I have no idea if these links are for my session only or will always
call up this product. For some reason, it doesn't show up when you
search for the FCC ID, which is MXF-U940930G
However, if you search for the manufacturers ID (MXF), then show all
items, this model shows up eventually. I set up the search to display
100 at a time, then used the search feature in the browser to find the
link.
The links work just fine. They're assorted photos and data for a
Gemtek USB 802.11g wireless client. It's a dual antenna (diversity)
system, where one of the antennas is external and the other is on the
circuit board. The FCC Data mumbles MIMO, but I don't think so.
>For some reason, it doesn't show up when you
>search for the FCC ID, which is MXF-U940930G
That's because the FCC ID search page has been broken since it was
introduced.
>However, if you search for the manufacturers ID (MXF), then show all
>items, this model shows up eventually. I set up the search to display
>100 at a time, then used the search feature in the browser to find the
>link.
Yep. That's exactly what I do.
I have no experience with the Gemtek USB client. Sorry.
Jeff Liebermann wrote:
> miso@sushi.com hath wroth:
>
> >Like I need another wifi product, I got this usb wifi at Fry's for
> >hacking (in the true sense of the word) purposes.
> >
> >The FCC links are
> >https://gullfoss2.fcc.gov/prod/oet/f...ive_or_pdf=pdf
> >https://gullfoss2.fcc.gov/prod/oet/f...ive_or_pdf=pdf
> >https://gullfoss2.fcc.gov/prod/oet/f...ive_or_pdf=pdf
> >https://gullfoss2.fcc.gov/prod/oet/f...ive_or_pdf=pdf
> >https://gullfoss2.fcc.gov/prod/oet/f...ive_or_pdf=pdf
> >
> >I have no idea if these links are for my session only or will always
> >call up this product.
>
> The links work just fine. They're assorted photos and data for a
> Gemtek USB 802.11g wireless client. It's a dual antenna (diversity)
> system, where one of the antennas is external and the other is on the
> circuit board. The FCC Data mumbles MIMO, but I don't think so.
>
> >For some reason, it doesn't show up when you
> >search for the FCC ID, which is MXF-U940930G
>
> That's because the FCC ID search page has been broken since it was
> introduced.
>
> >However, if you search for the manufacturers ID (MXF), then show all
> >items, this model shows up eventually. I set up the search to display
> >100 at a time, then used the search feature in the browser to find the
> >link.
>
> Yep. That's exactly what I do.
>
> I have no experience with the Gemtek USB client. Sorry.
>
> --
> Jeff Liebermann jeffl@comix.santa-cruz.ca.us
> 150 Felker St #D http://www.LearnByDestroying.com
> Santa Cruz CA 95060 http://802.11junk.com
> Skype: JeffLiebermann AE6KS 831-336-2558
I plugged it into my x64 system and it found a driver. [The Airlink 101
items I've bought thus far have had 64 drivers to my amazement.]
Netstumbler can't use it. The supplied site survey software works.
I'll have to test it on my own system since all my neighbors have
turned on encryption. [That wasn't always the case. ;-)]
Next up is to put a small RF connector on it. [The B mode is 50mw. Not
too shabby.]
miso@sushi.com wrote:
> Jeff Liebermann wrote:
> > miso@sushi.com hath wroth:
> > >For some reason, it doesn't show up when you
> > >search for the FCC ID, which is MXF-U940930G
> > That's because the FCC ID search page has been broken since it was
> > introduced.
I have had this happen to me, usually after saving a bookmark into one of
the links from a previous successful search.
Try clearing the cache in your browser, and begin a new search from one of
the top level forms. https://gullfoss2.fcc.gov/prod/oet/c...ericSearch.cfm
> I plugged it into my x64 system and it found a driver. [The Airlink 101
> items I've bought thus far have had 64 drivers to my amazement.]
That's my favorite way to install any Wifi device since WinXP-SP2. It used
to be a bad idea, but now it works well, often better than the latest
drivers from the labelled vendor.
> Netstumbler can't use it. The supplied site survey software works.
I thought NetStumbler worked with about anything, if you set it as NDIS5.
I think my Netgear WG511 is one of those, but I can't recall.
Is this "Airlink AWLL5025 MIMO USB XR 802.11g Wireless USB Adapter "?
You left off an "L". Or is the $15 unit missing an "L"? ;-) http://shop3.outpost.com/product/4703779 $29.99
--
---
Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5
dold@15.usenet.us.com wrote:
> miso@sushi.com wrote:
> > Jeff Liebermann wrote:
> > > miso@sushi.com hath wroth:
> > > >For some reason, it doesn't show up when you
> > > >search for the FCC ID, which is MXF-U940930G
> > > That's because the FCC ID search page has been broken since it was
> > > introduced.
>
> I have had this happen to me, usually after saving a bookmark into one of
> the links from a previous successful search.
> Try clearing the cache in your browser, and begin a new search from one of
> the top level forms.
> https://gullfoss2.fcc.gov/prod/oet/c...ericSearch.cfm
>
> > I plugged it into my x64 system and it found a driver. [The Airlink 101
> > items I've bought thus far have had 64 drivers to my amazement.]
>
> That's my favorite way to install any Wifi device since WinXP-SP2. It used
> to be a bad idea, but now it works well, often better than the latest
> drivers from the labelled vendor.
>
> > Netstumbler can't use it. The supplied site survey software works.
>
> I thought NetStumbler worked with about anything, if you set it as NDIS5.
> I think my Netgear WG511 is one of those, but I can't recall.
>
> Is this "Airlink AWLL5025 MIMO USB XR 802.11g Wireless USB Adapter "?
> You left off an "L". Or is the $15 unit missing an "L"? ;-)
> http://shop3.outpost.com/product/4703779 $29.99
>
> --
> ---
> Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5
Yes, I left out one of the L's, i.e. it is AWLL5025.
I'm running 0.4.0. It finds the airlink box in the devices section,
declares it NDIS5, but the adapter not present icon flashes at the
bottom of the screen.
I opened the box up last night. Pluck the rubber feet and remove 4
screws. The pcb just drops into the plastic should you want to put it
in a different enclosure. [Plastic until you don't want mimo.] The
antenna is held on by soldering the coax. I'm going to replace it with
a SMA jack.
got the AWLL5025 from local Frys for $19 + tax. The survey site
software detects a total 6 networks in my ghetto neighborhood, my
WRT54G running DD-WRT in client mode with 100mW of TX-power and 9dBi
ruber duck omni can do no better...
Netstumbler works with this adapter but cannot detect SSID of some
stations, Cain&Abel do all...
i gave my brother the PCI version of this RaLink-based adapter, the
AWLH5025 PCI which i also paid $19, and it can see more networks than
his D-Link DWL-G520M MIMO PCI, which he returned to CompUSA for $100
back
heck... i even bough the Atheros-based AWLH4030 PCI, paid $14 at Frys,
that can run Commview for WiFi.
oh and by the way, wireshark. formely ethereal, says the TX-power of
this card is 100mW!!!
cheers
miso@sushi.com wrote:
> Jeff Liebermann wrote:
> > miso@sushi.com hath wroth:
> >
> > >Like I need another wifi product, I got this usb wifi at Fry's for
> > >hacking (in the true sense of the word) purposes.
> > >
> > >The FCC links are
> > >https://gullfoss2.fcc.gov/prod/oet/f...ive_or_pdf=pdf
> > >https://gullfoss2.fcc.gov/prod/oet/f...ive_or_pdf=pdf
> > >https://gullfoss2.fcc.gov/prod/oet/f...ive_or_pdf=pdf
> > >https://gullfoss2.fcc.gov/prod/oet/f...ive_or_pdf=pdf
> > >https://gullfoss2.fcc.gov/prod/oet/f...ive_or_pdf=pdf
> > >
> > >I have no idea if these links are for my session only or will always
> > >call up this product.
> >
> > The links work just fine. They're assorted photos and data for a
> > Gemtek USB 802.11g wireless client. It's a dual antenna (diversity)
> > system, where one of the antennas is external and the other is on the
> > circuit board. The FCC Data mumbles MIMO, but I don't think so.
> >
> > >For some reason, it doesn't show up when you
> > >search for the FCC ID, which is MXF-U940930G
> >
> > That's because the FCC ID search page has been broken since it was
> > introduced.
> >
> > >However, if you search for the manufacturers ID (MXF), then show all
> > >items, this model shows up eventually. I set up the search to display
> > >100 at a time, then used the search feature in the browser to find the
> > >link.
> >
> > Yep. That's exactly what I do.
> >
> > I have no experience with the Gemtek USB client. Sorry.
> >
> > --
> > Jeff Liebermann jeffl@comix.santa-cruz.ca.us
> > 150 Felker St #D http://www.LearnByDestroying.com
> > Santa Cruz CA 95060 http://802.11junk.com
> > Skype: JeffLiebermann AE6KS 831-336-2558
>
> I plugged it into my x64 system and it found a driver. [The Airlink 101
> items I've bought thus far have had 64 drivers to my amazement.]
> Netstumbler can't use it. The supplied site survey software works.
> I'll have to test it on my own system since all my neighbors have
> turned on encryption. [That wasn't always the case. ;-)]
>
> Next up is to put a small RF connector on it. [The B mode is 50mw. Not
> too shabby.]
>got the AWLL5025 from local Frys for $19 + tax. The survey site
>software detects a total 6 networks in my ghetto neighborhood, my
>WRT54G running DD-WRT in client mode with 100mW of TX-power and 9dBi
>ruber duck omni can do no better...
>
>Netstumbler works with this adapter but cannot detect SSID of some
>stations, Cain&Abel do all...
>
>i gave my brother the PCI version of this RaLink-based adapter, the
>AWLH5025 PCI which i also paid $19, and it can see more networks than
>his D-Link DWL-G520M MIMO PCI, which he returned to CompUSA for $100
>back
>
>heck... i even bough the Atheros-based AWLH4030 PCI, paid $14 at Frys,
>that can run Commview for WiFi.
>
>oh and by the way, wireshark. formely ethereal, says the TX-power of
>this card is 100mW!!!
Which one? The spec sheet says that the AWLL5025 belches +13dBm
(20mw) for 802.11g and +17dBm (50mw) for 802.11b.
<http://www.airlink101.com/products/awll5025.html>
The AWLH4030 PCI is about the same at 10-14dBm (10-25mw) for 802.11g
and +18dBm (63mw) for 802.11b.
<http://www.airlink101.com/products/awlh4030.html>
So it is written, so it must be.
Wireshark and Wi-Fi Hopper both claim my HP laptops Broadcom something
MiniPCI card puts out 1300mw. What's happening is the NDIS5 function
call that returns the tx power from the driver is returning garbage.
oh, i mean the USB AWLL5025 card and the PCI AWLH5025 too, wireshark
won't return the TX-power value for the AWLH4030 PCI, the program also
notes that the accuracy of the returned values solely depend on the
card's drivers
so the broadcom miniPCI driver says it's got 1300mW... but why 1300mW
and not 3100mW? well, i have another theory beside thinking garbage
values being returned..
1300mW is about 31dBm!!! and i dont see why wifi cards cannot have
exactly that much of TX power. the FCC part 15 states that the limit
for 2.4GHz non-channel-hopping radios is 1000mW (or 30dBm) provided it
is attached to an antenna of 6dBi gain or less.... and for every 3dBi
increase in antenna gain, the TX power has to be reduced by 1dBm.
nothing further about the variations of radios+antennas
configuration...
but here comes the creative thinking.. from there, one may deductively
conclude that if the radio is permanently attached to a 3dbi antenna or
less, then its maximum TX power can be legally increased to 31dBi!!!
i suspect that notebooks manufactures been doing this with their OEM
wifi cards, especially with those miniPCIs, to keep their customers
happy.... of course, those cards are not intended for desktop use,
obviously, never to be sold as a part of a "highpower wardriving kit",
or to be sold seperately at all, even if they are hard coded to a
specific channel within the 2.4GHz spectrum
the wireless networking section at Frys, compared to other sections,
has the most returned items from pissed off customer who bought
brand-name wifi devices that put out 30mW... lol
cheers
Jeff Liebermann wrote:
> >oh and by the way, wireshark. formely ethereal, says the TX-power of
> >this card is 100mW!!!
>
> Which one? The spec sheet says that the AWLL5025 belches +13dBm
> (20mw) for 802.11g and +17dBm (50mw) for 802.11b.
> <http://www.airlink101.com/products/awll5025.html>
>
> The AWLH4030 PCI is about the same at 10-14dBm (10-25mw) for 802.11g
> and +18dBm (63mw) for 802.11b.
> <http://www.airlink101.com/products/awlh4030.html>
>
> So it is written, so it must be.
>
> Wireshark and Wi-Fi Hopper both claim my HP laptops Broadcom something
> MiniPCI card puts out 1300mw. What's happening is the NDIS5 function
> call that returns the tx power from the driver is returning garbage.
>
>
>
>
> --
> Jeff Liebermann jeffl@comix.santa-cruz.ca.us
> 150 Felker St #D http://www.LearnByDestroying.com
> Santa Cruz CA 95060 http://802.11junk.com
> Skype: JeffLiebermann AE6KS 831-336-2558
bi241@scn.org wrote:
> got the AWLL5025 from local Frys for $19 + tax. The survey site
> software detects a total 6 networks in my ghetto neighborhood, my
> WRT54G running DD-WRT in client mode with 100mW of TX-power and 9dBi
> ruber duck omni can do no better...
>
> Netstumbler works with this adapter but cannot detect SSID of some
> stations, Cain&Abel do all...
>
> i gave my brother the PCI version of this RaLink-based adapter, the
> AWLH5025 PCI which i also paid $19, and it can see more networks than
> his D-Link DWL-G520M MIMO PCI, which he returned to CompUSA for $100
> back
>
> heck... i even bough the Atheros-based AWLH4030 PCI, paid $14 at Frys,
> that can run Commview for WiFi.
>
> oh and by the way, wireshark. formely ethereal, says the TX-power of
> this card is 100mW!!!
>
> cheers
Mine (USB ralink) didn't work with netstumbler. :-(
I opened mine up and yanked the antenna. I cut some hardline with a SMA
on one end and plan on mating the two. It looks doable. [The idea is it
is cheaper and better to use a USB cable to position the radio rather
than have the loss in the coax.]
I also built a new biquad using what might be a time saving trick.
Instead of trying to shove coax into copper pipe to do the feed, I cut
the top (threaded part) off of a female to female N adapter with a
hacksaw. Now I have N connector and a feed in one step. I cut a hole in
the copper plate using a cheap ass Harbor Freight stepped drill bit.
[The drill bit set is about the only good thing I ever bought there.]
I made the loop as a circle rather than having corners. Get copper wire
and mark out two sequential segments 122mm in length. Don't start from
the end, but give yourself some working room so you can grab the free
end of the wire. I then wrapped the wire around a PVC adapter that was
close to the proper diameter to get the shape. Then you bend the wire
in the center to form one common point of the biquad loop. Trim the
wire at the other marks and solder to the center feed of the hacked N
to N adapter. Yeah, I'll get around to photographing this. Next up is
fitting it to a Direct TV dish. [I couldn't find the Echo Star dish.]
did you install the driver on the CD that comes with the card? the
updated driver seems not working well with netstumbler
i bought those airlink cards about a year ago and havent done any
modification. i did pop the USB plastic case open and saw two antennas
on this card. the external seems to be the TX and the one on PCB i
think is the RX... it has different antenna configuration than its PCI
counterpart, but the USB has a different chipset, the rt73 (vs rt61)
which i suspect having better receive sensitivity
so the perfect mod would be replacing the external antenna with a
reverse polarity SMA connector and hook it up with
a) yes, a very high gain omni or directional antenna
b) or an external amp, like the popular and available hawking HSB2
that can put out 500mW and comes with a 2dBi omni
Frys is having HSB2 on sale for $69.... for antenna, i would look for
one on eBay or other websites... i just can't stand the ridiculous
prices that they set on those simple devices at local electronics
retailers, even at Frys... despite the fact that i dont have enough
skill and too lazy to build one
i am not sure how this set up would work for MIMO design, as the
AWLL5025 specification says that it has diversity antenna
configuration... meaning it assigns TX to one antenna and RX to
another. This mod would probably improve just the TX side and leave
the RX side at the mercy of the chipset's RX sensitivity
but the AWLH4030 is a different story. it has one single antenna for
both TX and RX... so i removed the antenna and hooked it up to a
hawking HSB1 (yeah i've got the version 1 of the HSB) set the amp to
500mW, snapped in a 9dbi omni and ran wildpackets omnipeek. From my 2nd
floor apartment, i can see a wifi hotspot from a nearby scottish inn,
which is about 1.5 miles away as the crow flies.... by the way, the
setup is entirely indoor and done in my desk in the living room, and
no, there's no clear line-of-sight to any of the networks i was able to
"see" with this setup
contrary to popular beliefs, and politics, an external wifi amplifiers
does boost the receiving side of the radio it hooks up to, provided
that one single antenna is being used..... from my experience, the
Hawking HSB1 and HSB2 are bi-directional, output 500mW of TX power and
provide a +12dB RX gain, are relatively inexpensive and work well with
both OFDM and DSSS in half-duplex mode ...
my next wifi adventure would be buying another HSB, hook them up in
series, that would theoretically give me a +24dB boost in RX gain while
maintaining the output TX power within legal limit... i cant wait to
see how far my hotrod wifi toys can reach...
> Mine (USB ralink) didn't work with netstumbler. :-(
>
> I opened mine up and yanked the antenna. I cut some hardline with a SMA
> on one end and plan on mating the two. It looks doable. [The idea is it
> is cheaper and better to use a USB cable to position the radio rather
> than have the loss in the coax.]
>
> I also built a new biquad using what might be a time saving trick.
> Instead of trying to shove coax into copper pipe to do the feed, I cut
> the top (threaded part) off of a female to female N adapter with a
> hacksaw. Now I have N connector and a feed in one step. I cut a hole in
> the copper plate using a cheap ass Harbor Freight stepped drill bit.
> [The drill bit set is about the only good thing I ever bought there.]
>
> I made the loop as a circle rather than having corners. Get copper wire
> and mark out two sequential segments 122mm in length. Don't start from
> the end, but give yourself some working room so you can grab the free
> end of the wire. I then wrapped the wire around a PVC adapter that was
> close to the proper diameter to get the shape. Then you bend the wire
> in the center to form one common point of the biquad loop. Trim the
> wire at the other marks and solder to the center feed of the hacked N
> to N adapter. Yeah, I'll get around to photographing this. Next up is
> fitting it to a Direct TV dish. [I couldn't find the Echo Star dish.]
>so the broadcom miniPCI driver says it's got 1300mW... but why 1300mW
>and not 3100mW? well, i have another theory beside thinking garbage
>values being returned..
The garbage values theory was what the developers at Wi-Fi Hopper
responded with when I bug reported the problem. I've seen the same
bogus power report with other boards and drivers.
>1300mW is about 31dBm!!! and i dont see why wifi cards cannot have
>exactly that much of TX power. the FCC part 15 states that the limit
>for 2.4GHz non-channel-hopping radios is 1000mW (or 30dBm) provided it
>is attached to an antenna of 6dBi gain or less.... and for every 3dBi
>increase in antenna gain, the TX power has to be reduced by 1dBm.
>nothing further about the variations of radios+antennas
>configuration...
I don't want to get into interpreting FCC 15.247. The maximum power
output is 1 watt. Unfortunatly, they don't say where they measure
this 1 watt. It could be at the transmitter, or at the antenna. Hard
to tell. The common interpretation is 1 watt maximum at the antenna
with a 6dBi omni antenna. If you lower the gain of the antenna, you
cannot increase the power output to compensate. It would have made
much more sense for the FCC to specific EIRP (Effective isotropic
reference radiated power).
>but here comes the creative thinking.. from there, one may deductively
>conclude that if the radio is permanently attached to a 3dbi antenna or
>less, then its maximum TX power can be legally increased to 31dBi!!!
No. Or at least no according to several testing labs that submit FCC
Part 15 type certification reports. Nice try.
Incidentally, if you really want high power in a laptop, see:
<http://www.ubnt.com/products.php4>
>i suspect that notebooks manufactures been doing this with their OEM
>wifi cards, especially with those miniPCIs, to keep their customers
>happy.... of course, those cards are not intended for desktop use,
>obviously, never to be sold as a part of a "highpower wardriving kit",
>or to be sold seperately at all, even if they are hard coded to a
>specific channel within the 2.4GHz spectrum
I like conspiracy theories but not this time. Linux utilities report
the correct power output from the same cards that Windoze reports
garbage.
>the wireless networking section at Frys, compared to other sections,
>has the most returned items from pissed off customer who bought
>brand-name wifi devices that put out 30mW... lol
Jeff Liebermann wrote:
> bi241@scn.org hath wroth:
>
> >so the broadcom miniPCI driver says it's got 1300mW... but why 1300mW
> >and not 3100mW? well, i have another theory beside thinking garbage
> >values being returned..
>
> The garbage values theory was what the developers at Wi-Fi Hopper
> responded with when I bug reported the problem. I've seen the same
> bogus power report with other boards and drivers.
>
> >1300mW is about 31dBm!!! and i dont see why wifi cards cannot have
> >exactly that much of TX power. the FCC part 15 states that the limit
> >for 2.4GHz non-channel-hopping radios is 1000mW (or 30dBm) provided it
> >is attached to an antenna of 6dBi gain or less.... and for every 3dBi
> >increase in antenna gain, the TX power has to be reduced by 1dBm.
> >nothing further about the variations of radios+antennas
> >configuration...
>
> I don't want to get into interpreting FCC 15.247. The maximum power
> output is 1 watt. Unfortunatly, they don't say where they measure
> this 1 watt. It could be at the transmitter, or at the antenna. Hard
> to tell. The common interpretation is 1 watt maximum at the antenna
> with a 6dBi omni antenna. If you lower the gain of the antenna, you
> cannot increase the power output to compensate. It would have made
> much more sense for the FCC to specific EIRP (Effective isotropic
> reference radiated power).
>
> >but here comes the creative thinking.. from there, one may deductively
> >conclude that if the radio is permanently attached to a 3dbi antenna or
> >less, then its maximum TX power can be legally increased to 31dBi!!!
>
> No. Or at least no according to several testing labs that submit FCC
> Part 15 type certification reports. Nice try.
>
> Incidentally, if you really want high power in a laptop, see:
> <http://www.ubnt.com/products.php4>
>
> >i suspect that notebooks manufactures been doing this with their OEM
> >wifi cards, especially with those miniPCIs, to keep their customers
> >happy.... of course, those cards are not intended for desktop use,
> >obviously, never to be sold as a part of a "highpower wardriving kit",
> >or to be sold seperately at all, even if they are hard coded to a
> >specific channel within the 2.4GHz spectrum
>
> I like conspiracy theories but not this time. Linux utilities report
> the correct power output from the same cards that Windoze reports
> garbage.
>
> >the wireless networking section at Frys, compared to other sections,
> >has the most returned items from pissed off customer who bought
> >brand-name wifi devices that put out 30mW... lol
>
> That's one reason why I don't buy at Fry's.
>
> --
> Jeff Liebermann jeffl@comix.santa-cruz.ca.us
> 150 Felker St #D http://www.LearnByDestroying.com
> Santa Cruz CA 95060 http://802.11junk.com
> Skype: JeffLiebermann AE6KS 831-336-2558
Actually, what is returned at Fry's is handy to know. If there are lots
of returns, try something else. I know those on this usenet group are
Linksys fans, but most of what is returned to Fry's is Linksys.
If I think there are going to be problems with something, I always go
to Fry's because they will take back anything.
bi241@scn.org wrote:
> did you install the driver on the CD that comes with the card? the
> updated driver seems not working well with netstumbler
>
> i bought those airlink cards about a year ago and havent done any
> modification. i did pop the USB plastic case open and saw two antennas
> on this card. the external seems to be the TX and the one on PCB i
> think is the RX... it has different antenna configuration than its PCI
> counterpart, but the USB has a different chipset, the rt73 (vs rt61)
> which i suspect having better receive sensitivity
>
> so the perfect mod would be replacing the external antenna with a
> reverse polarity SMA connector and hook it up with
>
> a) yes, a very high gain omni or directional antenna
> b) or an external amp, like the popular and available hawking HSB2
> that can put out 500mW and comes with a 2dBi omni
>
> Frys is having HSB2 on sale for $69.... for antenna, i would look for
> one on eBay or other websites... i just can't stand the ridiculous
> prices that they set on those simple devices at local electronics
> retailers, even at Frys... despite the fact that i dont have enough
> skill and too lazy to build one
>
> i am not sure how this set up would work for MIMO design, as the
> AWLL5025 specification says that it has diversity antenna
> configuration... meaning it assigns TX to one antenna and RX to
> another. This mod would probably improve just the TX side and leave
> the RX side at the mercy of the chipset's RX sensitivity
>
> but the AWLH4030 is a different story. it has one single antenna for
> both TX and RX... so i removed the antenna and hooked it up to a
> hawking HSB1 (yeah i've got the version 1 of the HSB) set the amp to
> 500mW, snapped in a 9dbi omni and ran wildpackets omnipeek. From my 2nd
> floor apartment, i can see a wifi hotspot from a nearby scottish inn,
> which is about 1.5 miles away as the crow flies.... by the way, the
> setup is entirely indoor and done in my desk in the living room, and
> no, there's no clear line-of-sight to any of the networks i was able to
> "see" with this setup
>
> contrary to popular beliefs, and politics, an external wifi amplifiers
> does boost the receiving side of the radio it hooks up to, provided
> that one single antenna is being used..... from my experience, the
> Hawking HSB1 and HSB2 are bi-directional, output 500mW of TX power and
> provide a +12dB RX gain, are relatively inexpensive and work well with
> both OFDM and DSSS in half-duplex mode ...
>
> my next wifi adventure would be buying another HSB, hook them up in
> series, that would theoretically give me a +24dB boost in RX gain while
> maintaining the output TX power within legal limit... i cant wait to
> see how far my hotrod wifi toys can reach...
>
> cheers
<snip>
I am running X64, so I had to get the driver off the net. I haven't
tried the Airlink with netstumber on my notebook (win2kpro).
My understanding of diversity receive is there are multiple receive
antennas and one combination transmit/receive antenna. On my SMC card,
the combination TX/RX port is the one near the LED.
easy mate, interpreting the FCC, the IRS and the US Constitution
shouldn't be that difficult
you see, a standard industrial spectrum analyzer, with proper input
attennuator settings, hooked up directly to the RF transmitter at the
connector will show exactly the TX power of the device. Simple as that!
now, suppose the measure of TX power is at the transmitting antenna,
then of course there's another setup and calculation for the spectrum
analyzer to do just that, but it begs the questions
1) how far away from the transmitter should the spectrum analyzer be
positioned? 0 feet? 1 feet? 3 feet? 10 feet? 10 miles?
2) what is the standard for the field-probing antenna? loop? yagi?
omni? what about its sensitivity?
3) if the probing antenna is to be right at the transmitting antenna,
then what part of the transmitting antenna should it touches? the head?
the tail? the middle? the center? the rim? at what angle?
sounds like the things only a clown would do in a circus, eh?
oh and why not buy at Fry's?..... like, the things you buy from the
store would fry themselves... or what?
just kidding
Jeff Liebermann wrote:
> bi241@scn.org hath wroth:
>
> >so the broadcom miniPCI driver says it's got 1300mW... but why 1300mW
> >and not 3100mW? well, i have another theory beside thinking garbage
> >values being returned..
>
> The garbage values theory was what the developers at Wi-Fi Hopper
> responded with when I bug reported the problem. I've seen the same
> bogus power report with other boards and drivers.
>
> >1300mW is about 31dBm!!! and i dont see why wifi cards cannot have
> >exactly that much of TX power. the FCC part 15 states that the limit
> >for 2.4GHz non-channel-hopping radios is 1000mW (or 30dBm) provided it
> >is attached to an antenna of 6dBi gain or less.... and for every 3dBi
> >increase in antenna gain, the TX power has to be reduced by 1dBm.
> >nothing further about the variations of radios+antennas
> >configuration...
>
> I don't want to get into interpreting FCC 15.247. The maximum power
> output is 1 watt. Unfortunatly, they don't say where they measure
> this 1 watt. It could be at the transmitter, or at the antenna. Hard
> to tell. The common interpretation is 1 watt maximum at the antenna
> with a 6dBi omni antenna. If you lower the gain of the antenna, you
> cannot increase the power output to compensate. It would have made
> much more sense for the FCC to specific EIRP (Effective isotropic
> reference radiated power).
>
> >but here comes the creative thinking.. from there, one may deductively
> >conclude that if the radio is permanently attached to a 3dbi antenna or
> >less, then its maximum TX power can be legally increased to 31dBi!!!
>
> No. Or at least no according to several testing labs that submit FCC
> Part 15 type certification reports. Nice try.
>
> Incidentally, if you really want high power in a laptop, see:
> <http://www.ubnt.com/products.php4>
>
> >i suspect that notebooks manufactures been doing this with their OEM
> >wifi cards, especially with those miniPCIs, to keep their customers
> >happy.... of course, those cards are not intended for desktop use,
> >obviously, never to be sold as a part of a "highpower wardriving kit",
> >or to be sold seperately at all, even if they are hard coded to a
> >specific channel within the 2.4GHz spectrum
>
> I like conspiracy theories but not this time. Linux utilities report
> the correct power output from the same cards that Windoze reports
> garbage.
>
> >the wireless networking section at Frys, compared to other sections,
> >has the most returned items from pissed off customer who bought
> >brand-name wifi devices that put out 30mW... lol
>
> That's one reason why I don't buy at Fry's.
>
> --
> Jeff Liebermann jeffl@comix.santa-cruz.ca.us
> 150 Felker St #D http://www.LearnByDestroying.com
> Santa Cruz CA 95060 http://802.11junk.com
> Skype: JeffLiebermann AE6KS 831-336-2558
>easy mate, interpreting the FCC, the IRS and the US Constitution
>shouldn't be that difficult
True. It shouldn't, but it is. I've been dealing with the FCC on and
off since about 1968. These days, rules-n-regs are scribbled by
attorneys, not engineers. I'll spare you my list of horror stories
over the years.
>you see, a standard industrial spectrum analyzer, with proper input
>attennuator settings, hooked up directly to the RF transmitter at the
>connector will show exactly the TX power of the device. Simple as that!
Nope. Quiz time:
You have a spectrum analyzer that shows an 802.11g spread spectrum
signal that is approximately 25Mhz wide. Peak power on the scale is
0dBm to make the calculations easy. The spectrum analyzer IF
bandwidth is 500KHz. What is the "real" power (ignoring duty cycle)?
I'll supply the answer tomorrow. Note that this is not a trick
question and the numbers are quite real.
>now, suppose the measure of TX power is at the transmitting antenna,
>then of course there's another setup and calculation for the spectrum
>analyzer to do just that, but it begs the questions
What question? The FCC is usually very clear where to measure things.
They missed this time. However, I've learned from bitter experience
to NEVER ask the FCC for clarification, because I've always gotten the
answer I least expect, and often with unpredictable side effects.
>1) how far away from the transmitter should the spectrum analyzer be
>positioned? 0 feet? 1 feet? 3 feet? 10 feet? 10 miles?
You're measuring power output, not field strength. If you want to
measure RF field strength, there are some rather simple guidelines
intended to keep your spectrum analyzer out of the near field and only
pickup the far field. The only time the distance needs to be
specified for the test is when measuring incidentally radiation. For
field strength, anything resembling a calibrated antenna will work to
calculate the field strength.
>2) what is the standard for the field-probing antenna? loop? yagi?
>omni? what about its sensitivity?
The type certification, they're rather specific in what may be used.
Go to the FCC ID web pile and pick any likely FCC ID number for a
wireless device. The applicants are required to supply photographs of
their test setup, which includes the test antennas.
>3) if the probing antenna is to be right at the transmitting antenna,
It's not.
>then what part of the transmitting antenna should it touches? the head?
>the tail? the middle? the center? the rim? at what angle?
None. Look at the photos on the FCC ID web pile. They have to be far
enough from the unit under test to not be considered within the near
field.
>sounds like the things only a clown would do in a circus, eh?
Ummm.... I'm one of those clown. Thanks for sharing. Bye.
> Actually, what is returned at Fry's is handy to know. If there are lots
> of returns, try something else. I know those on this usenet group are
> Linksys fans, but most of what is returned to Fry's is Linksys.
I would say that's hard to judge. In the WiFi sections (more than one,
since there are some dedicated sections, including Linksys), there are
many empty shelf spaces, usually for the item you want, plenty of items in
the wrong shelf space, and some opened/returned/markdown units, with
markdowns of 12-15 cents, which fascinates me.
I would guess that they don't give Linksys their own dedicated space unless
they move lots of units, so the number of returns on the shelf would have
to be noted against the number sold.
Wifi is still an emerging market. Many of the units are purchased with
unreasonable hopes, like using Wifi while commuting on Caltrain... okay, so
that works now; or getting free access anywhere, or full coverage in a
home. Those units probably come back, maybe for refund, maybe to exchange
for a different brand.
The motherboard section is full of returns, often with no new units on the
shelf. For stores other than Sunnyvale, I don't know what that means, but
in Sunnyvale, I have overheard engineers selecting motherboards to take
back and test/certify against some product or another, after which it will
be returned to Fry's. But these are the same guys trying to make sure they
get one that is unopened.
> If I think there are going to be problems with something, I always go
> to Fry's because they will take back anything.
The home of the thirty day free trial for almost anything.
I have seen people return stereos with no packaging.
--
---
Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5
i played with the linksys WRT54G for a while and somehow got stuck in
DD-WRT concept of diversity antenna. and also i am skeptical about the
MIMO title that the Ralink chipset is advertised, after all, the
AWLL5025 is still within 802.11G specs, while MIMO seems to belong to
draft-N or whatever...
but yeah in true MIMO design, diversity mean multiple RX antennas, (and
mulltiple TX antennas too)
i often see draft-N wireless adpaters with three antennas, just like
the 802.11G AWLH5025 PCI adapter, but i was too lazy to learn about the
antenna configurations. let me give it a try. these are possible
configuration in a three-antenna setup
a) three TX/RX combos
b) one dedicated RX and two TX/RX combos
c) one dedicated TX and two TX/RX combos
d) two dedicated RX and one TX/RX combos
e) two dedicated TX and one TX/RX combos
i am still clueless about how many radios needed for one "draft-N"
adaptor. but i do hope that there's no final N. 802.11 B/G is good
enough for me, and for all, that's all we need for wireless
internet.... as for networking, i'd prefer and recommend the old
fashion way...
anyways, in the case of the AWLL5025 USB, the external antenna must be
the combo TX/RX. Thank you for pointing that out. it makes alot of
sense... and i think i am gonna hack the antenna after this... yes i am
serious!
cheers
miso@sushi.com wrote:
>
>
> <snip>
> I am running X64, so I had to get the driver off the net. I haven't
> tried the Airlink with netstumber on my notebook (win2kpro).
>
> My understanding of diversity receive is there are multiple receive
> antennas and one combination transmit/receive antenna. On my SMC card,
> the combination TX/RX port is the one near the LED.
bi241@scn.org wrote:
> i played with the linksys WRT54G for a while and somehow got stuck in
> DD-WRT concept of diversity antenna. and also i am skeptical about the
> MIMO title that the Ralink chipset is advertised, after all, the
> AWLL5025 is still within 802.11G specs, while MIMO seems to belong to
> draft-N or whatever...
>
> but yeah in true MIMO design, diversity mean multiple RX antennas, (and
> mulltiple TX antennas too)
> i often see draft-N wireless adpaters with three antennas, just like
> the 802.11G AWLH5025 PCI adapter, but i was too lazy to learn about the
> antenna configurations. let me give it a try. these are possible
> configuration in a three-antenna setup
>
> a) three TX/RX combos
> b) one dedicated RX and two TX/RX combos
> c) one dedicated TX and two TX/RX combos
> d) two dedicated RX and one TX/RX combos
> e) two dedicated TX and one TX/RX combos
>
> i am still clueless about how many radios needed for one "draft-N"
> adaptor. but i do hope that there's no final N. 802.11 B/G is good
> enough for me, and for all, that's all we need for wireless
> internet.... as for networking, i'd prefer and recommend the old
> fashion way...
>
> anyways, in the case of the AWLL5025 USB, the external antenna must be
> the combo TX/RX. Thank you for pointing that out. it makes alot of
> sense... and i think i am gonna hack the antenna after this... yes i am
> serious!
>
>
> cheers
Diversity as receive only has been around for some time. Military of
course, but some high end automobiles had diversity receivers for their
FM broadcast reception.
I can understand diversity receive. The receiver comes up with some
sort of figure of merit on the reception. It is multiple transmit
(output) that confuses me. I don't see how a transmitter decides which
antenna to use. In any event, if everyone had diversity in the receive
path, I don't see why it would be needed in the transmitter.
http://www.smc.com/index.cfm?event=v...&scid=&pid=346
SMC2532W-B
is the high power card I use in my notebook. It has diversity receive,
but one transmitter. They claim half a mile on the detachable antenna.
Hardly. However, I've done drive-bys of at least a mile with the
biquad. Make that the bad biquad, i.e. the two wire instead of the
coaxial feed. I haven't tried the good biquad over any distance yet.
Typically they are smooth, not knurled. [Should be about a dollar at
the ham flea market.] Hacksaw one end off, leaving the center pin
exposed. Then position the adapter so you get the right distance
between the antenna and reflector. I cut the copper plate, drilled the
hole, then tinned the area around the hole with solder. This made it
easier to solder the N adapter to the copper plate. You need a propane
torch. [Benzomatic]
>i played with the linksys WRT54G for a while and somehow got stuck in
>DD-WRT concept of diversity antenna. and also i am skeptical about the
>MIMO title that the Ralink chipset is advertised, after all, the
>AWLL5025 is still within 802.11G specs, while MIMO seems to belong to
>draft-N or whatever...
Correct. The marketting baloney that accompanies the Buffalo
WHR-HP-54G is disgusting. They use the term MIMO because it's the
latest and greatest, while there's nothing even remotely related to
MIMO inside the box. What Buffalo is pushing is that you'll get the
same performance as MIMO with their high power transmitter, and offer
some un-reproduceable tests to prove it. It makes me sick to see a
good product polluted by such technically inept marketing.
<http://www.buffalotech.com/technology/our-technology/high-power/>
>but yeah in true MIMO design, diversity mean multiple RX antennas, (and
>mulltiple TX antennas too)
>i often see draft-N wireless adpaters with three antennas, just like
>the 802.11G AWLH5025 PCI adapter, but i was too lazy to learn about the
>antenna configurations.
MIMO is not diversity. What "real" MIMO does is send data from 2 or
more antennas. The data arrives at corresponding antennas and
receivers, but delayed very slightly. The DSP is able to seperate out
the various delays and extract seperate data streams for each delay.
The result is a doubling in available bandwidth. See:
<http://www.airgonetworks.com/mimo/how/>
There's also a skool of thought that claims that MIMO is also adaptive
antenna patterns. This is where the access point contains a smart
antenna system that adds more gain where it's needed, and installs
nulls where it detects interference. See Ruckus Beamflex at:
<http://www.ruckuswireless.com/technology/beamflex.php>
I have a good laugh on this one. The system works, but Netgear
advertises their various routers mounted in the vertical (tower)
position, where the beam forming can't work.
If you're interested in reading about non-MIMO diversity reception
see:
<http://www.commsdesign.com/design_corner/showArticle.jhtml?articleID=16500279>
<http://www.commsdesign.com/design_corner/showArticle.jhtml?articleID=16501888>
<http://www.cisco.com/en/US/tech/tk722/tk809/technologies_tech_note09186a008019f646.shtml>
dold@15.usenet.us.com wrote:
> miso@sushi.com wrote:
>
> > Actually, what is returned at Fry's is handy to know. If there are lots
> > of returns, try something else. I know those on this usenet group are
> > Linksys fans, but most of what is returned to Fry's is Linksys.
>
> I would say that's hard to judge. In the WiFi sections (more than one,
> since there are some dedicated sections, including Linksys), there are
> many empty shelf spaces, usually for the item you want, plenty of items in
> the wrong shelf space, and some opened/returned/markdown units, with
> markdowns of 12-15 cents, which fascinates me.
>
> I would guess that they don't give Linksys their own dedicated space unless
> they move lots of units, so the number of returns on the shelf would have
> to be noted against the number sold.
>
> Wifi is still an emerging market. Many of the units are purchased with
> unreasonable hopes, like using Wifi while commuting on Caltrain... okay, so
> that works now; or getting free access anywhere, or full coverage in a
> home. Those units probably come back, maybe for refund, maybe to exchange
> for a different brand.
>
> The motherboard section is full of returns, often with no new units on the
> shelf. For stores other than Sunnyvale, I don't know what that means, but
> in Sunnyvale, I have overheard engineers selecting motherboards to take
> back and test/certify against some product or another, after which it will
> be returned to Fry's. But these are the same guys trying to make sure they
> get one that is unopened.
>
> > If I think there are going to be problems with something, I always go
> > to Fry's because they will take back anything.
>
> The home of the thirty day free trial for almost anything.
> I have seen people return stereos with no packaging.
>
> --
> ---
> Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5
I just purchased a refurb wifi router from Fry's . Netgear WNR854T for
$60. I wanted a 1gbps router with wan port, but figured might as well
get N wifi at the same time. These are factory refurbs in plain brown
boxes. There was an assortment of netgear products, maybe three of each
model.
Fry's is a poor place to get a mobo. They tend to sell older models of
the better brands, or mystery mobos. For a business, I can't see going
through the work to set up a mobo, only to test then return. More
likely would be to use a junky case and just remove the ram, CPU, and
drives, leaving the mobo in the case in the event you need it again.
Fry's records who returns what. I can't see someone making a habit of
doing returns not getting the evil eye, or at least being force to take
store credit rather than an exchange. I return something maybe every
two or three years.
Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> hath wroth:
>Nope. Quiz time:
>
>You have a spectrum analyzer that shows an 802.11g spread spectrum
>signal that is approximately 25Mhz wide. Peak power on the scale is
>0dBm to make the calculations easy. The spectrum analyzer IF
>bandwidth is 500KHz. What is the "real" power (ignoring duty cycle)?
>
>I'll supply the answer tomorrow. Note that this is not a trick
>question and the numbers are quite real.
Not even a guess? Oh well. This is a good example of why you can't
directly use a spectrum analyzer in place of a power meter or
bolometer with wideband (SS, video, UWB, etc) signals.
The indicated power level on the display is 0dBm. However, the power
is splattered over a bandwidth of 25Mhz. We want the equivalent
carrier power, or the power of the de-spread signal. So we add:
10 * log(25MHz/0.5MHz) = 10 * log(50) = 17dB
So, the real power is:
0dBm + 17dB = +17dBm
Even this is not exact because the power spectra is not equal power
across the 25Mhz bandwidth and the IF filter is not a brick wall at
500KHz. There's also quite a bit of power outside of the 25MHz
window. The rms (heating) power is also different because of the
transmit duty cycle.
Jeff Liebermann wrote:
> Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> hath wroth:
>
> >Nope. Quiz time:
> >
> >You have a spectrum analyzer that shows an 802.11g spread spectrum
> >signal that is approximately 25Mhz wide. Peak power on the scale is
> >0dBm to make the calculations easy. The spectrum analyzer IF
> >bandwidth is 500KHz. What is the "real" power (ignoring duty cycle)?
> >
> >I'll supply the answer tomorrow. Note that this is not a trick
> >question and the numbers are quite real.
>
> Not even a guess? Oh well. This is a good example of why you can't
> directly use a spectrum analyzer in place of a power meter or
> bolometer with wideband (SS, video, UWB, etc) signals.
>
> The indicated power level on the display is 0dBm. However, the power
> is splattered over a bandwidth of 25Mhz. We want the equivalent
> carrier power, or the power of the de-spread signal. So we add:
> 10 * log(25MHz/0.5MHz) = 10 * log(50) = 17dB
> So, the real power is:
> 0dBm + 17dB = +17dBm
>
> Even this is not exact because the power spectra is not equal power
> across the 25Mhz bandwidth and the IF filter is not a brick wall at
> 500KHz. There's also quite a bit of power outside of the 25MHz
> window. The rms (heating) power is also different because of the
> transmit duty cycle.
>
> --
> Jeff Liebermann jeffl@comix.santa-cruz.ca.us
> 150 Felker St #D http://www.LearnByDestroying.com
> Santa Cruz CA 95060 http://802.11junk.com
> Skype: JeffLiebermann AE6KS 831-336-2558
This depends on the "intelligence" of your spectrum analyzer. For the
audio spectrum analyzer I have, you just push a button and it computes
the energy in the bandwidth since it has all the information available
to do such a computation. I don't know if there are RF spectrum
analyzers with such intelligence, but I don't see why not.
In datacom (again, back to voice band communications), some modems used
guard tones to indicate the line contained data, not voice. The CCITT
specification is based on energy, so making such measurements (energy
in a bandwidth) is a desirable feature. That is, the tone had to be a
certain value relative to the data energy, which was spread out.
>I don't know if there are RF spectrum
>analyzers with such intelligence, but I don't see why not.
There are plenty that have enough intelligence to grind out true
power. I can't afford any of these. I can't even afford one with
obsolete IEEE488 bus.
>In datacom (again, back to voice band communications), some modems used
>guard tones to indicate the line contained data, not voice. The CCITT
>specification is based on energy, so making such measurements (energy
>in a bandwidth) is a desirable feature. That is, the tone had to be a
>certain value relative to the data energy, which was spread out.
Sorta. *ALL* modems 1200 baud and up include a scrambler. What the
scrambler does is evenly distribute the energy across the entire
bandwidth, thus reducing the peak power, and thus making it easier to
transmit. The required dynamic range is also reduced. OFDM and DMT
DSL modems do the same thing by splitting the data up into many
discrete carriers. The total energy in the bandpass is the same
whether scrambled or de-scrambled, but the peak power is quite
different.
However, this has nothing to do with what I was mumbling about. I was
questioning the original comment that one could just read the tx power
from a spectrum analyzer. With spread spectrum, it's not that easy.
Jeff Liebermann wrote:
> On 22 Jan 2007 12:14:21 -0800, miso@sushi.com wrote:
>
> >I don't know if there are RF spectrum
> >analyzers with such intelligence, but I don't see why not.
>
> There are plenty that have enough intelligence to grind out true
> power. I can't afford any of these. I can't even afford one with
> obsolete IEEE488 bus.
>
> >In datacom (again, back to voice band communications), some modems used
> >guard tones to indicate the line contained data, not voice. The CCITT
> >specification is based on energy, so making such measurements (energy
> >in a bandwidth) is a desirable feature. That is, the tone had to be a
> >certain value relative to the data energy, which was spread out.
>
> Sorta. *ALL* modems 1200 baud and up include a scrambler. What the
> scrambler does is evenly distribute the energy across the entire
> bandwidth, thus reducing the peak power, and thus making it easier to
> transmit. The required dynamic range is also reduced. OFDM and DMT
> DSL modems do the same thing by splitting the data up into many
> discrete carriers. The total energy in the bandpass is the same
> whether scrambled or de-scrambled, but the peak power is quite
> different.
Without the scrambler, it is possible to create data sequences that you
can't "clock recover."
>
> However, this has nothing to do with what I was mumbling about. I was
> questioning the original comment that one could just read the tx power
> from a spectrum analyzer. With spread spectrum, it's not that easy.
Hey, at least you have an analyzer that goes out to wifi bandwidth. ;-)
RF gear really holds it's value, more than audio test equipment.
>Without the scrambler, it is possible to create data sequences that you
>can't "clock recover."
Well, yeah. It does depend on the coding protocol and whether the
clock signal and synchronization is encoded into the data. It's kinda
easy with 802.11, where the preamble takes care of any sychronization
issues.
>> However, this has nothing to do with what I was mumbling about. I was
>> questioning the original comment that one could just read the tx power
>> from a spectrum analyzer. With spread spectrum, it's not that easy.
>Hey, at least you have an analyzer that goes out to wifi bandwidth. ;-)
>RF gear really holds it's value, more than audio test equipment.
Wrong. My pile of test equipment mostly quits at 1GHz. I use down
converters (mixers) to deal with anything on 2.4 and 5.7Ghz. I am
borrowing a Wiltron 610C with 6215D 1 to 4GHz plugin and VSWR bridge
which is VERY useful for antennas. As I recall, I recommended that
you look into one of these for antenna testing. However, I have to
return it to the owner next week. Grumble. Mostly, I borrow what I
need.
RF test iron does hold it's value better than audio, but only because
it requires more expensive calibration and repair exercises. If it's
working, it's quite valueable. If it's non-functional, it total
garbage. Also, lots of analog audio test equipment is being obsoleted
by DSP based digital processing test equipment.
At this time, I have more test equipment to repair, than is
functional. I also have 2 or more of everything as I have the bad
habit of buying two or more junk units, and conglomerating them into
one that works. It's often cheaper to buy a complete unit for parts,
than to try to find the individual parts.
On Jan 22, 5:29 pm, Jeff Liebermann <j...@comix.santa-cruz.ca.us>
wrote:
> On 22 Jan 2007 16:50:37 -0800, m...@sushi.com wrote:
>
> >Without the scrambler, it is possible to create data sequences that you
> >can't "clock recover."Well, yeah. It does depend on the coding protocol and whether the
> clock signal and synchronization is encoded into the data. It's kinda
> easy with 802.11, where the preamble takes care of any sychronization
> issues.
>
> >> However, this has nothing to do with what I was mumbling about. I was
> >> questioning the original comment that one could just read the tx power
> >> from a spectrum analyzer. With spread spectrum, it's not that easy.
> >Hey, at least you have an analyzer that goes out to wifi bandwidth. ;-)
> >RF gear really holds it's value, more than audio test equipment.Wrong. My pile of test equipment mostly quits at 1GHz. I use down
> converters (mixers) to deal with anything on 2.4 and 5.7Ghz. I am
> borrowing a Wiltron 610C with 6215D 1 to 4GHz plugin and VSWR bridge
> which is VERY useful for antennas. As I recall, I recommended that
> you look into one of these for antenna testing. However, I have to
> return it to the owner next week. Grumble. Mostly, I borrow what I
> need.
My RF generator (HP8660C) reaches wifi, but the last time I fired it up
the mainframe wasn't working. Well, the plug ins are the hard thing to
get. I use this shop in Morgan Hill to fix it. If you have attended
Foothill, you probably met the guy. Damn, I don't see his card in the
pile I have handy, but the guy is good.
Yes, the VSWR bridge is still on the list.
>
> RF test iron does hold it's value better than audio, but only because
> it requires more expensive calibration and repair exercises. If it's
> working, it's quite valueable. If it's non-functional, it total
> garbage. Also, lots of analog audio test equipment is being obsoleted
> by DSP based digital processing test equipment.
>
> At this time, I have more test equipment to repair, than is
> functional. I also have 2 or more of everything as I have the bad
> habit of buying two or more junk units, and conglomerating them into
> one that works. It's often cheaper to buy a complete unit for parts,
> than to try to find the individual parts.
Oh yeah, I know the deal with busted gear for parts. I was at the
Livermore swap meet years ago and saw a busted version of the analog
scope I use [HP1725A]. There was already a somewhat heated discussion
between a buyer and the seller. It was pretty entertaining as the buyer
had this thick Russian accent. The buyer really beat the guy down, then
didn't have the money. I think it was like $30, so I bought it, even
with the word "crap" written with a grease pencil on the screen. I
stashed it and maybe a year later my boss at the time buys some surplus
gear, and you guess it, it had a broken HP1725A. I let him pick at my
spare since he did me plenty of favors, and he got his scope going.
Eventually I bought that scope from him for a song, probably because he
felt guilty about picking out custom hybrids from my spare.
The analog gear I have is mostly from the 80's, so they do have DSP in
them.
Fry's cheapie: Airlink AWL5025 $15 
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