Brian,
Bandpass filters come in different band "widths". Some are full-band
filters that pass 902-928 MHz and some are single-channel filters that
are narrower and pass only one channel. The bandwidth of the two
Ubiquity filters are a little narrow to use across the entire band but
if you are using 912 or 917 as center frequencies, they should work
well. If you're using a lower center frequency, you'll need a filter
that has a bit wider bandwidth but which still attenuates the paging
frequencies a lot. The availability of good whole-band bandpass filters
seems to have deteriorated a bit in the last year. There are more
filters available but they seem to have poorer characteristics and
sometimes higher prices. I just looked at RFLinx and Hyperlinktech and I
am not happy with their current offerings. I did discover a notch filter
that is tuned to attenuate the paging frequencies while passing the
902-928 frequencies. I don't know the pricing but if it's priced
reasonably then it looks like your best bet. Here's the link:
http://www.microwavefilter.com/2ghzRelocation.htm#ism
It's the filter at the bottom of the page. If you call them to get a
spec sheet and to check pricing, please share that info.
Thanks,
jack
Brian Rohrbacher wrote:
Thanks, Jack. Would installing this one http://www.ubnt.com/cf.php4
be the correct move? Or is something else preferred.
Brian
Jack Unger wrote:
Brian,
A -36 dBm signal probably won't destroy your receiver or permanently
desensitize it however your best bet is to get confirmation from a
Motorola rep. The signals you see at 928-930 MHz are from one or more
paging transmitters. These paging signals could easily desensitize
your AP receivers temporarily and cause a temporary inability to hear
incoming SM signals.
Since you appear to be using antennas that are external to your APs,
you can insert a bandpass filter between each AP and its antenna. This
will attenuate the paging signals and allow the APs to receive SM's
from further away. If the paging transmitters ARE the cause of your
apparent AP receiver sensitivity deterioration, then the bandpass
filters should be helpful in reducing the frequency of occurance of
the problem.
jack
Brian Rohrbacher wrote:
How would that help? One sector is still pointing at the
interference.......Wouldn't that sector still make the radio fail, if
the -36 signal is what is doing it?
My question from the original post. Will that strong signal
desensitize the radio into failure? If not, then I need to figure
out what kills my radios. Why do they work fine for a month and then
die? I replace just the radio and they are fine for a while.
Brian
Marlon K. Schafer (509) 982-2181 wrote:
If you are that close to a source of interference you need to ditch
the omnis and sectorize our tower.
laters,
Marlon
(509) 982-2181 Equipment sales
(408) 907-6910 (Vonage) Consulting services
42846865 (icq) And I run my own
wisp!
[EMAIL PROTECTED]
www.odessaoffice.com/wireless
www.odessaoffice.com/marlon/cam
----- Original Message ----- From: "Brian Rohrbacher"
<[EMAIL PROTECTED]>
To: "Conversations over a new WISP Trade Organization"
<[email protected]>
Sent: Tuesday, February 20, 2007 7:05 AM
Subject: [WISPA] failing Canopy 900
I keep losing canopy 900 APs. I used the spectrum analyzer
yesterday and saw -36 signal on channels 928, 929, and 930. Will
that strong signal desensitize the radio into failure? because for
some reason SMs that used to be -65 are -80 (on both sides of the
like) and 17 out of 33 associations have dropped off the AP. I've
been fighting this for a year. I've installed my own grounding, a
lighting dissipater, 6 new APs, 2 new omnis, and 3 new cables. I
think I have ruled out anything that could be killing this AP
except if something RF is killing it. Any input will help.
Brian
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Jack Unger ([EMAIL PROTECTED]) - President, Ask-Wi.Com, Inc.
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