[LibreQoS] Rain Fade (was Ack-filtering)

Herbert Wolverson herberticus at gmail.com
Tue Oct 25 09:43:34 EDT 2022

I figured LTU was in trouble when they promised the moon, took years to
deliver anything, features kept dropping off the list and they went on a
posting spree of how MU-MIMO couldn't work outdoors. Glad we stayed away
from that one; it looks like Ubiquiti are quietly dropping it and going
802.11AX, which has the important features they dropped (OFDMA with tiny
sub-channels, in particular).

We have a bunch of 450m "medusa" running here (all 3ghz CBRS). Once we
found the magic combination of 5ms frames, GPS (via a SyncBox Junior), and
LTE Co-Existence Mode 2 (we have a lot of T-mobile in the area) it's been
pretty awesome. Top speeds aren't all that amazing (you can get 100 mbps
out of it), but it'll get 75 Mbps through some maple trees at 8 miles - and
that's really useful. Grouping has improved a bit in recent firmwares, but
still falls apart completely if you have more than 3-4 SMs who show up as
"not eligible" in sounding statistics. You have to watch the spatial
utilization from time to time to make sure you haven't flooded one of the
sub-channels. Overall, though - we've been really happy with it.  We
haven't loaded one much about 30 subscribers yet, and tend to use it as a
"5.x Ghz didn't work here" - but it really pushes the bits with 28 SMs at
8X and a couple of not-so-great ones.

The UI is funny. Many, many years ago we had Motorola WiMAX (the carrier
grade stuff that still had "clearwire" baked into the UI). The UI was
absolutely terrible. I'm pretty sure the Motorola group who developed it
went on to the Canopy group, because it's just like being back on that
system... (I poked around in one of their EMS management scripts and found
a hundred lines of x=1; y=1; x=y; y=x-y; etc. with a comment at the end ///
This should help my LoC count). I hope Cambium didn't keep that bit. :-|

We shied away from LTE, WiMAX burned a hole in our heads and our pockets!

On Tue, Oct 25, 2022 at 8:25 AM dan via LibreQoS <
libreqos at lists.bufferbloat.net> wrote:

> LTU.. huge potential but majorly flawed product line.  We've stopped all
> LTU deployments because every site we built we'd watch the modulations
> slide down over time.  Every new netgear router in a neighborhood
> (practically...) takes modulations down a step.  Too many mornings hunting
> for a new usable channel because of a new source of noise and
> LTU's inability to cope with it at all.  We have mixed sites with airmax
> and LTU and the airmax outperforms the LTU because of these issues.  We
> even see more rain fade on LTU than airmax because it's so bad with
> multipathing.  Any fresnel infraction and LTU degrades at 2-3x the rate
> that airmax does.
> Wave's 16 client limitation is a challenge, looking forward to the mesh
> units (omni).  We don't have any saturated APs yet but I'm sure that's
> coming.  Doing a 6 AP 180 degree deployment next week and hoping to get
> near 100 subs directly off of that in ~2 months.
> I'm holding some of that AX gear in hand... no AP to compare against
> though :/  High hopes considering what we get out of force 4xx which is
> 'plain' AX.  I don't know how soon we'll see something, zero FCC leaks on a
> new AP so kinda waiting on that.
> I sht on ubiquiti a lot, mostly because the company likes to pull the rug
> on customers and leave them with obsolete hardware and perpetual bugs, and
> doesn't seem to ask any operators what we need, and the list goes on.  That
> said, it's far faster and easier to deploy ubiquiti gear than anything
> else. Installers love it.  The price is great.  If UI drops a 4x4-8x8 90
> degree AX AP we will almost certainly go that route over cambium.
> I've run or am running most brands out there with few exceptions.
> Frankly, we're getting just as good or better performance out of ubiquiti
> gear that cambium and have a lower failure rate.
> We also run Baicells LTE in CBRS, and 450i/450m in CBRS and we're getting
> more data through the LTE product than the cambium in nLoS.  In LoS 450i
> delivers about 50% more and latency is half.  HATE the 450i/450m
> interface.  1995.  finicky products as well, mumimo only working with many
> subs and evenly spread over a 90 degree arc which rarely fits our
> deployments.  450 gear is a huge letdown for us.  450m can deliver really
> well if conditions are right, but if they're not then it's a huge expense
> for little gain.
> Have held out hope that Mikrotik would show up to the AX race but nothing
> really there.  I have a decent sized single radio mesh network on Mikrotik
> Omnitiks that is working really well.  Using some wireless wire shots to
> shorten mesh paths up a bit.  Sell 25Mbps plans off those in a low income
> area.  It's a wave1 AC wireless driver so some pitfalls there, but their
> newer drivers don't support 802.11s or WDS yet so can't upgrade.  Would
> really love to find a dual radio openwrt AX box to run batman-adv on for a
> dual radio mesh but haven't found such a thing yet.
> On Mon, Oct 24, 2022 at 6:43 PM Mark Steckel <mjs at phillywisper.net> wrote:
>> Dan,
>> Really appreciate the detailed breakdown of the various vendor gear. Very
>> helpful.
>> We started Airmax AC, dabbled with LTU but don't trust it enough to
>> really deploy. Waiting for things to shake out a bit before we build out
>> broadcast on a new major site. (There is 200 units in the building and
>> people are switching from Comcast to us in droves, so can wait on the
>> broadcast equipment.)
>> Have deployed some of the gen 1 Wave APs using AF50-LR as CPEs. Not as
>> big a fan as you yet. Finally received a couple of the new gen2 Wave APs.
>> planing to deploy them in the next couple of weeks along with Wave CPEs.
>> Cautiously optimisitc.
>> My biggest concern about the Wave APs is the current limit of 16 clients.
>> Hopefully Ubnt will increase this to 32, other wise will have to think
>> about a lot more micro-pops.
>> Any insight into Ubnt's new Airmax AX line?
>> We have 3.3 km AF11 link that has been rock solid for 3 years. Signal
>> hovers around -35 dBm. This past May, an insane storm* just massively
>> dumped rain for 8 minutes. Never seen anything like it. The rain caused 34
>> dBm of fade. even so, the link stayed up and the signal recovered quickly.
>> A typical heavy storm usually causes only about 5 dBm of fade.
>> Mark
>> * Mid-Atlantic coast
>> ---- On Mon, 24 Oct 2022 19:25:10 -0400 *dan via LibreQoS
>> <libreqos at lists.bufferbloat.net <libreqos at lists.bufferbloat.net>>* wrote
>> ---
>> How bad are y'all's gear doing with rain fade on various techs and
>> bands? in 08, in nica, I'd go from a working 70 db 10 mile shot to
>> nothin at 5ghz when it rained, and I just laughed at the people trying
>> to deploy 60ghz - but times change. I see a vendor trying to ship 60
>> with *really good antennas* into the office market...
>> big question to ask when so busy, please ignore me.
>> I have extensive testing with almost every gear out there.
>> 5Ghz, no appreciable fade in snow or rain.  Longest shot on network right
>> now is 26 miles on AF5xHD 5Ghz on 2' dishes and we push a solid 300Mbps
>> across this with zero fade.  Actually gets a tiny bit better in the rain,
>> ie it is technically fading a bit but so is all the noise so it's a minor
>> improvement.
>> I have 2x 7 miles force 425 links that are pushing 550Mbps.  And a 10
>> miles force 400c on 2' ubiquiti dishes that pushes 940 unidirectional in
>> 80Mhz.  No rain fade.  Lots of af5xhd and force4x links in different
>> distances.  We even mix in some LTU PtMP as PTP for price, ie LTU AP <>
>> LTU-LR or LTU-Pro for PTP.  Works well enough though this product is
>> susceptible to noise more than any other we use.
>> Cambium 60Mhz cnwave is fantastic, legit 120 meters per link node to node
>> or small CPE, 500M to big CPE, about 300 to the not-quite-released mid
>> CPE.  Pushing 1.7Gbps FDX on against my preseem box and my m2 macbook with
>> nperf UDP.
>> Ubiquiti gigabeam line, <1km ok, <800m even better.  AF 'LR' and 'XR'
>> rock solid at 2km, up to about 5km until they're down too much to be
>> usable.  Always backed up by a 5Ghz radio.
>> Ubiquiti Wave, legit AP<>CPE out 2km and never fails over.  4km w/ wifi6
>> failover.  Fantastic product... probably the one to beat.
>> Mikrotik 60Ghz 'ay about 200m on AP to small CPE, 500m AP to nRay.  Can
>> get a little more but it's really close and rain fade gets you.  These have
>> 'ac wireless backup in them so we can EASILY push 300m on the small and
>> 800m on the nRay knowing we have about 4 hours a year in 5Ghz failover.
>> Basically, and MIMO 5Ghz, 6Ghz, or 2.4Ghz product isn't going to
>> noticably fade.  MOST fade in these bands is actually thermal ducting
>> 'turning' the beam off aim.
>> 60Ghz should be considered 2 separate bands.  channels 1-4 are short
>> range, <1km in PTP, <300m in PtMP if you want to have links stay up.
>> channels 5,6 are 2-3x longer.  Unfortunately, only ubiquiti really playing
>> in this space right now, mikrotik's channel 5 support is at a lower output
>> power so it's 'ok'.  Tachyon coming into this space as well, but unproven
>> and AFAIK zero beta deployments.
>> 5Ghz <=200M service plans today with a well built network and good
>> AP/Antenna choices, <=500Mbps with WiFi6 tech.  technically a bit more, but
>> with reasonable ratios this is about right
>> 6Ghz <=900Mbps plans on live beta users.  OFDMA+MUMIMO is really
>> delivering here.
>> 60Ghz 'low' band cambium, 1.7Gbps legit across the mesh, twice that with
>> upcoming channel bonding.  base CPE 1Gbps port, mid 2.5gbps port, long
>> 10Gbps port(s).  Build out model here is for 'In the rain' so no effective
>> fade if built right.  if built wrong, fade to death.
>> 60Ghz 'high' band ubiquiti wave.  <=800Mbps.  Technically a bit more but
>> I haven't convinced a Wave AP to a Wave LR to do it.  I can however get 2
>> customers/radios up to 1.5Gbps across the AP.  Plan with built in fade and
>> intentional fail to 5Ghz beyond 2km.   Acceptable in Montana.
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