Hyperlink Omni Antenna Problem

So, I wanted to make a little hotspot in my neighborhood, so I
purchased an outdoor omnidirectional antenna from Hyperlink. I bought
the kit that came with a pigtail for my Dlink AP, extension cable,
antenna, lightning resistor, etc. Came out to be over a couple
hundred bucks for the whole thing.

Anyway, when I hook this up, my reception drops noticably. I did an
experiment in the house, right next to my NIC even, and saw that
signal strength with NO ANTENNA AT ALL was 100%. When I add the high
gain antenna, my signal drops to 79%. This is over a 5 foot distance,
mind you. I get almost nothing when it's mounted outside.

Hyperlink said it sounds like I need an amp. Well, hell, the 25'
antenna cable is not supposed to interfere with the signal to that
degree, and I'm sure as hell not going to spend several hundred more
dollars to fix their product, which doesn't seem to work.

Does anyone have any suggestions on other problems, or what I should
do here?

Thanks!

a 25' cable ??

That will cause a SIGNIFICANT signal drop - i try to keep mine to 3-4' .

"DrewJ" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) om...
> So, I wanted to make a little hotspot in my neighborhood, so I
> purchased an outdoor omnidirectional antenna from Hyperlink. I bought
> the kit that came with a pigtail for my Dlink AP, extension cable,
> antenna, lightning resistor, etc. Came out to be over a couple
> hundred bucks for the whole thing.
>
> Anyway, when I hook this up, my reception drops noticably. I did an
> experiment in the house, right next to my NIC even, and saw that
> signal strength with NO ANTENNA AT ALL was 100%. When I add the high
> gain antenna, my signal drops to 79%. This is over a 5 foot distance,
> mind you. I get almost nothing when it's mounted outside.
>
> Hyperlink said it sounds like I need an amp. Well, hell, the 25'
> antenna cable is not supposed to interfere with the signal to that
> degree, and I'm sure as hell not going to spend several hundred more
> dollars to fix their product, which doesn't seem to work.
>
> Does anyone have any suggestions on other problems, or what I should
> do here?
>
> Thanks!

DrewJ,

What does the writing on the cable say? Is it LMR400? If less quality cable
you can see a huge loss just over 25'. I have 75' LMR400 to Linksys AP and
Fab-Corp 21db omni antenna on tower with little loss.
I have used lesser quality cable with drastic loss.
FWIW

"DrewJ" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) om...
> So, I wanted to make a little hotspot in my neighborhood, so I
> purchased an outdoor omnidirectional antenna from Hyperlink. I bought
> the kit that came with a pigtail for my Dlink AP, extension cable,
> antenna, lightning resistor, etc. Came out to be over a couple
> hundred bucks for the whole thing.
>
> Anyway, when I hook this up, my reception drops noticably. I did an
> experiment in the house, right next to my NIC even, and saw that
> signal strength with NO ANTENNA AT ALL was 100%. When I add the high
> gain antenna, my signal drops to 79%. This is over a 5 foot distance,
> mind you. I get almost nothing when it's mounted outside.
>
> Hyperlink said it sounds like I need an amp. Well, hell, the 25'
> antenna cable is not supposed to interfere with the signal to that
> degree, and I'm sure as hell not going to spend several hundred more
> dollars to fix their product, which doesn't seem to work.
>
> Does anyone have any suggestions on other problems, or what I should
> do here?
>
> Thanks!

I don't see an LMR rating on the cable. It says WBC-400, which is
probably the same thing. For info about the cable I'm using, check
here:

http://www.hyperlinktech.com/web/cable_feed400.php

I researched all this 6 months ago before I bought the equipment. I
knew that the rating of the cable should work fine over 25'. Maybe
the connectors are bad, or there is a problem with the cable?

"SomeGuy" <(E-Mail Removed)> wrote in message news:<c15qdf$1eflbu$(E-Mail Removed)>...
> DrewJ,
>
> What does the writing on the cable say? Is it LMR400? If less quality cable
> you can see a huge loss just over 25'. I have 75' LMR400 to Linksys AP and
> Fab-Corp 21db omni antenna on tower with little loss.
> I have used lesser quality cable with drastic loss.
> FWIW

DrewJ wrote:

> Does anyone have any suggestions on other problems, or what I should
> do here?

My first thought here is that the lightning arrester is the culprit.
Immediate diagnostic is to remove the arrester from system, and to see
if that improves the situation noticably.

Your cable assembly is supposed to be of LMR400 spec cable. The
Hyperlink site implies that their cables are made of LMR400 cable, but
does not explicitly state so. I'm fairly certain that you do have a
LMR400 cable assembly. You DON'T want to increase the cable length if
you don't have to, because at these microwave frequencies, the cable
attenuation is massive with distance.

I'm using a 24dbi parabolic on the roof with 30' of LMR400 into a B/G
card, no arrester. I used that sucessfully for three months, connecting
into several APs, some several miles away. A couple of weeks ago, I
added a 1 watt amplifier to my setup. Works great, but the Broadcom
chipset based cards have an issue where the Rx circuitry doesn't like to
be overdriven. I should have gotten an amplifier with an attenuator for
the Rx side, to attenuate down the signal going into the Broadcom-based
WiFi card. I'll be using the two Broadcom cards (Buffalo) to feed an
AP, and another cheapo generic card to connect to other people's APs,
via the roof mounted antenna and amp. The amp makes ALL the difference
in the world for distance connecting......:-) Broadcom based cards are
not the best choice for using under Linux, I discovered, and am
receiving a couple of older PrismII chipset-based cards for use in my
Linux router box.

Regarding arresters, I'm banking on the hope that lightning will hit the
trees and electric poles which are here much taller than my roof/antenna
setup. Try that, and let us know what happens!

> Thanks!

Valentin Guillen <(E-Mail Removed)> wrote in message news:<(E-Mail Removed)>...
> DrewJ wrote:
>
> > Does anyone have any suggestions on other problems, or what I should
> > do here?


LMR400 cable will drop 3dB over 25 feet. Thats a 50% power loss
from the radio to the antenna.

Lighting arrester won't stop a direct hit. If your trees get hit, your
antenna will induce high levels of current into the radio.


Mike
(E-Mail Removed)
www.netopsed.com
Wireless training at it's finest
CWNA and CWSP Certification Training

After reading the original post again....

Something is really messed up. You must have a major
impedance mismatch, or perhaps the cable isn't LMR.

Are there any obstacles between you and the 25' cable and antenna
when the reading is taken? (like, say.... a steel bank vault)

"DrewJ" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) om...
> So, I wanted to make a little hotspot in my neighborhood, so I
> purchased an outdoor omnidirectional antenna from Hyperlink. I bought
> the kit that came with a pigtail for my Dlink AP, extension cable,
> antenna, lightning resistor, etc. Came out to be over a couple
> hundred bucks for the whole thing.
>
> Anyway, when I hook this up, my reception drops noticably. I did an
> experiment in the house, right next to my NIC even, and saw that
> signal strength with NO ANTENNA AT ALL was 100%. When I add the high
> gain antenna, my signal drops to 79%. This is over a 5 foot distance,
> mind you. I get almost nothing when it's mounted outside.
>
> Hyperlink said it sounds like I need an amp. Well, hell, the 25'
> antenna cable is not supposed to interfere with the signal to that
> degree, and I'm sure as hell not going to spend several hundred more
> dollars to fix their product, which doesn't seem to work.
>
> Does anyone have any suggestions on other problems, or what I should
> do here?
>
> Thanks!

Hmm, several other folks have made very valid points - not least the L-O-N-G
run of cable you presently have. There is however another rather important
point that you are perhaps overlooking.

A high gain unidrectional antenna gets the gain by "squashing" the radiated
signal to where it is wanted - basically coming out from the pole and
travelling horizontally. If you want an analogy (I know I do) then imagine
you have a bare bulb in the middle of the room. Lots of light but VERY
evenly spread out - like a sphere shaped glow - and you will be able to read
your newspaper a treat in the same room.

Now place the bulb inside a tubular lens designed to produce a "RING" of
light around the room. This ring will be MUCH brighter - as all the power is
being sent out in a "flattish" disk from the middle of the bulb. Now unless
you are reading the paper where that bright ring of light hits the wall you
might find it too dark - as the light (signal) is not longer being allowed
to spread out all over the place - only where it is being targetted.

SO..... the aerial is doing what you bought it for - it is sending the
signal out in such a way that if you could see the signal, it would look
like a powerful disk coming from the antenna and reaching out a long way
into the distance. When you had the little internal aerial, the signal came
out all over the shop - like a sphere instead of a disc.

That was my attempt (perhaps a bad one) to avoid phrases like "lobes" but
still convey the idea of the "shape of a beam". Anyone else who can do
better, please do - for all our sake!!

Having said that, is the signal reaching the places you want it too - and if
so, is there actually a problem or were you just commenting on something
that seemed a bit odd - but worked well enough to do the job reliably for
you?

If you have a HIGH gain omni (9-12db or more) you might find that unless
someone has their laptop/desktop antenna at a similar height too you, that
nearby stations find you harder to get than someone a hundred metres down
the road. the aerial SHOULD have come with some blurb about this angle - for
example, 10 degrees. This shows you how the signal will open out as distance
increases. Imagine a lighthouse (sorry, analogy time again), the beam does
not come out like a laser - rather it diverges - or fans outs. If you were
at the base of the lighthouse you would be bathed in nothing but moonlight
when the lamp above sweeps around. If however you were 500 metres out at
sea, you might get a dazzle each time the light comes around. VERY similar
effect with HIGH gain omni's.

Even the best theoretical antenna could only be 100% efficient, it simply
cannot send MORE signal in ALL directions. It can share it out all around
(like a sphere - 0dbi), it can tighly focus it in one direction or it can
"flatten out" the beam and send it all around - but at the expense of "blind
spots" underneath (and above) the antenna.

A VERY high gain Omni (collinear) might be ideal for a ship at sea - as
there is a pretty good chance that everything it wants to communicate with
will be at about the same nautical height. The antenna on the roof of the
local aero club however will NEED most of the signal going up above the
horizontal and will often be little more than a dipole.

LOL - Sadly, that only covers about 0.01% of antenna theory - it gets a bit
harder from there on!


BOTTOM LINE - Is it providing access to where you need it?

Mark