Point to Point WAN Link

I want to build a point to point WAN link using a WAP on 1 side and a
computer with a wireless card on the other to act as a ethernet bridge. The
link is approx. 750meters apart, however there is not alot of height
difference, only about 0.15° on both sides. tan^-1(2meters/750meters and
another problem is should i put an antenna on the roof and then run the coax
cable all the way down to the server room or should I run the fiber to the
roof and place the wireless eqipment there some how?



Thanks

"Yay Deutschland!" <(E-Mail Removed)> wrote in message
news:ItZve.1816156$6l.1698442@pd7tw2no...
| I want to build a point to point WAN link using a WAP on 1 side and a
| computer with a wireless card on the other to act as a ethernet bridge.
The
| link is approx. 750meters apart, however there is not alot of height
| difference, only about 0.15° on both sides. tan^-1(2meters/750meters and
| another problem is should i put an antenna on the roof and then run the
coax
| cable all the way down to the server room or should I run the fiber to the
| roof and place the wireless equipment there some how?
|

Link budget for any WiFi is light. I'd go for the AP close to the antenna
as i could get.

On Mon, 27 Jun 2005 20:39:04 GMT, "Yay Deutschland!"
<(E-Mail Removed)> wrote:

>I want to build a point to point WAN link using a WAP on 1 side and a
>computer with a wireless card on the other to act as a ethernet bridge. The
>link is approx. 750meters apart, however there is not alot of height
>difference, only about 0.15° on both sides. tan^-1(2meters/750meters and
>another problem is should i put an antenna on the roof and then run the coax
>cable all the way down to the server room or should I run the fiber to the
>roof and place the wireless eqipment there some how?

Keep coax cable runs short or your losses will kill the link. I don't
understand your trigonometry by methinks if the coax run is any more
than about 8 meters, you might as well go with PoE (power over
ethernet) instead of fiber. The problem with using fiber is that you
still have to supply power to the radio on the roof using copper wire.
Also, since one side goes to a single computer, you might be able to
save money by using a USB wireless adapter at that end. The limit is
about 5 meters for USB cables, but extenders are possible (but
expensive). If there's more than one computer at that end, never mind
and get a real wireless bridge. If you want path calculations, supply
some details, equipment selection, and cable lengths, and I'll run
them for you. Also, what's your minimum acceptable thruput, which is
usually limited by the broadband connection speed. See:
| http://groups-beta.google.com/group/...c1f6360282a331
for a sample calculation:

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831.336.2558 voice http://www.LearnByDestroying.com
# (E-Mail Removed)
# (E-Mail Removed) AE6KS

thanks for the link, i dertmined that the link is possible at my site. now i
have a question about the cables. I went to the local electronics store, and
they have SMA connectors (but no RP-SMA connectors) are there any
differences, since my AP uses RP-SMA? Also I tried looking for LMR600 cable,
which was unavailable here, and they suggested RG174 or RG58 instead, are
these cable any good for wifi use?

"Jeff Liebermann" <(E-Mail Removed)> schrieb im Newsbeitrag
news:(E-Mail Removed)...
> On Mon, 27 Jun 2005 20:39:04 GMT, "Yay Deutschland!"
> <(E-Mail Removed)> wrote:
>
>>I want to build a point to point WAN link using a WAP on 1 side and a
>>computer with a wireless card on the other to act as a ethernet bridge.
>>The
>>link is approx. 750meters apart, however there is not alot of height
>>difference, only about 0.15° on both sides. tan^-1(2meters/750meters and
>>another problem is should i put an antenna on the roof and then run the
>>coax
>>cable all the way down to the server room or should I run the fiber to the
>>roof and place the wireless eqipment there some how?
>
> Keep coax cable runs short or your losses will kill the link. I don't
> understand your trigonometry by methinks if the coax run is any more
> than about 8 meters, you might as well go with PoE (power over
> ethernet) instead of fiber. The problem with using fiber is that you
> still have to supply power to the radio on the roof using copper wire.
> Also, since one side goes to a single computer, you might be able to
> save money by using a USB wireless adapter at that end. The limit is
> about 5 meters for USB cables, but extenders are possible (but
> expensive). If there's more than one computer at that end, never mind
> and get a real wireless bridge. If you want path calculations, supply
> some details, equipment selection, and cable lengths, and I'll run
> them for you. Also, what's your minimum acceptable thruput, which is
> usually limited by the broadband connection speed. See:
> |
> http://groups-beta.google.com/group/...c1f6360282a331
> for a sample calculation:
>
> --
> # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
> # 831.336.2558 voice http://www.LearnByDestroying.com
> # (E-Mail Removed)
> # (E-Mail Removed) AE6KS

On Thu, 30 Jun 2005 22:51:44 GMT, "Yay Deutschland!"
<(E-Mail Removed)> wrote:

>thanks for the link, i dertmined that the link is possible at my site. now i
>have a question about the cables. I went to the local electronics store, and
>they have SMA connectors (but no RP-SMA connectors) are there any
>differences, since my AP uses RP-SMA? Also I tried looking for LMR600 cable,
>which was unavailable here, and they suggested RG174 or RG58 instead, are
>these cable any good for wifi use?

Wrong on all accounts. Wrong connectors and wrong coax cable. Also,
no numbers supplied to calculate the correct coax type. I still can't
understand your trigonometry.

If you're going to build your own cables, you'll need a crimping tool.
Don't bother trying to solder RF connectors unless you're prepared to
ruin a small pile before you get something acceptable. You'll need
tools for LMR-100, LMR-240, and LMR-400. You can get a tool that does
all three.
| http://www.fab-corp.com (Under "Coax Tools")
Well, that's not the one I was thinking of...
The HT-301K does all 3 sizes
| http://www.l-com.com/jump.jsp?lGen=d...ProductID=3957
(and it's cheaper). However, it will not crimp LMR-600. You don't
want to know the price of an LMR-600 crimper. Unless you have a very
long run, I don't see you using LMR-600 or larger.

You'll also need a coax cable stripper. I do it with a pocket knife,
but you'll again need considerable practice to get the spacing correct
and not touch the conductors. The cable stripper is easier.

The proper connectors are made by RF-Industries. There are many
sources for these which include RP-SMA. I get mine from Electrocom
and Digikey. Lots of others.

For the larger LMR-400 cable, you'll probably need to use Type-N
connectors and then use a pigtail to go from N to RP-SMA. If you try
to do it with an adapter, you're sure to break off the RP-SMA
connector.

Which size coax depends on the attenuation you're willing to tolerate
which is a function of cable length and type. You've supplied no
information by which this can be calculated, so I won't speculate as
to which cable is best for your application. Unless you have a very
short run (i.e. <1 meter) using RG-174 is a very bad idea. It's far
too lossy. RG-58 is a bit better but also useless for all but the
shortest cable runs. LMR-240 accepts an RP-SMA directly, without an
adapter which might be useful as no pigtail is required. LMR-400 is
good for longer runs.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831.336.2558 voice http://www.LearnByDestroying.com
# (E-Mail Removed)
# (E-Mail Removed) AE6KS