Espritmodel.com Telemetry Radio
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Old Apr 12, 2011, 03:28 AM
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thanks sir mark.. i have 9dbi 2.4ghz rubber duc omni ant. will this works?? how about the range?

louie
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Old Apr 12, 2011, 09:01 AM
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Originally Posted by louiealadph View Post
thanks sir mark.. i have 9dbi 2.4ghz rubber duc omni ant. will this works?? how about the range?

louie
BAD idea! One of the last things you want is a high gain omni antenna. The radiation pattern is flat as a pancake. They are also terribly inefficient!

-Alex
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Old Apr 12, 2011, 10:02 AM
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thanks for the advice sir alex. what do you preffered me to use as my Tx on my dx6i??? using the 1w boster?
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Old Apr 12, 2011, 12:40 PM
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You need a new radio. The DX6i is a parkflyer radio. no good for FPV no matter what you do with it.

Using a DX6i is sort of like trying to pull a heavy trailer with a compact car. In a pinch you can do it, but be prepared for a failure.

-Alex
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Old Apr 12, 2011, 12:52 PM
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I got the Futaba 6ex, I can't see why the spectrum and my futaba would'nt be any good for fpv.

What about adding UHF ??

--------

I do have another question too,
what is the very best video googles I can buy? Headplay? Fatshark? itheater?

I suppose the Headplay googles are the best because they got high res. (800x600)!?!?
Are video googles any good for watching movies etc?
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Old Apr 12, 2011, 01:14 PM
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Originally Posted by Foskje View Post
I got the Futaba 6ex, I can't see why the spectrum and my futaba would'nt be any good for fpv.

What about adding UHF ??

--------

I do have another question too,
what is the very best video googles I can buy? Headplay? Fatshark? itheater?

I suppose the Headplay googles are the best because they got high res. (800x600)!?!?
Are video googles any good for watching movies etc?
If you read in the document, there is no such thing as best in FPV. This goes for ALL equipment. I really dislike Headplays. Some people swear by them. I have an old set of R-Visions that I really like (not sure what they're called now). FatSharks look pretty good.

Remember what RC equipment is designed for. Line of sight, that's it. Once you leave line of sight distance, you are outside of what the manufacturer of the equipment had in mind and are now in dangerous territory.

Remember there are two kinds of receivers for RC: parkflyers which are designed for flight within 1500 feet and full range which are designed to go 3500 feet.

So which do you take out to 2 miles with an huge on board RF noise generator? Answer: NONE You can't get blood from a stone. That simple.

-Alex
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Old Apr 12, 2011, 01:38 PM
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Originally Posted by IBCrazy View Post
If you read in the document, there is no such thing as best in FPV. This goes for ALL equipment. I really dislike Headplays. Some people swear by them. I have an old set of R-Visions that I really like (not sure what they're called now). FatSharks look pretty good.

Remember what RC equipment is designed for. Line of sight, that's it. Once you leave line of sight distance, you are outside of what the manufacturer of the equipment had in mind and are now in dangerous territory.

Remember there are two kinds of receivers for RC: parkflyers which are designed for flight within 1500 feet and full range which are designed to go 3500 feet.

So which do you take out to 2 miles with an huge on board RF noise generator? Answer: NONE You can't get blood from a stone. That simple.

-Alex
What about the Headplay googles did you dislike? - what do you like about R-vision?
Can anyone recommend watching a movie in the glasses?
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Old Apr 12, 2011, 02:06 PM
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So does anyone have any recommendations on best bang for the buck (read: cheap) regarding a decent radio system to maybe take out to a couple miles?

It hurts me to set aside my spektrum equipment, but if it's necessary to be successful, I'm willing to do so. I just don't want to break the bank.
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Old Apr 12, 2011, 02:17 PM
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Originally Posted by Foskje View Post
What about the Headplay googles did you dislike? - what do you like about R-vision?
Can anyone recommend watching a movie in the glasses?
One word: color
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Old Apr 12, 2011, 02:18 PM
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So does anyone have any recommendations on best bang for the buck (read: cheap) regarding a decent radio system to maybe take out to a couple miles?

It hurts me to set aside my spektrum equipment, but if it's necessary to be successful, I'm willing to do so. I just don't want to break the bank.
Chainlink is the cheapest option right now - $200
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Old Apr 12, 2011, 06:55 PM
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Speaking strictly antennas, the signal is weakest (a LOT weaker) straight above and straight below the antenna. You might test mounting two vertical antennas (FPV tx and RC rx) directly above / below each other on a plane that is large enough to do that.

Be aware that the transmitter case and the FPV wiring can act like an antenna too. In the worst case you may have to route wiring to keep any wiring attached to the FPV transmitter away from any wiring attached to the RC receiver. Note that this is not 100% doable if you have an OSD (attached to the FPV stuff) that monitors the motor battery (attached to the RC stuff).

If the antennas (FPV tx and a single 2.4g RC rx antenna) both needed to be vertical and they are mounted more in a side by side configuration, I would get them as far away from each other as reasonable and then do RC range tests with the FPV transmitter on and off to make sure that the FPV isn't drastically reducing your RC range. This is how I would try to do it with a 2.4g RC radio that has only one receiver antenna. I would also run my RC transmitter antenna vertically.

Putting metal (or carbon fiber as CF also conducts electricity) near an antenna changes the signal pattern in strange ways. This is true of receivers and transmitters both and is worse for 2.4g RC and FPV frequencies because they are higher and have more "line of sight" problems. If your carbon rod (or metal, or even wet wood) gets between you and the antenna, then you can loose signal range at that angle. For general (non-FPV) flying, the range is so good that a 50% reduction just doesn't matter. For FPV, you eventually will want to fly to the limit of your range, so plan antenna position now for best range later.

Of course FPV tx antenna should always be mounted vertically (circular polarization and altitude record flights aside). If using a stock FPV rx antenna you should mount the FPV receiver up on a plastic pole (I use 2.5m PVC pole, as high as I can reach) with antenna vertical. Run power up the pole and video signal down the pole.

Avoid flying straight overhead, especially way high as the FPV antennas don't talk very well in that configuration, and when really high, it takes a much longer time to get away from being straight overhead.

Cliff
For the up/down configuration, it would be something along the lines of FPV Antenna pointing up, and RC Antenna pointing down? In addition, does the interference caused by conductive materials have anything to do with how conductive a material is? For example, would a copper rod cause more interference issues than a CF rod?
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Old Apr 12, 2011, 10:23 PM
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For the up/down configuration, it would be something along the lines of FPV Antenna pointing up, and RC Antenna pointing down?
Yes, but test it out. If it doesn't work in your airplane's configuration (like maybe in a small airplane with no landing gear), try other antenna configurations. (Be aware that this was suggested as a possibility for a 2.4g RC with a single receiver antenna.)

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In addition, does the interference caused by conductive materials have anything to do with how conductive a material is? For example, would a copper rod cause more interference issues than a CF rod?
Generally, interference (called shadowing, think about it...) will only happen with conductive materials. The degree of interference generally increases with the frequency and with the conductivity of the thing that is doing the blocking. The reason it blocks higher frequencies is because higher frequencies have a shorter wavelength and as the RF wavelength becomes smaller than the blocking object, then the RF will be blocked.

A 3 inch by 3 inch square of carbon fiber sheet would effectively block a 2.4g signal. A 3 inch by 1/8 inch piece of CF would partially block a 2.4g signal; more for a 2.4g antenna parallel to the CF and less for a 2.4g antenna perpendicular to the CF.

Plastic is usually OK. Wood may be slightly wet with sap inside (even finished wood products) and can cause a small amount of blockage. People are really wet and salty and cause a lot of blockage (to wavelengths smaller than your chest width). Carbon fiber is somewhat conductive and causes problems for wavelengths smaller than the piece of CF (which usually means FPV video or 2.4g RC). Metal is very conductive and will generally block wavelengths smaller than the smallest dimension of the piece of metal.

Cliff
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Old Apr 13, 2011, 12:07 AM
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Originally Posted by IBCrazy View Post
Chainlink is the cheapest option right now - $200
Good deal, thanks Crazy.

Been doing lots of reading on the Chainlink, and I'm wondering if I got that for my DX6i, would it make my DX6i inoperable with my existing 2.4 ghz receivers, or would it just be broadcasting on both?
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Old Apr 13, 2011, 01:46 AM
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Is it possible to take rssi signal from AR7000 and R921?
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Old Apr 14, 2011, 10:03 AM
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I havent plowed through all this thread yet, but the DX6i recommendations have me a bit concerned regarding my DX8. I'm thinking of a heli based FPV setup, and since I'm assuming the DX8 is using the same transmission protocol as the DX6i...does that fall into the not so recommended area?
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