diversity Rx Tx selection

RouterOS Wireless Networking
1

Hi ,

An idea, and as always want your feed back ! The problem here i knew diversity is not supported by ROS in 2.9 “don’t know about v3” , and i noticed that XR radios has a single mmcx as will as R5H , which means no need for diversity by them !

Assume we have an ideal environment with a noise floor level of -120 in 2.4Ghz and i want to connect a laptop user far a way “say 1 mile” with just the internal laptop radio , in the base station i have 4 radios XR2 attached to 4 sectors 20dbi each , now i should reach the clients laptops 1 mile far a way , but the clients may not able to reach the station because of the huge difference “10db” related to the internal radio cards almost “15dbm” and the XR2 26-28 dbm .

What i want to do here is attaching 4 parabolic antennas 90cm each with a good feeder “it will give a quite well 35dbi” in 4 directions exactly above the 4 sectors to work as receving only, the idea here is the beam of sector is 90 deg and the beam of parabolic will not exceed 5 deg ! but i want the sectors to TX only and parabolics+sectors to RX … the parabolic curvature will receive signals quite well “as far as i know” from a wide degree , a littlie amount of the signal should if reached the parabolic surface it will be reflected to the feeder easily and hypothetically will give a better receiving gain to the station radio rather than the receiving gain from the sectors, is that true ?

As always i’m waiting for the man who will disappoint me and blow the idea a way of my head :smiley:

Thanks …

Several links over ONE pair of antennas
2

You are correct. The higher gain antenna (the parabolic) will hands down make a difference. The idea of splitting your RX/TX is also a good one. I can say that I have tried this many times and theoretically it seems like it would work. In all my experiments I found that combining the signals from several antennas poses an interesting “phase” problem. Basically it requires a significant amount of tuning to ensure that one signal received does not cancel another from the corresponding receive antenna. In addition to the loss introduced in the combiner affecting the signal even more so. With your idea here I believe you are saying you would not use a combiner you would simply utilize the alternate ports on the radio card. Since the card does not use a combiner (its a switched circuit operated by firmware) you may be able to elliminate this problem. I would be greatly concerned with free space loss with such a low transmit on the laptop however. Even with a high gain antenna you can only amplify the signal that reaches the parabolic. Its an interesting concept.