I am atempting to link two sites via Wireless (2x RB433 with R52Hn and 19dBi Cyberbajt Giga Eter antenas).
The problem is I do not have clear line of sight (LoS) because of the steep descend in front of me (coastal area).
The link is working so/so. I only get -80 to -85 dBm and hence the link is dropping.
I know I should get in -65 dBm area but is this even achievable with better antennas and no clear LoS?
Would it be better to use 5GHz 23 DBi antenas with only 10 degree angle as opposed to 2,4GHz same degree angle.
The current antennas have 20 degree angle.
The current configuration is:
Bridge → Pseudo Station Bridge and Nstreme Enabled
The frequency is 2437 and the frequence usage is almost zero (no other Wireless signals)
If you don’t have line of sight then consider picking a location which has LOS to point A (internet Wlan) and point B (local Ap) as a relay or pick a new location for the local AP on high ground which is illustrated on your drawing, extra height is always good for a AP.
The link is working so/so. I only get -80 to -85 dBm and hence the link is dropping.
I know I should get in -65 dBm area but is this even achievable with better antennas and no clear LoS?
No antenna is going to help with no LOS all it will do is reduce the amount of time the link drops?
thanx for your replies, even though it is not what I wanted to hear
2x2 mimo → You mean 2x 19dBi Antena on each side (HT TX in HT RX Chains 0 and 1?) - one for TX and one for RX..
Or do I need special MIMO Antenas? Which yould you suggest.
As answered above better results will be with lower frequencies (2.4 GHz better than 5Ghz)
Put in your coordinates, antenna height, TX power, etc. and post back the results then we would be in a better position to suggest solutions, as it stands you have a drawing which is really not detailed enough and you could discover a lot of time wasted and money spent on the wrong type of equipment to link to the target AP.
A cheap & fun test is a “passive refletor”, if you have free access to the middle of the path.
A pair of 25dBi grids, back to back by a short piece of cable at a small mast may be do the job.
I did’t took a look at the numbers but calculation goes more or less like this:
AP = 23dBm
AP Antenna gain = 25dBi
500m free space loss (first leg) = 95dB
Passive 1 ant gain = 25dBi
Power at Passive 1 = -21dBm
Cable loss = 3dB
Passive 2 ant gain = 25dBi
Power delivered by passive 1 = -21-3+25 = 1dBm
500m free space loss (second leg) = 95dB
Power at client side = -94dBm
Client Antenna gain = 25dBi
Power at client = 25-94 = -69dBm
Re-run this numbers at some trusteable tool and play with frequencies & avialable antennas.
I never tried this on 2.4 / 5.8 but at 8, 18 and 23GHz. We used this turn around where one side of the ptp link was blocked by some building that was - maximum - 600 meter away. And where there was not antenna size limitations (e.g. a pair of 1.2m dishes at a 8GHz link ends, a pair of 1.8 or 2.4m passive, ~8Km between end points, passive at 500m from one side). Those links was 100M (ETH) or 155M (STM1). Connection between passive antennas was coax cable jumpers at 8GHz and waveguides jumpers above 15GHz.
In this cases, one lag at vertical, another at horizontal since its a co-channel scenario so better to improve rejection.
The Ligowave terrain picture says it all, bearing in mind this is ground level terrain no allowance for houses or trees which could further reduce LOS, in short you will not have a working link 24/7 for a AP maybe after a lot of time spent on trying different antenna’s + frequencies enough throughput for a single cpe but not for a AP ( if u do please let us know?), you need a relay or move your AP to higher ground, forget about wireless protocols NV2, 802.11 get LOS for the AP first the rest will follow afterwards.
With no perfect line of sight use circulair polariserd antennas but the link shal not be stable.
Test the traject with linktest and looks what signal you have
Well, why not? It just depends on the signal strengths at both end points. If the signals are good enough, conn. rates are high and you can pump data over it. Since in the middle the 2 antennas are just back to back inter connected with coax so theoretically you have no latency added.
I have been thinking of it to reach a remote hotel in a furthermore inhabited area in a deep valley surrounded by mountain ridges. From my central I can see one of the ridges (that could be reached with a 4-wheel drive through a long journey) and from that hotel you’ll see the same ridge. Nowhere near electricity to be found and solar panels with batteries have to be guarded against theft and guard against very high winds. For just a hotel it would make it too expensive for me… But two antenna’s on a big pole cemented into the rock would not make an interesting product to steel and can be made wind resisting while once it works no further maintenance would be needed. I made a link budget calculation some 2 years ago and with the 27dBi radio we had I could achieve a 60dBm signal level at both ends. I presume now with the high power cards that can be done better. It would be enough to put a 40-50Mb link running over it. I could than even serve some weekend bungalows in the same area through a small AP.
It never happened though, it was merely to give an alternative option to the hotel with higher bandwidth than what copper lines brought them. Due the crisis and the financial situation due its remote location the hotel changed hands already 4 to 5 times anyway and recently I even heard its completely abandoned… So I’m glad I never invested any in that project…
