Blair,
I use H-Pol sectors in most of my markets. I have been particularly
happy with the Superpass line. The plastic is kind of light down at the
N-type fitting and it has broken on me before where the cable was not
secured well. Performance has been outstanding though.
Good Luck,
Rick Harnish
President
OnlyInternet Broadband & Wireless, Inc.
260-827-2482 Office
260-307-4000 Cell
www.oibw.net
MSN: r_harnish62@hotmail.com
ICQ: 293578162
-----Original Message-----
From: Blair Davis [mailto:blair@wmwisp.net]
Sent: Friday, July 16, 2004 2:45 AM
To: karlnet@WISPNotes.com
Subject: [Karlnet] Re: Sector Antennas
>
>
>I currently have 2 16db H-pol sectors each with 100 deg beamwidth.
>
>I have a splitter and have carefully made the cables from the splitter
>to the sectors exactly the same length.
>
>I placed the sectors at the exact same height and at an angle
centerline
>to centerline of 100 deg with a separation of about 5inch.
>
>It seems to work, but I have some odd gaps in the coverage. There
seems
>to be a null about 10-15 deg wide in the middle of the 200 deg span....
>Also, the outer ends of the span have quite low gain.
>
>any ideas? Anyone done this before?
>
>Of course you're going to have nulls! All over the place too, not just
the center. That's a whacky setup you've got there... What are you
trying
>to accomplish?
>
>
>What I am trying to do is get 180-200 deg of coverage with H-pol. The
>>location is at a lake shore and I do not wish to waste power by
>>radiating toward the water.
>>
>>I have a similar setup using V-pol 120 deg sectors at another location
>>that works just fine.
>>
>>--
>
>
>The simple soloution is to use 1 radio per antenna. You can't expect
to split a TX signal to 2 antennas and not get nulls everywhere. Think
about throwing 2 stones into a pond, the waves created by each stone are
going to interact creating peaks & troughs (constructive & destructive
interference points), now extend this idea into 3 dimensions and
hopefully, you'll realize what you're doing wrong.
>
Antenna arrays have been used in radio/ microwave for decades to
increase gain, to narrow beam width or to change the radiation coverage
pattern. I just seem to have overlooked something in this particular
setup.
I have several V-pol arrays that work great. Coverage as designed, gain
is as expected and no weird nulls.
This is, however, my first H-pol array and nothing is working as
expected.
BTW, When I asked if anyone had done this before, I meant on H-pol.
Several years ago, it was very common for WISP's to use 2 or 3 V-pol
sectors in an array on a mast or tower to get more down tilt while still
getting 360deg coverage.
Blair Davis
West Michigan Wireless
269-686-8648
A Division of
Camp Communication Services, INC
-
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