antenna compatibility

I recently bought a DLink ANT24-0700 antenna to boost the range of my
NetGear MR814 router. I installed the antenna and saw no difference in
signal strength.
I called Dlink and they basically told me that it was against FCC
regulations to mix wireless devices from different vendors and that
they couldn't help me. When I asked if that is the reason why my
signal strength didn't change, he repeated his response and refused to
help.

My first issue is that nowhere in the description of this antenna does
it say that it must be used with only DLink products, but all I really
care about is finding out if there is a way to get this antenna to work
with my NetGear router.

I'd also like to understand 'why' it doesn't work. I understand that
there may be different implementations of protocols, etc. that would
prevent certain networking devices of one vendor from working with
another, but when it comes to an antenna, isn't it just transmitting
and receiving the wirless signal ? Why would mixing vendors not work.

If anyone can help me get this setup to work, I'd greatly appreciate
it.
Other suggestions are welcome as well.

Thanks,
John



JWD

"JWD" <(E-Mail Removed)> writes:
> I'd also like to understand 'why' it doesn't work.

The higher gain rubber duckie antennas are only higher gain in the
plane perpendicular to their axis. Off this plane they are actually
lower gain. Try pointing the antenna so that this high-gain plane
hits your wireless client. If that still doesnt' work any better,
then there is something else going on.

-wolfgang
--
Wolfgang S. Rupprecht http://www.wsrcc.com/wolfgang/

"JWD" <(E-Mail Removed)> hath wroth:

>I recently bought a DLink ANT24-0700 antenna to boost the range of my
>NetGear MR814 router. I installed the antenna and saw no difference in
>signal strength.

http://www.dlink.com/products/?sec=0&pid=416

Yep. That can happen. RF is magic.

>I called Dlink and they basically told me that it was against FCC
>regulations to mix wireless devices from different vendors and that
>they couldn't help me.

That's correct. The FCC part 15.204 clearly mumbled that you can
legally replace an antenna only if it is the same type of antenna
(omni, dish, panel, yagi, whatever) that was originally type certified
with the equipment, and only if it has equal or less gain. What
you're doing, by increasing the antenna gain is in violation of Part
15.204. Please surrender yourself to the FCC enforcement bureau for
correction.

http://www.access.gpo.gov/nara/cfr/w...7cfr15_04.html

>When I asked if that is the reason why my
>signal strength didn't change, he repeated his response and refused to
>help.

I'm not sure what he could tell you. Antennas are just one component
of your system. If there's a problem, it can somewhere other than the
antenna. Unless you're prepared to supply a complete description of
your topology, environemnt, and equipment, there's not much anyone can
suggest.

>My first issue is that nowhere in the description of this antenna does
>it say that it must be used with only DLink products, but all I really
>care about is finding out if there is a way to get this antenna to work
>with my NetGear router.

It should work with other products and manufacturers. It's just that
DLink support isn't terribly interested in supporting other products
and manufacturers.

>I'd also like to understand 'why' it doesn't work.

Sure. I just got through an interesting exercise where adding a
higher gain antenna actually *REDUCED* the coverage. The problem was
that this location overlooked a large part of the city. Netstumbler
showed about 50 access points. The higher gain antenna increased the
interference pickup from the city (through the window). Although the
signal strength to the various laptops and PDA's were increased around
the house, the not-so-minor detail that the main access point was
picking up crap from all over the city made it look like the
connection was unreliable anywhere in the house. I moved the main
access point to a more protected location, setup a direction antenna
(reflector), and it worked well enough (unless the laptop or PDA was
in the window).

Another common problem is antenna orientation. That Dlink antenna
claims 7dBi of gain. Unfortunately, it comes with 5ft of tiny coax
RG-316 or RG-174 cable which is good for about 43dB/100ft or about
2.5dB of loss. Therefore, the antenna gain is really only 4.5dB gain.

Range doubles for every 6dB of gain, so this antenna should yield
about 2.8 times the range. However, that's only in the horizontal
plane. If you are positioned above or below the antenna, such as on a
different floor of the house, the signal will actually be less with
the DLink antenna.

>I understand that
>there may be different implementations of protocols, etc. that would
>prevent certain networking devices of one vendor from working with
>another, but when it comes to an antenna, isn't it just transmitting
>and receiving the wirless signal ? Why would mixing vendors not work.

I think you misunderstood what the support personality from Dlink was
saying. He didn't say that it wouldn't work. He probably said that
he could not help you make it work.

The basic assumption of WLAN antennas is that they are all 50 ohms
impedance and are tuned to the 2400-2483.5MHz band. As long as the
connectors match, any antenna should function on any 2.4GHz access
point. Whether it will do what you expect is another story.
Unrealistic expectations are all to common. Since you haven't
described your environment, topology, or what you're trying to
accomplish, it's difficult to deduce why the better antenna didn't
work.

>If anyone can help me get this setup to work, I'd greatly appreciate
>it.

What setup? All we know is that you have an MR-814 router and a Dlink
antenna. How about some clues as to the environment, construction,
topology, client radios, and interference potential?

>Other suggestions are welcome as well.

See:
http://www.freeantennas.com
and see if the reflectors give you some ideas.

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

JWD <(E-Mail Removed)> wrote:
> I recently bought a DLink ANT24-0700 antenna to boost the range of my
> NetGear MR814 router. I installed the antenna and saw no difference in
> signal strength.

It's hard to say how much improvement you should see.

> I called Dlink and they basically told me that it was against FCC
> regulations to mix wireless devices from different vendors and that
> they couldn't help me.

He used to be correct. Radios and antennas needed to be tested in pairs to
receive FCC certification, part of the reason they have supposedly
unobtainable connectors on 802.11 radios. But that was relaxed to allow
various antennas, as long as they don't exceed certain parameters. It
might be that he is still correct, and Netgear never tested their radio
with anything but their stock antenna.
http://www.netgear.com/products/fcc_antennas.php indicates that is true,
the 814 is not listed. If it were listed for a Netgear 7db omni, my
understanding is that a DLink 7db omni would also be legal.

On the other hand, the FCC doesn't seem to care any more, and the DLink
page for the ANT24 says: "Works with Virtually Any 802.11b/g Compliant
Devices with a SMA or TNC Connector"

> My first issue is that nowhere in the description of this antenna does
> it say that it must be used with only DLink products, but all I really
> care about is finding out if there is a way to get this antenna to work
> with my NetGear router.

That's the spirit. It ought to work, assuming the connector fits. It
probably does work. How are you measuring the signal, and how much did you
hope to achieve? This is a 7dB antenna, so it's not going to shoot your
signal through walls to where there was no signal before, although it ought
to improve the signal that was already there, if it was of marginal
strength.


> another, but when it comes to an antenna, isn't it just transmitting
> and receiving the wirless signal ? Why would mixing vendors not work.

That's all. No protocol, no vendor ID, other than the half-hearted attempt
to have unusual connectors.

The signal pattern looks like a donut slid onto the antenna. The best
strength is going to be broadside to the antenna. The 7db antenna will
have a flatter donut than the stock antenna, stretching the signal farther
out, but less thickness. Maybe it isn't aimed correctly.

If you had no signal in your desired location, maybe you still won't.

If you have some signal with the stock antenna, you should see some small
improvement with the new antenna, but maybe not enough.

You could add a directional reflector. Instead of squishing the donut to
make it reach out farther, this reshapes the signal so that it heads more
off into one direction. This should work with either antenna.

http://www.freeantennas.com EZ-12, Windsurfer reflector.
printed on photo paper for thick stock, with aluminum foil glued to the
sail, provides a substantial boost in signal.
http://www.rahul.net/dold/clarence/EZ12-windsurfer.jpg

--
---
Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5

Thanks for the posts received so far.
I did a bit more testing today and although I do see a minor
improvement in signal strengh, it does not seem to be enough to help my
situation. To measure the signal, all I'm doing is opening up my
wireless card's utility program and monitoring the dB levels in the
Link Status window.

Anyway, here's more on my environment. I live in a townhouse/condo
where there are 4 houses connected together. The walls between each
house are cinder block which I know is not easy for a signal to
penetrate.
My brother-in-law owns the house on one end and I own the house on the
other. The router is in my brother-in-laws house and I'm trying to use
his signal. I do get a signal in certain locations of my house, but it
is very weak (-85 to -90 dB) and occasionally drops out.

There are no cordless phones in our complex and noone else has a
wireless signal so interference should be minimal. The biggest
obstacle is the two houses in between.

It seems as though my best bet might be the directional antenna that
was suggested in one of the posts, but maybe this environment is just
to difficult get a wireless signal working.

Thanks,
John

> I recently bought a DLink ANT24-0700 antenna to boost the range of my
> NetGear MR814 router. I installed the antenna and saw no difference in
> signal strength.

Explain how your stuff is laid out. What type of building construction?
Are these on different floors? What sort distances are there between the
devices. All these things matter and the wrong antenna can CERTAINLY make
things worse.

For example, I've got a 50's era rambler, brick on block with an early
variant of drywall. I've also got a 90's era sunroom attached to the back.
The coatings on the windows actually BLOCK most of the WiFi signal! But
even with that I've got a Linksys WRT54G with it's factory rubber ducky
antennas installed in a basement window well. It has line-of-sight up to
the sunroom. They have to be pointed at about a 75 degree angle to spread
their beam upward into the sunroom and downward enough to hit an office area
downstairs. The far upper corner of the house, a guest room only barely
gets coverage but everything else is ok. The 'donut' pattern of the beams
radiates enough to cover what we need. I swapped the 5db units with a 9db
pair. The coverage at the desk and in the sunroom was better but only by a
scant amount. But the coverage at the vertical fringes of the donut we
dramatically reduced. Now most of the rooms upstairs didn't get covered,
not just the far guest room. Not an improvement.

In the past I used a pair of parabolic reflectors around them and pointed
one toward the sunroom and one downward toward the office. Worked pretty
well, but this was for a lower performing BEFW114 (or something like that)
and the WRT54G that replaced it didn't need 'em. Made 'em from scratch
using cardboard, a glue gun and some 1/4" hardware cloth. STFW for more.

> My first issue is that nowhere in the description of this antenna does
> it say that it must be used with only DLink products,

Sure, but Ford parts don't explictly say they won't work in a Chevy either.
While I sympathize with the confusion it's not like one company would go out
of their way to say if it worked with anothers units. That and the FCC test
issues explained in other posts would certainly affect the situation.

It's not about protocols; they're all the same. It's about the beam
pattern. Better explain your setup and perhaps some suggestions can be
made.

-Bill Kearney

"JWD" <(E-Mail Removed)> hath wroth:

>I did a bit more testing today and although I do see a minor
>improvement in signal strengh, it does not seem to be enough to help my
>situation. To measure the signal, all I'm doing is opening up my
>wireless card's utility program and monitoring the dB levels in the
>Link Status window.

That's usually sufficient. Netstumbler running on a laptop is good
for finding the hot spots inside the house.

>Anyway, here's more on my environment. I live in a townhouse/condo
>where there are 4 houses connected together. The walls between each
>house are cinder block which I know is not easy for a signal to
>penetrate.

OK, so this is essentially an outdoor network. You're not going to
see much improvement going from a 2dBi rubber ducky antenna to what
appears to be a 4.5dBi antenna (7dBi minus coax cable losses). There
should be some improvement, but nothing spectacular.

Cinder block is well, a brick wall. Little goes through it. Are you
able to find a window with a view of the opposite end of the link?

>My brother-in-law owns the house on one end and I own the house on the
>other.

How far away? What manner of hardware and antenna does the
bother-in-law have? Is there line of sight?

As a general note, numbers are always better than descriptions. I can
make a good guess as to the gain of the direction antenna you'll
probably need to make this work if you supply some numbers.

>The router is in my brother-in-laws house and I'm trying to use
>his signal. I do get a signal in certain locations of my house, but it
>is very weak (-85 to -90 dB) and occasionally drops out.

That's very weak. You'll need line of sight and a directional
antenna. You might get a connection, but it will dropout as soon as
you start moving data.

>There are no cordless phones in our complex and noone else has a
>wireless signal so interference should be minimal.

Are you sure? Did you run Netstumbler, or better yet Kismet, to be
sure? I've been suprised many times.

>The biggest
>obstacle is the two houses in between.

Two houses? Are you trying to "drill" though those obstacles? There's
no way this is going to work without line of sight. Worse, even if
you do conjur enough antenna gain to get a connection, if anything
moves in these two houses, your signal will go up and down. I read a
story where someone was able to drill through an office building that
had opposing picture windows. That worked just fine until someone
moved a file cabinet in front of one window. Try to get line of
sight, even if it means antennas on the roof.

>It seems as though my best bet might be the directional antenna that
>was suggested in one of the posts, but maybe this environment is just
>to difficult get a wireless signal working.

With 2 houses blocking the RF path, I would say it's impossible.
However, you are apparently getting some signal through so some
tinkering might make it marginally useful. The reflectors on:
http://www.freeantennas.com
are very easy to build and produce impressive improvements in
directional antenna gain. Methinks it's worth a try.

>Thanks,
>John

Incidentally, if the houses in question are sufficiently close to run
wire, it's fairly easy to run 10baseT-HDX over CAT5 or coax cable up
to about 1000ft. Details on request.

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

> How far away? What manner of hardware and antenna does the
> bother-in-law have? Is there line of sight?

The hardware is a NetGear MR-814 and the antenna is the basic antenna
that came with it (unless I use my ANT24-0700 of course).
The houses are small. They are only about 17 feet wide. There is
definately no line of sight between my house and the brother-in-laws.
The router is in a closet in his first floor. I can get a signal on my
first floor if I get very close to the wall.

> As a general note, numbers are always better than descriptions. I can
> make a good guess as to the gain of the direction antenna you'll
> probably need to make this work if you supply some numbers.
>
> >The router is in my brother-in-laws house and I'm trying to use
> >his signal. I do get a signal in certain locations of my house, but it
> >is very weak (-85 to -90 dB) and occasionally drops out.
>
> That's very weak. You'll need line of sight and a directional
> antenna. You might get a connection, but it will dropout as soon as
> you start moving data.
>
> >There are no cordless phones in our complex and noone else has a
> >wireless signal so interference should be minimal.
>
> Are you sure? Did you run Netstumbler, or better yet Kismet, to be
> sure? I've been suprised many times.

I downloaded Netstumbler and there is only my brother-in-laws router
listed.

> With 2 houses blocking the RF path, I would say it's impossible.
> However, you are apparently getting some signal through so some
> tinkering might make it marginally useful. The reflectors on:
> http://www.freeantennas.com
> are very easy to build and produce impressive improvements in
> directional antenna gain. Methinks it's worth a try.

The antennas on freeantennas seem simple enough to make. Maybe I'll
give them a try.

> Incidentally, if the houses in question are sufficiently close to run
> wire, it's fairly easy to run 10baseT-HDX over CAT5 or coax cable up
> to about 1000ft. Details on request.

Yeah, I thought about this, but we wouldn't be able to run the cable
through the other houses either inside or out.

Thanks,
John

"JWD" <(E-Mail Removed)> wrote:
>Anyway, here's more on my environment. I live in a townhouse/condo
>where there are 4 houses connected together. The walls between each
>house are cinder block which I know is not easy for a signal to
>penetrate.
>My brother-in-law owns the house on one end and I own the house on the
>other. The router is in my brother-in-laws house and I'm trying to use
>his signal. I do get a signal in certain locations of my house, but it
>is very weak (-85 to -90 dB) and occasionally drops out.

You've got three cinder block walls? I'm surprised it works at all.
Have you tried things like putting your antenna in the attic (and
maybe your BIL's too)? Maybe each of you sticks an antenna out a back
window in sight of each other? Maybe you just pony up for your own
broadband? [If you start doing file sharing, he's gonna kick you off
anyway for eating all his bandwidth, and then all the money you spent
on gain antennas is wasted...]

William P.N. Smith wrote:
> "JWD" <(E-Mail Removed)> wrote:
> >Anyway, here's more on my environment. I live in a townhouse/condo
> >where there are 4 houses connected together. The walls between each
> >house are cinder block which I know is not easy for a signal to
> >penetrate.
> >My brother-in-law owns the house on one end and I own the house on the
> >other. The router is in my brother-in-laws house and I'm trying to use
> >his signal. I do get a signal in certain locations of my house, but it
> >is very weak (-85 to -90 dB) and occasionally drops out.
>
> You've got three cinder block walls? I'm surprised it works at all.
> Have you tried things like putting your antenna in the attic (and
> maybe your BIL's too)? Maybe each of you sticks an antenna out a back
> window in sight of each other? Maybe you just pony up for your own
> broadband? [If you start doing file sharing, he's gonna kick you off
> anyway for eating all his bandwidth, and then all the money you spent
> on gain antennas is wasted...]

Unfortunately we have no attic, they are flat roof houses.
What about adding a repeater in one of the houses in-between?
What exactly is a repeater? Is it a access point configured in a
special way or is it a separate device? How much would a repeater cost
?

John