Partial distortion on TV

mashaffer · 22nd October 2007, 01:11 AM

Well it is not what most of you would call a home theater but I was given a 24" console TV so I purchased a DVD player and an RF modulator. It sure beats watching on my old windows98 computer with 17" monitor.

Here is the setup. We don't have cable, satTV or any other VHS source and very few (weak) UHF broadcast stations available. I have wired it up thusly.

VHS ==> Modulator Antenna input
DVD Video ==> Modulator source input
DVD Audio ==> Stereo
Modulator Output ==> TV VHF input

I also have rabbit ears connected directly to the UHF input.

It seems to work pretty well except that when playing DVDs small parts of the screen get distorted (slanted over and fuzzy). At first it seemed to only be when credits ran or sometimes on the subtitles but upon further watching it seems to be related to very intense bright things which just happens to be such text most of the time but not always. When it occurs only the rasters where the bright parts are are affected. Also it often clears up just a second or so before the text disappears.

Any thoughts on what may be causing it? I am beginning to wonder if the output from the modulator might be overdriving the TVs input. All suggestions welcome.

mike

bluedeath · 22nd October 2007, 09:59 AM

Is due to the antenna RF interference, it was common in the eighties with the commodore 64 when a white screen was displayed (using the antenna only, the composite cable does not have this king of issue), try to fine tune the signal or, if possibile, tweak the settings of the modulator.

mashaffer · 23rd October 2007, 12:16 AM

Thank you for the input. Unfortunately the only adjustment on the modulator is a channel switch for 3 or 4. I tried ch4 but got a lot of distortion all the time.

I am using a 25' long 75 ohm cable between the modulator and the TV. That would not be a problem would it. Putting the DVD and mod next to the TV would be rather inconvenient but I could try it if you think it might make a difference.

mike

bluedeath · 23rd October 2007, 12:12 PM

The quick and dirty solution with the c64 was to do a knot on the cable, but honestly i dont' know if this can really help you.

22nd October 2007, 01:11 AM	#1
mashaffer diyAudio Member Join Date: Jun 2004 Location: Indiana	Partial distortion on TV Well it is not what most of you would call a home theater but I was given a 24" console TV so I purchased a DVD player and an RF modulator. It sure beats watching on my old windows98 computer with 17" monitor. Here is the setup. We don't have cable, satTV or any other VHS source and very few (weak) UHF broadcast stations available. I have wired it up thusly. VHS ==> Modulator Antenna input DVD Video ==> Modulator source input DVD Audio ==> Stereo Modulator Output ==> TV VHF input I also have rabbit ears connected directly to the UHF input. It seems to work pretty well except that when playing DVDs small parts of the screen get distorted (slanted over and fuzzy). At first it seemed to only be when credits ran or sometimes on the subtitles but upon further watching it seems to be related to very intense bright things which just happens to be such text most of the time but not always. When it occurs only the rasters where the bright parts are are affected. Also it often clears up just a second or so before the text disappears. Any thoughts on what may be causing it? I am beginning to wonder if the output from the modulator might be overdriving the TVs input. All suggestions welcome. mike

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22nd October 2007, 09:59 AM	#2
bluedeath diyAudio Member Join Date: Sep 2007	Is due to the antenna RF interference, it was common in the eighties with the commodore 64 when a white screen was displayed (using the antenna only, the composite cable does not have this king of issue), try to fine tune the signal or, if possibile, tweak the settings of the modulator.

23rd October 2007, 12:16 AM	#3
mashaffer diyAudio Member Join Date: Jun 2004 Location: Indiana	Thank you for the input. Unfortunately the only adjustment on the modulator is a channel switch for 3 or 4. I tried ch4 but got a lot of distortion all the time. I am using a 25' long 75 ohm cable between the modulator and the TV. That would not be a problem would it. Putting the DVD and mod next to the TV would be rather inconvenient but I could try it if you think it might make a difference. mike

23rd October 2007, 12:12 PM	#4
bluedeath diyAudio Member Join Date: Sep 2007	The quick and dirty solution with the c64 was to do a knot on the cable, but honestly i dont' know if this can really help you.

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