“Over Our Heads”: The KTRU Antenna, April 1971

Lacking something else to do I was reading some Sid Rich newsletters the other day and came across this great bit about the installation of the antenna on the roof. I’ve always enjoyed turning up pieces of Rice radio history so I was delighted to find this goofy drawing on the cover:

I hadn’t realized that Sid residents were cut off from all the glorious KTRU programming until the FM antenna was up and running:

Bonus: A while back John “Grungy” Gladu sent us some images of a later (I’m not sure of the date) antenna-raising, crediting Wiley Sanders ’78 for the photos. When I went back for a look at them I was happy to note that many of them actually look a lot like that goofy drawing above.

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9 Responses to “Over Our Heads”: The KTRU Antenna, April 1971

  1. Bill Peebles, Hanszer '70 says:

    Hooray for the guys who got off their butts and got it done!

  2. williamwatson says:

    The later antenna raising was part of the upgrade from 340 Watts Effective Radiated Power (ERP) horizontally polarized to to 650 Watts ERP with circular polarization. It took place in the spring of 1980, IIRC. We replaced the 250 Watt transmitter with one rated at up to 1000 Watts, but ran it at reduced power of 525 Watts. The new 3-bay antenna had some “antenna gain,” but I don’t recall that figure at the moment. Maybe it was 1.42?

    You can see the 1 5/8 inch “Heliax” feed line curving up from where Grungy is holding it at the edge of the elevator “penthouse” roof to the antenna pole. It looks like Mark Linimon at the bottom of the ladder. I think I’m standing at his left, also bracing the ladder. I can’t tell who’s up on the ladder holding the upper end of the heliax, nor who’s standing just left of the pole.

    The upgrade was possible as just an “minor change” in the license from the FCC, the maximum allowed for such a change. I think Margaret may have initiated the change, but the paperwork took a while. We had the “new” transmitter sitting in the production room for quite some time, waiting on approval. The new transmitter was about my age, built in 1961, and had the most straightforward final amplifier stage I’ve ever seen, with a pair of 4-400C power tetrodes in a push-pull configuration. The driver wasn’t as good, with (I think) a 6146 pentode in a grounded-grid configuration.

    The transmitter wasn’t really happy operating at such low power. It had a number of interlock relays to prevent damage. One shut down the finals if it detected loss of input drive, but just barely pulled in with our low power. If the transmitter was neglected, that relay would open and knock the station off the air.

    ktru kept this transmitter and antenna in operation until the 50 kW upgrade in the spring of 1991. It didn’t get enough attention, and started getting flaky that spring. The station staff called me down from Austin to help several times, as I was the last person who knew the gear and was “close enough” to help.

    • This would have been the winter of 80-81, because that is when I had access to a 4×5 camera through my photography class (with Peter Brown). I remember this happening in December, but I could be wrong.

    • Walter’s pictures show the faces better. It is Paul Williamson on the right, in the grey longer coat, holding the ladder.

      There are some better pictures I have seen which show everyone standing in a line after the antenna was up. I suspect Wiley has those.

  3. williamwatson says:

    Also, you can see the bottom antenna bay sitting on the roof by Grungy’s right foot. It was a short section of a spiral. The advantage of circular polarization over horizontal was that either a vertical or horizontal antenna could receive the signal. With a horizontally-polarized signal, only horizontal receiving antennae would work well.

  4. While Wiley was shooting the new antenna from the top of the elevator house, I was down on the roof shooting up. I’ve just loaded those into this album. I was crazy enough to set up a 4×5 view camera on the roof.


    I remember it being really cold up there.

  5. Richard Miller, BA 1975, MEE 1976 says:

    I remember helping raise the coax cable for the antenna. We had to lift it dead weight up Sid I do not recall if we used a utility chase or came up the elevator shaft but it was an effort to get it to the roof. I think this was in the frame of 74 to 76. The picture may be of that effort

  6. Gene Mutschler says:

    That heliax looks like it must have been nasty to work with. We used RG11, which is 1/2 inch, not 1 5/8, so it was much easier to handle. It was probably some of the same cable we ran in the steam tunnels between the buildings for the AM signal.

    Otherwise, this picture looks very much like a picture of the original event described would have looked — one person up on the ladder, with the others bracing it. I was the person on the ladder and insisted on a lot of bracing, since I was just coming off a case of the flu and was still feeling a little rocky. Plus, a ladder leaning against a pipe is not nearly as stable as one against a wall.

  7. Eugene Mutschler says:

    The article mentions how there was no AM signal at Sid Richardson, due to one of the two conduits containing only “a phone line”.

    This “phone line” would actually have been a large multi-line cable, supplying telephone service to the building, and, in fact KTRU FM used three different lines in it. There were two equalized lines for the stereo broadcast signal, plus another, DC-only line that was used to turn the transmitter on and off from the studios in the RMC.

    The equalized lines were essentially regular phone lines that were specially equalized by AT&T to carry FM-quality audio signals, which have much more bandwidth than normal phone lines (about 5 times as much) and were, consequently, more expensive than regular lines.

    The problem with AM was that the KTRU AM signal was not at all compatible with the AT&T cable and could not coexist with it.

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