Good Day
Would it be possible to clarify the LoS requirement for PTP 820 products?
I came accross an old link that is no longer available when I searched.
LoS is all over the documentation e.g. 820 User Guide and 820C Technical description particularly in respect of MIMO.
But no definitive statement of requirement.
Appreciate any replies…
https://www.cambiumnetworks.com/blog/ptp-820-line-of-sight-requirement/
Shaun,
The PTP820/850 has no mechanism to deal with multipath interference. Ideally, you should have 100% of the 1st Fresnel zone clearance. Depending on the link length, and capacity required, theory suggests that 60% 1st Fresnel zone clearance is acceptable, but you lose fade margin. My standard in planning PTP links is 100% 1st Fresnel zone clearance. I also test for space diversity requirement too. Link Planner (and any of the other PTP planning software, such as Path Loss) can calculate the ground or water reflection in relation to the direct ray. If the tower heights and terrain conspire to create a reflective path, you can have 100% 1st Fresnel zone clearance, but still have poor performance. The software will calculate what elevation the diversity antennna should be mounted on either or both ends of a link. The manual talks more about the hardware required for a spatial diverse link.
because PTP820 is 2x2 or 4x4 MIMO system, I believe it must have multipath interference mitigation / handling built-in.
I might be wrong, that happens to me quite often - I said “I believe”.
Hi Lubomir,
Licensed microwave is 1x1 SISO and single pol. For 2+0 systems you can do cross-pol or XPIC but you don’t have 2x2 single payload in licensed microwave like you do for PMP. Licensed microwave is required to be LOS for licensing so that multupath inteference isn’t created by reflections/diffraction.
I stand corrected : my apologies for misleading and providing incorrect info !