Oldest tower still standing

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wrsg915fm
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Oldest tower still standing

Post by wrsg915fm » Sat Dec 21, 2013 12:25 pm

This begs the question...what is the oldest tower still standing? WETZ in New Martinsville, West Virginia has a tower that is at least 60 years old, a freestanding Blaw-Knox model. Would KDKA's, a station over 90 years old, be the winner?

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Re: Oldest Tower

Post by NECRAT » Sat Dec 21, 2013 1:20 pm

KDKA's towers are 1937 - 1939. The towers at WTIC in Hartford are older than that, being put up in 1929. It would be interesting to figure out what the oldest broadcast tower in the country would be still standing.

Edit, this could be a very interesting discussion, so I have split it off for more visibility.
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Re: Oldest tower still standing

Post by kkiddkkidd » Sat Dec 21, 2013 4:17 pm

WSM's wiki notes 1932 as the original build date even though it was shortened in 1939. I seem to recall that WLW's Blaw-Knox was built just before WSM's. I know that WSM's Blaw-Knox is still the original but not sure about WLW.

WSM's tower almost came down in a small tornado a few years ago. There was a number of damaged cross braces and for a period it was off plumb by several feet. Watt had the cross braces reproduced and replaced and later found that some of the replacement cross bracing had been damaged again. That wasn't long before he bailed IIRC.

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Re: Oldest tower still standing

Post by RGORJANCE » Sat Dec 21, 2013 6:09 pm

WRJN-AM in Racine is 85 plus years old. It uses an insulated 4 leg self supporting tower. I think that the tower might have gone up in the late 40's to early 50-ish time frame. There was a still a GE slotted pylon FM antenna on the tower, no longer used, when I first visited the station in October of 1967. If the tower was up in 1950, that would put it at 63 years of age.

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Re: Oldest tower still standing

Post by kkiddkkidd » Sat Dec 21, 2013 6:48 pm

Many of the transmit antennas used in the 1920's was a cage / wagon wheel / T / fat dipole supported between wooden poles. WOAN was put on the air in 1922 by James Vaughn in Lawrenceburg TN with a cage antenna supported by wooden frames.

I don't know exactly when the change from horizontal T antennas to vertical radiators occurred but it was well underway by the early 1930's. You would think that the oldest surviving tower is one of the early adopters of the vertical AM transmit antenna.

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Re: Oldest tower still standing

Post by K4WRF » Sat Dec 21, 2013 10:12 pm

hello everyone! Long time no type...
good question about oldest standing AM tower. I don't know but the WSM-AM Blaw-Knox was topped out 81 yrs ago in September of 1932. The same crew that erected the WSM tower went to do the WLW BK, so WSM is slightly older by a few months. IDK about the WTIC BK's but they were not the first antennas at that site first used "T" antenna and they started at that site in 1929. WSM was one of the first vertical over counterpoise. By the mid or late 1930's, the dual cantilever style was not being used and linear construction was the norm. WBT could have been earlier but all of those have been replaced at one time or another. WSM was damaged as stated by Kevin kidd. We had fabricated and replaced 46 diagonals and one lateral above the waste (mid section) following a storm in late 2002. We thought there were several others that may have exceeded 3" bow tolerance. I departed in June of 2008, there has been no further structural consideration of the tower.
WWH

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Re: Oldest tower still standing

Post by R. Fry » Sun Dec 22, 2013 6:14 am

K4WRF wrote:... By the mid or late 1930's, the dual cantilever style was not being used and linear construction was the norm.
Probably that was due to the conclusion of Dr. George H. Brown et al of RCA Labs in Princeton with respect to the original Blaw-Knox of WCAU. In 1934 RCA was contracted to investigate and fix the reason that WCAU had a lot of nighttime self-interference at the edges of the useful, daytime groundwave contour.

In Brown's autobiography "and part of which I was", he wrote about the scale model testing RCA did based on WCAU's tower. The problem was much reduced when they removed the top 100' pole from that tower.

But Brown developed a dislike for the Blaw-Knox tower design, writing about it in his book, "Apparently no consideration was given to the electrical performance of the structure before inflicting it on unsuspecting broadcast stations who accepted the design in good faith."

Several years ago I did a NEC study of this based on the dimensions of the Blaw-Knox given in Brown's book (below). It looked to me as if their self-interference was related more to the height of that structure than its profile.

In 1941 WCAU moved the transmitter site from Newtown Square, PA to a site in New Jersey, where they installed a uniform cross-section tower. Their old Blaw-Knox was trashed by cutting one guy wire.


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Re: Oldest tower still standing

Post by kkiddkkidd » Sun Dec 22, 2013 7:48 am

K4WRF wrote: following a storm in late 2002.
Good lord was that 2002? I was thinking it was just 5 or 6 years ago. Where do the time go?
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Re: Oldest tower still standing

Post by kkiddkkidd » Sun Dec 22, 2013 7:57 am

Richard,

Thanks for posting the NEC of those towers. I had always wondered about how they compare to a uniform cross section tower. I had assumed that there wasn't a lot of difference but had never wondered enough to do a model.

Not to derail an interesting thread on tower age.... Was there any indication from Brown if his dislike for the design was anything other than the conceived increase in self interference or was there some other factor?

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Re: Oldest tower still standing

Post by R. Fry » Sun Dec 22, 2013 8:32 am

kkiddkkidd wrote:...Was there any indication from Brown if his dislike for the design was anything other than the conceived increase in self interference or was there some other factor?
Maybe we should start a new thread about early Blaw-Knox towers.

The WCAU Blaw-Knox included a 100-ft top pole of uniform OD -- making the tower about 5/8-wave in physical height, and probably more in electrical height due to its large average cross section. From re-reading that section of Brown's book I take it he didn't like that overall design (dual cantilever and top pole).

His fix was to remove the pole and replace it with a ring of steel beams mounted on an insulator, at the top of the structure. The ring was connected to the top of the tower by an adjustable inductor. Over a period of many months over two winters, "Mr Bennett," the rigger adjusted the coil following Brown's instructions, based on the reports he gathered from listeners up to 70 miles away.

When they finished, Brown writes that WCAU's nighttime fade-free area had increased to 4X its original value.

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Re: Oldest tower still standing

Post by K4WRF » Sun Dec 22, 2013 9:40 am

Thanks for posting that plot Richard! We conducted that same NEC analysis thinking that the antenna was still slightly long only to discover Brown was pretty much right on. The before after vertical elevation plot compares IIRC. WSM was reduced by 70' about the same time that WCAU sent theirs to the scrap-heap....

Recalling, it seems I read that the WCAU and WJZ (Boundbrook NJ) blaw/knox DC's went up about the same time and before WSM...

All the best...

ww

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Re: Oldest tower still standing

Post by BingNYEng » Sun Dec 22, 2013 11:29 am

The Marconi tower in Binghamton, NY still stands. It was erected in 1913.

http://nyslandmarks.com/treasures/13jan.htm

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Re: Oldest tower still standing

Post by level42 » Sun Dec 22, 2013 12:08 pm

WPAX in Thomasville, GA went on the air in December of 1922...but used a dipole until the Blax-Knox freestander was built in the late 1930s. That Blaw-Knox is still standing and in use. Not the oldest, but about the best condition one I've seen from that era. Additionally, we still have the original flashing neon call letters at the top of the tower...the light up downtown every evening from 6pm till 6am. How many towers out there still have that?

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Re: Oldest tower still standing

Post by COMMENG » Sun Dec 22, 2013 4:53 pm

Here is an article about George H. Brown:
Brown History.pdf
(568.38 KiB) Downloaded 479 times
Well, I had two Brown papers in PDF from the IRE on BC antennas and Grounding systems but I guess they were too large to upload.

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Re: Oldest tower still standing

Post by kkiddkkidd » Sun Dec 22, 2013 6:04 pm

BingNYEng wrote:The Marconi tower in Binghamton, NY still stands. It was erected in 1913.

http://nyslandmarks.com/treasures/13jan.htm
That is one of the towers that I had thought of but had it confused with the monster tower in Alpine NJ that Armstrong built in the late 30's for VHF / FM research.

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