Wax nostalgic about and learn from the history of early electronics. See articles
published 1929 - 1948. All copyrights hereby acknowledged.
Hobbyists in the technical realm have in many ways contributed mightily
to the advancement of professional scientific knowledge and practice.
This is partly because many hobbyists are also career technologists,
but the majority are tinkerers, experimenters and otherwise participants
who come from all walks of life geographically, economically, professionally,
and socially. Just as with university and corporate laboratories,
some of the discoveries are the result of structured, preconceived
plans of action and designs of experiments with certain goals in
mind; many, however, are due to serendipitous events that are recognized
by their participants as being significant. Such is the case of
'TV DX' as related in this story. TV DX is the use of unique opportunities
in the atmosphere's ionization state to facilitate signal transmission
and reception at distance much greater than normally experienced.
Data collected by amateurs were, during the era of over-the-air
VHF and VHF television broadcasting, included in studies and theories
created by professional scientists and engineers to help better
understand and predict communications phenomena - both for exploitation
and for interference avoidance. The same is true today for other
venues like solar activity observers and pollution status reporters.
<--- Very interesting
story of unintentional radio DXing (starts ~ 1/2-way in)
and TV DXing (starts ~ 3/4 way in)..
the sunspot count on its waning side, overall effects of the now-famous
11-year cycle are being studied, with particular interest in vhf
In past years, reports which told of extraordinary long-range
reception were often regarded as cases of mistaken identity or perhaps
even a deliberate hoax. However, during the past 12 months, we have
developed a sixth sense which makes us look twice at such dx loggings.
After all, dxing the TV frequencies has been largely a case of exploring
the unknown and uncovering new items of information, bit by bit,
until we have an end result which indicates a new form of dxing
and another mode by which the alert TV dx fan can drag in those
faraway television stations.
March, 1958, was a slow month dx-wise for the greatest majority
of TV dx fans across the country. One very unusual occurrence was
a full-scale Sporadic E skip break, on March 15, which brought a
6-hour Es session to just about every section of the country west
of the Mississippi. Signals were strong with much co-channel interference
as high as channel 6. At the height of the opening, Ron Pugh of
Ft. Bragg, Calif., switched to channel 7 to find KLZ-TV, Denver,
Colo., showing with fast-fading audio and video. Reception was short
lived, however, running from 1820-1832 PST. The distance involved
is nearly 950 miles and the event represents one more instance of
high-band signal propagation over a Sporadic-E skip distance during
a widespread Es opening on the lower channels.
Another totally unexplained series of loggings is reported by
Ray F. Boyd, Zirconia, N. C., when on the night of March 14 he logged
seven California stations, including KCOP, channel 13, and KABC-TV,
channel 7, both Los Angeles. These reports, if accurate, involve
distances of nearly 2,500 miles on the high-band channels and come
very close to providing a set of distances that may not be approached
in the near future by TV dx enthusiasts.
FM and TV DX
Although you may not be completely aware of it, your television
dx reports serve a very valuable scientific purpose. After Radio-Electronics
finishes with the compilation, the reports are filed away for later
study by prominent groups of scientists. Such reports are of definite
scientific interest, as they illustrate freaks of nature and are
therefore subject to further explanation by properly qualified authorities.
However, these reports do not serve as an end, but merely as
a means toward an end. To understand completely the actions of vhf-uhf
signals in our atmosphere, stratosphere and ionosphere, we should
study not only the piece-meal samples of the spectrum (such as TV
provides). We must also make use of every faculty available to us,
including every type of unusual dx report which falls within the
This is where the Frequency Modulation (FM) band enters the picture.
FM helps fill a frequency range which lays between channels 6 and
7. Many other services such as taxi, police, airport and amateur
have room within this range, but only FM is commercially available
to the public. We have good reason to believe that the FM band's
dx actions will resemble to some extent those of television channel
6, but we cannot be sure. To help fill in our knowledge holes, we
are instituting an FM dx section, to be run at the beginning as
a sidecar of the Television Dx Column.
Some major differences between the two, however, will be immediately
self-evident. As FM dxing is not an organized hobby on a national
scale, we will find it necessary to set our own limits as to what
constitutes dx via FM and expand these guide posts as the hobby
develops. We also wish to carry an occasional paragraph on antennas,
tuner - and the like, purely from a sensitivity standpoint. It is
hoped that both the hobby and column will grow together. To get
the ball rolling, FM dx reports, lists of stations received, and
so on are needed to begin our book of standards. Send along your
results for listing.
The first and last weeks of July normally produce a good deal
of Sporadic-E reception, with many sessions running as high as the
lower FM channels. The best hours of the day continue to be 0700-1000,
1200-1400 and 1700-2000, all local standard time. By August, E sessions
will begin to dwindle toward the normal fall low point, with any
sessions after Aug. 15 running from 1600-2100 local standard time.
E skip may hold up weakly as late as early September in southern
latitudes along the Gulf Coast. One period expected to be especially
hot for Es is July 25-28.
The summer months, with their slow-moving frontal systems and
evening temperature inversions, is always ideal for extending the
normal ground-wave range. Just after sunup and from sundown until
midnight are periods usually especially productive over coastal,
Gulf Coast and Great Lakes paths. Early evening and on until early
morning hours will bring the best high-band ground-wave reception
across the Great Plain States. Again, keep tabs on your fringe-area
stations and watch for signs of general improvement in fringe-area
The one major meteor shower of the year is due to become apparent
in the early morning hours of Aug. 5-15. The Perseids shower is
an annual occurrence, bringing joy to the heart of meteor-burst
enthusiasts all over the country. Bursts on the high-band TV channels
(7-13) are especially profitable during this period, peaking from
the 12th-14th. Careful planning and the checking of operating schedules
of station 800-1,400 miles distant on channels 1-13 may result in
some excellent loggings on your part, which you are not likely to
intercept by any other form of wave propagation.
Reporters to the TV Dx Column are urged to drop a postcard to
the TV Dx Column, Radio-Electronics Magazine, 154 W. 14 St., New
York 11, N.Y. In return we mail you a set of prepared dxing forms.
These are engineered to extract all necessary information from you
the dxer and make dx reporting as painless as possible. Oh yes,
they also function on the FM band ... send for yours today ... they're
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas
and reference material while performing my work as an RF system and circuit design engineer.
The Internet was still largely an unknown entity at the time and not much was available
in the form of WYSIWYG
All trademarks, copyrights, patents, and other rights of ownership to images and text
used on the RF Cafe website are hereby acknowledged.