Radio Amateurs To See Reallocation Of Portions Of Microwave Band

Had some good off-line feedback---

Combining some informal discussions with colleagues, it has become obvious (to me), IMO, that the expensive and impractical install of millions of 5G millimeter base stations--in a short time--has lost out to extended use of the midband (microwave) 5G.

The plan, which both was formulated and implemented at warp speed in recent months, loses the radio amateur 'shared' secondary use at 3450 to 3500 MHz as part of an expansion plan for a 3450-3550 MHz band , That band is adjacent to the CBRS band and extends the full 5G midband from 3450 to 3980 MHz. This is a substantial bandwidth swath that suits use in the next few years for well over 95% of 'cell.smart phone' users, which is, you and me.

5G millimeter has become dubious in the US --at present-- for practical reasons to date: 1) the cost for install is far higher per square mile than 5G install at mid-band; 2) the battery life in most user scenarios on a smart phone with 5G millimeter use is far lower than with 5G midband and 4G; 3) penetration through walls and windows is often (but not always) problematic with 5G millimeter; 4) water vapor issues (high humidity, rain, snow) produce changeable and marked path attenuation, not always compensated by more directive, beam steered millimeter antennas when counting the added TX power needed--and hence lower battery life.

Furthermore, few user scenarios with upcoming cell/smart phone models really need the full bandwidth capabilities of 5G millimeter in the US.

Will that change, say, 5 years from now? Well, killer apps drive usage, which in turn drives bandwidth usage. SO, yes, assume that will change.

If most cities in the US were as crowded as Seoul, Beijing, Hong Kong, and 30 other PRC cities, then we would be using 5G millimeter right now.

APPS will drive the change to 5G millimeter in the US. In the meantime, 5G midband/4G will do a vast majority of the data pass to your phone in the US.

The effect on ham radio is interesting. First, while we have lost (in Dec 2021) 50 MHz of bandwidth at 3450 to 3500 MHz, the 3300 to 3450 MHz shared-with-NTIA spectrum may survive. This is because the NTIA needs its own network and will be very unlikely to give it up for additional 5G 'sharing'. Our secondary allocation is a gnat in the eye of a whale, at worst, so its unlikely NTIA will want us out.

The interesting interplay in the next 5-10 years is the switch on of 5G millimeter, which itself will take any spectral pressure off more midband re-allocations. IOW we (Part 97) may NOT lose any more microwave spectrum to 5G for some time, if any, because it will not be needed.

Hope these opinions help in understand this complex landscape.

Your opinion may differ.

73
Chip W1YW

 

It's 2020, not 1960. You can easily get on microwave bands with SDR technology (at low power).

For example (47 MHz to 6 GHz):

https://www.nuand.com/bladerf-2-0-micro/

 

One would think that the ARRL would push hard to support and encourage outfits to produce equipment for hams that would put these bands withing reach. Of course that would be a lot to ask from the Elmer Fudds who throttle innovation within the ARRL.

 

A lot of those kinds of devices do not have the frequency stability to be truly useful as a ghz tx. Adalam Pluto is what many are using to access the new geosat. And out of the box, its reference xtal is not stable enough, and requires replacing with a gps locked frequency standard. Ppm drift is not noticeable at hf, but at 10gig, its problematic.

 

There are more expensive SDR's with excellent performance. Ettus Research products are in the "prosumer" category.

https://www.ettus.com/all-products/ub210-kit/

Phase noise performance at 3429 MHz (and this is through a downconverter on the receiver).

 

Most (all?) UHF++ devices really need a GPSDO

 

Ettus do make some really good gear and there are others also, but, which brings me back the the points I originally made, and that is both cost and ham operator density. Assuming one can afford the costs to get setup, are there going to be enough hams near by to experiment with? I live in a big city and have 50 hams within a 20Km circle of me. Assuming I could get a handful of them to come along for the journey, we could have something pretty cool happening. However, I am planning on moving soon to a regional town and as best as i can tell there are 2 hams there microwaves there becomes a different proposition, one where failure is the option. unless of course you want to spend many 10's of thousands of dollars doing moon bounce.

Mostly I am a homebrewer, at HF there is never a problem finding someone to test your latest creation with, and even without people there are the online SDR receivers to listen to yourself on. Risk verses reward is swung way to the reward side of the scale. Add on top of this the cost of test gear for homebrewing with in the microwaves and the whole financial equation falls apart, I just do not have 10K to spend on a spec-an or scope. Unless microwaves become commodity in nature, or we have some way of doing microwaves over greater distances than LOS, I just can never see them ever becoming the future of ham radio for anyone other than a small niche of seriously dedicated home brewers.

If someone comes up with some commodity application for ham radio in the microwaves, I will be there, but i cannot see that happening very soon. And dont get me wrong, I would like to do microwaves at some point, I have a tx here that will go to 6ghz and stable frequency standard, but, i do not know a single other person near me who is even remotely interested.

 

Chip,

A number of us concerned about spectrum loss and the future of experimentation in the hobby formed an ad hoc group, Future Of Amateur Radio Consortium/FOARC. Many/most of us are ARRL members, and while the ARRL is a key member in representing amateur interests, they're often bogged in their own politics-- try as they may.

FOARC is very interested in spectrum protection, but also broadened if governed mode expansion, bandwidth relaxation, and other things that bring us out of our AX.25 roots. Long ago, I branched into wired networking and when I came back to amateur radio, I was appalled; what was once an innovator's playground had been preserved like a fly in 1974 amber.

We're muddling along, but slowly are getting momentum. Inventors like you, researchers like me, politicos like Wayne Rash (ok, a great geek but plugged into DC) and others are going to try to form policy that suits the best interests of amateurs against the commercial tides that eat spectrum (even if it's with your inventions).

There's not much to see at FOARC.groups.io at the moment, but slowly we'll build it based on a consensus flat model. Constructive input from everyone is welcome there. I'm the admin

Join in if you can.

Your wisdom would be appreciated.

73

Tom (the other W*YW)

 

Tom,

That's a very kind invitation, and I think its very important to have all points of view represented in this issue.

My problem is others: 'I can't figure Chip out-- is he X or is he Y'? I am generally parts of both, and my natural tendency is to nudge people into the facts and the likely extrapolations of the future. I do not pretend to be unique in this, but on this issue I have insight I actually would prefer not to be troubled with.

For example (and take this as mere 'opinion' if you wish)--

* The FCC, under pressure from Congress and the MOBILE NOW act, found it incredibly easy to write off Part 97 for 3300 to 3500 MHz, because of our sparse use. They were begging, IMO, for OBJECTIONS to justify NOT doing this;

* The ARRL took a stance that not one milliHertz of the 3300 MHz band should be removed from Part 9,7 because of the extant users and the future possibilities. Not to in any way denigrate the fine but sparse efforts of hams that work that band, the case was, to be charitable, weak and not tenable. But it was taken as a 'negotiation stance' and to justify the monies for the Spectrum Defense Fund and the League's position as the 'National Association of Amateur Radio';

*US manufacturers ( full disclosure: I am one of them) know that its easier to extend a passband then to add a new, separated-in- frequency one. This also keeps prices down for the network as the equipment doesn't have to get pulled and replaced every two years or so.

* The carriers knew they needed more mid band spectrum. And who could argue? WE (users) are forcing the issue with an appetite for wireless bits that borders on being like the 'fressas at a Jewish wedding' (enjoy that analogy!), taken up 10 notches by: kids at home (schooling); Zoom; online gaming; streaming movies; online stretching classes; work at home; video trade shows; yadayada. The carriers are in no position technically nor logistically , nor by customer needs , able to do massive installs of millimeter repeaters. Not now. Sometime. But think the time of sunspot max...maybe.

* Finally, the NTIA needs its own (new) secure network. It understood that it could trade 'sharing' with increased speed of implementing a new network, It was the ONLY one who really gave up anything in forming the 3450-3550 MHz band. What did it get--besides a trump card for speed bootstrapping? Probably access to the commercial network in times of emergency. A backup on the commercial lines, as it were.

* So Part 97 went along for the ride on this one, a minor player in a very big game. Fortunately both the folks behind 5G ("HAMS") and some at the NTIA saw no downside to, at least for now, keeping us on the remaining 3300-3450 MHz.

BUT we better find better ways to use it more ASSIDUOUSLY. The 'secondary use' by Part 97 will always be tenuous and subject to change, and could change tomorrow.

I would be delighted to assist you guys in forming the logical basis for your concerns moving ahead, but kindly accept that you may not agree with my suggestions, and I am a-political in this (likely) political arena. Inventors are amongst the few who see progress-- irrespective of the path that gets us there.

73
Chip W1YW

 

So whats the solution? If microwaves are the future of ham radio, its going to need the microwaves version of a uBitx or QCX to put it in the commodity price point most tinkerers can afford and that is just not possible because stable frequency references/generation just costs so much more than a 25mhz xtal and si5351a. And I do not see anyone busting down the doors to bring a Ghz band transceiver to bear.

 

I can only proffer my opinion on the US strategy.

Hams--like the technically savvy of old-- will do what they always do: take what they have, combine it with other parts and technologies, and come up with something new.

I absolutely do not buy into the notion that ICOM or YAESU or JVC have to deliver us a spankin flawless box before hams use a microwave band. Not everyone needs to use a microwave band. No one said that. The problem is the sparseness of use on 3300 MHZ is so deafening that only a very small group of hams--enlightened ones IMO--held up our end on that band.

Granted, the experimental thrust of ham radio has been muddied by those who see experimentation as foreign, but Part 97's mission clearly states 'advancement of the radio art' here in the US. If you go to PRC (I haven't but talk with those who have)--hams are puttering away on microwave boxes big-time.

One of our issues here is that we confuse STEM with 'advancement of the radio art'. That is a confusion of EDUCATION with EXPERIMENTATION. One leads to the other, both are valuable, but they are BOTH separate and important in the future of ham radio in the US.

Your comment is actually very constructive because it points out impediments to that elsewhere. It would be cool if some hams put up experimental mods to eBay purchased (for example) commercial microwave gear for some of the GHz bands--on QRZed. MO.

IMO you had some hams pushing for the present 3300 MHZ status. Those same hams should step up and suggest some practical approaches along the lines you point out.

73
Chip W1YW

 

Build it and they will come, as the saying goes. If someone can do for microwaves what the bitx did for hf home brewing and experimentation, people in high density locations will come. NY, LA, London, Tokyo, ideal locations for microwaves, tumbleweeds Idaho, not so much. It just needs someone with skills and desire to build something dummies can follow.

 

I cannot see any simple solution for this.

"Microwaving" is a quite niche sector requiring some enthusiasm,perseverance and knowledge seldom seen today. Most "microwavers" I know of are engineers my age, with the occasional MSEE student thrown in.

Analysing the current SM microwave (1296 MHz upwards)
listings of confirmed activity, 109 individual calls can be identified, with an average age of 68 and a median age of 70. One (1) is below 40, and one (1) has a licence that has been issued during the last 17 years.
More than half are MSEEs.

Subtract 5% due to unreported SKs, and add 10 % for the scattered MSEE students that are interested in frequencies above 1296 MHz, we end up in about 120 reasonably active microwave amateurs. This is 1% of the total amateur population and around 10 % of those active.

I know the current SSA "VUSHF manager" from Uni (two years older than me), and his general view is that he fights an "uphill battle", as the rest of the SSA is completely dominated by the digital (FT-8) users, contesters and DX-hunters.

It is very reasonable to believe that both the fraction active, the age profiles and the attitudes towards "microwavers" are representative for European conditions.

My own predictions about what may happen in Europe in a 10-year perspective, starting with 432 MHz:

• 70 cm will lose its co-primary status and shrink considerably.
  Public Safety communications are looking for a 10 MHz piece of spectrum for LTE applications. As soon as the surveillance radar systems that also use this spectrum become phased out, expect an attack from the mobile radio community.
• 23 cm will also shrink considerably. It is already threatened in parts of Europe by the Galileo GNSS system which uses a 10 MHz channel in the middle of the band.
• 13 cm has already been lost or very much reduced. The Swedish stance that WiFi should be protected from interference may spread to other countries.
• 9 cm is only allocated on footnote basis in a small number of Region 1 countries. This footnote may become removed at a coming WRC.
• 6 cm may be lost to short-range links for autonomous car infrastructure and for 5G in population centres. Industry is already pressing hard for this.
• 3 cm is "prime spectrum estate" for backhaul links in 4G/5G infrastructure. In some countries, parts of the band have already been sold off.
• 1.5 cm and higher. Very uncertain because the development pace in mobile radio in the microwave range is so rapid. 74 GHz has already been threatened from car positioning systems.

The most alarming is the lack of interest from younger people. If there is only one (1) active under 40, the spectrum may become very difficult to defend in a 10-year perspective. In perspective, when I "dabbled" at 1296,2300 and 10000 MHz 45 years ago most "microwavers" were in their 20s and 30s.

Lawyers and accountants at the Swedish Administration already regard amateur radio as a "nuisance that the age profile ultimately will take care of", and the median age for "microwavers" is almost 5 years older than the rest.

"Time will tell"

73/
Karl-Arne
SM0AOM

 

This is an extraordinarily important point that few pick up on, Karl. Thanks for pointing it out.

73
Chip W1YW

 

I do not think that its a lack of interest, I know a lot of younger home brewers and the problem for most of us seems to be cost and the level of expertise required. Test gear for microwaves are cost prohibitive and HF is so forgiving in design, component tolerance and circuit layout. You just cant deadbug a microwave circuit and expect that it will work, something you can do at HF. I think that stops most of us from even trying.