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Old Mar 13, 2012, 04:42 PM
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Originally Posted by msev View Post
Which keywords should I search?
I think it's gonna be difficult to find a 5.8 ghz chip that's easy to use. With 2.4 ghz there is quite a few available. Basically you just need a 5.8 ghz receiver with RSSI and configurable channel.

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Originally Posted by rimshotcopter View Post
Dennis, I REALLY APPRECIATE your help, I found a number of problems and added a couple of resistors to the OSD. Adding the Resistors, I lost the background shading and for now, I am not going to worry about. I will build a new one and take into account everything that I have learned so far. HOWEVER, the biggest problem was with the VuPoint, seems the PAL/NTSC switch is reverse or I perceived it wrongly. Here is a sample of the video, going to do a field test soon. Thanks again!

http://www.youtube.com/watch?v=3a69_mktrgE
It's only ideas, and I can't promise anything. But it seems like the OSD text is a lot easier to read now. The skies are now blue, but I don't know if that's just caused by the view or the added resistors?
Good work
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Old Mar 13, 2012, 04:45 PM
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Which pin on the nano, should I use for rssi input? (lets say that I use A1 for battery voltage, so it's taken)

For ground i use the common ground right?

Those 3k and 9k voltage divider resistors are meant for how much cell lipo (I'll use my own but I'm interested)?
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Old Mar 13, 2012, 04:48 PM
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Originally Posted by msev View Post
Which pin on the nano, should I use for rssi input? (lets say that I use A1 for battery voltage, so it's taken)

For ground i use the common ground right?
RSSI is just a voltage representing the signal strength - so you can use any analog input. Just use whatever pin you prefer (I cant remember the default pin in the config). Remember to add a large resistor in series if necessary.

You don't need RSSI ground as the receiver should have same ground as the OSD.
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Old Mar 13, 2012, 04:50 PM
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Originally Posted by msev View Post

Those 3k and 9k voltage divider resistors are meant for how much cell lipo (I'll use my own but I'm interested)?
3k ohm / (3k ohm + 9k ohm) = 1/4.

That means 20 volt = 5 volt. 4.2 volt per li-po cell will allow 20 volt / 4.2 volt = 4.72 li-po cell ~ 4S li-po. (Always use a voltage divider a bit higher than needed)
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Old Mar 13, 2012, 04:52 PM
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Originally Posted by Dennis Frie View Post

It's only ideas, and I can't promise anything. But it seems like the OSD text is a lot easier to read now. The skies are now blue, but I don't know if that's just caused by the view or the added resistors?
Good work
I KNOW it is a combination of both because I tried many steps in between before arriving to this stage. I ended up replacing the two resistors with a trim pot, then adding a 470ohm resistor from the video feed to ground.
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Old Mar 13, 2012, 05:03 PM
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I guess its pin a1, i'll have to modify.

#define rssi_input 1 // The input pin

so I just write 0,2,4,5 etc whichever I want...3 is taken for current sensor.
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Old Mar 13, 2012, 05:05 PM
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Originally Posted by msev View Post
I guess its pin a1, i'll have to modify.

#define rssi_input 1 // The input pin

so I just write 0,2,4,5 etc whichever I want...3 is taken for current sensor.
Exactly
Just choose another pin than current-sensor and voltage-divider.
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Old Mar 13, 2012, 05:12 PM
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So I just need a normal 5.8ghz video receiver which has rssi? that won't be hard
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Old Mar 13, 2012, 05:19 PM
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Originally Posted by msev View Post
So I just need a normal 5.8ghz video receiver which has rssi? that won't be hard
Well, you could use a normal video-receiver and check RSSI at the few channels available - should give you an idea about the noise at the different channels. But you cant do much more than that.

I have just made a sweep from 410 mhz - > 460 mhz with 1000 steps (and 100 measurements on each channel = 100.000 RSSI-readings for a sweep). That should make it possible also to see devices with frequency-hopping.
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Old Mar 13, 2012, 05:31 PM
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Aha so the problem is the fixed channels...hmmm..no solution yet
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Old Mar 13, 2012, 05:34 PM
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410 mhz to 460 mhz sweep:

The top picture is with OpenLRS on.
The buttom scan is with TSLRS on.
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Old Mar 14, 2012, 03:56 AM
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So TSLRS wins in hopping ..What's the max channels openlrs can stabily hop ..I heard there is some instabillity if you hop too much ..haha

Just to confirm, so this receiver: http://www.hobbyking.com/hobbyking/s...5415&aff=46415

Which can feed out rssi, is not good for measuring the whole spectrum, since it has fixed channels,...but I could measure on all the channels, where the antennas have the best performance...

Btw I found another guy on a arduino forum that made a spectrum analyser using openlrs.

is the amplitude of the spectrum a measure of quality of antennas?
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Old Mar 14, 2012, 05:40 AM
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Originally Posted by msev View Post
So TSLRS wins in hopping ..What's the max channels openlrs can stabily hop ..I heard there is some instabillity if you hop too much ..haha

Just to confirm, so this receiver: http://www.hobbyking.com/hobbyking/s...5415&aff=46415

Which can feed out rssi, is not good for measuring the whole spectrum, since it has fixed channels,...but I could measure on all the channels, where the antennas have the best performance...

Btw I found another guy on a arduino forum that made a spectrum analyser using openlrs.

is the amplitude of the spectrum a measure of quality of antennas?
Yep, for now TSLRS definatly wins in hopping. The shown spectrum of TSLRS only indicates the spectrum it uses for hopping. It seems to jump pretty random within the frequency.

With a standard video-receiver and RSSI you can only get an indication of the background noise - you will need a SWR meter or something similiar to tune antennas.

I have seen spectrum analyzing done on RFM22B before, but not on OpenLRS. Anyway, it was all written yesterday, so not exactly a very time consuming project
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Old Mar 14, 2012, 06:00 AM
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So lets say for example your 2.4ghz rf chip is that like a 2.4ghz equivalent of rfm22b?

Can you tune your 2.4ghz antennas with that or is a swr meter the way to go?
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Old Mar 14, 2012, 02:46 PM
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Better but not Good

Did a field test this morning, the choice of location was not the best because I believe the interference was from the power lines. Secondly, the Resistor I added between the video feed line and ground, I believe is causing problems with the Picture HUE. Going to remove it and test again. Another issue is, when I focused the FOV lens, I used features close by, I need to figure out how to set it for infinity. Funny how these problems don't show up during ground testing.

http://www.youtube.com/watch?v=9wvahPgSrDM
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