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Horizontal vs Vertial Polarization

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Sceadwian

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If I'm not mistaken most television broadcast chanels are vertically polarized, yet all the yagi's I see on rooftops are horizontally polarized, can someone explain this?
 

Nigel Goodwin

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If I'm not mistaken most television broadcast chanels are vertically polarized, yet all the yagi's I see on rooftops are horizontally polarized, can someone explain this?

No idea what the situation is in the USA?, but in the UK 'generally' main stations are horizontal, and relay stations are vertical - a VERY tiny number of very small relays are horizontal, it's a question of squeezing in where they can.
 

steveB

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If I'm not mistaken most television broadcast chanels are vertically polarized, yet all the yagi's I see on rooftops are horizontally polarized, can someone explain this?

You just explained it. :)

You see that the antenna's are horizontally polarized, and you say that TV is vertically polarized unless you are mistaken. Hence, you are mistaken.

I generally trust my eyes over my memory; especially as I get older.

USA TV signals are horizontal.
 

Sceadwian

Banned
It's difficult to find the information on the net because there's no law requiring it, and if there's a standard it's not publicly available from the general FCC and TV station websites.

Just a tidbit I ran across, a big tidbit mind you.

**broken link removed**

So it's not JUST horizontal. That information is a bit out of date though. By the information in that article it never occurred to me that they could transmit the signal in more than one polarization method, and I completly forgot about circular polarization. This is why I fact check everything everyone tells me =) And why antennas and the details of RF propagation are so hard to find out I think, there's so MUCH contradicting information out there.
 
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RCinFLA

Well-Known Member
TV was originally spec'd for horizonal polarization, as was commercial FM radio. In recent times there has been circularly polarized TV transmitter antennas installed. Beside making transmit antenna easier, it gives some improvement to folks using indoor rabbit ears. The station is giving up some of it radiated power to vertical component.

For commercial FM transmission it really makes sense as majority of the listeners are in their automobiles with vertical wip antennas.

Satellite TV uses cross polarization to get more bandwidth out of their allocated spectrum. It's good for about 12 db to 18 db of isolation so the channels are typically half overlapped in center frequency assignment.

For satellite TV, either vertical / horizonal polarization is used or right hand / left hand circular polarization is use. Directv satellites TV in U.S. uses latter.
 
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