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Old Oct 11, 2012, 02:26 PM
"FPV"er not a "LOS"er
Wettfeat's Avatar
United States, NC, Charlotte
Joined Feb 2012
360 Posts
Quote:
Originally Posted by David22 View Post
Yes some people have derailed this thread unfortunately, and even post things nothing to do with fpv, they just are waste of post space.
Case in point...

Houston we have a troll...
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Old Oct 11, 2012, 04:06 PM
Wallop!
Martin7182's Avatar
Bussum, Netherlands
Joined Oct 2009
766 Posts
Quote:
Originally Posted by MASHTON View Post
Seriously David? You know good and well what other gear gets swamped by those +1W vtxs in close proximity. UHF control (maybe not your TSLRS that is what 2W and 8W boosted or something but the rest do), 2.4GHz control and GPS all get swamped.

Stand across from your friend and have a conversation, start walking away until you can't hear him anymore and mark the spot. Now put a radio in the mix and repeat set the radio on different volumes and repeat this test several times. As the radio volume gets louder the distance you can hear your friend decreases. This is an approximation of what we are doing to our gear every time we fly. A 1+ watt vtx is like putting a radio on full blast and walking away. The further away you get from the source the harder it gets to receive (hear) it. The receiver is essentially the plane's ears, you don't want someone screaming in it.
Nice explanation, but not necessarily true imho. It only counts for equal frequency bands. If I have a conversation it doesn't matter whether a bat is screaming in my ears. The other way around may be a problem for the bat; my voice probably contains harmonics a bat could hear. So harmonics could be bad. And magnetic coupling could be a problem in close proximity. Anyway high power doesn't add much to your range; you'll need 4 times more power to double your range. Often easier is to use a +6dB rx-antenna. It is lighter, prevents over-heating and saves battery power as well.

Quote:
Originally Posted by IBCrazy View Post
Of course if you don't believe me, then explain how a Yagi antenna works without any coupling effect.
-Alex
+1!

Martin
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Old Oct 11, 2012, 04:42 PM
doz
D.O.
Oklahoma
Joined Jan 2004
67 Posts
RE: topic toppling. David22 et all... seems like those who talk the most about arcane stuff provide the least useable information to new-comers. When there is to much arguing, NOBODY wants to listen or take advice. Maybe you guys should step back for a bit and let the intended nature of this forum re-establish itself?
Just sayin........
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Old Oct 11, 2012, 04:48 PM
"FPV"er not a "LOS"er
Wettfeat's Avatar
United States, NC, Charlotte
Joined Feb 2012
360 Posts
Alex,
I made one of your vee antenna's and it works well. I have it mounted on the wing of my Skysurfer and it works great going and coming but when its "sideways" oriented so I can see the fuselage lengthways the signal is gone. I assume this is normal since I'm using the stock antenna for the receiver. I just wanted your opinion on antenna's for the receiver.

I looked at your ground plane antenna but it won't fit inside my fpv box. Can I turn it into 1/8 wavelengths for the elements and if so how much range would I lose. I have 1.5W 900mhz vtx so I don't know. I'm going for 3 miles.
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Old Oct 11, 2012, 06:12 PM
BEOWULF
North vancouver, B.C. Canada
Joined Apr 2008
18,581 Posts
Yes it is important to stay on topic and not let personal feelings effect advice.



It is sad that some make personal,attacks and actually break rc group rules

What is most important is that we keep to the thread.

I will post some pictures on a different thread as this is not show us your plane, as newbies and others are confused about some things.

There seems to be confusion about how to set up a plane and not need to separate or go through unneeded learning curves

As the whole idea is to help people,out so they don't waste time and money experimenting but rather learn from others who have experimented already


IbI crazy is great man for staring this thread to help others out, very great thread

It's best to read rather than make wasteful comments and not waste others time


So please refrain from stupid wasteful posts that are nothing to help,others out please
Let me take some pictures and just post link to show us your plane

As many email me recently asking how I position my setup nice and close and not need separation even with high powered video Txs

Argueing is really a waste of time, it's best to say why is that, or how do you do this, or very interesting I never thought that was possible , or wow that actually has never been done before and all,other guys do it differently

New ideas to,fpv is very important because this hobby of fpv changes so fast

It's only been a few years since long range fpv became popular

If you can do long range short range is a joke in the sence iit is easy as pie









Quote:
Originally Posted by doz View Post
RE: topic toppling. David22 et all... seems like those who talk the most about arcane stuff provide the least useable information to new-comers. When there is to much arguing, NOBODY wants to listen or take advice. Maybe you guys should step back for a bit and let the intended nature of this forum re-establish itself?
Just sayin........
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Old Oct 12, 2012, 12:04 PM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,446 Posts
Quote:
Originally Posted by Wettfeat View Post
Alex,
I made one of your vee antenna's and it works well. I have it mounted on the wing of my Skysurfer and it works great going and coming but when its "sideways" oriented so I can see the fuselage lengthways the signal is gone. I assume this is normal since I'm using the stock antenna for the receiver. I just wanted your opinion on antenna's for the receiver.

I looked at your ground plane antenna but it won't fit inside my fpv box. Can I turn it into 1/8 wavelengths for the elements and if so how much range would I lose. I have 1.5W 900mhz vtx so I don't know. I'm going for 3 miles.
I'm not sure what you mean here, but shortening the antenna is generally a bad thing. There is a way to bend it, but this changes the radiation pattern. You could try a 4:1 balun on the ground plane antenna and that would allow you to make it smaller. You would still have considerable loss, but the balun gives you 400% more signal than just cutting it down alone.

If I were you, I'd build a patch antenna. Check my blog for the "fast patch". it takes about 20 minutes to build.

-Alex
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Old Oct 12, 2012, 01:09 PM
Closed Account
Joined May 2012
224 Posts
Range estimate?

2.3ghz
- 700mw
- one of your recievers
- Cloverleaf on plane and Skew planar on ground station
-
- Lots of evergreen trees 100ft high, open airspace though.
- around 400ft and slow, boring. or slow, boring and above 400ft
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Old Oct 12, 2012, 01:39 PM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,446 Posts
^ If keeping it at 400 feet, you range is going to be hindered by those tall pines. Your range will be approximately 8 times the distance from the nearest row of pine trees.

Above 400 feet, you should do 3 or 4 miles.

-Alex
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Old Oct 12, 2012, 02:26 PM
Closed Account
Joined May 2012
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Thanks!
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Old Oct 12, 2012, 06:34 PM
Registered User
United States, MN, Orono
Joined May 2011
568 Posts
Quote:
Originally Posted by David22 View Post
Do ground tests to find out if it effects range

Thanks, finally someone actually responded!

I know a ground test is a good idea, but if the Dragonlink really does have 40km of range, I won't be able to do a range test without getting in my car.
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Old Oct 12, 2012, 06:54 PM
OSUFPV - KF7VFT
Corvallis, OR
Joined Apr 2010
1,770 Posts
Quote:
Originally Posted by FPV_Habu_Flyer View Post
I know a ground test is a good idea, but if the Dragonlink really does have 40km of range, I won't be able to do a range test without getting in my car.
You should have a female 50ohm load balance connector that came with your
dragonlink system. Replace the antenna with that then rangetest your system.
They have on their website an expected meters to km conversion. It's a lot
easier than driving 40km.

-Blues
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Old Oct 12, 2012, 06:57 PM
God is my pilot
JimTMich's Avatar
United States, MI, Kalamazoo Township
Joined Aug 2006
2,395 Posts
OK, I got all the equipment for my first FPV.
250mW 5.8Ghz fatshark transmitter
bluebeam whips
1'extension cable for antenna if needed and a right angle adaptor if needed
RMRC 600 camera.
Everything works well on th bench.

I'm looking for the pilot feel, not the long distance pretty scenery feel, so I was thinking of mounting the camera on top of the wing above the cabin (hobbyzone supercub). I could mount it below the landing gear..... could I mount the camera out on the wing out of the prop view, or will that feel funny when the plane rolls because it's not centered.
Should I keep the Vtransmitter away from the control receiver, or just keep the vtx antenna away from the control receiver?

I have a 72mghz radio I'm going to be using for contro. (have 2.4ghz spektrum control at the moment)

i'm open for suggestions before I start cutting foam.... With your input,'I'll mock it up with blue tap and snap a picture for your final comments....
thanks
JIm
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Old Oct 12, 2012, 07:22 PM
Closed Account
Joined May 2012
224 Posts
One more question;
Where should I put my LC filter? Between battery and current sensor or ESC and current sensor? EZosd BTW
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Old Oct 12, 2012, 07:43 PM
BEOWULF
North vancouver, B.C. Canada
Joined Apr 2008
18,581 Posts
Pretty sure the dragon link has new switch or button or something now to act as dumbly load. This is great way to ground test at home and not need car. Older versions they said to take off rx antenna then gave out free dumbly load antenna. I am sure mike would send you free dumbly load antenna if yours is older version.

Range test is probably the most important part of fpv

Extensive range testing allowed me to put all fpv stuff in the plane within inches of each other.

Camera, esc, UHF rx, 1. Watt video tx, how ever a 1.5 watt would still pass ground test, it's all nice and close because nothing gives out noise that effects other components on the plane.

Without ground test you can have serious problems.





Quote:
Originally Posted by FPV_Habu_Flyer View Post
Thanks, finally someone actually responded!

I know a ground test is a good idea, but if the Dragonlink really does have 40km of range, I won't be able to do a range test without getting in my car.
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Old Oct 13, 2012, 12:51 AM
FPV in Hawaii
iskess's Avatar
United States, HI, Kailua
Joined Feb 2012
2,302 Posts
Ok David, we have been hearing that you know how to position the components closely together, even while using a 1.5W Tx. I understand this requires careful range testing, and the careful selection of the right components. You've said you have been PM'd and have helped others to recreate your success.
So please share with us what it is you do that makes this work so well. I don't really want to hear anymore about the fact that you can do this successfully, we would be better served hearing your specific techniques. Otherwise it isn't about education, but merely bragging and proving your point at Alex's expense. Let's make this constructive and educational.
Learn me something!
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