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Comment by jtbayly | Hacker News Reader

You can buy a set of pre-paired (configured) devices from Microtik for $195 that are 60Ghz 1Gbit full duplex that don't require any dish. I've used them, and they work well. (https://www.amazon.com/dp/B077992GG3)

The difference here seems to be a substantial increase in distance. 1.5km is a lot more than the 100-200m promised by Microtik.

Also, yes, any 60Ghz device is going to be line-of-sight only.

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The "wireless wire" are too short range to be useful for many things. A better example of an 802.11ad product shipping right now is this:

https://mikrotik.com/product/lhg_60g

Or this, which is $299 per end:

https://store.ui.com/products/af60-us

If you're going over 300-400 meters with these you need to keep in mind that the 60 GHz band sees EXTREME rain fade. People try to build links that are too long with these and have no fade margin. RSL should be something like -40 to -42 when properly aimed, which gives you about 20dB of fade margin.

Sure you can get a radio set to link up at 1.5km+ at -60 on a clear sunny day, but the slightest rain shower will have adverse affects on it.

The wireless wire is intended for indoor use, where you can move it around. Here automatic beam forming is more appropriate than a dish which means fixed installation requiring precision alignment and very narrow main lobe.

Beam forming is still good for outdoor use if it is cheaper. Dish is a significant part of the installation cost. In some places it is not easy or even possible to install a dish (for example, it might be prohibited).

They are waterproof and use PoE for power. They appear to be designed for indoor or outdoor use. I'm using them outside, as are many other people.

With 60GHz it would take a storm with a rate of rain approaching 55mm (2") per hour to exceed a 20dB fade margin. That is quite a severe rain. A slight rain shower should not significantly impact a 1.5km link at 60GHz.

In real world use if you want five nines availability of a 60 GHz link in Portland, OR, you need to keep the distance to about 700 meters or less. And it doesn't see really heavy rain showers (as Miami or Houston do), just constant drizzle. 300-400 meters max in Miami.

That's why lots of options are shipping with 5ghz failover.

Still not the best case to reduce bandwidth during heavy rain but at least it still works.

In central Kansas we would see rainfall exceeding that rate multiple times a year. I've seen it as high as 12"/hour for a few minutes.

Oh. My. At this point, I suppose you'd need Wifi for your boat? :-)

12"/hour is 0.2"/minute, so that for a couple of minutes doesn't make for ridiculous overall rainfall. Signal quality is affected by the current momentary rate, and having the signal drop for seconds or minutes is problematic.

It's not so much the rain fade as the oxygen absorption that really gets you with 60Ghz[1]. You can get better distance and reliability with 70/80Ghz. They're expensive though.

[1] https://www.rfglobalnet.com/doc/fixed-wireless-communication...

brisbane has 80-90% humidity and temps around 30 a lot of the time. what would persisting moist hot air do, to your rainfade?

Yeah, but both of those devices are dishes. What we're discussing is what's possible without a dish.

1.5KM makes 'wiring' a village possible from one relatively high structure, such as a church's bell tower.

In good weather...

Well for PTP have a fallback 2.4 Ghz with a pair of polarised Yaggi's and jack the power up.

What I mean by having a pair is have one channel vertically polarised and one channel horizontal double bandwidth

Line of sight truly means line of sight with 60GHz. As a human standing in the way is enough to mess with the signal so would a flock of birds I guess.

Do flocks of birds regularly hover in one place for an extended period of time? Coming up with increasingly bizarre limitations here.

They could fly down the beam ;)

Or better yet, oscillate along the path of the beam. And they would naturally have another flock to swap out when they tire plus another flock available as a hot swap in case something unexpected happens. :P

It also requires clear weather, so won't be enough to "wire" a village with reasonable expectation of service quality. At which point there is little reason to go with anything, but a passive optical network in a village.

It depends on what you mean by reasonable. In some places anything that faster than the non-existing 4G-connection they were promised 5 years ago will be reasonable.

These high frequency links might not be suited for bad weather or flock of birds, but they do enable low latency, high throughput most of the time. You can always downgrade to a lower frequency, much like how 5G operates, completely transparent for the clients.

People are not isolated from the rest of the world into specific areas, they know what broadband internet is like and this sets expectation of quality. I know of some organizations that use links on that frequency and not working in rainy, snowy or foggy weather always comes up, but they can deal with that, while consumers can't.

I'm thinking this is primarily point to point, not suitable for showering an area in sweet bits.

It is likely MIMO, I don't see any obstacle why it couldn't do multiple spatial channels simultaneously.

A village that small and unwired, rural, third world, would be happy with that line of sight limitation.

Not line of sight only. Many recent 60Ghz devices with better beam forming also work acceptably well using reflection off solid surfaces.

That's... actually impressive. I've built a point to point WiFi link before, with 802.11g.

I was under the impression 60GHz is for extremely short range applications, like wireless connectivity in a living room and such.

Really surprised it works that far, even if it needs LoS and perfect weather.

DIYers may find some helpful info here: https://hackaday.com/2015/04/07/build-a-phased-array-radar-i...

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