[Cover of Sullivan's book 2009, Cosmic Noise]
Sullivan's Cosmic Noise, Cambridge University Press, 2009


NATIONAL RADIO ASTRONOMY OBSERVATORY ARCHIVES

Papers of Woodruff T. Sullivan III: Tapes Series

Interview with Gennady W. Potapenko
At Potapenko's home in Pasadena, California
August 21, 1975
Interview Time: 14 minutes
Transcribed for Sullivan by Bonnie Jacobs

Note: The interview listed below was either transcribed as part of Sullivan's research for his book, Cosmic Noise: A History or Early Radio Astronomy (Cambridge University Press, 2009) or was transcribed in the NRAO Archives by Sierra Smith in 2012-2013. The transcription may have been read and edited for clarity by Sullivan, and may have also been read and edited by the interviewee. Any notes added in the reading/editing process by Sullivan, the interviewee, or others who read the transcript have been included in brackets. If the interview was transcribed for Sullivan, the original typescript of the interview is available in the NRAO Archives. Sullivan's notes about each interview are available on the individual interviewee's Web page. During processing, full names of institutions and people were added in brackets and if especially long the interview was split into parts reflecting the sides of the original audio cassette tapes. We are grateful for the 2011 Herbert C. Pollock Award from Dudley Observatory which funded digitization of the original cassette tapes, and for a 2012 grant from American Institute of Physics, Center for the History of Physics, which funded the work of posting these interviews to the Web.

Sullivan

Ok, this is talking with Dr. Potapenko at his home in Pasadena on 21 August 1975. Can you tell me a little bit about your background before you did this radio astronomy experiment?

Potapenko

Well, let me tell you first that I came from Moscow, Russia, 45 years ago about. And then I was doing some research on short waves.

Sullivan

About what time was this?

Potapenko

About 1930. And I remember I measured some radiation which I could not explain and which was from certain direction over the time or about certain direction. And then we started studying it with Don [Donald F.] Folland. Don Folland was my student, very able boy which studied those noises.

Sullivan

This is in 1930 now?

Potapenko

1930. And more and more, next year and next year, there are several years I don't remember how many, but several years that was, and then finally we started being a special type of receivers to receive the noises. Then I made some photo-pictures of equipment and some curves of the observations.

Sullivan

Right, and you sent me one of those...

Potapenko

And I sent that to you. So that's about all.

Sullivan

But, in the middle of this [Karl] Jansky did his work, and did you know about Jansky's work?

Potapenko

I did not know before I started receiving those noises but certainly I learned about them and later reported at Caltech about them.

Sullivan

And so, was your main motivation to try to confirm what Jansky had first of all?

Potapenko

No, just to, I was not in doubt about his work but to confirm that what those noises are.

Sullivan

Extent perhaps?

Potapenko

The extent, maybe.

Sullivan

So, can you tell me a little bit about exactly what you built, what sort of equipment?

Potapenko

I built a frame for a rhombic, you know...

Sullivan

A rhombic?

Potapenko

A rhombic, or I think that it was a rhombic, not a square. I made several dishes of this type and repeated this noise around or near the frequency corresponding to 12 meters, where it...

End of Tape 38B

Sullivan Tape 39A

Sullivan

So you were saying it was at 12 meters wavelength?

Potapenko

Yes, about, giving better results. And then we built several similar receivers and then finally an antenna, one wire antenna. The picture of which I did send to you. And we did some measurements using that antenna, and then Folland, that was summer. And Folland went home, then he did summer measurements.

Sullivan

In Utah?

Potapenko

In Utah.

Sullivan

Now, were the receivers that you built, was there anything special about them, were they extremely high sensitivity?

Potapenko

No, nothing. They were sensitive alright, but not especially high sensitivity.

Sullivan

And also, you did some work on it at an ocean beach site, it looked like from the picture- some of it was in the Mojave Desert, right?

Potapenko

Yes.

Sullivan

And some of it was by the ocean, was it not?

Potapenko

Yes, by the ocean...

Sullivan

Where was that?

Potapenko

That is Balboa. No, I don't remember. It was Caltech’s station, oceanographic station.

Sullivan

What kind of station?

Potapenko

Oceanographic. And we made some measurements there but nothing, I did it just to be sure that our waves go around...

Sullivan

It just wasn't a function of some particular location?

Potapenko

Yes. So we found out that they go around.

Sullivan

But you had two different kinds of antennas also, you had the circular antenna which was in the picture by the ocean, as well as the mast antenna with the long wire.

Potapenko

Yes, in the desert.

Sullivan

Why did you have these two kinds?

Potapenko

One just, the other one was straight wire. One antenna was more sensitive because it was larger.

Sullivan

And, how many days total of observations did you take roughly?

Potapenko

Oh, several days, not much...

Sullivan

Just a several days, but not months or...

Potapenko

Yes, because after that I stopped to design new antenna and Mr. Porter, whose name you know, helped me in that, in designing the antenna, and I did show it to Dr. [Robert Andrews] Millikan.

Sullivan

Now, I want to ask you about this new antenna. He helped you with the mechanical engineering side of it, I guess, or the structural engineering?

Potapenko

Yes from the beginning.

Sullivan

Right, and you knew how you wanted, what kind of antenna you wanted to have. What kind of antenna was it?

Potapenko

All one wire.

Sullivan

All one wire?

Potapenko

One wire.

Sullivan

I see, and how did the wire go, can you?

Potapenko

Yes, the antenna was straight pole, and from one pole to the ground was antenna. That's all. And the man was rotating, going around with it and talking the antenna with him.

Sullivan

I see, so it was the same kind as the kind you had in the Mojave Desert?

Potapenko

Yes, that was Mojave Desert.

Sullivan

Oh right but I'm asking you about the one that you designed with Porter.

Potapenko

That was for the same antenna. I mean, for the same type of antenna.

Sullivan

Oh, the same type of antenna? Right. Except, it was going to be bigger or...

Potapenko

Bigger antenna and it could accommodate loop antenna.

Sullivan

What kind?

Potapenko

Loop.

Sullivan

A lobe antenna, I see.

Potapenko

A loop!

Sullivan

Oh, a loop, I see. So you could mount a loop antenna on it?

Potapenko

Yes, could mount one wire or a loop antenna.

Sullivan

So this antenna that you and Porter designed, was it going to be pushed around by a person also or have a motor on it?

Potapenko

No, no, we wanted to accommodate that later, but to start with just using the antenna with an observer.

Sullivan

I wish I had the drawing here, but it looked more complicated to me than just a support, a single wire.

Potapenko

Yes, that's right. I said loop, wire or loop.

Sullivan

Right, but was the loop going to be above the structure...

Potapenko

Above, above.

Sullivan

Oh, I see, you had a huge rhombus above it, I see what you're saying, yes. And what was the rough dimensions of it? Oh, I see you had a man in the picture, right, so I can get an idea from that. Right...

Potapenko

Right. I don’t remember. I’d hate to make a mistake.

Sullivan

And you estimated that it was going to cost how much?

Potapenko

$1,000.

Sullivan

$1,000, which was quite a bit.

Potapenko

Yes, impossible for Caltech.

Sullivan

Right, in the middle of the Depression, right. And you tried to get the money, you said, from Millikan.

Potapenko

Yes [?] my expenditure. That would be his department.

Sullivan

And what was his reason for turning it down?

Potapenko

Too much money!

Sullivan

Too much money. He didn't think that it was important enough to?

Potapenko

No.

Sullivan

Did he know about Jansky's results at all?

Potapenko

Yes, because I gave a talk.

Sullivan

I see but still. Did you talk to the optical astronomers at all at that time?

Potapenko

I believe, [Jesse L.] Greenstein. [Sullivan: But Greenstein did not arrive at Caltech until 1948]

Sullivan

Right, he was interested in these things. He wrote a paper with [Fred L.] Whipple, in fact, in ’37 trying to explain these observations. And what did Greenstein say at the time?

Potapenko

Oh he wanted to. Ok.

Sullivan

Was he encouraging you to...

Potapenko

Yes, and he knew Porter. In fact, they worked in the same building.

Sullivan

Were there any other optical astronomers that you tried to talk to?

Potapenko

No, I don't remember, maybe, casually.

Sullivan

The reason I'm asking this is I'm trying to get some idea of the attitude of the optical astronomers towards radio astronomy in its early days...

Potapenko

Oh, they said, that is very interesting, one pulse at the same time from the same direction...

Sullivan

But it seems like most of them really didn't understand.

Potapenko

No, nobody knew it, nobody...

Sullivan

Well, they didn't even understand the nature of the measurements and so forth, because this radio engineering was so different from using the Mt. Wilson telescope.

Potapenko

Yes, certainly.

Sullivan

What about your own astronomy, did you just get a couple of books to learn astronomy for yourself or...

Potapenko

Oh, I learned astronomy when I was young. So I talked their language and read at that time.

Sullivan

But this was the only time you had a chance to do some research in astronomy.

Potapenko

Yes, or close it was.

Sullivan

Why did you not publish your results?

Potapenko

Because if Millikan says it is not important, why should I submit my paper?

Sullivan

Well, Millikan was wrong.

Potapenko

Millikan was wrong, yes.

Sullivan

And Folland, I guess, was just a graduate student who was following your lead more or less?

Potapenko

Yes. You remember that antenna, that stand for the antenna, he designed it, that in order that it from the factory.

Sullivan

The one that was by the ocean? Do you remember where that was now? The name of the site?

Potapenko

No.

Sullivan

But it's somewhere right near here?

Potapenko

Right near here...

Sullivan

Were those the only two sites that you used in this region?

Potapenko

No, I tried that in the garden belonging to Caltech.

Sullivan

Where?

Potapenko

Garden, a vegetable...

Sullivan

Oh, a garden! And, this was right on the campus?

Potapenko

No, not on the campus, on the end of Pasadena [Sullivan: Avenue].

Sullivan

And you got similar results there, also?

Potapenko

I don't remember whether they completely identical or were just similar.

Sullivan

Yes, right.

Potapenko

But that was before I went to Mojave Desert.

Sullivan

And the idea of going to the desert was to avoid interference, I assume.

Potapenko

Yes.

Sullivan

Maybe you were getting too much in the garden, do you remember that?

Potapenko

No, I got less in the garden at Caltech…

Sullivan

Really?

Potapenko

But enough to disturb me.

Sullivan

Well, I don't think of anything else to ask you now. Maybe I will later on. Ok, thank you.


Modified on Tuesday, 29-Jan-2013 08:49:54 EST by Ellen Bouton, Archivist (Questions or feedback)