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Old Jan 18, 2010, 07:34 PM
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Antennas 101 - Polarization, Gain, Diversity & Patterns

Antennas 101 - Polarization, Diversity & Gain Patterns (27 min 56 sec)


Here's a video i did to illustrate some of the fundamentals of Antenna configs, looking at gain, patterns, diversity setups and polarization principles.

This is NOT an MIT tutorial or whitepaper, it is simply a video that was produced to help non-technical people to understand and visualise some of the princples of some of the antenna configs we use for FPV.

Cheers

Andy

P.S - this video is designed to "unconfuse" people who have been completely put off and confused by over-technical and techno showoffs who care more about their technical prowess and being thought of as "clever" than actually trying to help people to understand a complex subject, in an easy way.. So what i'm saying, is this video is not for you... it's for everybody else..

Here's the YouTube Version due to popular demand:

FPV Antennas 101 - Polarization, Diversity & Gain Patterns (27 min 56 sec)


Thanks for your kind comments everyone, i'm pleased it's been so useful to people.
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Last edited by Andology; Jan 30, 2014 at 10:43 AM.
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Old Jan 18, 2010, 07:56 PM
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i like it so far! vimeo doesn't play nice with my machine so im downloading it.
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Old Jan 18, 2010, 08:03 PM
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Great video......I've been enlightened! Thank you Andy....
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Old Jan 18, 2010, 08:11 PM
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very helpful thanks a lot
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Old Jan 18, 2010, 08:13 PM
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Great information.....I am very new to FPV but am learning as much as I can as fast as I can. Thank you very much for a great instructional video!!
Alan
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Old Jan 18, 2010, 08:20 PM
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zaguruinzasky's Avatar
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andy can you please explain about 8dbi circular right hand and left hand? that's a missing part in my knowledge..

also, with thhese two antennas is there any better antenna that I could use in my TX instead of the whip ?

Thanks
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Old Jan 18, 2010, 08:47 PM
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You could use a dipole. A whip is a monopole and not as efficient.
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Old Jan 18, 2010, 08:52 PM
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Does the 900mhz dipole (that comes with dpcav tx) has a different pattern then the 2db shown in the video?
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Old Jan 18, 2010, 08:54 PM
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Andology's Avatar
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Quote:
Originally Posted by zaguruinzasky View Post
andy can you please explain about 8dbi circular right hand and left hand? that's a missing part in my knowledge..

also, with thhese two antennas is there any better antenna that I could use in my TX instead of the whip ?

Thanks
Left hand circular is what most use... without getting too bogged down in the technicals (which is what i tried to avoid in the video the right hand circular antenna and left hand circular used in a diversity system, one would basically get the "reflections" of the signals, almost the mirror image of the radio wave. Since we're not transmitting in circular polarisation, we don't need to worry about getting a match between left & right..

The Whip really is the best solution.. anything else is not going to give you the all round emission you get with a whip / low gain antenna... Even if you used an 8dBi patch antenna with 70 degree FOV, that's great when you're flying out, but when you are returning home, it's hardly going to be transmitting any signal to the GS direction..

Generally the greater range is achieved by higher gain RX antenna, not TX... unless both transmission and reception are locked down and both stationary, it's the better of the two evils..

Thanks for the comments so far, it took me around an hour to do the 3d and shoot the video guide, so i'm glad it's helped a couple of people so far.

Cheers

Andy
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Old Jan 18, 2010, 08:54 PM
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guys any link to a dipole suitable for fpv?

thanks
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Old Jan 18, 2010, 08:59 PM
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900mhz - http://www.dpcav.com/xcart/product.p...cat=266&page=1
2.4ghz - http://www.dpcav.com/xcart/product.p...cat=267&page=1
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Old Jan 18, 2010, 09:02 PM
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ah cool so you guys say that these antennas has a better range of the normal whip?
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Old Jan 18, 2010, 09:12 PM
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Well, rather than better range, i'd say, better pattern (less "black spots" around it).. Which i guess would lead to greater range in certain positions around it... but again, it's really the RX antenna that will massively improve range... like parabolic or grid antenna at say 24dBi would be serious range... but then you're really talking tracker stuff there. even a human spotter with binoculars would struggle with a 10 degree FOV!

Cheers

Andy
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Old Jan 18, 2010, 09:14 PM
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Quote:
Originally Posted by zaguruinzasky View Post
guys any link to a dipole suitable for fpv?

thanks
http://parts.digikey.com/1/parts/635...w-hwr-sma.html
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Old Jan 18, 2010, 09:14 PM
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can we send with two TX on same channel to have different polarizations ?
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