Wait, you're NOT supposed to step on the top of the sectors and dishes?
Well how do you know if the guy before you mounted things securely or not?!?
Josh Reynolds, Chief Information Officer
SPITwSPOTS, www.spitwspots.com <http://www.spitwspots.com>
On 09/25/2014 05:26 PM, Ken Hohhof via Af wrote:
I thought the standoffs were so tower climbers could climb past your
equipment without using them as footpegs.
*From:* Paul McCall via Af <mailto:[email protected]>
*Sent:* Thursday, September 25, 2014 7:51 PM
*To:* [email protected] <mailto:[email protected]>
*Subject:* [AFMUG] Standoff question, rule of thumb, etc.
Over the years we have employed different philosophies on mounting
sectors to towers. Our reference point was the Moto 100 series
connectorized radios with sectors. We started out with 18” standoffs
on a Rohn 25G tower, because some “smart guy” suggested that was what
we needed. Another smart guy suggested 24”, so some of them were done
like that. Then, someone else suggested that we really didn’t need
standoffs at all, that they could be mounted each on a leg of the
tower and we would be fine. (we always ran 3 120 sector/AP
configuration per tower in 2.4 Ghz). As far as difference that we
could measure, we found no difference in AP to SM performance when we
measured at any distance of connection. Maybe we were missing
something, but anyway, we settled on mounting them directly on the
tower leg.
Moving forward to today. We have been installing the ePMP 2.4 series
instead of 100 series 2.4s. The installation techs mounted them
back to back, with North/South on one frequency (Front/Back Frequency
Reuse configuration) and East/West on the other frequency. One of the
4 sectors had to have a custom mounting bar made to replace the short
stubby one that comes with the sector, thus allowing the 2 sectors
(North and East at 90 degree offset) to be put on one leg right near
each other. Again, this is Frequency Re-use a bit of a different
scenario.
Anyway, today in working with Cambium, they told us we need to have at
least 3 ft of vertical separation between each radio on the same
frequency, so North and East could be at one level (dif. Frequencies)
and South and West would be vertically separated. Alrighty then J
….. so we have 6 towers to go move things around on. We are going to
some test tomorrow on the first tower to see exactly how much
separation yields us how much F/B isolation. Using ePMP eDetect
feature, that should be pretty easy to see.
OK….so here is where I want opinions. Really I’d like “expert
advice”, but I will settle for opinions J
How far “should” these sectors be “stood off” from the tower, if at
all? I am not expecting to be able to measure any difference with
the F/B ratio data, so its back to this is “all theory”. Is the
standoff question a front to back issue at all, or a “we want the
metal” sector away from the metal tower a little bit?
Paul
Paul McCall, Pres.
PDMNet / Florida Broadband
658 Old Dixie Highway
Vero Beach, FL 32962
772-564-6800 office
772-473-0352 cell
www.pdmnet.com <http://www.pdmnet.com/>
[email protected] <mailto:[email protected]>
