New-York tribune., 1922-11-19
Radio Progress
Shows Trend to
Short Aerials
Recent Tests All Indicate
Best Results i'm Tuning
Are Obtained With Low,
Short, but Clear Antenna
Points asn Aerials Given
Oldtirne Aerials We're Long
Because of Inefficient
Receivers and DefectOrs

| One OF the most interesting phases
of radio development is the evolution
of, the receiving aerial, which in itself
/ is indicative of the trend Of all prog
rass in the art. With the improve
ment in sensitivity of RECEIVERS the
aerial itself has become smaller and
more efficient.
In the early days of wireless work
aerials were made as Iong as existing
physical conditions would permit, par
| ticularly on ships At that time the
general theory seemed to be that the
longer the aerial the greater would
be the distance over which signals
could be received.
extent true ine those days when the
art Of tuning was little understood,
when laws governing wave-length were
nonresident and spark signals wan
dered in over every possible adjust
! ment on q wireless receiver.
Short, Clear Wire Best
The remarkable change that has
taken place in the understanding Of
| what constitutes an efficient aerial was
emphasized in recent paper read by
Frank Conrad before the Institute OF
Radio Engineers on recent experiments
which laid specific emphasis on the
need Of using low, clear, singlewire
antenna for reception. For use on
short-wave reception this wire should
not be more than one hundred feet
| in length in order to get the best pos
sible tuning and selectivity. OF course,
| it is necessary to use very efficient
receiving set under those conditions.
viz II
development, of the loop aerial, which,
Of course, can only be used efficiently,
so far as broadcast reception is con-
cerned, with three types of receiving
equipment, namely, radio : frequency
amplification, super-heterodyne and
uper-regeneration, although for wire
| less telegraph work results can be
obtained with it in certain cases with
a regenerative type of receiver.
The indications for the future are
that aeriais for reception purposes
will be entirely eliminated, and even
! loop aerials will only be used as an
adjunct to tuning because of their di-
rectional effect.
Twenty years ago an operator at sea
would have wept in anguish at the
| thought of being assigned to q trans
atlantic liner which had an aerial less
than $50 feet from end to end, while a
single wire aerial was undreamed OF.
Only One Receiver Used
OF course at that time there was
only one receiver in general" use, and
it was the coherer set. The magnetic
detector was just making its appear
ance, and the possibilities of crystals
were becoming apparent.
So far as the coherer was concerned
there was no such thing as tuning. 1t
is true that there was a coupled circuit
i in the antenna, which was known by
the elegant name of "jigger." 1t con
sisted of two coils each with a fixed
number of turns and fixed coupling
between them---in reality it was fixed
transformer. Everything picked up by
the aerial was supposed to pass
through it and actuate the coherer, and
there is no doubt that this supposition
was maintained in practice.
More efficient tuners came very
slowly, but as there was but little i'm
provement in the sensitivity of detec-
tors, the advantage was at first not
very great. In fact the inefficiency of
tran uniting equipment practically
nullified the advantages of the tuners,
| and operators suffered in patience by
trying to receive through interference
rather than cut down the strength of
signals by tuning.
The two things which made the
| radio-phone possible also brought
about more efficient receivers and
tuners-the Invention of the vacuum,
tube, and the production of undamped
or continuous waves in transmission.
Development Trend Outlined
OF course what have outlined here
is the trend of development. For ordi-
nary radio-phone reception those who
can erect good, clear aerial should
use it. The shape, length and heighth
of the aerial for the radio fan will al
ways be governed by his local condi-
tions, but in q general way the follow
Iang points can be kept in mind:
In the first place the aerial for re-
ception should only consist of single
wire. It should be we'll insulated
wherever it is supported. 1t should
have as few angles in it as possible
under existing conditions. 1t should
not be. longer than 15o feet in the
case of the l. tyne, nor exceed that
length in fiat-top for the I type.
The l. type is the most directionai
IN its effect, and wherever used should
have its lead-in end pointed toward
the direction Of the station it is de-
sired to listen to. The t type will give
BETTER reception from all directions
IMAM the former type, and should be
erected by the fan who is situated in
the center of a number of broadcasting
stations, and wishes to hear from as
nf hn,> ~ i.