Antennas, Omni directional and directional same time

[mnoutdoors]

so the question is, what happens if you use Omni directional and directional at the same time.

 

[HVYMTL]

I believe it will mess up the impedance of the coax, and do more damage than good.. just my thoughts..

 

[Qoncussion]

Typically on a two antenna system, they are used in "diversity" - both sending and receiving signals, but the remote only ever uses the strongest of the two signals. I had both an omni and unidirectional antenna setup for my Phantom 2's FPV. It worked great.

 

[mnoutdoors]

So far it seems strong, it has some 8 watt help, I will try a flat panel also, I have a 15dbi Omni that’s on its way.
A 14 dbi flat panel on its way, and I’m currently using the 16dbi yagi on one and the 9dbi Omni on the other I might try a test with a 9dbi Omni and the yagi on the same amp and see what that result is, in the mountains around peaks and valleys you need all you can get.

 

[hainerob]

So far it seems strong, it has some 8 watt help, I will try a flat panel also, I have a 15dbi Omni that’s on its way.
A 14 dbi flat panel on its way, and I’m currently using the 16dbi yagi on one and the 9dbi Omni on the other I might try a test with a 9dbi Omni and the yagi on the same amp and see what that result is, in the mountains around peaks and valleys you need all you can get.

I would just keep with the directional antennas, the omni antennas tend to flatten their radiation pattern as you go higher gain.

Also, I notice that your Yagi is mounted for horizontal polarisation --- I would have thought that the mavic and controller would have been vertical...

 

[hainerob]

Typically on a two antenna system, they are used in "diversity" - both sending and receiving signals, but the remote only ever uses the strongest of the two signals. I had both an omni and unidirectional antenna setup for my Phantom 2's FPV. It worked great.

I don't believe both Antennas would be used for transmit, only for receive. You'll get an overlapping of waves if you had both transmitting.

 

[mnoutdoors]

The yagi has a 23 degree vertical lobe and a 26degree horizontal lobe do you think there is a lot of difference ?
Pretty much flying a straight line and pointed right at where it is flying. I’m not a antenna guy I’m just experimenting

 

[Qoncussion]

I don't believe both Antennas would be used for transmit, only for receive. You'll get an overlapping of waves if you had both transmitting.

I believe you are correct. The two antennas were on a Black Pearl FPV - receiving.

 

[hainerob]

The yagi has a 23 degree vertical lobe and a 26degree horizontal lobe do you think there is a lot of difference ?
Pretty much flying a straight line and pointed right at where it is flying. I’m not a antenna guy I’m just experimenting

Your talking about radiation patterns there, not polarity --- they are different. Its easy to test on equipment which gives you a signal readout in dBm, you've only got a mobile-phone type bar readout on the controller.

Anyway, if you were to fly your mavic to a distance where you have lost 1 or 2 bars of signal, hover there, and then rotate your yagi so the elements run vertically instead of horizontally. This should either immediately improve or degrade the signal by 25-50% depending on if its correct now or not.

Disclaimer: Do at own risk, I expect your mavic may need to be many miles/km away from you to perform this test!

 

[mnoutdoors]

Yes, 23 degree lobe and 26 degree lobe so with only the 3 degrees differential is it a concern if it’s set vertical or horizontal

 

[mnoutdoors]

I guess I could just rotate before I start out, I have a set path I use, between two mountains and see if it’s better or worse at distance. I only loose one bar on the video feed , no bars lost on the RC at my distance

 

[hainerob]

Yes, 23 degree lobe and 26 degree lobe so with only the 3 degrees differential is it a concern if it’s set vertical or horizontal

The lobes are where the antenna's best gain areas are. They dont relate to the polarity (or, not really for the sake of this discussion).

The polarity is about if the waves are going up and down or side to side. It kinda works the way polarized sunglasses do, if you turn them one way, they block out different light. You obviously want your glasses (yagi) pointed the right way for the light (mavic) your wanting to see.
You can read about it here: Antenna (radio) - Wikipedia

 

[mnoutdoors]

Ok, I’ll try it the other way once and see what it changes. Starting with it rotated
Thanks for the feed back

 

[mnoutdoors]

Well, I rotated 90 degrees this morning on the yagi’s And I lost distance almost 5000 feet sooner than the other
way I won’t judge it on one test alone. And I lost it on both the RC and the video not just the video like I did the other way

 

[hainerob]

Well, I rotated 90 degrees this morning on the yagi’s And I lost distance almost 5000 feet sooner than the other
way I won’t judge it on one test alone. And I lost it on both the RC and the video not just the video like I did the other way

I think that's probably fairly conclusive. I'd say that means the mavic is horizontal polarization. Proves though however that your yagi is actually doing something though.