hi friends…
I have a client for whom I have to design a PtP link.
With reference to the RB711UA-2HnD board and a 27dBi panel antenna (9 degree beamwidth) I plan to connect the two locations. There is a small mountain in between but Radio Mobile shows the signal successfully on both sides on the link.
Is this possible??. Can I even get 1 MBPS?? as this becomes a Non-Line of Sight link.
Below is the screenshot from Radio Mobile.
Well, I’m not so familiar with radiomobile but my experience and knowledge say that at best you might get irregular traces of signal on the other end. But for a reliable link, forget it. You need to setup a repeater tower on that hill in the middle.
wirelessrudy… thanx for your reply.
radio mobile is a very powerful tool. i also tried out this scene in the Motorola Link Planner and found out that it can too transmit signal successfuly in this situation.
it is actually very confusing.
Software tools go from theoratical presumptions. No matter how accurate they can be at time, real live is usually difference. In your situation I would not trust the tool solely but do a real life test. My bet is the real live is going to show it wont work… 
in this case for real life experience i need to put up 5 meter towers at both the places…
unaffordable for trials… 
Well, the only valid trial is the real one…
So, if you believe your software you’ll have to setup towers anyway isn’t it?
You have two options:
Without setting up your towers you will never find out if it works or not.
I have done this type of link, but I recommend you use 2.4GHz frequency becouse radio mobile maps are very old (around 2005), and radio mobile does not take into account the vegetation of the area. utilizes dual polarity.
So you have done such type of link? Can you show me. This link is shooting “through” a hill! Normal 2,4Ghz which is already chosen in the given example only performs reliable in LOS. In NLOS some connectivity can be established but only for low rates and not important traffic this could work.
The given example is not even close to a NLOS. It is a CBLOS which would mean “Completely Blocked LOS”.
So, unless you can give me the full details of such a link working I am not convinced it can.
Even with mimo I doubt if this could become a reliable working link, but maybe someone can prove me otherwise?
Radio waves will bend a little, when shooting up the hill. So some little amount of signal will be on the other side:
http://jefarion2.blogspot.com/2008/03/diffraction.html
I know that. As former licensed radio operator for the merchant navy this was part of my education.
But on microwave lengths the this effect is so little that the degrease of signal on the other end makes it hardly usable because in 802.11 we are limited in radiated power and the margin is so little the other end hardly gets any workable radio energy.
Secondly, the effect will be heavy influenced by atmospheric circumstances too which apart from the weakness it also makes it a very unreliable link.
So, only in very rare situations and with quit some luck you might be able to create a link and even than the reliability is low.
But ok, if you’re looking for a very low speed link (< 1Mb?) it might work but don’t expect to do Voip or higher bandwidths over it.
Therefore it is save to make the general presumption it is not going to work.
But the only way to find out is to really try it!