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Old 1-Apr-2019, 3:04 AM   #1
bobsgarage
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Antenna spotting in Kenosha #1

Well, I guess you figured it out, I have an antenna obsessive compulsive disorder problem. I probably going to have to get help. Who else would drive around antenna Town taking photos ?

But for now I figured I would submit some photos. To me this is a challenge but to some of you installers you might even have put these up in back in their day.

Let's get started. Who wants to ID this? To be honest I've never seen anything like it!


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Last edited by bobsgarage; 28-Apr-2019 at 2:02 AM.
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Old 1-Apr-2019, 4:08 AM   #2
OTAFAN
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Hey bobs:

I'm not the sharpest tack on this forum, but a wild guess would be some sort of variation on a folded dipole Log-periodic antenna.

Well, I'm sure I've embarrassed myself when the experts here reveal what type of antenna this actually is.....
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Old 1-Apr-2019, 1:12 PM   #3
JoeAZ
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I second the folded dipole log periodic VHF antenna.
That has to be very, very old. The rotor appears to
be Channel Master.
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Old 3-Apr-2019, 2:17 AM   #4
bobsgarage
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Arrow

Quote:
Originally Posted by OTAFAN View Post
Hey bobs:

I'm not the sharpest tack on this forum, but a wild guess would be some sort of variation on a folded dipole Log-periodic antenna.

Well, I'm sure I've embarrassed myself when the experts here reveal what type of antenna this actually is.....
I'm surprised others haven't come to ID this antenna. I'd really like to know. I wonder how effective it was. Something tells me it wasn't a good design.
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Old 3-Apr-2019, 3:45 AM   #5
OTAFAN
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Quote:
I second the folded dipole log periodic VHF antenna.
Well, I'm feeling a bit better about my TV antenna instincts. I've learned more about this "hobby" of mine than I thought. This forum has certainly helped my knowledge of the subject.

If JoeAZ narrowed it down to his above post, I'll accept that as pay dirt. But to specifically ID it bobs, we need a TV historian of sorts, I think. Hopefully, someone will post soon.

Keep the thread going if you have any other pics. I'm enjoying this!
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Old 3-Apr-2019, 12:59 PM   #6
JoeAZ
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My parents home had a similar antenna. No, it wasn't very good but
better than the typical dipole/UHF loop inside. The wires that connected
the elements frequently failed and had to be replaced. As I recall, it wasn't
terribly directional and we had issues with multipath.
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Old 3-Apr-2019, 6:33 PM   #7
tripelo
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Channel Master TW: Traveling Wave Antennas

Quote:
Originally Posted by bobsgarage View Post

But for now I figured I would submit some photos.
To me this is a challenge but to some of you installers you might
even have put these up in back in their day.
The antenna is a Channel Master 'TW' antenna. TW for traveling wave.
It was a revolutionary antenna in its day.

Previously, relatively high-gain antennas were narrowband (Yagis).

Broadband antennas for low & high VHF were much larger panel types
(CM Champion & BackStop etc, imagine a VHF 4-bays).

Or were some version of conical antennas (whisker-types for low and high VHF).

Announcement of Original Channel Master TW (image below)





Had one of these antennas until a tornado (years ago) took it out.

Found an advanced version of it on a scrap yard a few years back
It was in bad shape but could be restored.


Channel Master Super TW (image below)





Most of those elements that look like folded dipoles are not.
They are fat dipoles (the doubled part simulates a much fatter conductor for bandwidth).

In the original TW (1st image above),

All elements, except the last one, are driven.
The last one is an nondriven reflector.

The next to last element, is a shorted folded dipole (3-bar, for high impedance).

Even tho lots of driven elements, it operates on a different principle than log-periodic.

.
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File Type: jpg TW Announce 1956.jpg (123.8 KB, 310 views)
File Type: jpg Super TW.jpg (88.3 KB, 306 views)
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Old 4-Apr-2019, 3:43 AM   #8
bobsgarage
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Channel Master 7 element TW

Thank you Tripelo, not only did you identify the antenna but you gave us a lot of great information. The article about the antenna very interesting. What's even more amazing is that antenna is still up on the roof and it's probably 60 years old. They really built that antenna!

It's an interesting concept that I really actually don't understand but the whole idea and how it looks is very cool !
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Old 4-Apr-2019, 2:47 PM   #9
rabbit73
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Quote:
Originally Posted by tripelo View Post
The antenna is a Channel Master 'TW' antenna. TW for traveling wave.

It was a revolutionary antenna in its day.
Thanks for the description and images. I had never seen that before.

I found an article that gives more theory on the T-W antenna:
https://www.wtfda.org/mem/travwave.pdf
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Old 4-Apr-2019, 7:07 PM   #10
bobsgarage
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Quote:
Originally Posted by rabbit73 View Post
Thanks for the description and images. I had never seen that before.

I found an article that gives more theory on the T-W antenna:
https://www.wtfda.org/mem/travwave.pdf
interesting, isn't it? I think it's cool to find things that others haven't seen and have somebody explain about it. I'm going to make a few more posts like this. What do you think Rabbit? Fun or not?
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Old 5-Apr-2019, 3:06 PM   #11
tripelo
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Quote:
Originally Posted by rabbit73 View Post
...I found an article that gives more theory on the T-W antenna
Thanks, good to be able to appreciate accomplishments of the past.

Quote:
Originally Posted by bobsgarage View Post
interesting, isn't it?...
Yes, agreed.

Rabbit73 & bobsgarage, it is interesting.

The antenna engineers of the early 50s thru about mid 70s did remarkably creative design work.

.
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