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Old Dec 07, 2012, 10:45 AM
Love the sport, not the plane
Hawaii
Joined Oct 2009
1,231 Posts
I just got started with FPV, and I'm loving it! I just bought a digital prism 7" screen that everybody seems to have. I'm very disappointed how grainy and pixelated the video is from FPV. Is this because it transmits (5.8g 400mw) in low quality, or is the screen low quality? I have a sun shield too. How do I make it clearer. People just look like a few tiny pixels. It seems to be higher quality when I plug the receiver into my big tv at home. It prohibits me from getting close to anything because I can't tell what/how close they are.
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Old Dec 07, 2012, 11:32 AM
crashing build's character.
United States, AL, Dora
Joined Mar 2008
529 Posts
Quote:
Originally Posted by polix View Post
I have a boosted DX8, me and my buddy took positions around the lake for range tests (on the ground) and got 4km easy (transmitter + receiver 3 feet off the ground). We're actually heading out today to try and hit 7km. I just want to know what my limit is. I know that ground to air my range will be slightly further since i won't be dealing with fresnel issues. Regular DX7/DX8? I assume 2km would be close to your limit, but i'd try LOS ground to ground tests to be sure first.

I've only tried 3 frequencies (all with my 2.4ghz spektrum).

900mhz - very bad results, my DX8 kept frying the video receivers, even 20 feet from the base station
2.4ghz - yeah bad idea too lol
5.8ghz ... great! even from 12" away from the video receiver, my DX8 does not affect it. Not even a single glitch when i turn the dx on / off.

I'm moving to dragon link anyways, but i'll still be using the DX8 for my other planes, so i'm happy with the 5.8
how did you boost your dx8?
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Old Dec 07, 2012, 11:45 AM
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Joined Jan 2012
249 Posts
Quote:
Originally Posted by polix View Post
I have a boosted DX8, me and my buddy took positions around the lake for range tests (on the ground) and got 4km easy (transmitter + receiver 3 feet off the ground). We're actually heading out today to try and hit 7km. I just want to know what my limit is. I know that ground to air my range will be slightly further since i won't be dealing with fresnel issues. Regular DX7/DX8? I assume 2km would be close to your limit, but i'd try LOS ground to ground tests to be sure first.

I've only tried 3 frequencies (all with my 2.4ghz spektrum).

900mhz - very bad results, my DX8 kept frying the video receivers, even 20 feet from the base station
2.4ghz - yeah bad idea too lol
5.8ghz ... great! even from 12" away from the video receiver, my DX8 does not affect it. Not even a single glitch when i turn the dx on / off.
I'm moving to dragon link anyways, but i'll still be using the DX8 for my other planes, so i'm happy with the 5.8
Let us know what your results are today! I haven't used 5.8. Was thinking maybe in future trying it if and when i get another plane for fpv. Only used 1280 and it has worked ok with my 72mhz. Only been out 11/2 miles so far. But have enjoyed the heck out of that.
Happy flying!!
Michael
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Old Dec 07, 2012, 11:45 AM
The way of being is doing.
IMEIV's Avatar
Italia, Emilia Romagna, Ravenna
Joined Apr 2009
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Quote:
Originally Posted by miknce View Post
Dragon Link! nice system. Maybe some day down the road for me. Either that or RangeLink.
But i don't consider myself qualified to answer your question. IMHOP it certainly would not hurt to have wires twisted .Maybe Alex or someone else more qualified will jump in and give the answer to your question.
Have a blessed Day
Michael
Ok thanks Michael. I hope that someone will answer..
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Old Dec 07, 2012, 11:47 AM
The way of being is doing.
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Italia, Emilia Romagna, Ravenna
Joined Apr 2009
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Quote:
Originally Posted by IBCrazy View Post
^It's been a well known fact for many years that fancy cables and heavy shielding doesn't do nearly as much as simply twisting up your wires. The twisting action causes the EFI and RFI to run equally on all wires which balances the system. Add shielding after you have twisted your wires if you need more improvement.

-Alex
I'm flying with DragonLink UHF system. Do you think that with UHF system used for Tx is necessary to twist servo wires ? or not ?

And there is difference in performance between twisted wire and a toroid installation ?

thanks
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Old Dec 07, 2012, 11:55 AM
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couldn't resist....
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Old Dec 07, 2012, 12:22 PM
Wallop!
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Bussum, Netherlands
Joined Oct 2009
765 Posts
Quote:
Originally Posted by dylantorquerol View Post
I just got started with FPV, and I'm loving it! I just bought a digital prism 7" screen that everybody seems to have. I'm very disappointed how grainy and pixelated the video is from FPV. Is this because it transmits (5.8g 400mw) in low quality, or is the screen low quality? I have a sun shield too. How do I make it clearer. People just look like a few tiny pixels. It seems to be higher quality when I plug the receiver into my big tv at home. It prohibits me from getting close to anything because I can't tell what/how close they are.
Do you mean this one:?

7" TFT LCD Headrest Color Car Rearview Monitor VCR DVD

It has low resolution indeed; 480 x 234. Has nothing to do with your transmitter, but the quality depends on your camera too (although probably unnoticeable on this monitor). If possible, upgrade to a higher res. monitor/goggles.

Martin
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Old Dec 07, 2012, 01:07 PM
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Quote:
Originally Posted by williamjames View Post
2 questions regarding this:

1 - If I do go with this method, should I mount the VTx on the bottom of the wing or the top?

2 - I'll be running a shielded wire from the VTx (which will be on the wing) to my fuselage... The wing however is going to be taken off for transport... I'm wondering what method I should use to be able to easily connect/disconnect the cables?
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Old Dec 07, 2012, 03:17 PM
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Amherst, VA
Joined Jun 2006
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1. It doesn't matter.

2. I use servo cables and connectors.

-Alex
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Old Dec 07, 2012, 03:24 PM
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United States, OH, Mason
Joined Jan 2011
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Quote:
Originally Posted by williamjames View Post
Bump
Here are the pictures of my installation which is the same as you're considering. I used 2 twisted pairs from a cat 5 network cable to extend the vtx wires into the fuselage. I built a small bracket to hold the vtx off of the wing so that air would pass between the wing and the vtx for cooling. Everything is packing taped in. I used the prebuilt vtx cables that RMRC sells inside the plane and used a compatible plug connected to the vtx wires.

I'm pretty happy with the results. I get good video 4-5 miles out.

Kent
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Old Dec 07, 2012, 05:49 PM
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Thanks Alex.

Quote:
Originally Posted by IBCrazy View Post
1. It doesn't matter.

2. I use servo cables and connectors.

-Alex
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Old Dec 07, 2012, 05:51 PM
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Quote:
Originally Posted by KentF View Post
Here are the pictures of my installation which is the same as you're considering. I used 2 twisted pairs from a cat 5 network cable to extend the vtx wires into the fuselage. I built a small bracket to hold the vtx off of the wing so that air would pass between the wing and the vtx for cooling. Everything is packing taped in. I used the prebuilt vtx cables that RMRC sells inside the plane and used a compatible plug connected to the vtx wires.

I'm pretty happy with the results. I get good video 4-5 miles out.

Kent
Thanks Kent. Your build looks really good. I'm not too good with antennas but I'm assuming that's a inverted-V ? Is it circularly or linearly polarized? As well, what kind of antenna do you use for your ground station?

Thanks
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Old Dec 07, 2012, 08:38 PM
Engineer for Christ
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Amherst, VA
Joined Jun 2006
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^If you are asking these questions, you are not ready for Kent's setup. That is an intermediate/advanced pilots setup (He has a BiQuad on the ground station). You will do best with a cloverleaf on your airplane and a 7.5dbic helical on the ground. With 400mW transmit power, you should be able to easily go 4 miles without trying.

-Alex
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Old Dec 08, 2012, 08:31 AM
Noob with Issues
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United States, AZ, Maricopa
Joined Jul 2011
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IBCrazy... I want to get into FPV and I have watched all your videos. And I know you stress all the decisions are up to us. However us new comers may still not know whats best. so we rely on pros like you who have the expert knowledge and experience. Now that I'm done buttering you up I would love help getting a FPV set-up for X-Mas. I don't want a set-up that will limit me to straight and clear. I want a set-up that will go anywhere I advance and feel comfortable going. with as CLEAR a picture as I can get! I don't like wasting money so I don't want a piece of equipment that i will have to upgrade. ( as in not capable of a advanced function) I'm the type of guy who buys the right stuff the first time and not waste more money in the long run buying and buying and buying....I'm not saying I want or need everything now.. just the best basics that I can build up from....Thx I hope I made my self clear as to what I'm looking for..also I would like a somewhat compact ground station that tracks my plane for better quality.
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Old Dec 08, 2012, 10:03 AM
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Joined Nov 2012
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Quote:
Originally Posted by Martin. View Post
Just two suggestions Brandonros:
- Did you do a ground test with turned off control tx and other devices (e.g. cell phone, you never know)
- What about testing simple whip antennas on the vrx as well as vtx?

By trying things one at a time you could eliminate possible causes.

Martin
Well, to follow up to my problem on pg 509 here, I tried testing with a whip antenna both ground and air and I got a quarter mile with great video in flight. So since I know my module works, I'm thinking the RG58 I was using on my CL antenna is bad. It has a stranded wire core and every pic I see here people have solid cores in their RG58. Would this stranded core be my problem on the CL and SPW I built?
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