Why 2 aerials on a Wireless AP

I recently got a Netgear Pro wireless access point and can't find out
the purpose of the two aerials.

The manual makes no mention of them other than in the settings one can
chose either the Primary or Secondary aerial.

I assumed both would work simultaneously so one could set them at
different angles to give better coverage.

What is the point of the two then?
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Les Desser
(The Reply-to address IS valid)

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My Website http://www.thedragon.co.uk
"Les Desser" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>I recently got a Netgear Pro wireless access point and can't find out the
>purpose of the two aerials.
>
> The manual makes no mention of them other than in the settings one can
> chose either the Primary or Secondary aerial.
>
> I assumed both would work simultaneously so one could set them at
> different angles to give better coverage.
>
> What is the point of the two then?
> --
> Les Desser
> (The Reply-to address IS valid)

Spatial Diversity.

The signal arrives at the AP, the chipset inside can choose the better
signal from the antennas. As a device moves around its signal goes up and
down due to reflections adding and subtracting from the intended direct
creating peaks and troughs, with a max of 2 x signal (Additive interference)
and 0 (total cancellation). As mentioned before the signal will arrive at
each antenna with slightly different characteristics based on the
reflections caused by the environment should a poor signal be received on
one antenna, its very likely that there will still be a useable signal on
the alternate antenna.

A bit basic, but do a search on Google for spatial diversity antennas
arrays and you will get the full technical background.

In article <(E-Mail Removed)>, Paul
Landregan <(E-Mail Removed)> Sun, 5 Sep 2004 09:05:15 writes

>A bit basic, but do a search on Google for spatial diversity antennas
>arrays and you will get the full technical background.

Thanks - makes sense. Does that mean that both are used for receiving
but only one for transmission?
--
Les Desser
(The Reply-to address IS valid)

--
My Website http://www.thedragon.co.uk
"Les Desser" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> In article <(E-Mail Removed)>, Paul Landregan
> <(E-Mail Removed)> Sun, 5 Sep 2004 09:05:15 writes
>
>>A bit basic, but do a search on Google for spatial diversity antennas
>>arrays and you will get the full technical background.
>
> Thanks - makes sense. Does that mean that both are used for receiving but
> only one for transmission?
> --
> Les Desser
> (The Reply-to address IS valid)

Depends on the chipset. Draytek Tx on both equally.

In message <(E-Mail Removed)>, Paul
Landregan <(E-Mail Removed)> writes
>Depends on the chipset. Draytek Tx on both equally.

At the same time? I can't understand why they would as to do so could
cause blind spots all over the place.
--
Pete Devlin
[{//////news03//////at\\\\\secondrow/////co\\\\\uk}]
Give me a woman who loves beer and I will conquer the world.
Kaiser Wilhelm

In article <(E-Mail Removed)>, Paul
Landregan <(E-Mail Removed)> Sun, 5 Sep 2004 19:19:16 writes

>Depends on the chipset. Draytek Tx on both equally.

From the setup of the Netgear it seems either/or.

I have been buying Netgear equipment for years and have been fairly
happy, but I keeps seeing Draytek mentioned. Is there any general
consensus that Draytek routers and wireless APs are better?
--
Les Desser
(The Reply-to address IS valid)

--
My Website http://www.thedragon.co.uk
"Les Desser" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> In article <(E-Mail Removed)>, Paul Landregan
> <(E-Mail Removed)> Sun, 5 Sep 2004 19:19:16 writes
>
>>Depends on the chipset. Draytek Tx on both equally.
>
> From the setup of the Netgear it seems either/or.
>
> I have been buying Netgear equipment for years and have been fairly happy,
> but I keeps seeing Draytek mentioned. Is there any general consensus that
> Draytek routers and wireless APs are better?
> --
> Les Desser
> (The Reply-to address IS valid)

Draytek are widely used for professional business use, hence the higher
price tag, however they are highly configurable, very secure, good same day
support, via phone or email (I should know when BT Broadband kept crashing
the router), fixed within 3 hours, config error.

The old saying goes, you get what you pay for, as Draytek's arent cheap as
chips. But much cheaper than Cisco gear.
On the other hand, if your happy with Netgear, you will be more familiar
with its configuration, so why change. There's nothing wrong with Netgear,
and the other branded routers.

I have even managed to convert a Cisco only guy, into using Draytek for his
business installations. But thats just me.

Read reviews, and decide for your self based on your usage for the device.

[SNIP]

> At the same time? I can't understand why they would as to do so could
> cause blind spots all over the place.
> --
> Pete Devlin
> [{//////news03//////at\\\\\secondrow/////co\\\\\uk}]
> Give me a woman who loves beer and I will conquer the world.
> Kaiser Wilhelm

If they didn't, how can you establish external LOS links with directional
equipment, connected to either antenna socket?

In article <(E-Mail Removed)>, Paul
Landregan <(E-Mail Removed)> Sun, 5 Sep 2004 22:19:33 writes

>Draytek are widely used for professional business use, hence the higher
>price tag, however they are highly configurable, very secure, good same day
>support, via phone or email (I should know when BT Broadband kept crashing
>the router), fixed within 3 hours, config error.
>
>The old saying goes, you get what you pay for, as Draytek's arent cheap as
>chips. But much cheaper than Cisco gear.
>On the other hand, if your happy with Netgear, you will be more familiar
>with its configuration, so why change. There's nothing wrong with Netgear,
>and the other branded routers.
>
>I have even managed to convert a Cisco only guy, into using Draytek for his
>business installations. But thats just me.
>
>Read reviews, and decide for your self based on your usage for the device.

Thanks for all that - sounds a very fair summary.
--
Les Desser
(The Reply-to address IS valid)

In message <(E-Mail Removed)>, Paul
Landregan <(E-Mail Removed)> writes
>If they didn't, how can you establish external LOS links with
>directional equipment, connected to either antenna socket?

What directional equipment? Is there a gucci peripheral I should know
about? Signal or phase comparison is done in the receiving equipment.
How does a transmitting equipment "know" where the receiving equipment
is without receiving from it? I would be very surprised if any router
transmitted on both aerials simultaneously. It would cause lots of
problems and isn't necessary. Just my opinion loosely based on a small
amount of experience with directional comms, homing and radar systems.
--
Pete Devlin
[{//////news03//////at\\\\\secondrow/////co\\\\\uk}]
Give me a woman who loves beer and I will conquer the world.
Kaiser Wilhelm