Barry777
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Jun 22, 2010, 12:30 PM
Post #10 of 98
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Re: [heviarti] Kinda OT, one for Barry or JTS.
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Here's where an RF generator would come in handy, as you could slowly sweep throughout its range and see if you can reproduce a similar color bar - then you would know exactly at which frequency the interference is occurring, and design an LC network to shunt it out at the antenna terminals. Yes, the interference would generally be at one predominant frequency in most cases.
One thing you can try: Make a wire loop about 8 inches in diameter which is the UHF range, and substitute that in place of the outdoor antenna. If the interference disappears, you know it's probably somewhere outside the house. If it persists, it's probably coming from inside the house. UHF, being in a higher frequency range than VHF, would be more susceptable to any kind of interference. It could even be a building close by reflecting it from something else far away. At any rate, it's possible that nothing will help. Also you can try different types of homemade antennas, or a CB antenna, VHF, rabbit ears, a long wire, a moistened fingertip, etc. If you find something that eliminates the bar while still letting the signal through strong enough, you can use that for channel 35 and build a switch into the antenna system.
One vertical color bar suggests one very specific and very high frequency, whereas a horizontal bar would generally be something in the audio range. A wide bar that slowly moves up or down is usually some form of AC hum, which could be aging filter caps on any TV more than 10 years old, or the cumulative effects of many AC devices operating close by. Or nearby power lines, cell phone tower, etc. Keep in mind that what you're seeing could be a harmonic of the actual offending frequency, which makes pretty much anything suspect.
My passion for JVC is because they invented the VHS format ("Vertical Helical Scan", later changed to "Video Home System" for the idiot consumer masses), have very solid designs and the most peripheral accessories for their machines. Also, their high-end pro machines are expandable with optional TBC boards (a 3-board option), Time Code generator/reader boards, RS-422 control boards and digital noise reduction boards. The 822 uses balanced XLR connectors for all stereo audio, so you'll need to buy or make some adaptor cables, and all professional video equipment uses BNC connectors for the video signal.
I think JVC's are also best for easy serviceability, with removeable access panels for cleaning the heads and mechanism, and almost all boards are easily pulled out by removing one screw and swinging aside a retainer bar. They were designed for the busy professional who needed to clean heads every day, or swap out a board in, literally, less than 60 seconds. Most routine electronic adjustments are controlled in the software, and accessed from menus available both on-screen and using readout codes on the front panel. JVC is no-hassle performance, and lots of it.
I'm a huge fan of Sony for TV's, and went with Sony without hesitation for our first LCD TV. Sony is the absolute best quality for most electronic stuff, but I find their VCR designs a bit unstable. Heck, look how complicated they made their video format, and it's a real pain to align albeit better picture quality. Betamax servicing is an art in which the service manual is merely a starting point to get you going in the right direction. Mitsubishi is also great stuff, but they're more of a board-changeout situation on their TV's, with their boards costing several hundred dollars. Horrible service literature access - they don't like other people repairing their stuff. Hitachi is another great brand - no complaints about them at all.
I'm a firm believer in using professional grade equipment whenever possible, as this stuff is designed for continuous heavy use and generally has the tightest specs. I use professional HP office printers - and never, ever have a paper jam or inconsistent print quality. The way I figure it, the inventor of a technology has had the most practice building and perfecting it in most cases, and I have too much other stuff to do to spend my time tweaking and babysitting marginal equipment that was built to stay within a consumer budget. I spend money to save time, as opposed to most other folks. You can always make more money.
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Barry Fone - VCR Repair hobbyist and professional FAA Repair Station Avionics Bench Technician (top level). TEST EQUIPMENT: (4) Sencore VC93 VCR Analyzers, (11) Tentel gauges, Sencore VA48 and (2) VA62 Video Analyzers, Sigma Electronics TSG-375 NTSC/SMPTE Video Generator, several VCR Alignment Tapes, plus countless Oscilloscopes, Frequency Counters, Wow and Flutter Meters, Distortion Analyzers, Vectorscope, 136-channel Logic Analyzer, Signature Analyzer . . . . VIDEO GEAR: (6) JVC BR-S822U's, (3) JVC BR-7000 series, (3) JVC BR-S500U, (2) JVC BR-S800U, JVC GR-800U and (2) GR-860U Editing Controllers, Sony FXE-100 Video Switcher/Effects Generator, (5) Time Code Generator/Readers, (1) Sony SLO-1800 (Beta), (2) Alesis ADAT-XT, (1) Sony DXC-1200 TV Camera, Pioneer VP-1000 Laser Disc Player plus many consumer grade Beta and VHS VCR's. Passionate electronics enthusiast since 1973...most anything except computers. Check out my collection at www.barrys8trackrepair.com/MyVideoGear.html
(This post was edited by Barry777 on Jun 22, 2010, 1:02 PM)
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