) and the advent of high-quality, computerized models?

Obviously there are plenty of niches for ``exotic'' propagation modes, esp. when it concerns redundancy in times of war, and I simply cannot imagine the models being comprehensive and accurate (imagine modeling the millions of meteors daily for meteor burst communications), so there must still be niches, just for propagation.

Any insight? Thanks very much in advance.

The models used internationally tend to be those developed by the ITU over more than half a century. Much of this data was obtained using actual paths and in many cases, broadcast stations provided a very suitable beacon for propagation studies. Propagation above the HF region is generally regarded as statistical in nature, and even the occurrence of fading on point-to-point microwave is treated this way. Exotic propagation modes, such as tropo scatter, are also statistical in nature, with the median signal being greatly below that obtained for say, 1% of the time, so that high power is needed in order to obtain acceptable availability. Unfortunately, this then makes the system very antisocial because the frequency cannot be re-used except at a great distance. As a consequence, the trend in commercial point-to-point microwave systems has been away from very long hops except where unavoidable.
I think that military long range systems at HF and up would use protocols which automatically sound or ping the channel before sending and not rely on a separate beacon.

 

[rnabioullin]

The models used internationally tend to be those developed by the ITU over more than half a century. Much of this data was obtained using actual paths and in many cases, broadcast stations provided a very suitable beacon for propagation studies. Propagation above the HF region is generally regarded as statistical in nature, and even the occurrence of fading on point-to-point microwave is treated this way. Exotic propagation modes, such as tropo scatter, are also statistical in nature, with the median signal being greatly below that obtained for say, 1% of the time, so that high power is needed in order to obtain acceptable availability. Unfortunately, this then makes the system very antisocial because the frequency cannot be re-used except at a great distance. As a consequence, the trend in commercial point-to-point microwave systems has been away from very long hops except where unavoidable.
I think that military long range systems at HF and up would use protocols which automatically sound or ping the channel before sending and not rely on a separate beacon.

Interesting; so you're suggesting that propagation models, across all or almost all bands and propagation modes, are well-established, and with the combination of a pinging function, beacons aren't needed anymore, at least for propagation (which leaves just for testing)?

 

[sophiecentaur]

beacons aren't needed anymore,

Well, the level of sophistication in modern signalling could allow a lot of self measurement and monitoring with the channel equipment itself in many cases. It may not work for paths with no feedback.

 

[tech99]

A further consideration is that a beacon gives away its location on a continuous basis!