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 Any story with 'remote control' in its
title piques my interest, so of course this installment of "Mac's Radio Service
Shop" met the criterion. Unlike in this story where the remote turned out to
be wired, it it the wireless type - like those used to guide radio controlled
model airplanes, boats, cars, and helicopter - that really grab my attention.
Along with discussing the newfangled (in 1954) Regency television remote control
for changing channels, fine tuning the
 frequency, and adjusting volume, shop
owner Mac McGregor discusses how atmospheric conditions affect radio signal
strength. In discussing the advent of color TVs, the question arises re what
color the 'snow' (picture noise, for those who have never watched an OTA broadcast)
would be. An authoritative answer was received from RCA, but you'll need to
read the story to find out. For some reason the concept of colored snow make
me think of that old
 Frank Zappa song, "Don't Eat the
Yellow Snow."
As is often the case with these decades old stories, you learn a little about
the conditions of the era along with the main storyline. In this case Mac mentions
installing the Regency remote control for the benefit of a friend's child who
has contracted rheumatic fever and will be in bed for a few months. That was
before better treatment, including superior antibiotics, were available. We've
come a long way, baby, in all areas of science. Not everything about 'the good
old days' was very wonderful.
Note:
Regency RT-700 Remote Tuner photos are from the
RadiolaGuy.com website. I reproduced them here because they
are for sale and could disappear from the RadiolaGuy.com website someday.
Mac's Radio Service Shop: Remote Control and Colored Snow
By John T. Frye
 A sudden warm-up during the night had
left the entire city wrapped in a thick blanket of fog. As Barney entered the
service shop that February morning, he thought to himself that this would probably
be a "hot" television reception day in the ultra-fringe area. The moisture-saturated
air on the ground with drier air above it usually produced a condition in the
troposphere favorable for bending TV signals back to earth.
When he opened the door of the service department, he saw his hunch had been
right. A chassis on the trial-run bench was displaying a steady, crystal-clear
picture. As Barney watched, another channel was switched on and then another
and another until five different pictures were revealed. When the program carried
by each channel came into view, the fine tuning was adjusted and the volume
was cut down to zero and then brought back up. Yet the only other person in
the room was Mac, and he was sitting on a stool clear across the room from the
set.
"Hey!" Barney exclaimed, "what's going on here? How are you doing that?"
"Now calm down, Buster, or you'll flip your lid," Mac admonished. "It's being
done with this new Regency remote TV tuner," he explained as he tapped a small
mahogany cabinet resting in his lap. Watching closely, Barney saw the picture
and sound were being manipulated by two large dual-dials on the face of this
cabinet; and he also noticed the unit was connected to the set by a cable about
the size of a pencil.
"How does it work?" Barney asked.
"Inside the cabinet is a complete cascode tuner with its own power supply.
These concentric dials on the right select the channel and adjust the fine tuning
in the usual manner. The output of the tuner feeds through that small coaxial
line to the input of the set's i.f. system. Another connection is made to the
receiver's audio system so that this outside dial on the left can adjust the
volume. Finally, the remote control unit generates a d.c. voltage, either positive-
or negative-going, the amplitude of which is controlled by the inside dial on
the left; and this voltage is fed to the set for varying the contrast of the
picture. A 'local-distance' switch on the back of the unit permits placing proper
bias on the tuner for extremes of signal strength."
"Now let me get this straight," Barney interrupted. "If I understand you
correctly, that same little concentric cable is carrying an i.f. signal from
the remote control unit to the set, an audio signal from the set to the unit,
and a d.c. voltage from the unit back to the set. Why that little old chunk
of coax must be busier than a party line the night the banker's wife left town
with the traveling salesman! How do all those signals keep from getting into
each other's hair?"
"A good question," Mac said with a chuckle. "It is all done with an arrangement
of chokes, blocking condensers, and filters inside a small potted unit mounted
inside the set chassis. The coax line goes to this potted unit, and then leads
go from it to the various sections of the receiver controlled. Here," he said
as he tossed a yellow-covered instruction book across to the boy. "Take that
home with you tonight and see if you can figure how it is done by looking at
the diagram."
"Can you hook that outfit on to any receiver?" Barney wanted to know.
"Just about any. It comes in two models: one for sets with an i.f. around
21 megacycles and another for sets with an i.f. near 41 megacycles. A set with
an odd i.f. too far removed from these standard frequencies could not use the
remote tuner. Neither could the remote control be applied to an old set using
manual gain control without a.g.c. But outside of such rare cases, the device
will work on any set. It functions equally well with split i.f. and intercarrier
systems. When you want to use it for u.h.f. reception, you simply install u.h.f.
strips in the remote control tuner. If you want to employ a booster in conjunction
with the remote control tuner, there is an a.c. outlet on the rear of the cabinet
into which the booster can be plugged."
"How about using the unit in a weak-signal area? Can you get as good reception
with the remote unit as you do with the set's own tuner?"
"If you hook it on to a set employing a less-efficient type of tuner, you
will actually get better reception when the modern cascode circuit of the remote
unit is in use. In general, you should be able to use this remote control unit
in any area in which the set alone will receive a watchable picture."
"Whose set is this you are using?"
"The wife and I were visiting friends at Big City over the weekend:
They have a little boy with rheumatic fever who must spend the next few months
in bed. Television is the best thing they have found to keep him entertained;
but, like most kids, he likes to do a lot of channel hopping. That means his
mother has to dash in from the kitchen, laundry, or upstairs dozens of times
a day to adjust the set. I was telling them about this remote control gadget,
and they insisted I bring their set home and install the unit. We are going
to take it back to them tonight."
"That will certainly be a fine thing for him and his mother, and I can see
where it could be used to great advantage in a public place where the set must
be up high so everyone can see it but yet you want to control it from a convenient
location. Also, I can understand how elderly people will like not having to
jump up and down every time they want to change programs, touch up the tuning,
or adjust the volume; but I wonder if many other people - young and able-bodied
people, I mean-will buy them."
"I am sure they will," Mac said emphatically. "I remember that when automatic
gear shifts were first introduced a lot of people thought that they would only
be used by women and 'other' inept drivers. As soon as drivers in general found
out how convenient they were, though, everybody wanted them.
"Remote control of TV sets is not a brand-new idea, for we have had some
novel electrical-mechanical systems in the past that worked pretty well. This
unit here, however, is representative of several new all-electronic remote controls
that are being placed on the market by various manufacturers at this time; and
these new units have several things to recommend them. In the first place, they
can be installed easily and quickly and do not interfere with the normal operation
of the receiver. It is a well-known fact that you can do a better job of adjusting
a picture from the viewing position. That is proved by the wide use of that
earliest form of remote control: a wife in her easy chair instructing her husband
at the set exactly how to set the volume and contrast controls. Unless you are
a contortionist, it is practically impossible to set the controls on the set
without blocking the view of some of the watchers. Finally, a remote control
unit fits in beautifully with the radio-phonograph-TV custom installations that
are becoming so popular these days.
"I have been thinking these control units would be a good item for small
shops such as ours to stock and sell," Mac said musingly. "They are small and
take up very little room. Every owner of a set we repair is a potential customer.
We have the jump on an ordinary store because only a service technician is in
a position to install them.
"A technician friend of mine reports a kind of sneaky but effective way he
has of selling them. When he has to remove a tuner and send it in for repair,
he temporarily installs one of these units so the set can be used while the
tuner is away. He says not a single set owner so far has let him remove the
remote control when the repaired tuner is returned."
"Say, I think I know another use for that remote control unit," Barney exclaimed.
"Suppose I run the output of that coax line through a blocking condenser into
the antenna connections on my communications receiver tuned to twenty-one megacycles.
Then a short piece of twin-lead, run through a high-pass filter to the tuner's
antenna terminals ought to make dandy probe for detecting TVI-causing harmonics
leaking out of any transmitter. The receiver's S-meter would show instantly
any change in strength of those harmonics."
"It would probably work," Mac said with a grin; "but you remind me of a guy
who can't watch a steam shovel at work without thinking about how he could use
it to dig his garden potatoes."
Barney wandered across to the bench and picked up a large red-backed book
lying by Mac's elbow. "What's this?" he asked.
"Handle that with care," Mac warned. "I had a heck of a time borrowing that
copy. It contains the information RCA presented to the FCC when they were seeking
approval of their color television system."
"What kind of information?"
"Just about any sort you can think of, from detailed engineering description
of the apparatus used in transmitters and receivers to purely personal opinions
of the observers."
"I've read a lot about color television," Barney remarked, "but I have never
seen anything about how color receivers are going to compare with black and
white sets in fringe areas. How will color reception be affected by things like
adjacent channel interference and noise?"
Mac took the book from Barney and flipped the pages to a section near the
center. "Ah, here we are," he said. "Color and monochrome sets are about equally
susceptible to co-channel interference and to lower adjacent channel interference.
Color sets, though, are a little more disturbed by upper adjacent channel interference.
Color reception, too, is a little more susceptible than monochrome to random
noise. However when the noise is of the impulse type, such as is produced by
an electric razor, one type of reception is not bothered any more than the other.
And for good measure, I might add that observers decided multi-path reception
- 'ghosts' to you - interfered a trifle more with the enjoyment of color reception.
The important thing is, however, that in every comparison of the effect of interference
on color and black and white receivers, the difference was slight."
"That must be a pretty complete report," Barney conceded, "but let's give
it one more acid test. See if it can answer the same disturbing question everyone
pops at me when I try to talk about color television: What color is the snow?"
A slow grin spread across Mac's wrinkled face. "I know the answer," he said,
"but I must confess I did not find it in the book. I thought I knew what color
it would be, but I was not sure; so when everyone out here in the fringe area
kept asking the same question, I wrote to RCA and asked them. They came right
back with a telegram, which made me feel that I was getting serious consideration
of a rather silly question; but now we have an authoritative answer right from
the horse's mouth.
"As we might have suspected, snow on color television can be, and is, any
color through the whole spectrum. Since it is a manifestation of random noise,
it affects the color circuits as well as the others; and this results in the
snow's appearing as multi-hued sparkles of light."
Barney heaved a big sigh of relief.
"It may be a silly question, but I'm surely glad they answered it. You can't
imagine the awful thing it was doing to my ego to have to say, 'I don't know,'
every time someone asked about the color of the snow. Now I'll just snap, 'It's
technicolored, of course!' "
Mac's Radio Service Shop Episodes on RF Cafe
This series of instructive
technodrama™
stories was the brainchild of none other than John T. Frye, creator of the
Carl and Jerry series that ran in
Popular Electronics for many years. "Mac's Radio Service Shop" began life
in April 1948 in Radio News
magazine (which later became Radio & Television News, then
Electronics
World), and changed its name to simply "Mac's Service Shop" until the final
episode was published in a 1977
Popular Electronics magazine. "Mac" is electronics repair shop owner Mac
McGregor, and Barney Jameson his his eager, if not somewhat naive, technician assistant.
"Lessons" are taught in story format with dialogs between Mac and Barney.
Posted March 11, 2016
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