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reverse polarity on wireless antennas

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nealric

Member
Joined
Sep 9, 2002
Location
under the floorboards
I recently ordered an omni antenna for my wireless lan off ebay. Stupid me did not notice that the conector was reverse polarity. I can't find any way to adapt my pigtail (standard n-male) to the antenna (reverse polarty n-male). So the question is:

Can I use the anenna at all- do the wireless cards have a specific polarity?

Can I get an mmcx to n female reverse polarity pigtail (google left me emphty handed)

Are there wireless cards that use reverse polarity?

Edit- I was just lookin at the website of the manufactuere and they state that all their antennas use standard (not reverse polarity) connectors ??? Im very confused.
 

Ddruid_SMP

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May 18, 2003
Location
Missouri
I would wait and see what shows up before getting too worried.. Polarity only refers to the 'style' (as to which side is male/female of the center conductor inside the connector) of the connector, it has nothing to do with 'polarity' of the signal. At worse you may have to order a new pigtail or build your own adapter.
 
OP
nealric

nealric

Member
Joined
Sep 9, 2002
Location
under the floorboards
I would wait and see what shows up before getting too worried.. Polarity only refers to the 'style' (as to which side is male/female of the center conductor inside the connector) of the connector, it has nothing to do with 'polarity' of the signal. At worse you may have to order a new pigtail or build your own adapter.

Thats just the thing- it did show up and i cant connect it :(

I read some vauge articles about the whole polarity thing existign to preventing certain connections that wouldnt work anyways- ie even if I spliced the cables togeather it wouldnt work.
 

Ddruid_SMP

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Joined
May 18, 2003
Location
Missouri
Again, it has nothing to do with any 'polarity', only the style of the center conductor pin. Buy a female n-connector and a rvp female connector and some lmr400 and crimp the ends on, or contact a wireless eq reseller (electrocom) and purchase a new pigtail for your wireless card with the proper connector for your omni. I would avoid trying to splice the two together, you will introduce a high amount of antenuation into the line.

The only polarity you need to be concerned with is whether the omni you bought is horizontal or verticaly polarized.

Do you have any pictures of what you are working with?
 

Ddruid_SMP

Member
Joined
May 18, 2003
Location
Missouri
One of my 12dbi Vertical polarized omni's (spare)
MVC-294S.JPG


N-Female connector (If it were RP the center pin would be opposite of what it is now)
MVC-295S.JPG
 

BioS

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May 3, 2002
Location
SoCal
Here my question Ddruid_SMP, I get one of the Directional antenna for my wireless PCI card. The problem it using the SMA connector and cable it bit too short to extent to the roof. Is any female of male adaptor availble? Where can i find some of the SMA cable?
 

Ddruid_SMP

Member
Joined
May 18, 2003
Location
Missouri
BioS said:
Here my question Ddruid_SMP, I get one of the Directional antenna for my wireless PCI card. The problem it using the SMA connector and cable it bit too short to extent to the roof. Is any female of male adaptor availble? Where can i find some of the SMA cable?

There are several different ways of going about it, the biggest influence is the distance you are shooting (How much DB can you afford to lose) and length of the cable run.

If it were me I would avoid using any adapter inline, and instead run a single unbroken conductor. I use nothing smaller than LMR400 when possible (And shorter than 50'). You can purchase crimp connectors for whatever cable you are using in just about any style. I order alot from Electro-Comm. They may have what you are looking for.

To answer your question though, You should be able to purchase something like a female to female sma adapter and short length of precut/terminated LMR cable to extend it to the roof. The pigtail below uses LMR195.

I only have one radio that I use that has an SMA connector on it and all of my Antenna's and other radio's have N-Female connectors/pigtails so all I stock is N-Male crimp connectors. When I use the radio with the SMA connector I use an SMA to N-Female pigtail and run LMR400 between the two connectors:
MVC-297S.JPG
 

Ddruid_SMP

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Joined
May 18, 2003
Location
Missouri
There is no 'set' maximum, only an acceptable loss. Every different cable has semi-predictable attenuation per foot. For example LMR400 has an attenuation (at 2000mhz) of 6db (roughly 4mw) per 100 ft. Every connector you use also attenuates some of the signal. There are just too many factors to give an exact length, but in general I avoid using more than 50' of LMR400, if I feel the length of the run will be significantly greater than 50' I use an outdoor ethernet radio and just run cat 5.
 
OP
nealric

nealric

Member
Joined
Sep 9, 2002
Location
under the floorboards
heres the antenna

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3024171753

can you give me an idea of what an rvp connector looks like?
I have two pigtails (place I ordered sent me two by accident)- Its an mmcx to n-male.
I have a really good electronics + radio supplier that probably has anything- you just need to know what to look for as its all just in random bins. Cable length wont be an issue since its goin to be used mostly indoors and for a little wardriving (and my wireess nic is usb)- 2 feet max- do I still need lmr-400?
 

Ddruid_SMP

Member
Joined
May 18, 2003
Location
Missouri
nealric said:
heres the antenna

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3024171753

can you give me an idea of what an rvp connector looks like?
I have two pigtails (place I ordered sent me two by accident)- Its an mmcx to n-male.
I have a really good electronics + radio supplier that probably has anything- you just need to know what to look for as its all just in random bins. Cable length wont be an issue since its goin to be used mostly indoors and for a little wardriving (and my wireess nic is usb)- 2 feet max- do I still need lmr-400?

Have a look here (I don't have any rvp connectors): hyper
The only difference is the style of the center pin.

You can get away with something other than lmr400 (lmr200 would probably work just fine), the smaller the cable the greater the loss, so you will want to keep it as short as possible to minimize the amount of loss.

The connector on the omni you linked to is female btw (Confusing aint it?).