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  #61  
Old 03-14-2016, 11:46 PM
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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.
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Old 03-16-2016, 09:23 AM
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Probably worked better than those boomerang jobs
especially on VHF.
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  #63  
Old 06-17-2018, 11:31 AM
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I just picked this up from an estate sale. The label on the box is too damaged to read much. It's 90" long, and some crumpled newspaper in the box is from Denver, 1952.
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File Type: jpg antenna5.jpg (96.8 KB, 27 views)
File Type: jpg antenna1.jpg (29.1 KB, 14 views)
File Type: jpg antenna2.jpg (107.3 KB, 19 views)
File Type: jpg antenna3.jpg (107.5 KB, 19 views)
File Type: jpg antenna4.jpg (115.6 KB, 18 views)
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  #64  
Old 06-17-2018, 11:40 AM
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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  
Old 06-17-2018, 12:15 PM
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Originally Posted by Ed in Tx View Post
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.
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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Old 06-17-2018, 12:52 PM
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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  
Old 06-17-2018, 01:04 PM
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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?
I think that the extra element is connected correctly on the foreword driven element... screwed to the center of the bend. I would guess that the rear DE has holes for similar attachment of the extra element.

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
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  #68  
Old 06-17-2018, 01:11 PM
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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.
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  #69  
Old 06-17-2018, 03:21 PM
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Originally Posted by jr_tech View Post
I think that the extra element is connected correctly on the foreword driven element... screwed to the center of the bend. I would guess that the rear DE has holes for similar attachment of the extra element.

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
Yes, the middle section is sitting on the floor next to it because all the screws are missing. I'll have to replace the missing hardware and see what it can do. It might be good to receive channel 7, and FM.

It's funny to think that it's been around since 1952, and the first time it will be used will be to receive digital TV.
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  #70  
Old 06-17-2018, 04:53 PM
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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.
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