pelco PTZ and termination/Video signal prob (pic added)

[ronbo 0]

this may be a long one, but here it goes.

 

equipment

Pectra IV SE PTZ

RDT Analouge 5.8 inc radio modem

 

problem

 

at certain point where high contrast is in image get a black blob with turns to horizontal tearing and a gerneral look of interferance on the screen.

 

what ive dont so far

 

changed loads of settings on the wirless tran/recev switched of the telemtary modem, used a different dome , and now a different unit(inc back box)

and still the same prob, spoke to RDT and we sort of confirmed the wirless is not at fault and it could be the camera, altho ive try another pelco PTZ and it the same prob, altho a static work completly fine.

 

on the pelco firmware 2.11 i change the vidio leval from high and it just slighly makes it better but only slightly !!!

 

the question

why is it that two pelco domes could have not the right video level (1v) i know if it not precice enough the RDT tech said it could cause a problem, but cant understand why two domes should have the same issue (if it is that)

 

ps the video signal is fine direct from the camera on my test monitor, dont have a video singnal tester to hand at the mo

 

any ideas?

 

cheers

Edited April 5, 2010 by Guest

[ronbo 0]

after talking with pelco tech they check the vidio signal and its nothing unsuall he pointed me in the direction of Termination at controle end

 

now what i did last night was before the camera goes into the geovision i put my test monitor on the coax end and my video picture was alot better with no real bad blob or tearing !! wich is good but how do i over come this as geovision does not terminate or un terminate?

 

or have i actually found the problem or and i going in the right direction ??

 

posted a version in geovision forum too if thats ok rory

[survtech 0]

You could add a terminator using a "T". Not the most elegant solution, but if it works...

 

[ronbo 0]

so just solder a 70 ohm resister on it ya?

[tomcctv 190]

so just solder a 70 ohm resister on it ya?

 

the pic you have posted has rolling on it (you can see the start of it in top left corner) this looks like a power problem. what power are you putting to your ptz and how and how long is the run ???

[ronbo 0]

its 24 v ac the run is about 3 meter and its a pelco external psu measured at about 26 v ac

 

these are remotely mounted together

 

it also stays at the top dont move down like most psu fault ive had

[ronbo 0]

UPDATE

been down there for most of afternoon kept the 75ohm resister in the wireless tramsmitter and used my test monitor on the controle end and the black blob went with only a small distortion- which is good so i moved the wireeless tx and cam,era further away from the Recever and it got even better ( thinking that the video signal would not be so strong) therefore not so high at recever.

 

so thought if i need to terminate the tft, i put a resister on my test monitor but this made it worse- (but this would be double term)

 

so at the top of screen i still get the tearing and less noticable i get it over the rest of screen so could this be another prob.

[ronbo 0]

ive left the termination resister in the wireless transmitter and the blob ges, and just gets worse when i ain at bright light

 

i then moved from ten meter range to about 50 meter from trans to wireless reciever and gets really bad

 

would this be the wireless amplifiying a small prob or the wireless with too much output?

[ronbo 0]

got hold of a signal meter this is what ive found

i cant see a definate pattern altho can see the video leval is lowafter being transmitted

 

Termination resister in transmitter .. without termaination resister

direct from camera

 

video level 1.15 setting High..............video level 1.07 setting high /

1.21 setting normal

 

 

at dvr end

 

video level 0.69-0.89.................video level 0.92 setting high /

0.86 setting normal

..............................................0.94/1.01 in 1.36 in high contrast area

 

wireless recever

 

video level 0.64 setting normal.............

video level 0.91 normal/high

video level 0.77 setting high

 

 

at transmitter with Y connector9 IE (though wireless but before transmitted)

 

video level 0.48 setting high.........................video level 0.64 setting high

video level 0.40- 43 setting normal...............video level 0.56 setting normal