1258 Mhz receiver behaviour

[Joe90]

Hi,

We just bought 2 of these with matching transmitter.

The screen just go black when the signal strength change and then come back after a second or 2

We tried CP antennas and stock ones, It does not seem to make any differences.
We tried different screens, no differences.
We tried powering with lipo on both sides, no differences.
Our screen show static when transmitter not emitting and receiver plugged in.

Is that normal behaviour or something is wrong ?
Does it go away in flight ?

I would prefer seeing static instead of blank screen.

My friend already contacted RMRC but I wanted to see if some else could share experience.

Thanks

[McCleary.11]

I am sorry if I read any part of your post wrong, I am just trying to get a clear picture (no pun intended ) of whats going on.

We just bought 2 of these with matching transmitter.

You are saying you bought 2 1258 Receivers and one 1258 transmitter, correct? What models are you referring to exactly?

The screen just go black when the signal strength change and then come back after a second or 2

It sounds like this could be a camera issue since it is going black and not to static. I once accidently used a 6v camera on 12v and it would pulse in and out every few seconds going from normal to black. Can you post a picture of your setup with as much of the wiring shown as possible?

We tried powering with lipo on both sides, no differences.

You lost me here. You tried a Lipo on both sides of what?

Our screen show static when transmitter not emitting and receiver plugged in.

Again, it sounds like the receiver is working correctly since it is not going to static when the Tx is on, and does go to static with the Tx turned off. It seems that the transmitter is not always getting video to transmit and just goes to black.

Is that normal behaviour or something is wrong ?

Does it go away in flight ?

Yes! something is definetly wrong here and do not fly it yet!

It would really help to get some pics or video of your setup if possible.

[Keith]

Agreed^ A black screen usually means the receiver is getting a signal from the transmitter, but not a video signal from the camera. Could be faulty wiring, loose connector, issue with the camera, etc. If you've got two different setups doing it, that might complicate things a bit, or maybe narrow it down by looking at what's common between the two. Details about your setup will help for sure.

[Joe90]

It may not be a connection since I am able to reproduce this with everything not moving and by just moving me around or other obstacles.

receivers : http://www.readymaderc.com/store/ind...oducts_id=1020

Transmitters : http://www.readymaderc.com/store/ind...oducts_id=1016

Any combination of matching frequencies with any transmitter/receivers does that
Different antennas don't seem to change things (CP from True RC or stock ones)


We tried different power supply and batteries even using a Y + lipo to power the receiver and transmitter.

Maybe it's the input impedance of the camera that screw things.
This is a KX-171

Thanks

[Teacup]

Misread just ignore this

[McCleary.11]

Do you have a different video source or camera that you can try out? I have used a DVD player to test before if you dont have a spare camera. Is the correct voltage going to the camera?

[Joe90]

Good idea for different video source.
We checked camera voltage en 12V is correct for the one we have KX-171
Tests were done inside in the bench we plan to fly Third person LOS tomorrow to see.
What seem to happen is when the signal strength change rapidly there is black screen.
Maybe that in flight the signal strength will not change fast enough to induce that.

Thanks

[Joe90]

In flight it's the same.
On or off. when black it last for 2-3 sec. This seem real long

Tried the receiver tuned on 910MHz with and it worked well.
The difference being the transmitter and antennas.
910 MHz was CP as well with my homemade CP antennas

It seem to me that the transmitters are the problem.

[McCleary.11]

On or off. when black it last for 2-3 sec. This seem real long

Yes, something is definetly wrong here.

Tried the receiver tuned on 910MHz with and it worked well.
The difference being the transmitter and antennas.
910 MHz was CP as well with my homemade CP antennas

Can you explain the 910mhz part a little more? The equipment you linked is 1.3 only, so I'm a little confused.

Since the video is going on and off (not any static), it should not be an antenna problem. Changing them around most likely won't fix anything. I mostly use the stock whip antennas on my 1.3 gear anyways.

It seem to me that the transmitters are the problem.

I know that sometimes products can be faulty, but I really think its unlikely that you have two bad transmitters. Something else has to be going on here. If you do end up sending them back to RMRC, I can test them and can report back if you want. Have you been able to try out an alternate video source yet?

I hope you can get some good flying in soon. I know it can be very frustrating!

[Joe90]

910 MHz

In order to see if the problem come from the receiver or the transmitter I
Keep 12 ch receiver select channel 0 for 910 MHz plugged in home made crosshair.
then use a 910MHz transmitter (race wood ) and it worked well. no black screen, just some static with is ok when going trough wall...
Used fatshark and original screen with this setup. they behave the same. Both are working similar.

This tell me that the receiver seem to work as expected.

So this seem to come from the transmitter end.

Our test rig is really simple
1- 3S lipo on transmitter and camera plugged with a Y cable
2- KX-171 camera plugged directly on the transmitter. No OSD, No BEC.
3- CP antenna from True RC and Stock tested

What was different for the 910MHz test

1-camera was sony WDR600
2-Transmitter was Racewood 910MHz 500mW
3-Antennas...

Tested in flight and it behave the same, we have a really good picture but it can cut black anytime.

Here a quick video : http://youtu.be/P78XH6ZzfgM

Should be there in 10 minutes (uploading)

Thanks