New-York tribune., 1904-09-04
HERTZ WAVE METER.
important Aid to Practical Wireless
TeIegraphy.

When the system Of communication with
den and Slaby closely identified comes into
general use It will be necessary to make adjust
ments of apparatus which not now required.
TO prevent the picking up of messages by the
wrong receiver. when two or three sets Of in
struments are working in the same field, use
will be made Of the process known tuning.
TO the waves sent out by a transmtter it will
be found desirable to give a certain definite fire.
quency which is different from that Of the
waves from another transmitter. The receiv-
ers which are to cooperate Herewith will be
regulated that each will be more sensitive 10
one frequency than to any other Thus they
will exercise the power of selection. and inter
ference will be averted. The operations of tun-
ing can be easily performed. If proper attach
ment is made to the sending and receiving In
struments
How wide a difference Of wave frequency is
possible has not yet been fully determined IN
struments have been worked at 100000 sec
ond and $4,000 second with excellent results
But how much higher than the former rate and
how much lower than the latter It will prove
feasible TO go has not been ascertained. Again.
there seems to be uncertainty about the length
OF the interval between frequencies which must
be observed to avoid interference. However.
fifty rates can be found sufficiently distinct
from each other to insure independent action
By that statement he means that fifty receivers
at a single station might be employed to take
messages at the same moment, and would work
satisfactorily, II each had been adjusted to dif-
ferent wave frequencies. and II the sending sta
tions had made corresponding use or the tuh-
ing system. It IS not probable that so great q
number of frequencies would ever be needed at
any one point IN the world. but great variety
will be required to permit a full development OF
the possibilities OF the invention
Ordinarily OF course. there would De perfect
understanding in advance between the operators
who are sending and receiving IN regard TO the
frequency to be used For instance the CunaFd
steamships each have two receivers one tuned
TO respond 10 the messages of passing vessels
and the short range coast stations which re-
port steamship arrivals, and the other tuned 10
pick UP news messages from Table Head Nova
Scotia and Poldhu. Cornwall. The rates here
enployed were prescribed beforehand by Mar
conf so that there Is no confusion or connict.
In future commercial and military service there
viii undoubtedly be a similar Encouragement
Generally speaking. too, when receiver has
been tuned 10 q particular frequency It Will be
deemed expedient to leave 1t unchanged.
Nevertheless, it will often happen that an op-
orator will wish to alter the frequency OF his in
strument or. having q spare receiver, will want
to use the latter for exceptional purposes. For
legitimate or illegltimate reasons he may wish
to supplement his regular work with search
for messages which are being sent with a diff
ferent pitch, wave frequency. from that to
which he Is accustomed. he may not know the
rate at which this other message is being sent.
Two hostile fleets might be in the same vicinity.
each equipped with wireless instruments which
In all
ders and reports On the flagship OF feet
the receiver would be mainly needed to take re-
sponses from other vessels under the same COM
mand. However. IL the operator could steal the
messages exchanged by the eneuy's vessels he
might secure information OF the highest value.
The other fleet might be altogether out Of sight,
but its proximity being suspected, It would be
tions. If the wave frequency employed oy ths
enemy was known. OF course. It would be SIM
pie matter to adjust a spare receiver thereto;
but If II was not known. how could II be ascer-
tanned In time TO be OF any use?
A device has been invented which. IL Is as
serted viii perform that function almost in
Simultaneously At one time it took from half
a day to a day to discover unknown wave
frequency. long series of tedious tests was
necessary II the expert had clew. Now
much moro rapid work can be done with
Hertz wave meter" Three or four electricians
said to have devised the apparatus inde-
pendently. One of them IS Mr.. Tesla, another IS
Dr. Saby, the author OF one of the German
wireless systems. and a third IS Frenchman
named Oudln. Although some of the technical
features OF the apparatus. which described
by a Berlin correspondent OF The Scientific
American" are not intellgible to the average
reader the principle of the instrument is readily
understood. The velocity with which Hertz
waves travel IS always the same. 1t is identical
with the speed Of light. Hence II only fifty
thousand are emitted in a second. they will be
longer than those sent out at the rate OF
million q second. Obviously, therefore. the
former waves will be longer than the others.
In fact since the speed is uniform. the number
of waves 10 a second can be determined II their
length can be learned. What the Hertz wave
meter does IS to measure this.
DIR. Slaby Is the inventor OF the instrument
tried only IN his laboratory at Charlottenburg
In the hands of two different assistants II gives
quick results. and has apparently demonstrated
its efficiency. How many other such meters
have been perfected and used already In other
parts OF the world. 70 learn what wave fire.
quencies were in service in the neighborhood OF
the investigator, must for time remain a mat
ter of conjecture only. When man Is playing
the spy he usually keeps mum.
The mere existence of such an instrument
opens UP startling possibilities. If Il be true
that wave frequencies can be quickly detected
in the manner here suggested. secrecy of COM
munication would apparently be endangered
That fact might not be a serious drawback to
the adoption of wireless telegraphy, but it would
dictate a resort 10 a number of precautions like
the use of a code to render the stealing or
sages harmless.
WHERE THE LINE WAS DRAWN.