After thoroughly examining the ship externally for as much as a whole day, they would proceed to functional tests. Pressures were applied to parts of the propulsive mechanism to discover leaks. Trial switching operations were run so that the electropneumatic gear might not escape the inquisition.
Finally, Wiegand and his gang would go over the pilot's compartment with a finetooth comb. He and his electrician checked inverters, gyros, computers, switchboards and instrumentation, using portable test panels. They would open relay covers to ascertain the contact pressures or to try the soldering on a cable terminal.
Wiegand recorded his findings in a red notebook of evil repute, where he also laid out the repair work to be done, with some assistance from his troubleshooters, by the crew of the ship just victimized. The latter would procure any required parts from one of the cargo ships.
His reports to Holt on the mechanical state of affairs kept the engineers and captains under constant pressure, for he never hesitated to lay the blame for any unsatisfactory condition exactly where he thought it belonged. It was not long before they were so intensive in their own inspections that "Trouble John" (as they called him) found trouble in finding trouble that he might enter in his horrid red book.
Holt discovered that Wiegand's tireless X-ray eyes slowly but surely brought him the assurance that he need no longer fear that human mental inertia would prove a Satanic factor in his computations. This it might easily have happened, lulled as were the men by the monotony of their seemingly endless voyage, and as susceptible as were the involved mechanisms to neglect. Holt had enough to worry about without that.
Chapter 16 — Interplanetary Radio
Holt found much of his diversion in listening to the tales of adventures on the five continents related by the three interplanetary hitchhikers, Billingsley, McRae and Ross.
One day, however, they professed boredom with the confined cabin of Polaris and Holt happily sent them off on a visit to Lussigny in Oberth. Here the old radio man lived in monastic seclusion, completely preoccupied with his High-Duty radio set. The adventurous three had no particular technical background, but they hoped that the sour Canadian might explain to them how he managed to maintain unbroken communication across so many million miles of sky. The Earth and Moon appeared no more distinctly that a bright dual star, but the newscasts and music which sprang from the loudspeakers were as clear and undistorted as though they came from a local station around the corner.
As Billingsley and company approached Oberth in a busy bee, they could see beyond one of the wide wings of her landing craft hanging obliquely in space, an odd structure some 1,000 feet away from her and wholly separate from the bulky cargo ship. It looked like a silver drum, with hemispherical heads, from which extended two four-legged frames on opposite sides. One frame had at its terminal a circular, parabolic, opaque reflector like those of war-time radars, while the other bore a gutter-like, elongated mirroring surface within which was a thick, black tube.
The odd device was one of the two High-duty radio sets borne by the cargo vessels, although only this one from Oberth had been put into operation. The bee slipped into the guides at the side of the drum and the men floated inside through the rapidly opened doors. After greeting Lussigny, who crouched in front of an enormous instrument panel, they managed to inveigle themselves into such open spaces as could be found amid the electrical apparatus that filled the compartment.
"Frank," said Billingsley, "it's jolly good of you to let three radio ignoramuses into your high-voltage jigsaw puzzle. If you're not too busy playing radio-footsie with Venus, or something equally abstruse, give us a bit of a lecture on how your interplanetary hookup works!"
Lussigny did not deign to respond to this sally beyond stating that they were in direct, two-way communication with a similar station in Lunetta's orbit.
"It's just like any two radio stations talking to one another," he remarked, "only the distances are greater. There are no innovations nor peculiarities about the sets themselves."
"You talk as though all these millions of kilometers were a secondary consideration," bellowed Billingsley.
"As a matter of fact, they're only one of many, equally important factors," answered Lussigny. "When we began to work out this set, all the radio people argued that we couldn't radio across interplanetary distances. So we just worked up some calculations and proved to the doubters that for forty years they've had the technological means for radioing reliably clear across the solar system."
"What!" shouted the three visitors, amazed.
"Certainly, right across the whole 12 billion kilometers of Pluto's orbital diameter.
Actually, we might transmit almost twice that far, if you want real accuracy, for the figures showed 23 billion."
"Must call for almost infinite power to transmit that far…"
"Not at all. 60 kilowatts is all we need and we get them quite easily at the frequency we've selected for this example. For this limiting case, in which we sought to demonstrate to the experts the performance of today's radio equipment, we left out such fancy trimmings as music or voice transmission. At those extreme ranges, we only claim to do business with the simplest and crudest type of communication, namely dot and dash.
"Music and voice transmissions are rather tricky, for we have to have what radio people know as "bandwidth." Bandwidth means that the receiver, when tuned to a certain wavelength, must also receive a band of longer and shorter waves at the same time, if it is to pick up the modulations with which speech or music affects the carrier wave. When you want to transmit all the finer points of music from an instrument like a violin or cello, the tonal quality of which is determined by its overtones, the truer the transmission is to be, the greater the bandwidth required.
"But there is an unpleasant obverse to the case of great bandwidth. When you turn up the volume on your domestic receiver, you've all noticed that there's a background noise which increases and largely blurs the reception of distant stations, and this noise is caused by unavoidable heat effects in the tubes of the receiver. In radio technology, there's an inevitable relationship between the noise level and the bandwidth, in that the noise level increases in the same ratio as the latter.
"Reasonably good reception requires that the useful "signal power" of the reception be a multiple of the noise power. But the noise level is entirely a vice of the receiving equipment, and has no connection with the distance from which the signal comes. On the other hand, the power of the signal itself decreases as the square of the distance of the receiver from the transmitter, so that, if the distance is doubled, the signal strength is diminished to one fourth, and so on. So you see that if we wish to radio over great distances, we must reduce the bandwidth so that the noise level is correspondingly reduced. This is the most important viewpoint in setting up interplanetary radio sets. In the arithmetical example to which I referred concerning radio transmission right across the solar system, we assumed that the bandwidth was reduced to 120 cycles per second. In our computation, we picked a wavelength of 50 centimeters, corresponding to a frequency of 600 megacycles, or 600 million oscillations per second. This means practically that the receiver accurately tuned to a 120 cycle bandwidth can only receive such wavelengths as do not vary by more than 60 oscillations from the 600 million.