We've tested this some time ago, and few of our clients using it for long time now...
and this are problems we have met:
1. Floating signal (for ex. day -69 night -75) = floating speed, you can't do anything to remove this efect, that's the worst problem...
depends on weather/humidty/temperature/electromagnetic fields
2. Sometimes nonsymetric [very irregular] (for ex 30Mbps download / 11Mbps upload) propably mikrotik bug, but we're not sure about, cos such long link is very bit advantage...
3. Problems with placing dish on high towers, we used 28dBi GRID instead
4. Problems with high power mPCI's - we've used only SR-5 on transmit side, on recive side we used wmia-123AG - that was working the best
5. the best throughput of dual @ 26km
2x SR-5 (only for transmit)
2x Intel Bayfield 865GBFL
2x Intel Celeron (northwood, selected -> lower temperature) 2,4GHz
2x WMIA-123AG (only for rec)
4x Grid 28dBi (5320MHz + 5620MHz)
2x Chieftec/Delta power supply
2x Intel Gigabit NIC's
2x DOM with MT 2.8.21 and 2.9.x (where x was 5,6,8,11,13,14,17)
4x mPCI->PCI adapters
2x Legrand outdoor boxes
4x Andrew cabling with Andrew connectors, ANRITSU SiteMaster tested
4x Pigtails ufl->Nfemale
2x Fiber - GigabitETH coverter
Fiber uplink on towers,
2x online UPS from APC conected directly to PC's power supply
WITHOUT any kind of surge/lighting protection
first conclusion:
best performance was on pair 2.9.11 + 2.9.11 mt's
on table bandwidth test show us abut 75Mbps full duplex real world UDP (good(tm) ;) ) but not as good as on two wmia 123AG where was about 81/83Mbps
on link:
Signal strengh :
second conclusion, normal traffic (backbone 30Mbps, but shaped per user, max was seen 18/12)) upto 10000pps, ping below 1ms to 1,5ms normal, sometimes 2-3ms
third - maximum throughput in normal condition:
half duplex 33-35Mbps download and 12-24 (very unstable) upload
full duplex... should be 30/10, but when download goes up to 25Mbps upload drop to 1-4Mbps, "little" asymetrical
best performance, wery good weather:
MT's forced to 36Mbps (-67dBm / -68dBm)
45Mbps downlink hdx
28Mbps uplink hdx (unstable)
full duplex 29/8 - still asymetrical
we swaped chanels, (previous downlink was 5620, now 5320) but situation won't change, still downlink has better signal, and better performance.
Because it's on 100m towers we can't experiment as long as we want, especialy that is 1200 user main (and only :/) backbone
so 130Mbps on 26km, i think that's little hard to do, but not impossible.
If you will have tuned antennas and very much time to test you probably gain 130Mbps fdx.
If u want i will try new 2.9.23 and 2.9.22 versions maybe smtg will work better or maybe someone want to login with read priviledges and see it ?
UPDATE:
I forgot that isn't single link but two links connected cos provider can't see our tower :
Provider<-> FastETH <-> MT < = 2km ~70Mbps fdx real world = > MT - GiabitETH - MT < = 26km as i wrote before = > MT - GigabitETH - copper2fiber converter 150m fiber ------ converter - GigabitETH - Linux server
UPDATE2
i forgot ;-)
You can make the same but 2x 13km links, we have experience with them (about 65Mbps fdx very stable throughput on 14km) even you don't need high power cards, you'll need only good 28dBm grid's antennas