If the modulators are not on the same channel then I think the problem is a feature of the modulator, it is a "off through" type. This type of modulator will only allow rf to pass through when the power is removed, this is to prevent interference from external RF on the same channel. Two ways to fix this 1 Find the pin diodes that are shorting the input when the power is applied and remove them 2 Get a "mixed boost" modulator. Regards Lee Mason ----- Original Message ----- From: "dtth" To: Sent: Saturday, March 09, 2002 12:35 PM Subject: [EE]:Multi-video to RF converter I'm trying to cascade multiple video to RF converter and send all these RF signal to TV antenna input so that I can see multiple CCD camera images on my TV. So far I'm trying to get video from two CCD cams but problem arise when I turn on the power of the second converter. If the second converter is of, I can see video from CCD cam 1 clearly but when I switch on the second converter, the video is lost. Comments are welcome :-) Regards, Donny Tan -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.