What are 2 antennas being used for? WRT54G and many others have 2 or
even 3 antennas. There are a number of things I could envision what
they might do with this. Anyone know what they actually are doing?
Here are some possibilities.
1. Split band. For dual band models, one antenna could be attached
to 2.4 GHz RF circuitry, while the other is attached to 5 GHz RF
circuitry. This would avoid the need for an internal splitter and
a dual band antenna.
2. Split RX/TX. One antenna could be used for receive, while the other
is used for transmit. I don't see any significant advantage to this
unless the TX power is low enough to still allow RX on a different
channel for models than can operate on 2 channels at the same time.
For remotely wired antennae, this might be an advantage.
3. Diversity. Two receivers work together in case one antenna position
would be in a null spot for another device, the 2nd antenna might
get the signal. Transmit might also select which antenna provides
the better path to the destination. With extra compnents used to
realize the receive advantage, this might not be done.
4. Directionality. Similar to diversity, but an RF stage taking signal
on both antennae at the same time can get up to 3db gain in certain
directions (and be entirely deaf in others). This could be used to
enhance certain weaker devices and/or null out interference sources.
TX could do the same. This would be difficult for the average user
to manage, and require extra components, so I doubt it would be done.
5. Placement. Wire a remote antenna on ONE of the connectors to get
coverage in two distinct places.
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / spamtrap-2006-07-24-1415@ipal.net |
|------------------------------------/-------------------------------------|
>WRT54G and many others have 2 or even 3 antennas.
Two antennas are diversity receive.
Three antennas are MIMO which is quite different.
No antennas are beam forming or beam steering.
>There are a number of things I could envision what
>they might do with this. Anyone know what they actually are doing?
Well, it would be nice if you would limit the question to a specific
model or type of radio.
>Here are some possibilities.
Wait a minute. You're asking a question and offering multiple choice
answers? I recognize your deductive abilities but wouldn't it be
better if you ask and not guess?
>1. Split band. For dual band models, one antenna could be attached
> to 2.4 GHz RF circuitry, while the other is attached to 5 GHz RF
> circuitry. This would avoid the need for an internal splitter and
> a dual band antenna.
That's not the way it's usually done. Most dual band access points
use common antennas for both bands. However, there are chipset that
seperate the bands and it could be done this way. It's very common
with the new 4.9Ghz/2.4Ghz MotoMesh access points, that have seperate
antennas for each band. However, for commidity access points, the
antenna is usually (not always) common for both bands.
>2. Split RX/TX. One antenna could be used for receive, while the other
> is used for transmit. I don't see any significant advantage to this
> unless the TX power is low enough to still allow RX on a different
> channel for models than can operate on 2 channels at the same time.
> For remotely wired antennae, this might be an advantage.
That was done on some access points about 5 years ago, where one
antenna was outside, and the other was inside the plastic box. I
vaguely recall the DLink DWL-900AP+ was one of these. The inside
antenna was almost totally useless for transmit, so all transmissions
were from the outside antenna. I'm not sure why they even bothered
with receive diversity.
>3. Diversity. Two receivers work together in case one antenna position
> would be in a null spot for another device, the 2nd antenna might
> get the signal. Transmit might also select which antenna provides
> the better path to the destination. With extra compnents used to
> realize the receive advantage, this might not be done.
>4. Directionality. Similar to diversity, but an RF stage taking signal
> on both antennae at the same time can get up to 3db gain in certain
> directions (and be entirely deaf in others). This could be used to
> enhance certain weaker devices and/or null out interference sources.
> TX could do the same. This would be difficult for the average user
> to manage, and require extra components, so I doubt it would be done.
Well, with two rubber ducky antennas, you'll never realize enough gain
to make the effort worthwhile. Worse, with the antennas twisting in
random directions, there's no way to aim it. That's not going to
happen.
However, there is a class of access points that use beam streering,
and another that uses beam forming, for directing the signal. Inside
the box is an elaborate antenna array. For beam steering, the idea is
to put the peak at toward the client radio. Beam steering is
considerably more elaborate in that it also aims the peak, but also
detects sources of interference and directs a null at the
interference.
| http://www.ruckuswireless.com/technology/beamflex.php
>5. Placement. Wire a remote antenna on ONE of the connectors to get
> coverage in two distinct places.
That doesn't work. Read the Cisco article mentioned previous for
details. Another major problem is that traffic through the access
point, from one antenna to the other doesn't get switched fast enough.
If you were to try to use it as a repeater between antenna ports, it
would need to switch antennas on literally every packet. The
diversity algorithm is nowhere near that agressive.
--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>
John Navas <spamfilter0@navasgroup.com> hath wroth:
>On 24 Jul 2006 19:30:05 GMT, phil-news-nospam@ipal.net wrote in
><ea373t0r5p@news4.newsguy.com>:
>
>>What are 2 antennas being used for? ...
>
>Spatial diversity.
><http://en.wikipedia.org/wiki/Diversity_reception>
Not applicable. The above article is for common techniques used in
telecom wireless. In all cases mentioned, the multiple signals
received are combined in some manner. This is NOT done in any
commodity Wi-Fi routers. It would be too expensive to have two
identical receivers in one box. Instead, the methods of Wi-Fi
diversity are called "switched diversity" or "selection diversity" as
mentioned in this article:
| http://www.commsdesign.com/design_co...cleID=16500279
These requires only one receiver and are admittedly not as effective
as full time diversity (as described in the Wikipedia article).
On Mon, 24 Jul 2006 23:20:39 -0700, Jeff Liebermann
<jeffl@comix.santa-cruz.ca.us> wrote in
<1kdbc2l413qhadf47cb2hqpgsmufbuc7qt@4ax.com>:
>John Navas <spamfilter0@navasgroup.com> hath wroth:
>
>>On 24 Jul 2006 19:30:05 GMT, phil-news-nospam@ipal.net wrote in
>><ea373t0r5p@news4.newsguy.com>:
>>
>>>What are 2 antennas being used for? ...
>>
>>Spatial diversity.
>><http://en.wikipedia.org/wiki/Diversity_reception>
>
>Not applicable.
Close enough for this context.
>The above article is for common techniques used in
>telecom wireless. In all cases mentioned, the multiple signals
>received are combined in some manner. This is NOT done in any
>commodity Wi-Fi routers. It would be too expensive to have two
>identical receivers in one box. Instead, the methods of Wi-Fi
>diversity are called "switched diversity" or "selection diversity" as
>mentioned in this article:
>| http://www.commsdesign.com/design_co...cleID=16500279
>These requires only one receiver and are admittedly not as effective
>as full time diversity (as described in the Wikipedia article).
Update the article. ;)
--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>
On Mon, 24 Jul 2006 22:58:11 -0700 Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote:
| phil-news-nospam@ipal.net hath wroth:
|
|>What are 2 antennas being used for?
|
| Diversity reception.
|
|>WRT54G and many others have 2 or even 3 antennas.
|
| Two antennas are diversity receive.
| Three antennas are MIMO which is quite different.
| No antennas are beam forming or beam steering.
So only one of the antennae is used for transmitting.
Dare I ask which one :) ... ah, answer below.
|>There are a number of things I could envision what
|>they might do with this. Anyone know what they actually are doing?
|
| Well, it would be nice if you would limit the question to a specific
| model or type of radio.
It's a generic question because I see a number of radios with 2 or 3
antennas. The answer for one model would not necessarily give me an
idea of the scope of what is being done overall. If two different
models do different things, I'd like to get an idea of possibilities.
|>Here are some possibilities.
|
| Wait a minute. You're asking a question and offering multiple choice
| answers? I recognize your deductive abilities but wouldn't it be
| better if you ask and not guess?
The examples were intended to give the scope and level of answer I am
looking for in that question. Were one of those guesses true, it would
be an exact answer to my question. It's not really a multiple choice
question. If the answer is something else, then all guesses are wrong.
|>1. Split band. For dual band models, one antenna could be attached
|> to 2.4 GHz RF circuitry, while the other is attached to 5 GHz RF
|> circuitry. This would avoid the need for an internal splitter and
|> a dual band antenna.
|
| That's not the way it's usually done. Most dual band access points
| use common antennas for both bands. However, there are chipset that
| seperate the bands and it could be done this way. It's very common
| with the new 4.9Ghz/2.4Ghz MotoMesh access points, that have seperate
| antennas for each band. However, for commidity access points, the
| antenna is usually (not always) common for both bands.
And so not likely concurrent operation on both bands at the same time
other than simultaneous receive.
|>2. Split RX/TX. One antenna could be used for receive, while the other
|> is used for transmit. I don't see any significant advantage to this
|> unless the TX power is low enough to still allow RX on a different
|> channel for models than can operate on 2 channels at the same time.
|> For remotely wired antennae, this might be an advantage.
|
| That was done on some access points about 5 years ago, where one
| antenna was outside, and the other was inside the plastic box. I
| vaguely recall the DLink DWL-900AP+ was one of these. The inside
| antenna was almost totally useless for transmit, so all transmissions
| were from the outside antenna. I'm not sure why they even bothered
| with receive diversity.
|
|>3. Diversity. Two receivers work together in case one antenna position
|> would be in a null spot for another device, the 2nd antenna might
|> get the signal. Transmit might also select which antenna provides
|> the better path to the destination. With extra compnents used to
|> realize the receive advantage, this might not be done.
|
| This is the most common arrangement. What's not obvious is that there
| is a MAIN and AUX antennas. The radio sits on the MAIN antenna most
| of the time and only tries the AUX antenna if it detects a high error
| rate. The main advantage is to reduce frequency selective fadeing in
| a reflective environment (such as all indoor systems). See:
| | http://www.commsdesign.com/design_co...cleID=16500279
| | http://img.cmpnet.com/commsdesign/cs...eat1-jan03.pdf
| | http://www.cisco.com/en/US/tech/tk72...8019f646.shtml
| for a few articles on the common methods of wireless diversity.
You're right, MAIN vs. AUX was not obvious. I suppose if I have worked
on trying to guess every possible combination of how to do things, that
would have come up among them.
So for transmit, it would alayws be from the MAIN antenna, and leave it
up to the other end to have receive diversity in the event that MAIN on
one unit to MAIN on the other unit happened to be a bad RF path.
|>4. Directionality. Similar to diversity, but an RF stage taking signal
|> on both antennae at the same time can get up to 3db gain in certain
|> directions (and be entirely deaf in others). This could be used to
|> enhance certain weaker devices and/or null out interference sources.
|> TX could do the same. This would be difficult for the average user
|> to manage, and require extra components, so I doubt it would be done.
|
| Well, with two rubber ducky antennas, you'll never realize enough gain
| to make the effort worthwhile. Worse, with the antennas twisting in
| random directions, there's no way to aim it. That's not going to
| happen.
The distance between them would dictate a beam pattern, if merged at
the RF level. But it would be more confusing with wireless networking
than it would be trying to adjust rabbit ears on an analog TV (digital
TV is going to mess that up, too).
| However, there is a class of access points that use beam streering,
| and another that uses beam forming, for directing the signal. Inside
| the box is an elaborate antenna array. For beam steering, the idea is
| to put the peak at toward the client radio. Beam steering is
| considerably more elaborate in that it also aims the peak, but also
| detects sources of interference and directs a null at the
| interference.
| | http://www.ruckuswireless.com/technology/beamflex.php
Much more expensive, no doubt.
|
|>5. Placement. Wire a remote antenna on ONE of the connectors to get
|> coverage in two distinct places.
|
| That doesn't work. Read the Cisco article mentioned previous for
| details. Another major problem is that traffic through the access
| point, from one antenna to the other doesn't get switched fast enough.
| If you were to try to use it as a repeater between antenna ports, it
| would need to switch antennas on literally every packet. The
| diversity algorithm is nowhere near that agressive.
Or basically be 2 radios in one, just on the same band and programmed
to not transmit at the same time (unless on different channels, but
then, that's a different animal).
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / spamtrap-2006-07-25-1037@ipal.net |
|------------------------------------/-------------------------------------|
>... MAIN vs. AUX was not obvious. I suppose if I have worked
>on trying to guess every possible combination of how to do things, that
>would have come up among them.
>
>So for transmit, it would alayws be from the MAIN antenna, and leave it
>up to the other end to have receive diversity in the event that MAIN on
>one unit to MAIN on the other unit happened to be a bad RF path.
I think transmit will typically occur on the current antenna; i.e., if
AUX is getting the best receive signal, then it will be used for
transmit as well. Using only MAIN for transmit would be a poor design.
--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>
>You're right, MAIN vs. AUX was not obvious. I suppose if I have worked
>on trying to guess every possible combination of how to do things, that
>would have come up among them.
It's easy enough to check. Find a dual trace oscillosope and connect
CH A to the diversity switch IC and CH B to some place that indicates
if the radio is transmitting. See what it's doing. I did this about
3 years ago with a WRT54G in my rather sloppy attempt to reverse
engineer how the diversity switch actually worked (and to figure out
which is are the left/right and main/aux antennas). I also tried to
connect a red/green LED to the diversity switch IC to indicate what it
was doing, but the switching rate was just too fast to be useful.
If I have time, I'll do it again. It's fairly easy, but the local
temperatures have been far to high to do anything useful in the shop.
>So for transmit, it would alayws be from the MAIN antenna, and leave it
>up to the other end to have receive diversity in the event that MAIN on
>one unit to MAIN on the other unit happened to be a bad RF path.
It apparently varies with chipset. As I vaguely recall (not sure),
the Broadcom chipset in the WRT54G switches TX along with RX. I
believe (not sure) that some chipsets can be set to work either way.
One thing I do recall is that the switch spent almost all its time on
the MAIN antenna.
Not really. See: http://www.netgear.com/products/details/WPN824.php
as an example. About $90. It's the mechanical parts that add cost.
The smart antenna board eliminates a mess of connectors, cables,
antennas, hardware, assembly labour, found in conventional diversity
access points and is probably a cost savings.
>| That doesn't work. Read the Cisco article mentioned previous for
>| details. Another major problem is that traffic through the access
>| point, from one antenna to the other doesn't get switched fast enough.
>| If you were to try to use it as a repeater between antenna ports, it
>| would need to switch antennas on literally every packet. The
>| diversity algorithm is nowhere near that agressive.
>Or basically be 2 radios in one, just on the same band and programmed
>to not transmit at the same time (unless on different channels, but
>then, that's a different animal).
What do you mean by 2 radios in one? I'll guess you mean full duplex,
which is possible but has not commonly been implimented in consumer
wireless. BelAir Networks and some others have dual radio access
points that can act as repeaters. It's used in mesh networks to
eliminate the bandwidth reduction caused by single channel systems. No
diversity of any kind as each antenna is connected to a seperate
radio.
| http://www.belairnetworks.com
There was also Bermai, which had a dual receiver (TwinRX) diversity
system for 802.11a that was targeting consumer wireless multimedia.
With two receivers, they implimented full time diversity reception
with no switching.
| http://www.commsdesign.com/design_co...cleID=16501888
The company closed down in 2004. No idea what happened to the assets
or IP rights.
"John Navas" <spamfilter0@navasgroup.com> wrote in message
news:lficc29devvqpkqhbenvk7dboa7uniati0@4ax.com...
> On 25 Jul 2006 15:56:40 GMT, phil-news-nospam@ipal.net wrote in
> <ea5evo031d2@news3.newsguy.com>:
>
>>... MAIN vs. AUX was not obvious. I suppose if I have worked
>>on trying to guess every possible combination of how to do things, that
>>would have come up among them.
>>
>>So for transmit, it would alayws be from the MAIN antenna, and leave it
>>up to the other end to have receive diversity in the event that MAIN on
>>one unit to MAIN on the other unit happened to be a bad RF path.
>
> I think transmit will typically occur on the current antenna; i.e., if
> AUX is getting the best receive signal, then it will be used for
> transmit as well. Using only MAIN for transmit would be a poor design.
>
Or it could just transmit on both antenna at the same time; which would
probably be the most sensible way, as well as the easiest.
"Paul" <ukuntu@localhost.com> wrote:
>Or it could just transmit on both antenna at the same time; which would
>probably be the most sensible way, as well as the easiest.
Actually, this could be the worst possible thing to do, depending on
phasing and antenna separation (to say nothing of antenna angle) you
could get some really bizarre antenna patterns. [The thought of
external antennas in this situation makes my brain hurt.]
On Tue, 25 Jul 2006 16:44:25 GMT John Navas <spamfilter0@navasgroup.com> wrote:
| On 25 Jul 2006 15:56:40 GMT, phil-news-nospam@ipal.net wrote in
| <ea5evo031d2@news3.newsguy.com>:
|
|>... MAIN vs. AUX was not obvious. I suppose if I have worked
|>on trying to guess every possible combination of how to do things, that
|>would have come up among them.
|>
|>So for transmit, it would alayws be from the MAIN antenna, and leave it
|>up to the other end to have receive diversity in the event that MAIN on
|>one unit to MAIN on the other unit happened to be a bad RF path.
|
| I think transmit will typically occur on the current antenna; i.e., if
| AUX is getting the best receive signal, then it will be used for
| transmit as well. Using only MAIN for transmit would be a poor design.
It could be a cheaper design (no TX switch), maybe by a few pennies. And
maybe TX only on MAIN is adequate if the peer has 2 antennae. Of course
the latter assumption cannot be depended on. So TX follow best RX would
be a good idea. Better would be to test TX on each antennae and remember
which works best per peer for the off chance one antenna works better for
RX and the other worked better for TX, such as when the peer has split RX
and TX without switching. But the adde software cost and extra test TX
step might not be worth the few cases where this could help.
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / spamtrap-2006-07-27-0016@ipal.net |
|------------------------------------/-------------------------------------|
On Tue, 25 Jul 2006 19:29:26 GMT Paul <ukuntu@localhost.com> wrote:
|
| "John Navas" <spamfilter0@navasgroup.com> wrote in message
| news:lficc29devvqpkqhbenvk7dboa7uniati0@4ax.com...
|> On 25 Jul 2006 15:56:40 GMT, phil-news-nospam@ipal.net wrote in
|> <ea5evo031d2@news3.newsguy.com>:
|>
|>>... MAIN vs. AUX was not obvious. I suppose if I have worked
|>>on trying to guess every possible combination of how to do things, that
|>>would have come up among them.
|>>
|>>So for transmit, it would alayws be from the MAIN antenna, and leave it
|>>up to the other end to have receive diversity in the event that MAIN on
|>>one unit to MAIN on the other unit happened to be a bad RF path.
|>
|> I think transmit will typically occur on the current antenna; i.e., if
|> AUX is getting the best receive signal, then it will be used for
|> transmit as well. Using only MAIN for transmit would be a poor design.
|>
|
| Or it could just transmit on both antenna at the same time; which would
| probably be the most sensible way, as well as the easiest.
There may be a case where transmit on both can reach the peer better than
either alone. However, if the peer is in the null of the resultant pattern
then doing this is counter productive. OTOH, a different phasing between
the two antennae might be usable to target the peer better. But that is
definitely more circuitry to independently rephase the antennae.
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / spamtrap-2006-07-27-0020@ipal.net |
|------------------------------------/-------------------------------------|
> But the adde software cost and extra test TX
> step might not be worth the few cases where this could help.
Ding, ding! Give that man a prize. At $50 typical retail for most wifi
routers every penny counts. That and since the units are so cheap it's
often better to use more than one. Taking care to properly configure the
channels, of course. Something far too many installations fail to take into
consideration.
If your access point is on channel 11 and there are other access points also
on that same channel, then MOVE yours to a new channel.
>It could be a cheaper design (no TX switch), maybe by a few pennies. And
>maybe TX only on MAIN is adequate if the peer has 2 antennae. Of course
>the latter assumption cannot be depended on. So TX follow best RX would
>be a good idea. Better would be to test TX on each antennae and remember
>which works best per peer for the off chance one antenna works better for
>RX and the other worked better for TX, such as when the peer has split RX
>and TX without switching. But the adde software cost and extra test TX
>step might not be worth the few cases where this could help.
There's a bit more going on with diversity than is obvious. The
manufacturers would have eliminated the 2nd antenna long ago if they
thought they could save a few pennies. Diversity significantly
improves the reflection immunity of an indoor system, but such
improvements are not what sells commodity routers. Price is what
sells commodity routers.
One manufacturer did try to remove the 2nd antenna. The Dlink DI-614+
and DI-624 went from two antennas to one antenna in later mutations. I
was told that retail sales immediately dropped. It wasn't a
performance issue. Customers perceived that two antennas are somehow
better than one and considered a single antenna router to be inferior.
DLink still sells some older products with one antenna, but all the
new DLink routers have two (or three).
> OR do like I just did. Buy a "N" Router and force your next door guy to
> another channel. To piss him off put it on the same channel as he is. It
> does not affect yours, But it does his. :) My Motto in this case is what
> comes around goes around.
Hmmm, and with that sort of attitude I'd avoid standing anywhere near you
should thunderclouds start forming. Sounds like you're asking for it with
that sort of attitude.
Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> writes:
> Customers perceived that two antennas are somehow better than one
> and considered a single antenna router to be inferior.
"Look at the tail fins on that baby. It must be fast or else why
would they put tail fins on it???"
I've always suspected that the whole two antenna hack started by
someone wanting to differentiate their offerings from the crowd.
On Thu, 27 Jul 2006 14:33:38 -0400, "Bill Kearney"
<wkearney99@hotmail.com> wrote in
<fbednerfDvKemlTZnZ2dnUVZ_oydnZ2d@speakeasy.net> :
>> OR do like I just did. Buy a "N" Router and force your next door guy to
>> another channel. To piss him off put it on the same channel as he is. It
>> does not affect yours, But it does his. :) My Motto in this case is what
>> comes around goes around.
>
>Hmmm, and with that sort of attitude I'd avoid standing anywhere near you
>should thunderclouds start forming. Sounds like you're asking for it with
>that sort of attitude.
Amen. With a neighbor like that I'd probably move.
--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>
On Thu, 27 Jul 2006 09:22:17 -0700, Jeff Liebermann
<jeffl@comix.santa-cruz.ca.us> wrote in
<dpphc2hu3ubpr2f693kskllke5e9e3np7n@4ax.com>:
>phil-news-nospam@ipal.net hath wroth:
>
>>It could be a cheaper design (no TX switch), maybe by a few pennies. And
>>maybe TX only on MAIN is adequate if the peer has 2 antennae. Of course
>>the latter assumption cannot be depended on. So TX follow best RX would
>>be a good idea. Better would be to test TX on each antennae and remember
>>which works best per peer for the off chance one antenna works better for
>>RX and the other worked better for TX, such as when the peer has split RX
>>and TX without switching. But the adde software cost and extra test TX
>>step might not be worth the few cases where this could help.
>
>There's a bit more going on with diversity than is obvious. The
>manufacturers would have eliminated the 2nd antenna long ago if they
>thought they could save a few pennies. Diversity significantly
>improves the reflection immunity of an indoor system, but such
>improvements are not what sells commodity routers. Price is what
>sells commodity routers.
Not that simple. Poorer performance tends to result in a higher return
rate, which can be a killer on cost that far overwhelms the small
savings. And people don't just buy on price alone -- reviews and
recommendations are factors, for which performance is also important.
>One manufacturer did try to remove the 2nd antenna. The Dlink DI-614+
>and DI-624 went from two antennas to one antenna in later mutations. I
>was told that retail sales immediately dropped. It wasn't a
>performance issue. Customers perceived that two antennas are somehow
>better than one and considered a single antenna router to be inferior.
>...
And they were right, whether they knew the exact reason or not.
--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>
John Navas <spamfilter0@navasgroup.com> hath wroth:
>Not that simple. Poorer performance tends to result in a higher return
>rate, which can be a killer on cost that far overwhelms the small
>savings.
Chuckle. Return rate is a problem but not for the obvious reason that
it affects the bottom line. The return rate on commodity wireless is
sufficiently small that at least one manufacturer just throws them
away and only retests them if a major distributor returns them en
masse. They also unload them with large rebates, which requires
destroying the packaging to collect, which therefore reduces the
return rate. Return rate is a killer only because it trashes brand
name recognition, which is the major reason consumers buy any
particular device. If you look carefully at the advertising in the
consumer magazines (not the trade journals), you'll probably notice
that much of starts by congratulating the consumer on having made an
intelligent choice and goes on to assure the consumer that the company
is behind its products 150%. In other words, they're going for the
repeat business based on name recognition.
>And people don't just buy on price alone -- reviews and
>recommendations are factors, for which performance is also important.
Yep. Just ask Joe Sixpack which reviews he's read on his wireless
router. Ummm...well...er...ah... Maybe it came with my computer?
You, me, and Dilbert probably read reviews in detail. Only a few of
my customers do that. Mostly they have a friend or consultant that
has a wireless something, and they just buy the same thing and blame
their friend or consultant when it doesn't quite work.
>>Customers perceived that two antennas are somehow
>>better than one and considered a single antenna router to be inferior.
>And they were right, whether they knew the exact reason or not.
Sure. Perception is everything. Few can explain why two antennas are
better, but intelligence and technology doesn't count with decisions
based on perception.
There are other things that are amazingly important for retail sales.
Color is one. Colors all have subliminal meanings. I walked in to a
customer with a Watchguard SOHO router. It's in a bright red plastic
box, apparently to capitalize on the firewall features. My customer
asked if I had something in a different color? Huh? She said that it
reminded her of blood, which made her feel awkward. I replaced it
with an antiseptic white Netgear WG-614, which was deemed acceptable.
Weight is also an important feature. Given two almost identical
products, the average consumer will usually pick the heaviest product.
There's a perception that you get more for your money if it's heavier.
I learned this the hard way when designing marine radios. We
literally put a lead brick inside the box and sales immediately
improved.
Criteria for commodity router selection (most important on top):
1. It's cheap.
2. A friend has one that works.
3. I've heard of the manufacturer from somewhere.
4. The box and color look cool.
5. It weighs like something that should work.
6. The literature is incomprehensible, so it must be powerful.
7. Larger numbers are always better.
108Mbits/sec instead of 54Mbits/sec.
Is 802.11z later than 802.11b? 5.7GHz is bigger than 2.4Ghz.
8. The flashing lights sure look nice. What do they mean?
9. This box has more acronyms than the other box.
10. I read a review that said all I had to do is plug in the
wireless router and it's ready to go.
Optional:
11. Jeff L said it sucked so I guess I'll try it.
On Thu, 27 Jul 2006 17:29:22 -0700, Jeff Liebermann
<jeffl@comix.santa-cruz.ca.us> wrote in
<5qkic2pp2h9nu3epo681cu7qba2hp9shqk@4ax.com>:
>John Navas <spamfilter0@navasgroup.com> hath wroth:
>
>>Not that simple. Poorer performance tends to result in a higher return
>>rate, which can be a killer on cost that far overwhelms the small
>>savings.
>
>Chuckle. Return rate is a problem but not for the obvious reason that
>it affects the bottom line. The return rate on commodity wireless is
>sufficiently small that at least one manufacturer just throws them
>away and only retests them if a major distributor returns them en
>masse. They also unload them with large rebates, which requires
>destroying the packaging to collect, which therefore reduces the
>return rate. Return rate is a killer only because it trashes brand
>name recognition, which is the major reason consumers buy any
>particular device.
My professional experience in that business is quite different. The
cost of returns, even if scrapped, is very high, typically measured as
the cost of quality -- you have to take them back to be sure retailers
aren't cheating you. Most manfs will at least retest them, because the
vast majority of returns (>90%) are fully functional, and can easily be
recouped as refurbs. If scrapped, they are usually at least broken down
for parts, or at least recycled for valuable materials.
>If you look carefully at the advertising in the
>consumer magazines (not the trade journals), you'll probably notice
>that much of starts by congratulating the consumer on having made an
>intelligent choice and goes on to assure the consumer that the company
>is behind its products 150%. In other words, they're going for the
>repeat business based on name recognition.
Again, not that simple. What goes around, comes around. Retailers hate
returns, and tend to trash whatever product is giving them the most
grief, which directly leads to lower sales. No good manf is going to
knowingly take that risk.
>>And people don't just buy on price alone -- reviews and
>>recommendations are factors, for which performance is also important.
>
>Yep. Just ask Joe Sixpack which reviews he's read on his wireless
>router. Ummm...well...er...ah... Maybe it came with my computer?
>You, me, and Dilbert probably read reviews in detail. Only a few of
>my customers do that. Mostly they have a friend or consultant that
>has a wireless something, and they just buy the same thing and blame
>their friend or consultant when it doesn't quite work.
Sometimes, which I think supports my point, but most rely on branding
and on the retail salesperson, which is why the return rate is so
critical.
>>>Customers perceived that two antennas are somehow
>>>better than one and considered a single antenna router to be inferior.
>
>>And they were right, whether they knew the exact reason or not.
>
>Sure. Perception is everything. Few can explain why two antennas are
>better, but intelligence and technology doesn't count with decisions
>based on perception.
I didn't say that. With all due respect, I think you're being way too
harsh and cynical. Knowing the exact reason is unimportant when the
market mechanism is working, as it is here. That's why branding is so
important. Consumers will mercilessly desert a brand that betrays them,
and loyally support safe brands even when a guru thinks some other
product might be better, because it really isn't better, since it hasn't
earned their market trust. What makes trust such a powerful force is
that it's so hard to earn and so easy to lose.
>There are other things that are amazingly important for retail sales.
>Color is one. Colors all have subliminal meanings. I walked in to a
>customer with a Watchguard SOHO router. It's in a bright red plastic
>box, apparently to capitalize on the firewall features. My customer
>asked if I had something in a different color? Huh? She said that it
>reminded her of blood, which made her feel awkward. I replaced it
>with an antiseptic white Netgear WG-614, which was deemed acceptable.
>
>Weight is also an important feature. Given two almost identical
>products, the average consumer will usually pick the heaviest product.
>There's a perception that you get more for your money if it's heavier.
>I learned this the hard way when designing marine radios. We
>literally put a lead brick inside the box and sales immediately
>improved.
I've been doing this much of my professional life, and my experience is
that these are just small factors. Change the color on a product that's
lost market trust and it's still toast.
>Criteria for commodity router selection (most important on top):
> 1. It's cheap.
> 2. A friend has one that works.
> 3. I've heard of the manufacturer from somewhere.
> 4. The box and color look cool.
> 5. It weighs like something that should work.
> 6. The literature is incomprehensible, so it must be powerful.
> 7. Larger numbers are always better.
> 108Mbits/sec instead of 54Mbits/sec.
> Is 802.11z later than 802.11b? 5.7GHz is bigger than 2.4Ghz.
> 8. The flashing lights sure look nice. What do they mean?
> 9. This box has more acronyms than the other box.
> 10. I read a review that said all I had to do is plug in the
> wireless router and it's ready to go.
>Optional:
> 11. Jeff L said it sucked so I guess I'll try it.
You left out some of the most important criteria:
0a. It's sold by my store.
0b. The salesperson in my store recommends it.
You seem to have a very low opinion of people. I think that's both
unwarranted and sad -- they may simply have different priorities than
you and me, which to them are valid, no matter what we might think of
them.
--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>
John Navas wrote:
> On Thu, 27 Jul 2006 14:33:38 -0400, "Bill Kearney"
> <wkearney99@hotmail.com> wrote in
> <fbednerfDvKemlTZnZ2dnUVZ_oydnZ2d@speakeasy.net> :
>
>>> OR do like I just did. Buy a "N" Router and force your next door guy to
>>> another channel. To piss him off put it on the same channel as he is. It
>>> does not affect yours, But it does his. :) My Motto in this case is what
>>> comes around goes around.
>> Hmmm, and with that sort of attitude I'd avoid standing anywhere near you
>> should thunderclouds start forming. Sounds like you're asking for it with
>> that sort of attitude.
>
> Amen. With a neighbor like that I'd probably move.
>
I bought this house. He is just a renter. I changed mine and then a day
or two later he change to match mine. I just got tired of it. So now I'm
in charge. :)
On Fri, 28 Jul 2006 01:18:17 GMT, Kevin Weaver
<kevinkeithweaver1@sbcglobal.net> wrote in
<44C965DB.8080208@sbcglobal.net>:
>John Navas wrote:
>> On Thu, 27 Jul 2006 14:33:38 -0400, "Bill Kearney"
>> <wkearney99@hotmail.com> wrote in
>> <fbednerfDvKemlTZnZ2dnUVZ_oydnZ2d@speakeasy.net> :
>>
>>>> OR do like I just did. Buy a "N" Router and force your next door guy to
>>>> another channel. To piss him off put it on the same channel as he is. It
>>>> does not affect yours, But it does his. :) My Motto in this case is what
>>>> comes around goes around.
>>> Hmmm, and with that sort of attitude I'd avoid standing anywhere near you
>>> should thunderclouds start forming. Sounds like you're asking for it with
>>> that sort of attitude.
>>
>> Amen. With a neighbor like that I'd probably move.
>>
>I bought this house. He is just a renter. I changed mine and then a day
>or two later he change to match mine. I just got tired of it. So now I'm
>in charge. :)
If you're going to send me email, at least have the courtesy to use a
valid return address; otherwise, please do not send me email -- I'll see
your responses here in any event. Thanks.
My apologies to everyone else.
--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>
John Navas wrote:
> On Fri, 28 Jul 2006 01:18:17 GMT, Kevin Weaver
> <kevinkeithweaver1@sbcglobal.net> wrote in
> <44C965DB.8080208@sbcglobal.net>:
>
>> John Navas wrote:
>>> On Thu, 27 Jul 2006 14:33:38 -0400, "Bill Kearney"
>>> <wkearney99@hotmail.com> wrote in
>>> <fbednerfDvKemlTZnZ2dnUVZ_oydnZ2d@speakeasy.net> :
>>>
>>>>> OR do like I just did. Buy a "N" Router and force your next door guy to
>>>>> another channel. To piss him off put it on the same channel as he is. It
>>>>> does not affect yours, But it does his. :) My Motto in this case is what
>>>>> comes around goes around.
>>>> Hmmm, and with that sort of attitude I'd avoid standing anywhere near you
>>>> should thunderclouds start forming. Sounds like you're asking for it with
>>>> that sort of attitude.
>>> Amen. With a neighbor like that I'd probably move.
>>>
>> I bought this house. He is just a renter. I changed mine and then a day
>> or two later he change to match mine. I just got tired of it. So now I'm
>> in charge. :)
>
> If you're going to send me email, at least have the courtesy to use a
> valid return address; otherwise, please do not send me email -- I'll see
> your responses here in any event. Thanks.
>
> My apologies to everyone else.
>
I did the reply to *all* If it was sent to you, my mistake.
On Fri, 28 Jul 2006 02:16:42 GMT, Kevin Weaver
<kevinkeithweaver1@sbcglobal.net> wrote in
<44C9738C.8030901@sbcglobal.net>:
>John Navas wrote:
>> If you're going to send me email, at least have the courtesy to use a
>> valid return address; otherwise, please do not send me email -- I'll see
>> your responses here in any event. Thanks.
>>
>> My apologies to everyone else.
>>
>I did the reply to *all* If it was sent to you, my mistake.
In Mozilla Thunderbird, hit Reply to just follow-up on the newsgroup --
Reply All also copies the poster by email, as can be seen in the
displayed reply addressing.
--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>
John Navas <spamfilter0@navasgroup.com> hath wroth:
>My professional experience in that business is quite different. The
>cost of returns, even if scrapped, is very high, typically measured as
>the cost of quality -- you have to take them back to be sure retailers
>aren't cheating you. Most manfs will at least retest them, because the
>vast majority of returns (>90%) are fully functional, and can easily be
>recouped as refurbs. If scrapped, they are usually at least broken down
>for parts, or at least recycled for valuable materials.
That depends on the value of the product. I've been told that the
handling and testing costs far exceeds the value of the hardware and
that it is cheaper to toss the returns. One manufacturer breaks open
the boxes, yanks the boards, tosses the plastic, and runs the boards
back through the manufacturing and test lines.
Certainly, the higher value products will probably have some method of
refurbishing or remanufacturing the returns. In the case of routers,
my guess is only about 80% are functional. The failures are
predominantly flash upgrade failures and power supply induced damage
(reverse polarity, too much voltage, AC instead of DC, etc). However,
the bottom of the line products go straight into the trash.
>Again, not that simple. What goes around, comes around. Retailers hate
>returns, and tend to trash whatever product is giving them the most
>grief, which directly leads to lower sales. No good manf is going to
>knowingly take that risk.
True. However, the manufactories make it worse by substituting
inferior revisions for existing products with the same product name
and packaging. The WRT54G v5 is a great example. Retailers had
little problems with the WRT54G v1.1 thru v4 until the v5 arrived.
This substitution of products under the name and packaging is done
specifically so that the retailers will not have a good excuse to
return the unsellable "old" products en masse when replaced by a
better new product. However, with the WRT54G v5, the replacement
product was defective and trashed the long history of Linksys selling
a superior product. In marketing, this is commonly called "pissing in
the soup". The customer can't tell the difference until they try it.
>>>And they were right, whether they knew the exact reason or not.
>>
>>Sure. Perception is everything. Few can explain why two antennas are
>>better, but intelligence and technology doesn't count with decisions
>>based on perception.
>I didn't say that.
I just reworded your premise. If they don't know the exact reason
they're doing something, they're basing their decision on perception,
not logic, reason, research, or even opinion. It just "feels" like
the right product with two antennas, or something similar.
>With all due respect, I think you're being way too
>harsh and cynical.
True. I should be more diplomatic and respectful of the American
consumer. However, that's no fun. Whether I'm cynical or not has
little to do with the validity of my assertions.
>Knowing the exact reason is unimportant when the
>market mechanism is working, as it is here.
I spent a few years working in marketing solely on trying to
understand those reasons. It was difficult because many reasons were
apparently irrational and illogical. Those that paid me found it very
important to know those reasons.
>That's why branding is so
>important.
Brand loyalty is a great replacement for knowledgeable buying. It
takes way too much effort to educate the customer. It's much easier
to create a good impression for the company or to reassure the
customer that they bought the right product.
>Consumers will mercilessly desert a brand that betrays them,
>and loyally support safe brands even when a guru thinks some other
>product might be better, because it really isn't better, since it hasn't
>earned their market trust. What makes trust such a powerful force is
>that it's so hard to earn and so easy to lose.
Generally true but there are a few odd exceptions. Many people will
latch onto a brand and continue to buy the brand, even though they
have had a less than desirable experience with its products. The
problem is that people just don't want to admit that they made a
mistake. I can rattle off some examples, but I don't wanna get
diverted there.
>I've been doing this much of my professional life, and my experience is
>that these are just small factors. Change the color on a product that's
>lost market trust and it's still toast.
Really? DLink has a history of regularly repackaging existing
products. In all cases, it represented a demonstrable increase in
sales. It isn't always a case of finding the right color. It's often
just a packaging change in order to get a "fresh" look on the shelves.
Color and packaging may not make the product, but it certainly can
ruin a good product if improperly selected.
>>Criteria for commodity router selection (most important on top):
>> 1. It's cheap.
>> 2. A friend has one that works.
>> 3. I've heard of the manufacturer from somewhere.
>> 4. The box and color look cool.
>> 5. It weighs like something that should work.
>> 6. The literature is incomprehensible, so it must be powerful.
>> 7. Larger numbers are always better.
>> 108Mbits/sec instead of 54Mbits/sec.
>> Is 802.11z later than 802.11b? 5.7GHz is bigger than 2.4Ghz.
>> 8. The flashing lights sure look nice. What do they mean?
>> 9. This box has more acronyms than the other box.
>> 10. I read a review that said all I had to do is plug in the
>> wireless router and it's ready to go.
>>Optional:
>> 11. Jeff L said it sucked so I guess I'll try it.
>You left out some of the most important criteria:
>
> 0a. It's sold by my store.
> 0b. The salesperson in my store recommends it.
OK, I'll accept that. It's a fair assumption that the salesman will
push the products he has in stock, not something that the customer has
to buy elsewhere.
>You seem to have a very low opinion of people. I think that's both
>unwarranted and sad -- they may simply have different priorities than
>you and me, which to them are valid, no matter what we might think of
>them.
Try not to read too much between my lines. I have no specific opinion
of people in general. I try to understand them, accept what I find,
and sometime offer my observations for those that might profit from
the experience. Joe Sixpack certainly has different priorities.
However, I suspect when faced with unfamiliar territory, we all can
fall into one of the aforementioned observations, rather than doing
the proper research. I've make a few spectacular purchasing mistakes
so I'm also not immune.
What are 2 antennas being used for? 