Bought one of these because I have a customer that has a long skinny
building that he wants to add wifi to and I was hoping the better receiver
and higher transmit power would offer him a little better coverage and from
what I can tell it does have a better radio.
I messed around with the stock firmware for a little while but I don't like
leaving things alone so I flashed it with DD-WRT V23 SP2 as I've done with
many WRT54G/L's, super easy.
What I am now curious about is what the recommended TX power output is for
this radio and if there are any options in DD-WRT that are either enabled by
default and don't need to be or anything that is disabled and should be
enabled..
>Bought one of these because I have a customer that has a long skinny
>building that he wants to add wifi to and I was hoping the better receiver
>and higher transmit power would offer him a little better coverage and from
>what I can tell it does have a better radio.
For long and skinny, put the wireless router at one end of the
building, and use a reflector to direct most of the power down the
length of the building:
<http://www.freeantennas.com>
>I messed around with the stock firmware for a little while but I don't like
>leaving things alone so I flashed it with DD-WRT V23 SP2 as I've done with
>many WRT54G/L's, super easy.
Yep. I like DD-WRT.
>What I am now curious about is what the recommended TX power output is for
>this radio
I read somewhere that DD-WRT will automatically recognize the
differences between the WRT54G and WHR-HP-G54 transmitters and adjust
the power ranges accordingly. I'm too lazy to verify if this is true.
One dumb question is just how high power is the Buffalo WHR-HP-G54
transmitter? The data sheets and web pages offer no numbers:
<http://www.buffalo-technology.com/products/product-detail.php?productid=124>
So, we go to the FCC ID web pile at:
<https://gullfoss2.fcc.gov/prod/oet/cf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout =500&calledFromFrame=N&application_id=165435&fcc_i d='FDI-09101577-0'>
where the test reports shows on page 29:
802.11b +24.5dBm (282mw)
802.11g +25.8dBm (380mw)
You could run those power levels and be the first to dominate the
neighborhood. Of course, your ranges will not be symmetrical. The
WHR-HP-G54 will transmit over a much larger area than it can receive
from a typical +15dBm (30mw) laptop radio client. What's a little
more intereference and pollution on an already crowed band?
Hint: Run as little xmit power as necessary. +20dBm (100mw) should
be more than enough. Any more is probably no better than jamming.
>and if there are any options in DD-WRT that are either enabled by
>default and don't need to be or anything that is disabled and should be
>enabled..
See the list of wireless options at:
<http://www.informatione.gmxhome.de/DDWRT/Standard/V23final/Wireless_Advanced.html>
I usually change:
Transmit rate Auto -> whatever speed is appropriate for backhaul.
AP Isolation Off -> On (isolate clients to prevent attacks)
Preamble Long -> Auto (unless you have very slow clients)
Make sure the defaults:
Frame Burst Disable
Afterburner Off
are set if you do *NOT* have any clients that need these features.
On the basic settings page at:
<http://www.informatione.gmxhome.de/DDWRT/Standard/V23final/Wireless_Basic.html>
there's some issue about which mode to use. If you have 802.11b
clients that need to connect, set it to "Mixed" mode. If you have
only 802.11g clients, use "G-only".
There are a huge number of settings that I setup and/or change on the:
Administration -> Management
Administration -> Services
pages. I can't offer any advise on setting up these pages without a
clue as to what you're doing.
"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
> For long and skinny, put the wireless router at one end of the
> building, and use a reflector to direct most of the power down the
> length of the building:
> <http://www.freeantennas.com>
Actually there phone/data room is close the the center of the building so it
will likely end up there.. hopefully with good coverage.
> I read somewhere that DD-WRT will automatically recognize the
> differences between the WRT54G and WHR-HP-G54 transmitters and adjust
> the power ranges accordingly. I'm too lazy to verify if this is true.
That's what I read also but I did not check it before I sold it off to a
friend (not customer with longish building).
So I just bought a WHR-HP-G54 and a WHR-G54S to do some harder testing on
and try and find out for myself exactly which one of these models is the
better router... or...whatever...
>
> One dumb question is just how high power is the Buffalo WHR-HP-G54
> transmitter? The data sheets and web pages offer no numbers:
> <http://www.buffalo-technology.com/products/product-detail.php?productid=124>
> So, we go to the FCC ID web pile at:
> <https://gullfoss2.fcc.gov/prod/oet/cf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout =500&calledFromFrame=N&application_id=165435&fcc_i d='FDI-09101577-0'>
> where the test reports shows on page 29:
> 802.11b +24.5dBm (282mw)
> 802.11g +25.8dBm (380mw)
> You could run those power levels and be the first to dominate the
> neighborhood. Of course, your ranges will not be symmetrical. The
> WHR-HP-G54 will transmit over a much larger area than it can receive
> from a typical +15dBm (30mw) laptop radio client. What's a little
> more intereference and pollution on an already crowed band?
I agree about not running more power than is necessary, I feel that 96mW is
plenty for most applications because even doubling power from there is only
a 3db increase which prolly wont account for much and doubling again (256)
is close to the max the radio will output.
I guess what I was really looking for was if the HP has the built in amp
what the best setting was so as not to over drive it's input.
> There are a huge number of settings that I setup and/or change on the:
> Administration -> Management
> Administration -> Services
> pages. I can't offer any advise on setting up these pages without a
> clue as to what you're doing.
As of right now all any of my Linksys and Buffalo routers are doing is
acting as a routers, firewall and ap's for small home LANs. We are building
a 802.11 network to link around town with and are looking for devices that
will allow people to access the network.. be it with these boxes or
something else such as http://www.wisp-router.com/itemdesc.asp?ic=LS2&eq=&Tp
Which is a very nice bridge but still needs a router behind it.. Less money
in two of the linksys or buffalo boxes if someone needs to save cash.
On Sun, 11 Feb 2007 01:48:02 GMT, "Adair Witner" <buhbear007@mail.com>
wrote in <mBuzh.74829$qO4.21709@newssvr13.news.prodigy.net> :
>"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
>
>> For long and skinny, put the wireless router at one end of the
>> building, and use a reflector to direct most of the power down the
>> length of the building:
>> <http://www.freeantennas.com>
>
>Actually there phone/data room is close the the center of the building so it
>will likely end up there.. hopefully with good coverage.
In that case, assuming you only have one floor to cover, you may want a
high-gain omni antenna; e.g.,
Buffalo 6.5 dBi High Gain Omni Antenna WLE-HG-NDR.
<http://www.buffalotech.com/products/wireless/wireless-accessories/65-dbi-high-gain-omni-antenna/>
--
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>
>"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
>
>> For long and skinny, put the wireless router at one end of the
>> building, and use a reflector to direct most of the power down the
>> length of the building:
>> <http://www.freeantennas.com>
>Actually there phone/data room is close the the center of the building so it
>will likely end up there.. hopefully with good coverage.
I'm not sure that's going to be such a great idea. The typical phone
room is usually full of electronics, some of which -might- generate
enough RFI to cause receive problems. I've only seen this once, so
it's unlikely, but still should be considered if there are problems.
The wires found on the walls of phone rooms make a truly impressive RF
shield. Think of it as a partial RF screen room. The doors on most
office building equipment rooms are metal (fire code requirement). The
walls have foil backed insulation (fire code requirement). The floors
and ceiling are usually poured concrete, which is rather impervious to
RF.
Basically, you have to get the signal into the hallway. I've only
done one PITA phone room installation. The building owner and
planning department would not allow me to install the access point in
the hallways. Even though I quoted chapter and verse from the NEC on
low voltage wiring, they were adamant. However, they would allow me
to install additional metal conduit from the phone room to the hallway
to route a non-powered antenna. So, the access point ended up in the
phone room closet with about 10ft of LMR-240 to a downward facing
patch antenna in the hallway.
>That's what I read also but I did not check it before I sold it off to a
>friend (not customer with longish building).
Beware of selling to friends. They have the irritating habit of
returning with questions, more questions, and even more questions.
>So I just bought a WHR-HP-G54 and a WHR-G54S to do some harder testing on
>and try and find out for myself exactly which one of these models is the
>better router... or...whatever...
Dunno. I've only used the WHR-HP-G54.
>I agree about not running more power than is necessary, I feel that 96mW is
>plenty for most applications because even doubling power from there is only
>a 3db increase which prolly wont account for much and doubling again (256)
>is close to the max the radio will output.
Rules-of-thumb:
6 dB is 4 times the coverage area.
12 dB is 4 times the range.
18 dB is 8 times the range.
or just:
range = 10^(dB/20)
Also:
3 dB is double the coverage area (for omni antenna).
6 dB is 4 times the coverage area.
or just:
coverage = 10^(dB/10)
However, that's for antennas, which offer a gain boost in both
transmit and receive. That's not the case with just increasing the
transmit power, which only works in one direction. If you increase
the power at both ends, you'll see a range increase. However, just
increasing the power at one end doesn't necessarily improve the usable
range if the return signal is marginal.
>I guess what I was really looking for was if the HP has the built in amp
>what the best setting was so as not to over drive it's input.
That's a problem with the WRT54G/GS series, where the internal power
amplifier doesn't stay particularly linear with increased drive. See
lousy spectrum analyzer photos at:
<http://explorer.cyberstreet.com/wrt54g/WRT54g-spectraloutput.html>
I keep wanting to make better photos, but never simultaneously have
the time, the inclination, or the test equipment. Sigh. Anyway,
everything 200mw and above start to look fairly bad with lots of
locally generated intermod products. I would say 100mw is safe with
150mw possible. There have also been persistent rumors of WRT54G
radios blowing up running at full (250mw) power.
The WHR-HP-54G apparently has a bigger power amplifier that has been
tested to perhaps 400mw. I don't think you have to worry about
overdriving it. However, I am worried that the settings in DD-WRT
don't correspond to the actual power output.
>> There are a huge number of settings that I setup and/or change on the:
>> Administration -> Management
>> Administration -> Services
>> pages. I can't offer any advise on setting up these pages without a
>> clue as to what you're doing.
>
>As of right now all any of my Linksys and Buffalo routers are doing is
>acting as a routers, firewall and ap's for small home LANs.
No. What I meant by what you're doing is what services (DHCP, HTTP
server, DNS relay, QoS, VPN, SNMP, etc) you're planning on using. No
two installations tend to be the same and these setting will vary
radically and there are not "standard" settings. Just go down the
list, see what you need, and enable/configure those.
>We are building
>a 802.11 network to link around town with and are looking for devices that
>will allow people to access the network.. be it with these boxes or
>something else such as http://www.wisp-router.com/itemdesc.asp?ic=LS2&eq=&Tp
>Which is a very nice bridge but still needs a router behind it.. Less money
>in two of the linksys or buffalo boxes if someone needs to save cash.
Ok, so you're building a WISP (wireless ISP). Equipment that is
suitable for high reliability, high traffic, and a large number of
users is quite different from the common commodity wireless router.
For example, you will probably want to use access points instead of
routers. Your router will probably be a Cisco something that can
handle the volume and the abuse. You'll need some form of traffic
manager to prevent bandwidth hogging. You'll need to implement
logging, monitoring, and abuse detection.
Equipment will be the least of your problems. The real problems will
be how to manage and bill the users, how to deal with problems (i.e.
support), and how to guarantee reasonably reliable service in a very
crowded and polluted frequency band. Some light reading:
<http://www.isp-planet.com/fixed_wireless/>
<http://www.isp-planet.com/resources/how_to/fw.html>
Basically, you need to have *ALL* the features and facilities of a
wire line ISP, with the added bonus of a marginally reliable method of
delivery. Are you sure you want to do this?
"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
>
> I'm not sure that's going to be such a great idea. The typical phone
> room is usually full of electronics, some of which -might- generate
> enough RFI to cause receive problems. I've only seen this once, so
> it's unlikely, but still should be considered if there are problems.
> The wires found on the walls of phone rooms make a truly impressive RF
> shield. Think of it as a partial RF screen room. The doors on most
> office building equipment rooms are metal (fire code requirement). The
> walls have foil backed insulation (fire code requirement). The floors
> and ceiling are usually poured concrete, which is rather impervious to
> RF.
You make a good point and maybe that's the way it is in Cali but this is not
going to be the case with this phone room.
I am a telephone tech for a company that does voice and data cabling both
copper and fiber. We do phones, security, cameras, nursecall systems as well
as other random stuff that as well as being an amateur radio operator makes
me very aware of where to place equipment.
> Beware of selling to friends. They have the irritating habit of
> returning with questions, more questions, and even more questions.
Thats ok I don't mind helping my friends. most of them pay me for my time
unless I don't feel like charging them.
>
> Rules-of-thumb:
> 6 dB is 4 times the coverage area.
> 12 dB is 4 times the range.
> 18 dB is 8 times the range.
> or just:
> range = 10^(dB/20)
>
> Also:
> 3 dB is double the coverage area (for omni antenna).
> 6 dB is 4 times the coverage area.
> or just:
> coverage = 10^(dB/10)
>
> However, that's for antennas, which offer a gain boost in both
> transmit and receive. That's not the case with just increasing the
> transmit power, which only works in one direction. If you increase
> the power at both ends, you'll see a range increase. However, just
> increasing the power at one end doesn't necessarily improve the usable
> range if the return signal is marginal.
Good stuff to keep in mind however I read that the buffalo has a better
receiver over say the wrt's so i'm just trying to match them up accordingly.
>
> That's a problem with the WRT54G/GS series, where the internal power
> amplifier doesn't stay particularly linear with increased drive. See
> lousy spectrum analyzer photos at:
> <http://explorer.cyberstreet.com/wrt54g/WRT54g-spectraloutput.html>
Nice pictures.
>
> The WHR-HP-54G apparently has a bigger power amplifier that has been
> tested to perhaps 400mw. I don't think you have to worry about
> overdriving it. However, I am worried that the settings in DD-WRT
> don't correspond to the actual power output.
Ditto, but I read along with the power amp comes a preamp and or better
tweakable receiver.
> Ok, so you're building a WISP (wireless ISP). Equipment that is
> suitable for high reliability, high traffic, and a large number of
> users is quite different from the common commodity wireless router.
> For example, you will probably want to use access points instead of
> routers. Your router will probably be a Cisco something that can
> handle the volume and the abuse. You'll need some form of traffic
> manager to prevent bandwidth hogging. You'll need to implement
> logging, monitoring, and abuse detection.
>
> Equipment will be the least of your problems. The real problems will
> be how to manage and bill the users, how to deal with problems (i.e.
> support), and how to guarantee reasonably reliable service in a very
> crowded and polluted frequency band. Some light reading:
> <http://www.isp-planet.com/fixed_wireless/>
> <http://www.isp-planet.com/resources/how_to/fw.html>
> Basically, you need to have *ALL* the features and facilities of a
> wire line ISP, with the added bonus of a marginally reliable method of
> delivery. Are you sure you want to do this?
You make some pretty big assumptions about what we plan to do and actually
all of them are wrong.
The 802.11 network is comprised of people who are mostly ham radio operators
that are interested in doing something different than just talking on there
radio. Our group did a presentation at one of the local ham club meetings
and people were fasinated in almost every aspect of the system.
Computers and the internet have drawn alot of people away from the radio and
are trying to do our part to bring them back and renew some form of
interest.
Almost everyone nowa days has a broadband internet connection and some form
of small wireless network in there home and this network is a way for all of
us to learn something and get people active as well as possible provide
community service with the system as it grows.
Our goal is to offer services over the WLAN such as, intranet website and
forums, FTP site, APRS and Packet traffic (between real nodes) and whatever
else anyone wants to include such as IP cameras and just about anything else
that can be converted and sent in an ethernet packet.
We do not plan to sell internet service to anyone.
On Sun, 11 Feb 2007 20:08:08 GMT, "Adair Witner" <buhbear007@mail.com>
wrote in <IIKzh.75125$qO4.50178@newssvr13.news.prodigy.net> :
>"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
>> However, that's for antennas, which offer a gain boost in both
>> transmit and receive. That's not the case with just increasing the
>> transmit power, which only works in one direction. If you increase
>> the power at both ends, you'll see a range increase. However, just
>> increasing the power at one end doesn't necessarily improve the usable
>> range if the return signal is marginal.
>
>Good stuff to keep in mind however I read that the buffalo has a better
>receiver over say the wrt's so i'm just trying to match them up accordingly.
I seriously doubt there is a significant difference. All low-end Wi-Fi
devices use a limited selection of standard chipsets, all of which
deliver roughly comparable radio performance. Antenna(s) are what
matters most.
--
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" <spamfilter1@navasgroup.com> wrote in message
> I seriously doubt there is a significant difference. All low-end Wi-Fi
> devices use a limited selection of standard chipsets, all of which
> deliver roughly comparable radio performance. Antenna(s) are what
> matters most.
I totally agree but coming from a back ground of radio I know that everyone
has a different idea about how to do the same things and some people do it
better IMHO.
My friend that I sold my WHR-HP-G54 to had been through two different
wireless routers and was unable to keep his G4 Mac connect through two walls
of his house.. After doing some inspecting with the WiSpy and tweaking on
the router (which was also done days before the buffalo swap) he is able to
maintaine a 100% solid connection to the router now which is sitting in the
same spot as all the others have been..
So is it the better antenna on the buffalo vs the netgear and whichever
other router he had or could the maybe slightly better receiver and more
transmitter power be helping a little?
Our next step if he was still having trouble was to install another antenna
on the router.
I'm a big fan of using good antenna's but even a good antenna on a crappy
radio wont make it work that much better.
Here in our installation, for our base station, I went from a WRT54G
to a WHR-G54S to a WHR-HP-G54.
The Buffalos are on DD-WRT, the original Linksys v5 was stock FW.
Although I failed to do thorough comparison testing, especially with
the Linksys, I can make a few comments:
First I had the linksys v5 going there, but decided to go with the
Buffalo WHR-G54S and DD-WRT. I sold the Linksys.
I was running the WHR-G54S on DD-WRT V23sp1 at 84mw transmit. All
was well. Then I subbed in the WHR-HP-G54 on DD-WRTv23sp2 and
started testing. Everything else, including the external antenna rig,
remained the same, and I tested it on the same afternoon.
With the HP set at 28mw transmit, people noted that they were getting
weaker signals than with the non-HP Buffalo at 84mw. One client with
great reception went from 5 bars to 4, another marginal went from 2
bars to 1.
I cranked up the power on the HP to 84mw and everybody had the same
signal strength showing on their clients.
Conclusion: 84 on the HP (with v23sp2) gives you about what 84 on the
non-HP gives. The linksys I had at the base was weaker still, but it
had stock firmware. Why is 84mw on the HP working like 84mw on the
non-HP ? Well, after a thorough discussion on the DD-WRT forums....
nobody knows !
"Brainslayer" (the DD-WRT maestro) isn't talking. See: http://www.dd-wrt.com/phpBB2/viewtopic.php
t=1595&postdays=0&postorder=asc&start=60&sid=6b479 dd2c2bfa0b52d07011230a9b059
or see topic: "Buffalo WHR-G54S vs WHR-HP-G54S"
Be sure to read all the way through as there are various different
conclusions made along the way. The best takeaway I got from this
thread is: use V23SP2 and go with 84-100 but it might be better to use
SP1 and go with 10mw. They changed something from SP1 to SP2 but
they're not telling. My guess is that they don't exactly know how the
change affected output and are waiting for the users to sort it out.
I can add that the other day I cranked the HP up to 150 mw when I
connected some distant clients. It barely improved (as expected)
their received signal, but then, an hour later, when it was getting
baked in the sun, it stopped working. (I forget the details, sorry)
Upon inspection, it was hotter than usual. I cooled it off, rebooted
and immediately knocked it back down to 84. Worked fine again. I
don't know what really happened. I'm not trying higher power again (
over 100mw) on SP2.
I'm planning to put in sp1 sometime (at 10mw) and see how it works.
OK. On the RECEIVE side, the HP really shines and I can see a greatly
increased signal quality and level as shown in the DD-WRT status. I'm
basically getting 6-10 dB improvement on the receive end with the HP
over the non-HP. Funny, but it seems that the HP is more a "rabbit"
than an "alligator".
Somebody said the HP actually has a different Broadcom chip than the
non HP - it's an "E" (for enhanced?)
Quote:
"The BCM5352E also features Broadcom's new BroadRange technology, a
standards-compliant hardware enhancement that extends the range of 54g-
based wireless devices. The technology uses advanced signal processing
techniques to provide the industry's best receive sensitivity,
enabling Wi-Fi users to maintain high-speed wireless connections at up
to 50% further from an access point.
BroadRange technology uses advanced digital signal processing
techniques to provide the highest receive sensitivity of any 802.11g
chipset on the market. "
Somebody else said:
"The unit has actually 2 amps. There is one on the Tx line, and one on
the Rx line. That is clearly visible on the schematics and photos
found in the forum. The amplifier, that was affected by the boardflags
was the Rx amp. And the amplifier affected by the 10mW setting is the
Tx amp. (It even makes sense if you really think about it).
The Tx amp is Anadigics AWL6153 "
All this came off the DD-WRT forum. I don't know if they are correct.
I now have another Linksys WRT-54G V2.2 running DD-WRT about 400
meters away from the Buffalo HP. It's working as a repeater in WDS.
The linksys seems weaker on the receive side. Maybe on the transmit
side too.
Both are set at 84 mw transmit.
On the Buffalo HP side, I see a 19% signal quality, or -78 signal.
On the linksys side, DD-WRT reports -88 signal at 8% quality.
Now, one might assume that the Linksys has a stronger signal and
that's why it shows stronger on the Buffalo HP, but based on all the
other indications, I see it as another sign that the HP is 10 db more
sensitive than the standard Broadcom device.
In sum, from my experience in the field here: Set the HP at 10mw with
v23sp1 or 84mw with v23sp2. Don't expect more power than the regular,
but expect much better sensitivity. Don't know why that is for me.
Maybe 10mw with sp1 is better and I need to change versions !
>You make a good point and maybe that's the way it is in Cali but this is not
>going to be the case with this phone room.
You're lucky. Most of the phone rooms I've dealt with are in the most
RF disgusting locations. This one isn't an RF screen room but is
fairly typical of what I get to deal with. Behind the plywood is
something I've only seen once, foil backed drywall. The floor is
concrete and the ceiling is foil backed fiberglass matting. The door
is solid core wood which passes RF just fine. However, the foil
wasn't the big problem. This phone room is on the 2nd floor and
overlooks a mess of other 2.4Ghz users. That includes a headset
distributor that has an unshielded test bench. Way too much
interference.
>I am a telephone tech for a company that does voice and data cabling both
>copper and fiber. We do phones, security, cameras, nursecall systems as well
>as other random stuff that as well as being an amateur radio operator makes
>me very aware of where to place equipment.
Ok. I won't lecture you on RF transmission through various materials.
>> Beware of selling to friends. They have the irritating habit of
>> returning with questions, more questions, and even more questions.
>
>Thats ok I don't mind helping my friends. most of them pay me for my time
>unless I don't feel like charging them.
I have friends and I have customers. The difference is that the
customers pay me.
>Good stuff to keep in mind however I read that the buffalo has a better
>receiver over say the wrt's so i'm just trying to match them up accordingly.
Where did you read that? I'm curious if whomever came up with that
line actually did any measurements (and how they did the
measurements). Measuring RF receive sensitivity for 802.11 is both a
mess and expensive. The required BER (bit error rate or packet error
rate) testers are expensive. Very few even bother to specify how they
measured it, and to what BER reference point.
I've been playing with DLinks numbers from their data sheets lately.
Judging by the distribution, I think they actually measure the
sensitivity and post the results. See:
<http://802.11junk.com/jeffl/rx-sens/receiver%20sensitivity.htm>
The 5dB variation among various models is actually fairly large but
typical of what I've seen for setup, calibration, and cable errors.
Both the WHR-HP-G54 and the WRT54G/GS/GL use the Broadcom BCM2050 RF
chip in all models. This is clue on the architecture:
<http://www.hotchips.org/archives/hc15/2_Mon/11.broadcom.pdf>
Hmmm... 4dB system noise figure.
Note the rx sensitivity curves on Pg 28 and 35. Basically, they're
the same for all boards that use this chip with some issues that may
cause the sensitivity to deteriorate:
1. The numbers may not include the losses through the TR switch, BPF
(band pass filter) or diversity switch. (I can't tell as there are no
test conditions specified).
2. The numbers do not include deterioration caused by digital noise
pickup from the baseband, router, and switch chips on the same circuit
board.
3. The numbers do not include G10/FR4 circuit board losses, which can
be substantial.
Barf. You can't see the graticule so I can't overlay the FCC spectrum
mask to see if it will still pass Part 15.247 certification. The
upper grid line is not visibly calibrated so I can't check if it's
actually putting out the power claimed.
>Ditto, but I read along with the power amp comes a preamp and or better
>tweakable receiver.
Well, I'll break open the box and take a look (when I have time). It's
possible. I can't tell from the type certification pictures.
<https://gullfoss2.fcc.gov/prod/oet/cf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout =500&calledFromFrame=N&application_id=165435&fcc_i d='FDI-09101577-0'>
>The 802.11 network is comprised of people who are mostly ham radio operators
>that are interested in doing something different than just talking on there
>radio. Our group did a presentation at one of the local ham club meetings
>and people were fasinated in almost every aspect of the system.
Mostly hams? Get them licensed.
Like ARRL's (HSMM) High Speed MultiMedia Radio or Hinternet? If you
do it on anything other than 2.4GHz or 5.7GHz, I'm all for it. That's
improving the state of the art, experimentation, etc. Otherwise it's
just another Wi-Fi WLAN. In other words, build something, not just
buy it off the shelf.
Also, of the dozen or so over-powered access points I've tracked down,
2 of them were owned by hams claiming that their ham license entitles
them to trash all unlicensed operation.
<http://en.wikipedia.org/wiki/Hinternet>
>Computers and the internet have drawn alot of people away from the radio and
>are trying to do our part to bring them back and renew some form of
>interest.
Winlink, APRS, PSK31, synchronous CW, STV, etc all use computers.
>Almost everyone nowa days has a broadband internet connection and some form
>of small wireless network in there home and this network is a way for all of
>us to learn something and get people active as well as possible provide
>community service with the system as it grows.
>Our goal is to offer services over the WLAN such as, intranet website and
>forums, FTP site, APRS and Packet traffic (between real nodes) and whatever
>else anyone wants to include such as IP cameras and just about anything else
>that can be converted and sent in an ethernet packet.
>We do not plan to sell internet service to anyone.
>Somebody said the HP actually has a different Broadcom chip than the
>non HP - it's an "E" (for enhanced?)
Unfortunately, the two photos of the HP and non-HP versions cannot
offer much help. There's a shield can over the RF section and a head
sink covering the router chip on the non-HP.
<http://img122.imageshack.us/my.php?image=whrg54s8oy.jpg>
<http://img114.imageshack.us/my.php?image=whrhpg544hf.jpg>
>"The BCM5352E also features Broadcom's new BroadRange technology, a
That's the router and ethernet switch chip as a "system on a chip". No
RF involved.
The chip also varies depending on WRT54G/GS/GL firmware version. See
table at bottom of:
<http://www.linksysinfo.org/forums/showthread.php?t=47124>
Most of the current WRT54G/GS/GL models use the BCM5352 chip.
Look at the WHR-HP-G54 photo at:
<http://img114.imageshack.us/my.php?image=whrhpg544hf.jpg>
Notice the BCH2050 chip labeled IC13 in the general lower left area.
That's the radio section. There is an obvious TX power amplifier
labeled IC3 (large square thing to left and down from the BCH2050).
There appears to be an RX MMIC? RF amplifier as TR2, but I'm not sure.
I guess I have to crack open mine and take some photos.
>Most of the current WRT54G/GS/GL models use the BCM5352 chip
Ah. I see that the v2.2 WRT has the same pair of chips as the HP: the
5353E and the 2050.
So that is obviously not what makes the HP the more sensitive one....
> Look at the WHR-HP-G54 photo at:
> <http://img114.imageshack.us/my.php?image=whrhpg544hf.jpg>
> Notice the BCH2050 chip labeled IC13 in the general lower left area.
> That's the radio section. There is an obvious TX power amplifier
> labeled IC3 (large square thing to left and down from the BCH2050).
> There appears to be an RX MMIC? RF amplifier as TR2, but I'm not sure.
> I guess I have to crack open mine and take some photos.
>
Great. It would be nice to understand why it shows such an improved
signal level - as measured by DD-WRTs signal metering.
When will somebody sort out the amp thing in the HP and DD-WRT? I
would've expected to see more transmit power from the HP than the non-
HP in the field. But maybe cranking up the main chip in the
unamplified router has the same effect, in a dirtier or hotter way...
Seeing as I seem to have a "rabbit", I'd like to give it more voice,
you could say, get the transmit back up to receive level. I wish I had
tested the HP with Buffalo FW before flashing it, to get a reference
level.
Steve
John Navas wrote:
> On Sun, 11 Feb 2007 20:08:08 GMT, "Adair Witner" <buhbear007@mail.com>
> wrote in <IIKzh.75125$qO4.50178@newssvr13.news.prodigy.net> :
>
>
>>"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
>
>
>>>However, that's for antennas, which offer a gain boost in both
>>>transmit and receive. That's not the case with just increasing the
>>>transmit power, which only works in one direction. If you increase
>>>the power at both ends, you'll see a range increase. However, just
>>>increasing the power at one end doesn't necessarily improve the usable
>>>range if the return signal is marginal.
>>
>>Good stuff to keep in mind however I read that the buffalo has a better
>>receiver over say the wrt's so i'm just trying to match them up accordingly.
>
>
> I seriously doubt there is a significant difference. All low-end Wi-Fi
> devices use a limited selection of standard chipsets, all of which
> deliver roughly comparable radio performance. Antenna(s) are what
> matters most.
>
Hmmm,
I thought HP meant higher power output (with built-in amp.) Anyhow my
household coverage improved with this router from Linksys one.
"seaweedsteve" <seaweedsteve@gmail.com> wrote in message >
> I'm planning to put in sp1 sometime (at 10mw) and see how it works.
Post back when you test this.
>
> In sum, from my experience in the field here: Set the HP at 10mw with
> v23sp1 or 84mw with v23sp2. Don't expect more power than the regular,
> but expect much better sensitivity. Don't know why that is for me.
> Maybe 10mw with sp1 is better and I need to change versions !
This is good info to have and exactly the type of discussion I was hoping to
see out our people who have actually used them so thanks again.
I will have WHR-HP-G54 and a WHR-G54S here in a few days that along with my
spair WRT54GL will do some testing before and after flashing with DD-WRT.
"seaweedsteve" <seaweedsteve@gmail.com> wrote in message >
> Seeing as I seem to have a "rabbit", I'd like to give it more voice,
> you could say, get the transmit back up to receive level. I wish I had
> tested the HP with Buffalo FW before flashing it, to get a reference
> level.
> Steve
>
I plan on doing some testing with stock firmware when I get both buffalo
routers in hand in the next few days..
Anyone want to reccomend some testing methods?
I have two WRT54GL routers both with DD-WRT 23 SP2 and a few wireless cards
with different antennas.
I can monitor signal levels from several points using different radios and
antennas. I can create WDS links from all three routers to the other
linksys. etc..
>
> I consider this whole situation to be a complete can of
> worms right now. Fortunately, with stock firmware my modem
> seems to be working quite well right now, so long as I don't
> get carried away with bittorrent stuff. Power-wise, my
> laptop always shows maximum signal strength and connection
> speed. So I'm gonna leave it as is until everything is
> sorted out.
>
> Or maybe flash Tomato instead. :-)
I agree, of course. I will add that it's a fairly happy can of worms,
no real problems, it works well enough. Just less understanding of
our controls than some of us like. It's still amazing that we get
this. I paid $40 for my the HP and it's so much more than $40 or $60
will get in other realms. Hell, it's the cost of ONE auto tire. A
plastic toyota TRIM piece costs more... Amazing tools at negligable
cost.
Anyway, we want more info, but I don't regret putting dd-wrt on the
buffalo HP. I just regret testing it first.
On Feb 12, 10:28 pm, "Adair Witner" <buhbear...@mail.com> wrote:
> I plan on doing some testing with stock firmware when I get both buffalo
> routers in hand in the next few days..
> Anyone want to reccomend some testing methods?
> I have two WRT54GL routers both with DD-WRT 23 SP2 and a few wireless cards
> with different antennas.
> I can monitor signal levels from several points using different radios and
> antennas. I can create WDS links from all three routers to the other
> linksys. etc..
>
> Adair
I imagine the real radio dudes will have something to say, but
obviously you want setups that are as much the same as possible.
Control over variations. Luckily the signal strength is relative; as
long as the measurement is steady and repeatable, than it's useful for
comparison to me. Also, outdoor range is what I care about and will
give me the best idea.
Maybe this: WRT54GL in DDWRT as your base station.
Maybe a high gain antenna, maybe stock.
Clear outdoor LOS, clear fresnel.
Test all three other routers (WRT, WHR, WHR-HP at fixed distances and
compare realtime signal readings on the signal meter in the base
station status window.
Swap out the client ends in the same time period (afternoon- or
evening?) to avoid too much climate variation.
For test distances choose several or maybe just find the limit of the
weakest router/FW setup and measure what the betters can get. Or
measure the max distance for each to connect at 12or 18 Mbps. That's
what I wanna know, anyway. Othersmay want to know how close each has
to be to get a connection at 54,128 or a certain thruput.
Measurement. The base has DD-WRT, so you can use it's signal meter to
measure the TRANSMIT power of all permutations of client. Transmit
power is easiest.
RECEPTION: For the clients that have DD-WRT, you can compare their
signal readings to see how sensitivity varies as you swap them out in
the connection to the controlled base station.
Maybe Jeff will have something to say about Bit Error Rates and such.
For testing the Buffalos or Linksys reception w stock FW, um....Well,
measuring and comparing reception for each hardware rig across various
firmwares, may be the hardest part.
Back to transmission: another transmit power test for each router hw/
fw rig would be to use Netstumbler with a proxim or some other fully
compatible card and, keeping your laptop fixed at a given distance,
swap out each router/FW config as a base station. Save and compare
the data from NetStumbler for each.
WDS. Security. Should you be in WDS or just cliet? With or without
security? With WPA-TKIP the minimum for how we actually use it....
I look forward to hearing about what you are getting.
>1. Nobody has ever formally tested the HP with stock
>firmware versus any DD-WRT version to see if DD-WRT controls
>either transmit or receive power the same way as the stock,
>or specifically whether any version of DD-WRT achieves the
>same transmit power in the HP as the stock firmware.
True. More specifically, the manner in which most users are doing
their testing is IMHO rather useless. For example, almost all users
rate their improvements based on increases in the signal strength on
either the client or using Netstumbler. That's fine but the real
indication of improvements is in an increase in S/N ratio and a
corresponding increase in thruput. Many such measurements are made
without any traffic moving, which tends to reflect the last reading
instead of the current conditions.
If proper equipment and measuring techniques are not available, then I
can recommend a simple alternative. Fix the wireless speed in the
access point to 54 Mbits/sec. Start playing some streaming video or
initiate a download from a local server (or get some traffic moving).
Start walking away with the laptop until the download craps out. It
will be quite sudden and obvious as there will not be any compensation
due to slowing down the wireless connection rate when the speed is
nailed to 54 mbits/sec. Then, change whatever your testing (new AP,
better antennas, etc) and take another walk. The longer range wins.
>2. Nobody has ever demonstrated that the HP has more
>transmit power than the regular WHR, or than the Linksys
>WRT.
The FCC test results for the WHR-HP-G54 rate the unit at:
802.11b +24.5dBm (282mw)
802.11g +25.8dBm (380mw)
Actually, the 802.11g output is somewhat lower at the higher OFDM
speeds but that also applies to most 802.11g devices.
Typical output from the WRT54G is +17dBm (50mw). That's about 8dB
less than the Buffalo HP. That's 2.5 times improvement in range,
which is where Buffalo gets it's advertised 3x improvement in range.
range = 10^(dB/20)
However, you're correct that nobody has bothered to put a watts
guesser or spectrum analyzer on the output to verify the numbers.
>Several have demonstrated a clear difference in
>receive sensitivity in the HP with the right board flags
>set in DD-WRT.
No, they've demonstrated an increase in receive *GAIN* by enabling an
RF amplifier inside the BDM-2050 chip. This amplifier is normally
disabled when using an external amplifier such as the one that appears
to be on the WHR-HP-G54 circuit board. Having the 2nd amplifier
running will not improve the sensitivity as the sensitivity is almost
totally determined by the first RF amp. It will increase the signal
and noise equally (plus adding it's own noise) resulting in zero net
gain in sensitivity. However, it will reduce the dynamic range by
lowering the overload point, and will really look impressive on
Netstumbler looking only at the signal part of the S/N ratio.
>Claims of extended range for the HP on the
>Buffalotech website do not necessarily mean it has more
>transmit power - indeed, the manuals for the HP and the
>regular both show the same transmit power in the specs.
Huh? Neither data sheet show anything about power output. Zero,
zilch, nothing. Only the 3x, 8x and other marketing hype. See for
yourself.
<http://www.buffalo-technology.com/documents/pdf/WHR-HP-G54_DS.pdf>
<http://www.buffalo-technology.com/documents/pdf/WHR-G54S_DS.pdf>
However, the FCC data is much more accurate. See the test reports at:
<https://gullfoss2.fcc.gov/prod/oet/cf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout =500&calledFromFrame=N&application_id=165435&fcc_i d='FDI-09101577-0'>
<https://gullfoss2.fcc.gov/prod/oet/cf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout =500&calledFromFrame=N&application_id=373093&fcc_i d='FDI-04600264-0'>
The WHR-G54S shows at TX power output of:
802.11b +19.1dBm (80mw)
802.11g +16.0dBm (40mw)
That's considerably less than the WHR-HP-G54.
>3. Nobody knows which version of DD-WRT actually works best
>with the HP.
Agreed. Also, nobody seems to know how to test what works best.
>I consider this whole situation to be a complete can of
>worms right now. Fortunately, with stock firmware my modem
>seems to be working quite well right now, so long as I don't
>get carried away with bittorrent stuff. Power-wise, my
>laptop always shows maximum signal strength and connection
>speed. So I'm gonna leave it as is until everything is
>sorted out.
Bah. All I can say is that my 3 Buffalo WHR-HP-G54 routers works as
well or the same as those with the stock firmware. However, I'll
admit that I haven't done any real testing other than the usual
empirical guesswork. Just my general impression.
>I plan on doing some testing with stock firmware when I get both buffalo
>routers in hand in the next few days..
>Anyone want to reccomend some testing methods?
I'll assume you do NOT have any RF test equipment.
1. Use IPerf to get performance statistics at various ranges, power
levels, and through varies number of walls. Try it with the speed set
to "auto" and also locked to the highest available speed
(54Mbits/sec). Also, experiment with various wireless settings. Try
to roughly duplicate the IxChariot found on:
<http://www.smallnetbuilder.com>
<http://www.smallnetbuilder.com/content/view/26563/53/>
Do the test with one laptop, where nothing changes during the test.
Don't try to optimize anything or squeeze the last bit of range out of
the laptop. Just run the test for a comparison and record the
conditions including:
1. Make and Model
2. Firmware and exact version
3. Power setting
4. Range
5. Number of walls
6. Iperf Upload Mbits/sec
7. Iperf Download Mbits/sec
8. Indicated connection speed on client.
9. Any other changes (antenna, 802.11b compatibility, other
settings, orientation, position of moon).
Note that I did NOT include signal level and SNR. While these would
be interesting, I think they will just confuse the issue. The basic
question is "how far and how fast"? An Excel spreadsheet would be
handy.
2. Fix the wireless speed in the access point to 54 Mbits/sec. Start
playing some streaming video or initiate a download from a local
server (or get some traffic moving). Start walking away with the
laptop until the download craps out. It will be quite sudden and
obvious as there will not be any compensation due to slowing down the
wireless connection rate when the speed is nailed to 54 mbits/sec.
Then, change whatever your testing (new AP, better antennas, etc) and
take another walk. The longer range wins. Also try it with various
settings such as 802.11b compatibility, frame burst mode, Turbot-G,
etc. Leave the settings on the laptop alone.
>I have two WRT54GL routers both with DD-WRT 23 SP2 and a few wireless cards
>with different antennas.
>I can monitor signal levels from several points using different radios and
>antennas. I can create WDS links from all three routers to the other
>linksys. etc..
Keep it simple. Try to change only one thing at a time.
After reading Jeff's post, I realize that I should've kept my mouth
shut about testing. It's so tempting to put some sort of faith in
those signal meters....
>But will that let the router communicate with a client at a
>longer range, or at a faster speed, or both?
Good, but slightly ambiguous question.
There are exactly 3 parameters that are involved.
1. Range
2. Speed (mbits/sec)
3. BER or PER (bit error rate or packet error rate)
You can trade any one of these for the others. For example, if you
lock the speed to 54Mbits/sec and start walking, the BER will increase
with range until it craps out. However, if you let the speed remain
at "auto", the speed will drop as you walk, keeping the BER constant
(at about 8% PER), until it totally craps out. You can go much
farther if the speed is allowed to drop but of course, much slower.
Notice that I didn't throw signal level into the previous explanation.
That's because it's a fixed function of the BER or PER. It's a family
of curves that relate signal level, Signal to Noise level, and
BER/PER. If you know one, you can derive the others. I could replace
the BER/PER in the above list of 3 parameters with SNR (or signal and
noise levels) and get the same results.
>I thought I
>had seen reports in the forum of people getting a lot
>farther on their "walk tests" using an HP. Would the extra
>receive gain produce that result?
Yes, it will. It's a symmetry problem. Let's try it with a simple
WHR-HP-G54 and laptop system. To keep things simple, let's use the
numbers for 54MBits/sec and lock the speed at 54Mbits/sec.
WHR-HP-G54 Laptop
TX power +24dBm +15dBm
Antenna gain +2dBi 0dBi
RX sens -66dBm -66dBm
I'm assuming identical receivers at this point, which is not a very
wonderful assumption. I'm trying to use realistic numbers but the
receive sensitivity is a best guess.
The gain from the WHR-HP-G54 to the laptop is:
24 + 2 + 0 - 66 = -40 dB
and in the other direction is:
15 + 0 + 2 - 66 = -49 dB
Therefore, there is 9 dB more system gain in one direction. During
the walk test, the receiver on the WHR-HP-G54 will crap out before the
one on the laptop.
So, if the receiver sensitivity (not the gain) on the WHR-HP-G54 were
to improve by some mythical amount, the range would increase because
the WHR-HP-G54 would hear the laptop furthur, while the laptop would
continue to hear the WHR-HP-G54 over the same distance. This is the
alligator effect.
The problem is that it's highly unlikely that tinkering with the
receive pre-amplifier or onboard 2nd pre-amp is going to produce a 9dB
improvement in receive sensitivity. Certainly GaAsFET front end
amplifiers will help by perhaps 2-3dB, but not 9dB. I've been
recording the receive sensitivities of various devices and vendors and
find that the spread is rather large among those that bother to
measure the sensitivity, but not enough to assume that the WHR-HP-G54
is among the better units.
Not even close to finished:
<http://802.11junk.com/jeffl/rx-sens/receiver%20sensitivity.htm>
Frankly, what I'm seeing is widespread guesswork among vendors on
receiver sensitivity. For example, I just traversed the Ubiquiti web
pile grabbing rx sensitivity numbers from the spec sheets. What I
found is that all 2.4Ghz devices seem to have exactly the same
sensitivity at all speeds and corresponds exactly to the published
specs for the Atheros chipset. Yeah, right. Never mind the losses
through the maze of connectors inside the box before the signal gets
to the Atheros chipset.
>The data sheets may not, but the operator's manuals do.
>Here's an excerpt from my HP manual. I don't have it now,
>but my memory is that the WHR-G54S was exactly the same,
>both as to transmit power and receive sensitivity:
>
> > Nominal Output Power: 19dBm (802.11b), 16dBm (802.11g)
That agrees with the FCC data for the WHR-G54S.
> > Receiver Sensitivity -83 dBm -87 dBm -91 dBm -94 dBm
> > (depends on data rate)
Nice of them to specify at what speeds those numbers were conjured.
Extra credit if they specify which procedure was used and at what
BER/PER they were tested.
> > Delay Spread (at FER of <1%) 65 ns 225 ns 400 ns 500 ns
> > (depends on data rate)
That's a measure of how much multipath and reflections the chipset can
handle.
>Well, I'll continue to watch things with great interest. I
>should also say that I've been very impressed with the HP's
>radio performance. I've tried taking the laptop into the
>back yard, which means the signal is going through half a
>dozen walls, and everything still works quite well.
You had me shopping on eBay for RF test equipment last night. I
managed to resist the temptation.
>After reading Jeff's post, I realize that I should've kept my mouth
>shut about testing. It's so tempting to put some sort of faith in
>those signal meters....
Grumble.... Just lock the speed at 54Mbits/sec and take a walk until
it craps out. That's easy enough. My guess is you'll be lucky to go
more than about 20ft using the stock antennas.
On Tue, 13 Feb 2007 17:49:45 -0600, Peabody
<waybackNO784SPAM44@yahoo.com> wrote:
>And I would assume that in the case of a laptop with
>built-in Wi-Fi, the laptop's transmitter would typically be
>the limiting factor.
Yep. If the access point transmitted at the more typical power level
of +15dBm, then the system would be roughly symmetrical.
>And by the way, where is the antenna
>in such a laptop? Is it in the lid?
Most of the new laptops have two antennas around the LCD frame,
usually at the top. Some are on the sides. However, there are a few
that have the antenna in the base and at least one with the antenna on
the hinge:
<http://802.11junk.com/jeffl/antennas/laptops/slides/compaq-2120us.html>
Yech.
>I guess the point that I was trying to make is that the HP
>could actually have better connectivity range without
>necessarily having more xmit power, if the receive
>sensitivity was materially better than average.
That's certainly possible but not proven.
>But then the question arises as to whether it might be
>better sometimes to have LESS receiver sensitivity.
Nope. Only if there were a strong signal out of band issue that was
causing blocking or intermod mixing. That's unlikely for the typical
home user.
>If
>there are other transmitters in the area, could you actually
>be worse off picking up more of them. I'll try to answer my
>own question by saying no, the relative levels of the
>incoming signals (the "signal" and the "noise") are the same
>regardless of sensitivity of the receiver.
Yep. That's the way it works. If you increase the gain of the
receiver, you amplify both the signal and the noise equally. The
resultant signal to noise ratio is the same. More crudely, an
increase in gain does NOT necessarily mean an increase in sensitivity.
>Well, ok, it was
>just a guess. But do you find in practice that it may help
>to reduce sensitivity in some cases?
Sorta. There are many cases where too much sensitivity is a waste of
effort. For example, in HF communications, the atmospheric noise in
the 2 MHz thru about 16 MHz region is sufficiently strong that a high
sensitivity receiver is a waste of effort. Better to keep the
sensitivity low and use the receivers dynamic range to raise the
overload point so that it can handle nearby strong stations better.
The same principle might apply to 2.4GHz if one was building an
outdoor wireless access point that might have to tolerate strong
interference and overload signals. However, the trend is toward more
and more sensitivity and simply not worry about overload issues.
>Yeah, but the manuals for the WHR-G54S and the HP both have
>the same specs. In fact, I think the only difference in the
>entire Specifications sections was the power supply voltage.
>But now it's clear that the manuals mean nothing.
Now you know why I don't read manuals. I would tend to trust sources
that have actually performed the measurments (FCC ID data, various
reviewers, independent labs, etc). Everybody lies, but that's ok
because nobody reads the test reports and manuals.
>I just rely on my basic concept of
>RF stuff - it's magic.
You can do that to a point. Eventually the mechanical analogies and
gedankenexperiments break down and you have to do the math or drag out
the test equipment. You can't see RF. That's what the test equipment
is for. It's the eyes of the RF blind techs and enginee
Buffalo WHR-HP G54 