We have a subscriber 3.5 miles from our tower - and the utility has put up a new AP on the water tower that is .25 from our customer. Our incoming signal is on 919 mhz (915 to 923 mhz if i understand the canopy bible best) and his AP is on 916 mhz (912 to 920 mhz). He is vertically polorized with a 13-15 db yagi hitting 2 substations between 6 and 9 miles away. I’m sure he’s done this as “cleanly” as possible - but he’s still killing this one SM - albeit not near as bad once we’ve matched up control slots, max distance, and downlink percentage.
We are horozontally polorized. I think we pick him up -48 and our own AP is -62.
We’ll still get a drop on this link for 30-45 seconds from once a day to sometimes once an hour.
Two questions…
1) Shouldn’t timing prevent this? Shouldn’t his AP and my AP be transmitting and receiving at exactly the same time, thus allowing our equipment to co-exist?
2) If timing won’t prevent this, do we have any other options but to drop this customer? We can’t move to any other frequency band due to the tree line in the distance between his location and our AP.
Is he running Canopy also?
Why not move to 906 or 924 or ask him to do the same?
change the channel to 906. 924 wouldnt really do much ass it overlaps 919. there really is only three usuable channels on 900 906 915 924 everything else overlaps.
VLAN1 wrote: change the channel to 906. 924 wouldnt really do much *** it overlaps 919. there really is only three usuable channels on 900 906 915 924 everything else overlaps.
That is correct - there are only 3 non-overlapping channels.
Only stray from 906, 915 and 924 when you REALLY REALLY have to. I have one AP that is about 15 miles away from everything else that I have to operate in 912 due to interference across the board - it was the cleanest part of the spectrum (with 2-3Mhz above and below not terribly bad either).
Timing will help, but you want to give yourself 9MHz separation between your channels if possible (ie: you could operate on 919 and him on 910 - however again the non-overlapping center channels are where you want to be).
GPS timing prevents your access point from interfering with his, and vice versa. That assumes that you both use the same number of control slots, up/down %, and so forth.
It does this by keeping both of your APs, yours and his, transmitting at the same time. That way, they both switch to receive mode at the same time, so they never hear each-other (even through they may be -60 or whatever to each other)
The problem is that they are both transmitting at the same time… If your customer can receive his signal, even way off line but very close at -50 and see yours at -48 then they can’t tell the two apart.
There’s not much you can do but switch frequencies or move the customer’s antenna so it can only see yours and not theirs. Some times moving it much LOWER helps accomplish this even though it lowers your own signal level, especially if you are receiving his way out of line/propagation pattern.
best answer yet twinkletoes…makes perfect sense to me now.
SOMEHOW…we’re still transmitting pretty good. still got some other things i wanna try…(including shooting the tower from BEHIND the customer’s house)