You are here

Getting around an obstacle

3 posts / 0 new
Last post
w8erd
Getting around an obstacle
We have occasional need to get around an obstacle such as a hill in our portable operations.  2.4 ghz.
A simple approach would be to use a portable node with a 15 dbi omni off to the side, and that might work.
Or we could try a Rocket with 2 directional antennas.  Comments and suggestions?  Thanks!

Bob W8ERD
KE2N
KE2N's picture
obstacle

Perhaps your obstacle is pretty solid. But, if not, then you need to consider the case where your two nodes may just barely be able to link (-90 dBm) despite the obstacle. OLSR will tend to prefer the one-hop path to the stronger two-hop path. Or it may alternate between the two with fading effects.  I am not sure what is the best way to handle that. Using different SSID's and DtD linking might prevent the problem, but it would mean at least one more radio than the simplest arrangement.

Since you said "a rocket" I take it you are considering the split-MIMO arrangement.  That means a single-polarity link.  If the rest of your system is single-pol then that would be worth trying (absent the problem just mentioned). If your system is otherwise running as MIMO, then this middle bit might be a bottleneck.
 

w8erd
obstacle
So might we be better off to use a highly directional antenna behind the hill, pointed to the side toward our relay node?
Such as a 24 dBi dish?  Even though we might not need the greater signal strength at the relay point, that should decrease the
faint signal coming over the hill?

Bob W8ERD

Theme by Danetsoft and Danang Probo Sayekti inspired by Maksimer