#61
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Sony's VCA-4 automobile television antenna is a weird one. I guess it worked great when you were travelling but unless you had antsy kids in the back, wouldn't it be a little hard to watch?
I put magnets in mine so I can stick it to my car's ragtop. Officially the last guy in town doing that. |
#62
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Probably worked better than those boomerang jobs
especially on VHF.
__________________
"When resistors increase in value, they're worthless" -Dave G |
#63
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Last edited by andy; 11-18-2021 at 04:55 PM. |
#64
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Judging from the length, it looks like a low band VHF 2-6 Yagi with two folded dipole driven elements, probably to spread the useful frequency range.
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#65
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Looks that way. Having each folded dipole very near a dipole element is one of the wackier things to me, but I'm not an antenna expert. Maybe just a way to transform 75 ohms to 300? I wonder how efficient this was?
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Audiokarma |
#66
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It would be interesting to plug the design and dimensions into some modern day antenna modeling software.
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#67
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Quote:
IIRC, some marketing people dubbed this a "NEW, IMPROVED TRIPOLE DESIGN" ... Supposedly improved the impedance matching of the two DEs to 300 ohm line. jr |
#68
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I had the same kind of RS antenna on a rotator. I got up to 175 miles reception. I lost it and would give almost anything for another.
__________________
Rick (Sparks) Ethridge |
#69
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Last edited by andy; 11-18-2021 at 04:55 PM. |
#70
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300 ohm twinlead will give you the perfect chance to resurrect another 1950s practice: aluminum foil wrapped around the line and sliding back and forth to tune/detune any mismatch. Of course, you cannot get the fine feedback with digital that you could with analog.
I was so happy when they got rid of that stuff. Prone to picking up local motor interference, and needed to be spaced away from metallic antenna support structure. The town house I moved to in 1974 had a pre-installed VHF folded dipole in the attic, with twinlead of course, to a living room antenna outlet. Couldn't understand why it was SO lousy until I traced the twin lead and found it was routed through the wall by wrapping it around a convenient electrical conduit. |
Audiokarma |
#71
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Hi All, i'm a little late to this party, but i thought i would post a pic of my 60's UHF twin bow tie antenna that i still use today.
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#72
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Actually a pretty reliable antenna. When we compared indoor antennas for digital reception, this one was surprisingly OK, coming close to the "Silver Sensor" log periodic design. I don't have enough intuitive antenna knowledge to explain why that is so, with the reflector so close to the active elements.
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#73
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A friend of mine uses one for DTV even now.
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#74
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Quote:
I have built several of the biquad antennas, and indeed they seem to perform best with short reflector spacing. http://martybugs.net/wireless/biquad/ https://buildyourownantenna.blogspot...alculator.html jr |
#75
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Quote:
Many apartments had only VHF-only MATV systems, and that little wonder usually pulled in at least two of the three Philadelphia independent UHF stations, provided you were up a story or two and facing the right direction.
__________________
"When resistors increase in value, they're worthless" -Dave G Last edited by DavGoodlin; 07-13-2018 at 03:56 PM. |
Audiokarma |
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