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Some Excerpts from W2DU's Reflections 3




 
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Author Topic: Some Excerpts from W2DU's Reflections 3  (Read 11599 times)
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W2DU
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Walt, at 90, Now 92 and licensed 78 years


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« on: January 01, 2009, 05:12:32 PM »

In a previous thread, "It Was Chistmas Eve 40 Years Ago" there appeared to be some interest in the history of the early space age. Son Rick, W8KHK, present some of my work, specifically ECHO, and I posted some excerpts from Reflections 3 in Posts 28, 29, 37, and 38 in the aforementioned thread. However, the post in #38 is an incomplete diagram of the tx to antenna coupling circuit. The original complete diagram is missing.

I tried to post some additional pics, but they were to large to fit, so I have been reducing them to a postable size. Since there are several that you might find interesting I'll have to post them in separate threads.

In this post you'll find the complete section describing the development of the transmitting antenna array that flew on the World's first weather satellite, TIROS 1, a pic of the spacecraft, and one showing me making adjustments to the radiating elements on a full-scale electrically-equivalent model of the spacecraft.

In following threads I'll post pics of the matching networks that couple the four xmtrs to the antenna array. The four transmitters operate simultaneously on four different frequencies.

Walt, W2DU


* Electrical Test Model.jpg (61.19 KB, 708x555 - viewed 787 times.)
* The TIROS 1 Story for AMFone.doc (81 KB - downloaded 406 times.)

* TIROS 1.jpg (63.85 KB, 558x705 - viewed 742 times.)
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« Reply #1 on: January 01, 2009, 05:24:34 PM »

Early space for me was very interesting. As a kid you just had to feel for all the hard work when a rocket would just clear the pad and turn sideways and be blown up. I remember the family dancing in the livingroom when one finally kissed the sky.
At the same time we would get work stories from my Dad from the P&W test stands. I'll never forget the one "We have a motor that burns bunker oil." (later figured it out that it was JP7)
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« Reply #2 on: January 01, 2009, 06:31:37 PM »

Continuing from my original post. The following pics concern the matching networks that coupled the four xmtrs to the four-monopole antenna array. The networks were designed to couple four xmtrs to the antenna array operating simultaneously on four different frequenies, with radiation circularly polarized on all frequencies. One xmtr at each frequency radiates right-hand CP and the other radiates left-hand CP, which is the nature of the outputs of diplexers, otherwise known as 'rat races'.

One pic is of the matching networks fabricated in stripline printed-circuit boards, one for 136 MHz and the other for 235 MHz. This unit is rather beat up after being shown at hamfests and ham club meetings. Another pic shows the circuit diagram of the networks, while the third shows the actual layout of the stripline. The two circuit boards are mounted together as in a sandwich, with their four output terminals connected together for feeding the four monopoles in the array. The sleeve portion is the principal radiator for the 235 MHz band, while the rod extension and the sleeve combination comprise the radiator for the 136 MHz band. More TIROS pics to come later.

Walt, W2DU


* Coupler.jpg (74.11 KB, 820x615 - viewed 776 times.)

* Circuit Diagram.jpg (116.65 KB, 925x1267 - viewed 770 times.)
* Coupler description.doc (190 KB - downloaded 380 times.)
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« Reply #3 on: January 01, 2009, 07:05:36 PM »

In the next set of pics we show W2DU on right and technician John Luzansky on the left in the antenna lab at the David Sarnoff Research Center in 1958, also showing the 4:1 scale model of one-half of the spacecraft backed by a 4 x 4 foot aluminum panel ground plane. This arrangement was used for impedance measurements (hundreds) of different configurations of the radiator to find a configuration that would yield a 50 + j0 impedance. For 4:1 scale-model measurements the frequency must be four times the operating frequency. For these measurements the signal generator was an HP-612 and the impedance-measuring instrument was an HP-805 slotted line. There were no other impedance-measuring devices available in 1958. The other devices used were the Smith Chart and slide rule--no hand calculators available either!

The next pic shows mechanical technician Herb DeCerbo attaching the W2DU antenna array to the spacecraft.


* Scale Model.jpg (55.49 KB, 693x540 - viewed 778 times.)

* Herb DeCerbo.jpg (51.59 KB, 390x519 - viewed 731 times.)
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« Reply #4 on: January 01, 2009, 07:17:08 PM »

Still continuing, the next pic shows W2DU setting up a model of the spacecraft with an empty 3rd-stage Delta rocket, the rocket that gives the spacecraft its final push into orbit. W2DU is preparing to take radiation pattern measurement of the combination to determine whether the rocket in the near field of the antenna array will seriously affect the pattern in a way that could blackout the signal prior to orbit. It turned out that the fiberglass casing of the rocket didn't affect the radiation pattern.

The next pic shows the spacecraft atop the Delta 2 rocket at launch pad 17A. The spacecraft is at the 12th story level with the gantry pulled away.

The third pic shows the spacecraft surrounded by the nose cone, or fairing. The floor level with the gantry in place is at the 12th story. The pic shows W2DU peering into the fairing to determine whether the ends of the radiators fit properly inside the nose cone.

More pics to come.

Walt, W2DU


* With 3rd-Stage Rocket.jpg (243.32 KB, 2538x1863 - viewed 749 times.)

* No Gantry.jpg (36.9 KB, 550x693 - viewed 790 times.)

* Fairing.jpg (233.57 KB, 1396x1791 - viewed 786 times.)
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« Reply #5 on: January 01, 2009, 07:33:58 PM »

There was a receiver desensing problem in TIROS 8, because the 136 MHz beacons on this spacecraft were connected to the command receiving antenna. Consequently, a fix was required. Maxwell invented a coaxial resonator, weighing seven ounces that cured the problem by using the resonator as a virtual short circuit at the unwanted frequency in the feedline to the receiver. Actually, two resonators separated by a quarter-wavelength line provided 56 dB of isolation, 28 dB for each resonator. Maxwell was granted a patent on his resonator, shown in the first pic.

The second and third pics show the five watt video xmtr (using pencil tubes, no solid state yet), and the 30 milliwatt beacon xmtr, top and bottom views.

More pics later.

Walt, W2DU


* Patent.jpg (74.06 KB, 617x891 - viewed 836 times.)

* 235 MHz xmtr.jpg (96.78 KB, 468x351 - viewed 766 times.)

* 108 MHz Beacon xmtrs.jpg (98.76 KB, 468x351 - viewed 769 times.)
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« Reply #6 on: January 01, 2009, 07:35:36 PM »

Wonderful Walt, many thanks for posting!

Are you planning on releasing "Reflections 3" soon?
I don't want you to give away the farm, but with the chance in ownership at WorldRadio, I was wondering what is up.

I'm still hoping for a new release from "Kurt Sterba and Lil' Paddle", but I fear that hope may be in vain.
I've read and reread "Aerials I,II and III" so many times they are dog eared.

Glad to see you back on the board, and best wishes to you and your family for 2009.


-Bruce W1UJR
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« Reply #7 on: January 01, 2009, 09:18:52 PM »

Hello Bruce,

Can't say when Reflections 3 will be out, because I'm just now discussing it's publication with a publisher. Getting it published has taken several quirks, but right now the chances look good.

I'm curious concerning what you mean by "...chance in ownership of World Radio." You must know that CQ Communications has purchased World Radio. Do you know something I don't?

Speaking of Kurt's 'Aerials', I don't know who edited Aerials II and III, but I edited Aerials I. I've been accused of being 'Kurt', but taint so. The original Kurt was Pete Onigian, W6QEU, but he gave it up several years ago. I have no idea who followed him into the role.

I'm still recovering from the catastrastrope that occurred Nov 4, and am still wobbly, but Jean and I have our tickets for returning to our home in DeLand, FL on Jan 8. We are still in Michigan with more snow than I can handle.

Walt

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« Reply #8 on: January 01, 2009, 09:23:58 PM »

Sorry OM, my spelling boo-boo, intended "change" rather than "chance".
Yes, I was referring to the CQ purchase.

Ok on W6QEU.
Editions I, II and III all seem to read as if they were the same person, I just assumed it was all one author.
Was Peter also responsible for "Lil' Paddle" as well?
Her bio seemed to suggest she was of British ancestry, and had served in the Signal Corp.

I look forward to adding "Reflections 3" to my bookshelf!
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« Reply #9 on: January 01, 2009, 11:00:35 PM »

Walt,
This is so cool. man I have not used a slotted line in 30 years. As a kid watching UNITED STATES continue vertical past the top gantry was a good feeling. I bet you guys in the trenches went crazy. You put on quite a show for us.
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« Reply #10 on: January 02, 2009, 02:27:10 PM »

Hello Bruce,

To set the record straight, all three issues of 'Aerials' were published before Onnigian stopped writing the column, which is why the writings appeared to be by the same person. I don't remember seeing a bio on 'Lil Paddle', so I don't know if she even existed, except perhaps in Kurt's mind.

I too, am looking forward to the time when Reflections 3 will be on your bookshelf.

And a Happy New Year to you and yours.

Walt, W2DU

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« Reply #11 on: January 02, 2009, 04:57:11 PM »

Continuing some historical aspects of the early space age, the picture in the attachment is of TIROS 4, showing the innards of the spacecraft. In the center you'll see the printed circuit board (with the hole in the center) containing the stripline circuitry of the RF matching networks.

The pic of the layout of the network circuitry appears in an earlier post, the one showing the description of the networks.

Three more pics coming up.

Walt, W2DU


* Internal TIROS.jpg (245.22 KB, 1300x971 - viewed 789 times.)
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« Reply #12 on: January 02, 2009, 05:52:24 PM »

During the 1970's I was an antenna consultant to AMSAT. The designers of OSCAR 7 wanted a 2.304 GHz beacon aboard and I was assigned the task of designing the antenna. I chose to use the familiar quadrifilar helix that later proved so successful on the TIROS N series of weather satellites.

The first picture shows me presenting the tiny quad helix to Jan King, W3GEY, one of AMSAT's lead engineers. The other two people, from the left are RCA engineer Randy Bricker and Walter Ozman, W2WGH. The room in which I presented the antenna is one of the clean room at Princeton's RCA Space Center, where all the TIROS and other spacecraft were built. At the right in the picture is one side of the new spacecraft, TIROS 9, the first TIROS using a flywheel for stabilization. With all previous TIROS models, 1 thru 8, the entire spacecraft was spinning for stabilization. The reason for changing the stabilization method was to allow the camera side of the spacecraft to face Earth continually to allow more camera time. Also in the picture you'll see an eigth-sided unit, which is a mockup of OSCAR 7 placed in the position where it will ride alongside the TIROS 9 spacecraft during the launch into orbit.

In the second picture the beacon antenna can be seen mounted at the bottom left of the OSCAR spacecraft.

The third picture is from Reflections 2, showing Tom Vorhies, K2EQU, presenting me with a 'double bazooka' at my retirement dinner. As you may know from reading the QST and Ham Radio articles I wrote explaining why the coaxial dipole, aka double bazooka, doesn't derive it's somewhat greater bandwidth than a simple dipole as a result of the reactance developed by the coaxial sections, but instead derives the additional bandwidth by virtue of the loss in the coax. My articles appeared in Ham Radio in August 1976, and the one in QST was in the Technical Department column in the September 1976 issue. The QST article is repeated in both the 1st and 2nd editions of Reflections. Hope you get a good laugh from the picture.


* Quadrifilar on OSCAR 7.jpg (146.64 KB, 1128x903 - viewed 749 times.)

* OSCAR 7 to AMSAT.jpg (42.13 KB, 720x585 - viewed 793 times.)

* bazooka.jpg (66.84 KB, 757x594 - viewed 828 times.)
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