Okay, now that you have explained the wiring configuration (thanks), we can diagnose where the problem is and fix it.
The first thing I would recommend is to check the video right after it comes out of the clerk's computer. Do you have access to a flat panel monitor with both VGA and composite video inputs?
Play a high quality video or DVD in the PC and check the picture on the flat panel VGA input and then again from your scan converter. I like using test patterns but a HQ Mormon Message will do.
You will need to swap the VGA cable between the VGA input on the monitor and the scan converter.
Don't run the VGA from the PC through the scan converter and then to the monitor as this will degrade the picture (which may be your entire problem). (See my personal note at the bottom)
Look for and compare the following (please forgive me if you already know how to do this):
* Black levels: You should be able to see the same amount of detail in the darkest most areas of the picture through both inputs. If not, you may need to make BRIGHTNESS adjustments on the scan converter.
* Contrast: Again, check to see if the two inputs have the same quality in the really bright portions of the picture. Again, if the composite input is not the same (washed out or darker), adjust the CONTRAST control on the scan converter.
* Color: Check and compare the color saturation.
Bottom line, the picture viewed from the VGA input and composite input (via the scan converter) should be very similar (the scan converter will NOT yield the same high quality picture, but we're looking at brightness, contrast and color levels here).
If all is well, move to the Satellite closet and check to see if you have EXACTLY the same picture coming directly after the baluN. If the picture has degraded in any way, there is either a problem with the wiring or the baluN is bad. From my personal experience, most cheap baluns are crap. I now spend more money and get good ones.
If the picture is good, reconnect the balun to the manual switch and keep going. You should have the same quality image on the flat panel when you connect to the podium's RCA composite video jack. If not, it indicates a problem with either the manual switch, video distribution equipment or cabling.
Also, connect an antenna cable to the TEST POINT "F' connector on the front of the Pico Macom PCM55 RF modulator and switch your manual switch to the test video, then compare the picture on a TV set. If the picture coming out of the Pico Macom PCM55 is bad, stop and have the FM Group call in a qualified TV distribution technician. Don't make any adjustments to the unit unless you know what you're doing. BTW, I've seen a LOT of Pico Macom PCM55's bad in my day. Our stake has replaced both of ours in the past 5 years.
Personal Note: I've use the scan converter you're using, but ended up tossing it. If you decide to keep using it, the adjustments on it which WILL improve your picture but even with my experience in video and studio work, this scan converter is finicky. The unit's brightness and contrast must be adjusted every time the unit is turned on...and that's difficult because most of the time you'll need to run into the next room to see the effects of the adjustments (in addition, the controls are very confusing because the right button lowers and the left button increases values...I was always getting messed up.) I got so frustrated with it I tossed in the corner and purchased a professional, commercial VGA scan converter (a used one for $50, the same price I paid for the new crappy unit).
I recommend Extron scan converters such as the VSC50, VSC75 or VSC100. These are discontinued products so you can pick them up real cheap. In addition to the very stable composite video output and clean picture, there is an overscan/underscan option and position KNOBS (
see picture). I just checked eBay and they're going for less than $50, including shipping (
link). If we find you're scan converter can't do the job, I'd suggest picking up one of these.