Hi, I'm building a cantenna to extend the range of my Linksys WMP11
wifi card. I have determined that the WMP11 takes a RP-SMA connection,
and I just ordered a "LMR-195 Rev Polarity R/A SMA Male - N Male"
pigtail today. I know I'll need an N Female chasis mount connector to
recieve the N Male end of the pigtail for my cantenna, but I'm
wondering if the N Female connector needs to be reverse polarity as
well, or can it be just a regular old N Female connector? Any help
would be appreciated.
whitton@atlantic.net wrote:
> Hi, I'm building a cantenna to extend the range of my Linksys WMP11
> wifi card. I have determined that the WMP11 takes a RP-SMA connection,
> and I just ordered a "LMR-195 Rev Polarity R/A SMA Male - N Male"
> pigtail today. I know I'll need an N Female chasis mount connector to
> recieve the N Male end of the pigtail for my cantenna, but I'm
> wondering if the N Female connector needs to be reverse polarity as
> well, or can it be just a regular old N Female connector? Any help
> would be appreciated.
I appreciate the replies; however, I read the document and my question
still stands. I understand the procedure to build a cantenna, but I
just need to know if the N Female connector needs to be RP. I have a
suspicion that it doesn't. Maybe I'll try a regular connector first and
if it doesn't work go to RP. Thanks.
>I appreciate the replies; however, I read the document and my question
>still stands. I understand the procedure to build a cantenna, but I
>just need to know if the N Female connector needs to be RP. I have a
>suspicion that it doesn't. Maybe I'll try a regular connector first and
>if it doesn't work go to RP. Thanks.
Maybe if you understood the purpose of the reverse polarity
connectors, it might help.
The FCC had this bright idea of preventing people like yourself from
modifying unlicensed wireless hardware by requireing the manufacturers
to use uncommon and proprietary RF connectors on the radios. The
weird connectors were certainly uncommon 10 years ago, but have become
commonly available from numerous vendors. There was an attempt to
require even more proprietary connectors, but that proposal was
dropped by the FCC as being too expensive to impliment.
The result is that only the connector attached to the radio is reverse
polarized or weird. All the other connectors are conventional,
normal, non-weird, and commonly available. Same with test equipment,
dummy loads, patch cables, and adapters. The common pigtails and
adapters sold by various vendors are always reverse polarized on one
end and normal polarity on the other end.
When you build your can antenna, the panel or bulkhead mount "N"
connector on the antenna will be a normal polarity. So will the "N"
connector end of the pigtail. However, the other end will probably be
some reverse polarized connector to fit your WMP11 radio.
A cheezy way to avoid the hassle is to use a RP-SMA to N adapter at
the WMP11. See: http://cgi.ebay.com/ws/eBayISAPI.dll...tem=5793385065
That makes all the connectors normal "N" connectors. One problem is
that the SMA adapter is very easy to break. If this is going into a
fixed location (i.e. rooftop), the adapter will work well. If it's
going to move around, such attached to a laptop, use a pigtail
instead. Another problem is that you still have to pay for the N
connectors on the cable ends so the adapter is just an added expense.
whitton@atlantic.net wrote:
> I appreciate the replies; however, I read the document and my question
> still stands. I understand the procedure to build a cantenna, but I
I thought the pictures on the turnpoint page would help.
I meant to add the comment that I ordered my pigtail and matching N
connector at the same time.
Jeff pointed out that the "reverse" stuff is nonsense promulgated by the
FCC that is now largely abandoned, with lots of vendors using the same
connectors. Hawking antennas come with RP-SMA on the end of the cable, and
an RP-SMA to TNC adapter, covering a lot of the popular devices with two
connectors that theoretically were only available from the original
manufacturer for a particular device.
One remaining point is "male" verses "female", where the definition
definitely is in conflict from one connector-vendor website to another.
Fortunately, it doesn't matter much. The RP-SMA connector that you order,
whether called "male" or "female", only seems to come in one gender,
whichever that is.
On the "N" side, the terms are standardized, as are the connector
applications. N Female is usually at the devices, N Male on both ends of
the cable for normal use. There are no reversed N connectors, just
standard male and female. For your cantenna application, you got an
adapter cable long enough to go from your special connector to the N-Male
on the cantenna.
When I ordered mine, I only got 19", which is okay for hand held locating,
but isn't long enough for comfortable use. I still use that for locating
rogue WAPs at work, but nothing else.
Eventually, I went to a mini-USB dongle where cable length doesn't add RF
loss.
>One remaining point is "male" verses "female", where the definition
>definitely is in conflict from one connector-vendor website to another.
Clue: The sex of the connector is NOT determined by the center pin.
Most connector vendors have givenup on the male and female
designation, which is often ambiguous. The current fashion is plug,
jack, and receptacle.
>Fortunately, it doesn't matter much. The RP-SMA connector that you order,
>whether called "male" or "female", only seems to come in one gender,
>whichever that is.
>On the "N" side, the terms are standardized, as are the connector
>applications. N Female is usually at the devices, N Male on both ends of
>the cable for normal use. There are no reversed N connectors, just
>standard male and female.
>>On the "N" side, the terms are standardized, as are the connector
>>applications. N Female is usually at the devices, N Male on both ends of
>>the cable for normal use. There are no reversed N connectors, just
>>standard male and female.
>sez you! All I pointed out is that there are differing labels on the parts
>on different vendor web sites.
No problem. I just wanted to muddy the waters a bit.
>Okay, I give. What is the definition of that one?
I dunno. Reverse threaded connectors are not very common. Actually,
I've never actually seen one on any type of equipment. In some cases,
it might be a good idea where reversing two connections might blow
something up.
>That's sick. Why do those exist?
Ummm.... entertainment value? Add to the confusion?
De-standardization? Product differentiation? Proprietarization?
Connector standards are a good thing. Every company should have one.
>> Your nightmares may vary.
>Nope. I have a consistent nightmare.
I'm always glad to be a part of someones nightmare.
Gone to fix a wine bottling machine. No RF required.
> > Clue: The sex of the connector is NOT determined by the center pin.
>
> sez you! All I pointed out is that there are differing labels on the parts
> on different vendor web sites.
>
> > How about a reverse *THREAD* SMA connector?
Hey I have a great idea, how about they use left hand threaded
connectors too, and what about some imperimetric pitch for a change too.
> Hey I have a great idea, how about they use left hand threaded
> connectors too, and what about some imperimetric pitch for a change too.
That would be in the spiriti of the original regs, wouldn't it?
> :)
And the smiley refers not to the possibility of the connectors that you
refer to here, but the original strangeness of the regs. ;-)
CB radios all had "standard" antenna connectors. I wonder what was so
frightful about 802.11 that caused the "proprietary" rules? Both of these
turned out to be wildly more popular than was first envisioned, I think.
--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8,-122.5
On Sat, 30 Jul 2005 10:41:25 GMT, David Taylor <djtaylor@bigfoot.com>
wrote:
>> > Clue: The sex of the connector is NOT determined by the center pin.
>>
>> sez you! All I pointed out is that there are differing labels on the parts
>> on different vendor web sites.
>>
>> > How about a reverse *THREAD* SMA connector?
>Hey I have a great idea, how about they use left hand threaded
>connectors too, and what about some imperimetric pitch for a change too.
It's a lesson that has to be learned over and over again in each
industry. To prevent accidentally misconnecting air hoses and
hydraulic hoses in vehicles, aircraft, and welding rigs, the threads
are different. The logic is good and it has undoubtably prevented
many accidents. However, it has not stopped a clever mechanic, who's
solution to a "bad fit" problem is to get a bigger wrench. I've lost
count of how many times I've tried to brute force a "mini-UHF"
connector into an "F-connector". They look very similar but have
different center pin diameters and threads.
Given the availabliliy of different SMA connector mutations, I would
certainly have used them to prevent accidentally reversing the input
and output in one of my ancient power amplifier designs. Personally,
I would prefer "keyed" connectors, but they tend to be expensive to
build, especially in small sizes.
Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote:
> industry. To prevent accidentally misconnecting air hoses and
> hydraulic hoses in vehicles, aircraft, and welding rigs, the threads
> are different.
Not so good on truck brake air hoses. The emergency line and the service
line are the same, just different colors, which doesn't help much on a
twenty year old trailer, especially when the red manufacturers label on one
fitting is brighter than the red color coding on the other fitting.
--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8,-122.5
Cantenna Polarity Question 
Linear Mode
