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Oct 06, 2014, 11:29 AM
Tri-Quad-Hexa-Octo-copters!!

R/C frequencies and propagation 101


Hi Buzz,
The 2.4Ghz and 5.8Ghz will propagate through glass, but attenuate rapidly though the human body, water, bricks, building, trees, etc. The reason most serious long range Gents use 433Mhz for control is that lower frequencies do propagate much better with less chance of signal loss. These comparisons are using the same mw power levels.
Good info here:
FPV Video and RC Control Frequencies | FPV for Me

Also note that control or video signal ranges can be affected by many factors, so it is nearly impossible to predict accurately. There are theoretical power/frequency maximums if all conditions were perfect, but it is rare that anyone will fly in a location where all conditions are perfect. Lots of things can affect range, such as local broadcasts on the same frequency, mutlipath interference from reflections off of human bodies, trees, buildings, car, etc., and loss of the line-of-sight between the transmitter and receiver antennas. Even the moisture in the atmosphere can negatively affect achievable Tx/Rx range.

Cheers,
Jim
Quadrocopter and Tricopter Info Mega Link Index
Quote:
Originally Posted by Buzz
No problem, Dave. I'm no frequency expert either but I have read that 5.8 penetrates best. If I'm wrong about that I can't figure out how I can fly from inside the house and never get a dropout. It's magic! I don't doubt what Alex is saying... it's just not working that way with mine. I don't have a clue why.
Hmmmmm, you know, I do live in one corner of the Bermuda Triangle!

Buzz
Last edited by jesolins; Oct 06, 2014 at 12:45 PM.
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Oct 06, 2014, 11:37 AM
I got FPV fever
CurrentDude's Avatar
Quote:
Originally Posted by Buzz
No problem, Dave. I'm no frequency expert either but I have read that 5.8 penetrates best. If I'm wrong about that I can't figure out how I can fly from inside the house and never get a dropout. It's magic! I don't doubt what Alex is saying... it's just not working that way with mine. I don't have a clue why.
Hmmmmm, you know, I do live in one corner of the Bermuda Triangle!

Buzz
5.8 GHz compared to 2.4GHz ... latter has half the frequency .... carries less energy. 5.8 GHz can blast through where 2.4 fails. Makes any sense?

Cheers
Oct 06, 2014, 12:30 PM
Empire Support
T J Gilbert's Avatar

My Head's Starting To Hurt


There's too much confusion here w.r.t. frequency penetration.
Maybe this diagram will help...
Oct 06, 2014, 12:34 PM
I got FPV fever
CurrentDude's Avatar
Quote:
Originally Posted by T J Gilbert
There's too much confusion here w.r.t. frequency penetration.
Maybe this diagram will help...
I take all have the same mill watt output?

Cheers
Oct 06, 2014, 12:52 PM
Empire Support
T J Gilbert's Avatar
Quote:
Originally Posted by CurrentDude
I take all have the same mill watt output?
Cheers
Man, I don't know...
I suppose they should or the chart would be useless.
And I kind of think the 1.2 Mhz on the chart should be 1.2 Ghz, but it's still correct...
It's all over the internet, if you search, that lower frequencies penetrate walls and building materials better than higher frequencies.
You can find layman's explanations and PhD explanations with everything under the sun in between.
Just search...
Oct 06, 2014, 02:54 PM
Old Fart
d_wheel's Avatar
Quote:
Originally Posted by T J Gilbert
Just search...
I think that's the problem TJ. We have people on here with tens of thousands of posts spouting garbage. They don't have time to search between posts. And I'm not referring to jesolins. He gave a great response.
Oct 06, 2014, 03:12 PM
Forever WTTM Pilot #7
Buzz's Avatar
Quote:
Originally Posted by d_wheel
I think that's the problem TJ. We have people on here with tens of thousands of posts spouting garbage. They don't have time to search between posts. And I'm not referring to jesolins. He gave a great response.
Well, pardon the heck out of me! I must have been mistaken when I saw that this thread is titled ...."New Product Phantom Quadcopter." I won't bother you again.

Buzz
Oct 06, 2014, 03:28 PM
Empire Support
T J Gilbert's Avatar

@Buzz


Don't be so sensitive, Buzz.
You simply started the conversation and responded to other posts.
The posts after yours confirmed that some don't understand the wavelength vs. penetration theory, and we can all hope that now we all will refresh our education on such technical matters and move on...
Last edited by T J Gilbert; Oct 06, 2014 at 03:58 PM.
Oct 06, 2014, 04:03 PM
I got FPV fever
CurrentDude's Avatar
Quote:
Originally Posted by T J Gilbert
Man, I don't know...
I suppose they should or the chart would be useless.
And I kind of think the 1.2 Mhz on the chart should be 1.2 Ghz, but it's still correct...
It's all over the internet, if you search, that lower frequencies penetrate walls and building materials better than higher frequencies.
You can find layman's explanations and PhD explanations with everything under the sun in between.
Just search...
If asking a question irritates you so much then I'd not bother posting here either.

In my experience I find when you ask a question which takes someone beyond his/her comfort zone, normally people get irritable.


Cheers
Oct 06, 2014, 04:09 PM
Forever WTTM Pilot #7
Buzz's Avatar
Quote:
Originally Posted by d_wheel View Post
I think that's the problem TJ. We have people on here with tens of thousands of posts spouting garbage. They don't have time to search between posts. And I'm not referring to jesolins. He gave a great response.

---------------------------------------------------------------------------
Garbage? Spouting? Sensitive? Why would anyone think that was sensitive?
Oct 06, 2014, 04:18 PM
Empire Support
T J Gilbert's Avatar

Sorry Guys...


I'm not trying to set anyone off.
I just provided information (which was questioned), and then stated that the answers to the posed questions were a simple search away...
I'll bow out here, and let the arguments you're looking for continue...
Oct 06, 2014, 04:28 PM
Forever WTTM Pilot #7
Buzz's Avatar
I'm finished. Sorry I butted in.
Oct 06, 2014, 05:50 PM
Registered User
rmorhan's Avatar
Quote:
Originally Posted by Buzz
I thought it was 5.8 that would penetrate obstacles. I fly all over the place and I've never had a loss of signal. The 2.4 FPV is not affected either. I live in Florida and the mosquitoes are terrible when the wind dies enough to fly. To get rid of that problem... I take the Phantom outside, arm it and I go back in the house.
I sit in an easy chair in front of a large picture window and I fly all over the place.
I've even flown over the house and into the back yard, sitting in the living room.
I did get some breakup a couple of times.... but it always comes back.
It seems like a cement block house would block 5.8... but I've never seen any interference.
buzz, not to jump all over you but weren,t you the guy that lives 2 miles from an airport & has low flying planes overhead a lot? sounds like a recipe for disaster if your flying fpv beyond line of sight with no spotter !referring to your phantom as a nifty spy cam made me cringe as well. I love my phantoms but why is it I believe they will cause the end of our hobby as we know it??? just saying...rob m
Oct 06, 2014, 06:13 PM
Registered User
Ok, got tired of reading about 30 pages of the 1887 pages on here, LOL

I'm getting back into the hobby being on and off RC for the past 10 years

I'm mainly getting back into it this time, because of my intrest in flying FPV and making awesome video's to share on You Tube with my new Gopro Hero4 Black I just picked up yesterday

Only thing I see in the Phantom line made for the Hero is the Phantom 2 with the H3-3D Gimble

Before I drop $829 on the RTF kit with the H3-3D, I'm not crazy about the radio having 4 AA batteries

I have a Spektrum DX8 when I was flying. How does their transmitter do , any good?

How is the Phantom 2 compared to the DJI F450 for Gopro. I had 2 DJI F550's in the past, but sold them after getting frustrated spending 30 hours learning the build, Naza V2 etc

This time around, I want a RTF , like the Phantom 2

Also any good smaller quads to practice in doors with for like $100 ?

I've only flown fixed wing airplanes in the past
Oct 06, 2014, 06:45 PM
Empire Support
T J Gilbert's Avatar
Quote:
Originally Posted by fltekdiver
Ok, got tired of reading about 30 pages of the 1887 pages on here, LOL
I'm getting back into the hobby being on and off RC for the past 10 years
I'm mainly getting back into it this time, because of my intrest in flying FPV and making awesome video's to share on You Tube with my new Gopro Hero4 Black I just picked up yesterday
Only thing I see in the Phantom line made for the Hero is the Phantom 2 with the H3-3D Gimble
Correct, unless you want to get a P1 or P2 with a solid mount (no gimbal).
Before I drop $829 on the RTF kit with the H3-3D, I'm not crazy about the radio having 4 AA batteries
4 AA is all the Phantom Tx's have ever had, and the are not hard on them...
I have a Spektrum DX8 when I was flying. How does their transmitter do , any good?
You'd need to modify the P2 with a Spektrum Rx to be able to use the Spektrum Tx...
If you're asking how the DJI Tx stacks up compared to the Spektrum Tx, it does the job it's designed for, but without most of the Spektrum bells and whistles...

How is the Phantom 2 compared to the DJI F450 for Gopro. I had 2 DJI F550's in the past, but sold them after getting frustrated spending 30 hours learning the build, Naza V2 etc
If you mean payload carrying capacity of F450 vs P2, the F450 may be a little ahead since it can handle 4S compared to the P2's 3S, but the P2 seems to carry the H3-3D + GP3 fine. So, I assume it will be okay with the GP4. (Be sure to study up on the early problems (minor) being encountered with the GP4 so far.)
This time around, I want a RTF , like the Phantom 2
Also any good smaller quads to practice in doors with for like $100 ?
Since you have had F550's in the past, why would you need to practice? Flying the P2 is really easy!
I've only flown fixed wing airplanes in the past
Even if you never got the F550's in the air, your fixed wing experience should serve you well if you study the manual and do some initial indoctrination/test flights with the P2...
See red...
And Good Luck!


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