NetPC
join:2004-04-29
45900
| Grid ?
I have used Panel antennas for all of my installs and some sectors at some locations for my APs. I have to seperate them alot on the tower to keep down interference.
I have seen many towers in the city and in photos that use grid antennas right next and behind each other. Do grids cause less interference than panel antennas? I know most grids are for PtP not PtMP unless in adhoc mode. I use 2.4 freq would grid antennas cause less interference than panel or sectors?
I have several areas where the houses are very close together 50 or more. Would adding a grid on the tower and pointing it to a housing development where houses are close together cause less interference than a panel or sector for PtMP. Houses are very close.
I have been trying to hit a few housing developments with one panel or sector which works fine but I get alot of disconnects that are only for a second or so but VOIP users are complaining. Thanks |
|
cmaenginsb
Premium,MVM
join:2001-03-19
Palmdale, CA
| Grids typically have better front to back ratios so in those cases they will work better. However because the feedhorn sticks out from the grid they are still vulnerable to sidelobe interference, but because of how a grid works it's not being collected so the gain is fairly low.
19 DB grids have the same beamwidth as 19 db panels, we actually only used a panel at a customer location if we were concerned about looks.
For distribution though, the design of the sector (and a "smart" antenna like the Vivato) gives an ideal beamwidth. We have used grids for distibution in a few cases where we only needed to cover a 7 degree swath. |
|
Semaphore
Premium
join:2003-11-18
Arnprior On.
| reply to NetPC
I know of several PtMP systems using only grids on the CPE end - partly for range, but even in close they prefer them for the beamwidth. A Yagi will give you a fairly tight beam to but the Front to Back ratio is lower and will be more susceptible to interference from the back side. |
|
NetPC
join:2004-04-29
45900 | reply to NetPC
Thanks for the help. I see alot of grids in the city I think it is to keep down interference. I will do some testing and see how it goes. Anyone use the Vivato equipment. Looks very nice any idea on the price? |
|
cmaenginsb
Premium,MVM
join:2001-03-19
Palmdale, CA | reply to NetPC
It is to both reduce interference and by providing a higher power signal allow for transmission over the noise.
As to Vivato it's extremely expensive, like in the thousands. |
|
John Galt
What...me panic??
Premium
join:2004-09-30
Happy Camp
| said by cmaenginsb  :...like in the thousands. Nearly tens of thousands, in the case of the outdoor rated units.
But a case can certainly be made for its use, in a number of circumstances.
»www.vivato.net/download/VP2200%2···heet.pdf
»www.verilan.com/store/customer/p···6&page=1
Interesting PowerPoint presentation of a University deployment including testing results:
»www.verilan.com/store/customer/p···6&page=1
--
A is A |
|
