Leikhim, Joe wrote:
>
> Sergio;
>
> Here are some things to consider;
>
> 1. You have a path loss of 110 dB at 2.4 GHZ.
Well, you are right, but we have to take into accounts the Gain of the
Transmitting and receiving antennas, which have 14db each.
So we have 110dB - 2 *(14dB) -> 82 dB for the path loss, so I could
have 94 - 82 -> 12 dB over the -80 dBm Rx sens
> 2. Your system gain is 94 dB (+14 dBm Tx PO, -80 dBm RX sens)
> 4. Is the path unobstructed? Any obstacle near the path could cause a
> reflection.
No we have a clear line of sight, that could be tested by the transit,
because there is only 2 miles between points.
> 5. Does the link work properly when all the equipment is within a
> reasonable distance, say 100 feet? To preclude problems unrelated to the
> path.
I should have tested this before mounting the antennas.
6. What type of transmission line and what is the length of thea
cables?
> I assume you are using proper RF connectors?
Well the antenna already comes with the 50 feet of Belden 9914 Duobond
II-Braid RG-8 Type 50 Ohms 1C10 Shielded E108998 cable, supplied by TTI
Wireless
> 7. Power lines should not be a problem especially with vertical
> polarization.
>
> 8. Antennas should be boresighted to each other. A small laser can be
> helpful to orient the antenna's, do this at night. Be careful not to
> blind your helper.
>
> Sergio Depres wrote:
> >
> > Hello, everybody, I'm glad of finding this list. Here it is my problem:
> >
> > We are installing an outdoor wireless datalink (2 miles), we have
> > confirmation that our 2 antennas have different heights.
> >
> > Building1: Height of the building - 48 feet. Mast -> 18 feet Total -> 66
> > feet
> > Building2: Height of the building - 39 feet. Mast -> 27 feet Total -> 66
> > feet
> >
> > The thing is that the First building's roof is almost at the same level
> > that the roof in the building two, so in fact our antennas have a
> > vertical disalignment of about
> > 9 feet.
> >
> > We are using right now vertical polarization, and our performance is
> > very poor.
> >
> > Question1: For the 2.4GHz band, using vertical polarization, 7-10
> > elements Yagi antenna, what could be the allowed disaligment on the
> > vertical axis?
> >
> > Question2: We have seen a couple of high voltage cables that are inside
> > the propagation path, what could be the best polarization for avoiding
> > them.
> >
> > Question3. Does anybody know if there is any site license required for
> > outdoor applications of 2.4GHz wireless datalinks?
> >
> > Here is more data if somebody needs them to understand better what I'm
> > saying.
> >
> > Distance between linked offices: 2 miles.
> >
> > Antenna: 2.4GHz Yagi Antenna manufactured by TTI Wireless.
> > As far as I remember there are about 7 to 10 elements.
> >
> > RF specs:
> > Modulation: Spread Spectrum- DQPSK
> > Output Power:14dBm
> > Receiver sensitivity:-80dBm
> >
> > --
Thank you
--
Sergio G. Depres, IS Responsible
Atlas Paper Mills
3725 East 10th Court Hialeah, FL 33013 USA
Phone: 305-835-8046 Fax 305-691-6018
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