[Reber, 1988]
Reber giving a lecture at Ohio State University, 1988 (Photo courtesy of NRAO/AUI/NSF)


[Reber, 1995]
Reber with the reconstructed Jansky antenna, 1995 (Photo courtesy of NRAO/AUI/NSF)


NATIONAL RADIO ASTRONOMY OBSERVATORY ARCHIVES

Papers of Woodruff T. Sullivan III: Tapes Series

Interview with Grote Reber
At the University of Washington
October 25, 1975
Interview Time: 3 hours, 16 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 of 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.

Please bear in mind that: 1) This material is a transcript of the spoken word rather than a literary product; 2) An interview must be read with the awareness that different people's memories about an event will often differ, and that memories can change with time for many reasons including subsequent experiences, interactions with others, and one's feelings about an event.

Part 1 | Part 2 | Part 3 | Part 4

Sullivan

Ok, this is continuing with Grote Reber on 25 October í75. So you had a broad horizon?

Reber

Well, pretty much around the horizon. I remember Oahu was just on the horizon slightly north of west. So it gave an opportunity for trying this interferometry thing on a great scale. And I did get some results, but not very good results.

Sullivan

Why did you think the sea interferometer was more promising than the Michelson interferometer that Ryle was developing?

Reber

It was the best possibility in principle anyhow of being the variable space interferometer. When the source is right on the horizon the spacing simply would be zero. And as the source rises, then the spacing between the real antenna and image antenna under the sea rises at twice the height of the mountains, in this case would be a maximum of 6 km. So I had the possibility of an interferometer where the spacing changed from zero to 6 km in about a half an hour or thereabouts. So we would get patterns that started out very slow and increased in speed and got to be very fast. And at some place, if the source had finite size within its limits, the pattern would disappear. This would tell you something about the size of the source. Similarly, if there was a pair of sources, you get pairs of patterns and these would beat. And then you'd get a compound pattern. And furthermore, since it rose from the sea at a different angle than it set into the sea, you'd get ideas about the cross-section of this source in two different directions.

Sullivan

Right and you could do all this with a single antenna?

Reber

Yes. And it did work after a fashion, that is, I could measure the strong sources, Cassiopeia and Cygnus. I was able to demonstrate Cygnus was a double in one direction but single in the other direction. And there were a few other sources. I measured Taurus and bumped into Jupiter, a few things like that. But for the effort involved and the difficulty in doing the observations it wasn't warranted.

Sullivan

You had this short article in Nature in '55 and you say that the, "details of these studies will be described elsewhere." I don't think there ever was a detailed paper.

Reber

About what?

Sullivan

About the Hawaiian observations, was there?

Reber

Oh, yes. There was an elaborate paper that appeared in the Geophysical Journal.

Sullivan

Oh, that's right, I haven't gotten that one yet, in '58 or '59, something like that [Sullivan: Journal of Geophysical Research, 1959]?

Reber

Something like that. It gives all the calculations about positions and the curvature of the Earth and everything else. It turned out to be a difficult kind of thing to do because I neglected this business of manmade interference, which was bad enough back in Illinois. But you see, here you were up on this tremendously high mountain, 3 km high, looking out unobstructedly all over. And consequently I was getting interference from great distance, that is, for instance they had a pineapple cannery and they had a place where they made the tins and they had spot welders. This was maybe 15 miles away and that stuff, when they ran, just roared in there, and I could even encounter radio interference from Oahu, Honolulu, about maybe 90 miles away. Well, it was a direct line. And so you were in a very exposed position, just exactly what you didn't want. What you need, of course, is a hollow place surrounded by hills. So from this point of view it was a poor thing.

Sullivan

But you had to go there to get the long baseline, to get high?

Reber

That's right.

Sullivan

Which years then were you working up in Hawaii?

Reber

About 1951 to 1954, about three years out there. I took one year to get it going. I must have made observations in '52, '53, and '54, something like that.

Sullivan

This was all supported by Research Corporation?

Reber

Yeah.

Sullivan

And then what was your next move?

Reber

Well, then I cast about for something else to do. I wasn't part of any institution or part of any organization where I had to report to anybody and be on any given premises at any given time.

Sullivan

I gather that's not your style.

Reber

Yes. Well, so you might say I was foot-loose and fancy free in the sense that I wasn't committed to making observations out there at Boulder, Colorado for the rest of my life, or something like that. And so if I decided in my own mind that if it wasn't worth spending more time, money, and effort on this Haleakala experiment, I could scrap the thing. We hadn't spent an awful lot of time and money on it. Iíd extracted out of it what I could, which wasn't very much. And I thought well, why fuss around with this at all anymore? Why not try something entirely different? And I think I told you I had already made investigations as to where the ionosphere had the lowest electron density.

Sullivan

Right, but could you just briefly repeat that because we werenít taping then?

Reber

Yes. I thought all right, now is the time to give that thing a whirl. You see, here it was '54, well this is in the solar activity minimum. And this would be an auspicious time. I was a little late actually. And I had made contacts down there in Australia and found out this circumstance where there were poles, wires, and a hut, and power, telephone, and water. So I quickly hashed up some electronic gear for around 2 megacycles and took it down there.

Sullivan

Right, but before you go further though can we just get the story of when you went and plotted up the NBS data? I didn't get that on tape before. Was that while you were in Hawaii, that you went to Washington, D.C.?

Reber

No. Iíve sort of forgotten the details. It was NBS data and I think I looked at a lot of that while I was still in Washington. But NBS also had an ionosphere station on Maui, the same island I was on. And undoubtedly yes, I did. I spent a lot of time there looking over their stuff. But this wasn't a thing that was done in a few weeks. This was done in patches over a period of several years, you might say, while I sort of collected my ideas. And I think the graphs I told you about, the maps were plotted while I was in Hawaii.

Sullivan

These were maps of the maximum usable frequency?

Reber

Maps of the minimum critical frequencies.

Sullivan

Well, the critical frequency of the ionosphere?

Reber

The critical frequency of the ionosphere.

Sullivan

As a function of position on the Earth?

Reber

As a function of position of the Earth for different seasons of the year, summer, winter and equinoxes. There were contours: inside a given contour, the critical frequency dropped to some level or less. And these contours turned out to be in the northern hemisphere rather long streaks that were arcs starting up at Prince Rupert, British Columbia and going down through Winnipeg toward Duluth and across Lake Superior in the direction of Toronto and then back north again up beyond Quebec and St. John's. At the time I didn't really hardly believe these. I thought that they were a peculiar set of contours induced by some peculiarity, the way the data was taken or the location of the observers, or what have you. It was not a real demonstration of what actually happened in the ionosphere. But, in fact, it was, because in the late Ď60s, the Canadians put up a few Alouette ionosondes and they plotted their contours and lo and behold they were the same thing.

Sullivan

Really, amazing.

Reber

Or very close.

Sullivan

What causes this streak? Are there any ideas what causes it?

Reber

Well, no, not really. It seems to be a combination of effects which has something to do with the fact that the magnetic axis of the Earth is not coincident with the rotational axis of the Earth and that these particular regions are shielded from the particles that fall in by this geometric combination.

Sullivan

I see.

Reber

Because it doesn't appear again over in Siberia. It's strictly on the side where the magnetic axis is displaced as far as possible from the polar axis.

Sullivan

And so you get less ionization in that part of it?

Reber

That's right. And a similar thing occurred in the southern hemisphere, although there are not enough stations and there's so much water out there that you can't delineate it in that detailed a fashion.

Sullivan

So there is a similar streak in the southern hemisphere?

Reber

Apparently. Yes, there probably is, but I've never seen it drawn by anybody. The Alouette people haven't done or reduced their data in that fashion. Anyhow...

Sullivan

Well, you found another hole in Tasmania?

Reber

Yes. That's right, in the southern hemisphere, and it seemed to be on the basis of the rather more limited data available, a deeper hole. That is the electron density dropped lower, meaning the critical frequencies got lower. So I decided to go down there, partly on the basis of adventure, partly on the basis that the southern sky looked more interesting with the center of the Milky Way and the Magellanic Clouds and one thing and another overhead, partly due to the practical proposition that I was offered the facilities of these poles and wires and huts and things. So I went down there.

Sullivan

Was this hole in Tasmania known about before you plotted this stuff?

Reber

Well, no. I got a lot of advice from the pundits that I was wasting my time. I forget all the reasons why it wasn't any good, but in essence, oh, I think one of the reasons proposed that it wouldn't work was that there would be a lot of absorption in the ionosphere. And another reasons proposed was that I'd get a lot of radio interference from manmade stations. And even if I could find a clear channel, I'd probably get drowned out by atmospherics and I don't know what all. But when you started to question these people on the base for their pessimism, they really didn't have anything. But thereís a philosophical point here. That is, if these people thought it was any good, they'd be doing it. So when you go out and you get this kind of reaction, it's to be expected. They're interested in the things they are interested in, whatever they are. And they think those things are good, therefore they're doing them. So you come and suggest something else, and they haven't given it any thought and off-hand it very different from anything they have ever thought of and it can't be any good because if it was any good they'd...

Sullivan

They'd already be doing it.

Reber

Exactly.

Sullivan

That's a good point.

Reber

Well, in any case, what happened was...

Sullivan

When did you go down to Tasmania, actually?

Reber

I got down there on the first of November, 1954. Well, I arrived in Sydney then, but I didn't get to Tasmania until some weeks later. That's summertime. And I got my equipment all organized and going by February or so, which is still summertime. But I remember we tried it out until along in March, which was autumn, and it was rather cumbersome. I had one of these high-speed recorders and the idea was- see, I had listened to all of the pundits and so I'd naturally gotten influenced by them. And the idea was that by having a high-speed recorder, the pen would come back quickly with a short integration time and thereby arrive at the background level in between the surges of atmospherics. And this is true when there are atmospherics around. But it's not true under the observing conditions, because there aren't any atmospherics. We set the thing up and during the day had tuned it to some frequency about 2200 kilocycles, and then went away and let it run and then came back in about three days and looked to see what I'd caught. And lo and behold on the very first night the ionospheric hole had opened up and I got a beautiful trace without any atmospherics or interference or anything. And the succeeding two nights weren't as good because the electron density didn't drop back far. But then as winter came on, I got a long series of traces. What happens is that when the electron density really does such that the critical frequency is below the observing frequency, then there is sensibly no absorption. And since there is no absorption, there is no reflectivity in the ionosphere either. And so all the manmade stuff and atmospherics disappears out in space, it doesn't come back. It's got a void out there. And all the stuff that would be bouncing back and dribbling in...

Sullivan

It has to come directly to you, that's the only way it can get there?

Reber

Yes. And also it turned out that the cosmic static intensity at those frequencies is very high and so it drowns out anything else. So when the observing conditions are good to get suitable data, then they're so good that you aren't bothered by any terrestrial stuff. There's an in-between situation, that is, you can have the daytime situation where the ionosphere is absolutely opaque and then the D-region goes away and you still have critical frequencies which are much too high. And then the critical frequency drops gradually, particularly in the evening, it doesn't do it uniformly and slowly, apparently the ionosphere breaks up into blobs gradually and these things gradually dissipate. So there's a transition region from anywhere of a half an hour to several hours. And during this period the cosmic static leaks through and the pen is going up and down gradually, anywhere from a period of a minute or less to a period of several minutes or half an hour. Well, these are not useful data. But then once the hole really opens and becomes transparent, and the hole is big enough to encompass the entire antenna beam, it draws absolute straight beautiful traces. The signal-to-noise ratio is as good as any of those. There's nothing in there of the atmospherics.

Sullivan

Very interesting.

Reber

And so when the circumstances were good, they're very good.

Sullivan

When the signal comes, the noise goes away, very interesting.

Reber

Right.

Sullivan

But I haven't asked you, what was your motivation to go to these very low frequencies? What made you think of them?

Reber

I never did know much about this microwave stuff, and furthermore it seemed to be in good hands, that is, these fellows that were doing it seemed to know what they were doing. They've got resources far beyond anything I have. And there's no sense to me to try and compete with them. That's silly. They're all knocking themselves out competing with each other. Why not use your wits, if you've got any, and do something different. And here was a situation which seemed to be worth exploring. Iíd gotten all this pessimistic advice and maybe because they really didn't know anything. These people who were giving me this pessimistic advice were merely telling me they don't know. And there wasn't anybody that knew.

Sullivan

And they hadn't even bothered to try to know, either.

Reber

So how could I lose? Again, I was in a situation just like in Illinois, i.e., all I had to do was do something new and different and keep my eyes open and see what happens.

Sullivan

But I gather also that you had made the decision that your style was to work alone and that you weren't going to join them? By this time there were groups that you could have joined, undoubtedly.

Reber

Oh, I could have, sure.

Sullivan

But that you just liked to work by yourself.

Reber

Well, yes. Supposing I joined a group, I had two choices. Either I worked with them on what they were doing and participating in it to the extent that I could, or I engaged myself in a lot of arguments with them about trying to do something different. There was no point to that.

Sullivan

Yes, why not just do it yourself.

Reber

If I was going to do something different, I might as well do it on my own instead of engaging in a lot of arguments.

Sullivan

Right. The only possible advantage would be that you could get more funding if you were part of an institution.

Reber

Perhaps. I never was really short of money, that is, I could have spent more perhaps, but the mere spending of a lot of money doesn't necessarily mean that you'll get any results.

Sullivan

No, that's certainly true. Where does Ellis fit in here?

Reber

He's the one that invited me down there, really. He was a graduate student at the University of Tasmania and he supported himself. He was running the ionosphere station for the ionosphere prediction service with the Australian government. And I donít remember how I got in contact with him. It may have been through some paper he wrote in one of the journals. I guess that was it, because he had been writing papers on the ionosphere. In fact, I think some facet of that that he used for his thesis at the university. Anyhow, it was through him that I learned that they had moved their ionosonde from one place to another, and that the old station was open. So I went down there and he thought it was a good thing, so he joined up with me and we did these together. And he's been working at more or less ever since.

Sullivan

Ellis has?

Reber

Right.

Sullivan

And, well, you have too in one form or another.

Reber

Yeah.

Sullivan

What do you think in your opinion are the primary results that have come out of this low frequency research?

Reber

The intensity of the stuff continues to rise as low as the frequencies weíre able to measure. The absorption due to ionized hydrogen in the Milky Way begins to show at even 20 megacycles in Shainís results, not greatly, but it's there. Ellis' results at frequencies down to around 5 megacycles show it more pronounced. And at 2 megacycles it was even much more pronounced. This is not surprising. However, at 20 megacycles Shain's results show that there is still a long and complex bright continuum spread along the Milky Way and that at higher galactic latitude it gets fainter and fainter. But at lower frequencies this phenomenon is still present, but not so pronounced. When you get down to 2 megacycles, the situation becomes more extreme. It turns out that at 2 megacycles the background is not bright along the Milky Way, the background is brightest at high galactic latitudes. And you have strung along the Milky Way a series of deep absorption ridges. So at 1 megacycle the situation should become even more extreme, that is, the bright region should contract to some very bright small area around the galactic pole. And probably the absorption regions along the Milky Way will coalesce into a rather large band getting even darker and wider. And if integrated over the whole sky you'd probably find that the total integrated intensity would drop because of the large amount of absorption. So, limiting the discussion to the 2 megacycles which we have data on, it's very evident that there is some very bright region outside the Milky Way that's producing these celestial radio waves and that they are being absorbed by the ionized hydrogen within the Milky Way.

Sullivan

When you say outside, might that include a halo of the Milky Way or do you mean truly extragalactic?

Reber

Well, it's certainly large compared to the Milky Way, but not twice as large, maybe 20 times as large. It may be connected with the Milky Way, perhaps. Although the absorption is so complex and so great that you cannot identify this bright region as having a structure associated with the Milky Way.

Sullivan

But how is it that you get a handle on this size? Is this the paper here, the '68 paper?

Reber

The '68 paper, yeah. You see, this is the brightest region in here [Sullivan: 3 MHz observations of mid Ď1960s], but there's one little bright streak around here that's not up much. These are in dBs. I can't read that, I think that's 22, 21, 20. And this is Centaurus here, and this is the deepest, darkest patch right on zero degrees longitude and latitude. Then there are these two more or less equal dark patches on each side. I think this is the thing associated with the Gum Nebula, or is it that one? I can't remember which one. There's another little patch up in here. But in any case, if there's any structure to this bright region, it's very large compared to the Milky Way.

Sullivan

Because the bright regions extend to all latitudes?

Reber

Seemingly so.

Sullivan

Is that the reason then?

Reber

That is, if the bright structure were...

Sullivan

If it were just local, then you wouldn't see the absorption here, then so it has to be somewhat larger than the Milky Way.

Reber

But itís got to be a lot larger than the Milky Way, that is, for instance, if this is the visible Milky Way and we're out here somewhere...

[Break]

Sullivan

Right, you were saying about Jansky's antenna reconstruction.

Reber

Yes. I was there at Green Bank, rehabilitating my antenna in 1960. And this was to be on the left-hand side of the front entrance to the NRAO Observatory. And so I thought it would be nice if a reproduction of Jansky's antenna was erected on the right-hand side of the front entrance. It would be suitable and appropriate. And so nobody there seemed to be interested, but I wrote to Southworth who was retired from Bell Labs, and suggested the project to him, and that if he thought it was a suitable type of project he would know the proper people at Bell Labs to take the matter up with, which he did. And he got a positive response, saying that he had contacted the Laboratory and that they had decided that this would be a fine thing and furthermore they had investigated the matter and they were able to locate all the drawings from which the original antenna was made and furthermore by good fortune the man was still on their staff who had built Jansky's original antenna.

But he was going to retire pretty soon. And that they had made a pretty thorough search and the only thing they could find left from Jansky's original antenna was the speed reducer. And that they were willing to undertake the reconstruction of this according to the original drawings, just the way Jansky had it. But they were handicapped by the fact that they didn't have any more hardware except the speed reducer and that it was imperative to find some wheels and axles from Model-T Ford cars and that there weren't any available at this late date in automotive junkyards. And did I have any suggestions? Yes, I did have a suggestion. That I was out there in the boondocks in West Virginia, and that I would put an ad in the local Marlinton paper, which I did a number of times, to find out if there was anybody in the farming community around there that had any old Model-T Ford cars laying around. And I was able to locate a suitable number of Ford Model-T front axles and wheels, which required a minimum amount of work to repair, which I did get. And we also by good fortune found that we could get the tires and tubes. I think these were 21 inch wheels with 4-40 tires. These tires and wheels were being manufactured today and sold through Sears and Roebuck, because they were a popular item with these antique car addicts. So I collected the wheels and the axles, and they bought the tires and tubes and all the rest of the gear and manufactured the whole thing. And it was brought down there and put together after I left. So I helped organize the reproduction.

Sullivan

I see, you chipped into that but it was actually the carpenter that worked on it, that supervised the reconstruction?

Reber

Yes. At least from what I understand. The same carpenter that built the thing. And he wanted to make changes in it to make it better and they wouldn't let him. They wanted it the way was originally.

Sullivan

As an historian, Iím glad of that. Well, thank you very much.

Reber

All right. Iím getting sort of worn out.

Sullivan

That ends the interview with Grote Reber on 25 October 1975.

Part 1 | Part 2 | Part 3 | Part 4



Modified on Tuesday, 23-Dec-2014 14:30:20 EST by Ellen Bouton, Archivist (Questions or feedback)