Cantenna Polarity Question

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 find David Taylor's site to be well done.

Uh-oh. It doesn't seem to be available today. the source of the design, and has some very clear pictures.

Does now, maybe the host was rebooting their server, no can't be, it's Linux now not NT, the salesman said it would *NEVER* need rebooting! :)

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:

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.

Exactly the response I was looking for. Thank you very much!

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.

How about a reverse *THREAD* SMA connector? |

Ditto. Reverse polarity "N" connectors: |

thread "N" conectors: | Your nightmares may vary.

No problem. I just wanted to muddy the waters a bit.

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.

Ummm.... entertainment value? Add to the confusion? De-standardization? Product differentiation? Proprietarization?

Connector standards are a good thing. Every company should have one.

I'm always glad to be a part of someones nightmare.

Gone to fix a wine bottling machine. No RF required.

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.

New Zealand uses mini-USBs in various parabolic reflectors.

Bob Alston's coffee can Dold's coffee can used the turnpoint calculator to decide where to poke the hole. Taylor's standard USB cantenna

sez you! All I pointed out is that there are differing labels on the parts on different vendor web sites.

Okay, I give. What is the definition of that one?

That's sick. Why do those exist?

Nope. I have a consistent nightmare.

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.

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.

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.