leading companies has made some experiments which indicate the possibility of that, although it is not here yet by a number of years. In England they have tried it. They have a system in England but we do not know yet the effectiveness of that, whether it is worth while or not.

Senator BARKLEY. This intermittent transmission that you spoke about a while ago, about a wave skipping, appearing at one place and then being lost and reappearing somewhere else, like a lost river. Does that apply simply to retransmission of communication by wireless, or does it also apply to the average broadcasting of programs by radio stations?

Lieutenant Commander CRAVEN. This skipping starts at about 6,000 kilocycles, or we will say 4,000 kilocycles. It is on the higher frequencies that you notice it. It does not take place in the ordinary broadcast bands. It is due to the fact that these high frequencies, according to a certain mathematical formula which I do not know, are refracted and there by the nature of this layer they are carried through without refraction back to earth. The area that they are carried through is of course that which is lost to the surface of the earth.

Senator KEAN. Might it not be this way: That in going up to this Heaviside layer, if they went up at a certain angle, then they are reflected back at that angle, depending upon the height of this layer, at what angle they strike that layer, and therefore the reflection would be different.

Lieutenant Commander CRAVEN. There have been some experiments in trying to float these things at different angles as as to get rid of all this skip distance and fading effect. But somehow it is too high to climb, and there is something that happens up there that man can not control. But there have been attempts made, and there are certain theories that it can be done. However, I have not seen anything practical as yet.

Senator HOWELL. Have experiments been sufficiently successful to demonstrate the theory of the Heaviside layer?

Lieutenant Commander CRAVEN. I think you will find that scientists disagree on this thing, as to what it is; although there is general agreement that ionization is up there, but just exactly what happens I do not believe there is full agreement. That is well above my head, and I do not know much about it; I do not believe that anyone else knows much about it either.

Senator KEAN. Nobody has been up there to see anyhow.
Lieutenant Commander CRAVEN. No, sir.

Senator DILL. Have you something else to present?

Lieutenant Commander CRAVEN. There is a total of 620 channels in this high-frequency spectrum above 6,000 kilocycles if you use two-tenths of 1 per cent separation, and there are 371 fixed service channels, 92 marine channels, 19 aviation channels, 33 amateur channels, 34 broadcasting channels, 25 Army channels, 40 Navy channels, and 6 other Governmental channels.

Senator DILL. Do you know why the amateurs are restricted here and not allowed to go down into the extremely high frequencies? Lieutenant Commander CRAVEN. The amateurs are stopped at 23,000 kilocycles, but they are allowed above.

Senator DILL. A large portion of this is in fixed services?

Lieutenant Commander CRAVEN. Yes, sir.

Senator DILL. What is meant by that?

Lieutenant Commander CRAVEN. Point to point commercial services. Now, in this particular part of the spectrum there are approximately 371 available to the entire world for fixed services, and these stations each require at least three waves so as to complete long distance communication, or across the ocean, this is due to skip distances and the day and night effect.

Senator DILL. What separation do you have in the channels here? Lieutenant Commander CRAVEN. There you have two-tenths of 1 per cent separation.

Senator DILL. That is for how many kilocycles?

Lieutenant Commander CRAVEN. Two-tenths of 1 per cent of the kilocycles, say at 20,000 kilocycles that gives a separation of 4 kilocycles, and at 7,000 kilocycles it is a separation of 10 kilocycles. Senator DILL. How many wave lengths, estimated of course, are there between 23,000 and 30,000 kilocycles?

Lieutenant Commander CRAVEN. I have not that figure with me but I can bring it. There are not so very many more.

Senator DILL. All right. I thought you might have that figure here.

Lieutenant Commander CRAVEN. On this one phase here the nations of the world must divide these high frequencies amongst the various stations and you will find at the present time that there are very few stations existing which are able to keep two-tenths of 1 per cent separation, although it is possible to have one-tenth of 1 per cent separation.

Senator HOWELL. Is it not theoretically possible to do even better than that?

Lieutenant Commander CRAVEN. Yes; theoretically speaking, but for practical purposes the nations of the world have not reached a standard to give you even two-tenths of 1 per cent at the present time. Although it is practically possible right now, there are not many people who are doing it.

Senator HOWELL. It can be done by using a crystal?

Lieutenant Commander CRAVEN. Yes, sir; by temperature regu lated crystals. The Government, and the Federal Radio Commission as a part of the Government, and various organizations are making a study of just what to do in this situation. The United States must have a certain number of channels, and so must all other nations, and we are now facing that problem. But the number which the United States will have, regardless of whether at one-tenth of 1 per cent or two-tenths of 1 per cent, will be very limited.

Senator HOWELL. You say we can now go up to about 40,000 kilocycles?

Lieutenant Commander CRAVEN. Around that number, but we do not know much about it.

Senator HOWELL. And we may be able to go very much beyond that.

Lieutenant Commander CRAVEN. Yes. We do not know what is going to happen in radio.

Senator HOWELL. You were speaking of a 20-kilowatt station in connection with the use of the shorter waves; what is the cost of such a station?

Lieutenant Commander CRAVEN. I should think a station to give proper telephone relay broadcasting service would cost-a good one, I mean-in the neighborhood of about a million dollars.

Senator HOWELL. What are the chief factors that enter into that cost?

Lieutenant Commander CRAVEN. It is the large development work that has to take place, research; and in the next place the apparatus itself is very complicated-has many tubes in it-and it requires a good deal of floor space and a rather large building, and a particular kind of antenna system, and a very high degree of precision of instruments to make them effective at the two-tenths of 1 per cent we have here. It requires the highest engineering skill in order to make it practically possible.

Senator PITTMAN. Is there any such plant in existence, I mean such as you mention now?

Lieutenant Commander CRAVEN. I believe there is one being constructed, or one or two companies are experimenting along this line. But I do not believe we have yet what I would call effective service.

Senator PITTMAN. We could find out the cost from those people? Lieutenant Commander CRAVEN. Yes, sir.

Senator PITTMAN. We would know then the items of cost.

Lieutenant Commander CRAVEN. Yes; they could give you some idea of it.

Senator HOWELL. That would be very interesting, to be able to separate these items of cost.

Senator PITTMAN. I should like to find out myself.

The CHAIRMAN. Have you read this bill, S. 6?

Lieutenant Commander CRAVEN. Yes, sir; I read the bill proposing a communications commission.

The CHAIRMAN. Have you come across anything that you would like to criticize in it from an engineering standpoint?

Lieutenant Commander CRAVEN. No, sir; I have no criticism to make of it at all. But I think Captain Hooper has certain things he wants to present.

The CHAIRMAN. Well, have you finished your statement now? Lieutenant Commander CRAVEN. Yes, sir.

The CHAIRMAN. Any more questions by members of the committee? [A pause, without response.] Some of the members of the committee would like the hearing to go over until Wednesday to hear Captain Hooper, and if it is agreeable the committee will now adjourn until 10.30 o'clock Wednesday morning. Captain Hooper will then be present to make his statement.

(Thereupon, at 11.45 a. m., the committee adjourned until Wednesday morning, May 22, 1929, at 10.30 o'clock.)

51014-29-PT 7—5

COMMISSION ON COMMUNICATIONS

WEDNESDAY, MAY 22, 1929

UNITED STATES SENATE,

COMMITTEE ON INTERSTATE COMMERCE,

Washington, D. C.

The committee met, pursuant to adjournment, on Monday, May 20, 1929, at 10.30 a. m., in room 412 Senate Office Building, Senator James Couzens presiding.

Present: Senators Couzens (chairman), Pine, Howell, Metcalf, Brookhart, Glenn, Kean, and Dill.

The CHAIRMAN. The committee will please come to order. Captain Hooper, you may proceed to tell us what you have in mind. You have been here at several of our hearings and know pretty well what we are asking about.

Captain HOOPER. I think so.

STATEMENT OF CAPT. S. C. HOOPER, DIRECTOR OF NAVAL COMMUNICATIONS, NAVY DEPARTMENT, WASHINGTON,

D. C.

Captain HOOPER. I will say, Mr. Chairman, that I have had an opportunity to hear the questions asked some of the witnesses, particularly those propounded to General Gibbs, and therefore Í have prepared a paper, and think I have covered the whole subject, so that if interruptions could be avoided I would be able to present the matter in perhaps a clearer form, and then questions could come later on.

The CHAIRMAN. We will try to hold the committee in check as much as possible during the presentation of your main statement. Captain HOOPER. The naval communication system is under the office of the Chief of Naval Operations, administered by the Director of Naval Communications. Operation, traffic, and policy come under this section. The Bureau of Engineering, Radio Division, handles research, material, and maintenance.

The naval communication policy is as follows:

(1) To maintain and operate a naval communication system based on the requirements of the fleet in war.

(2) To reduce by thorough indoctrination the number and length of communications.

(3) To provide and operate radiocompass stations as required. (4) To develop such radio communications as may aid maritime and aviation interests.

(5) To cooperate with the radio and cable organizations of the United States and other countries and to safeguard the communication interests of the United States, both public and private.