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Not all old adages are still true.
Waaaay back in the last century, even as recently as the late 1990's and early
2000's, that is to say before the advent of 2.4 GHz, spread spectrum radio
systems, brushless motors, and LiPo batteries for model use, you could make the
argument proclaimed here in this American Aircraft Modeler magazine
editorial that "R/C models today are just too expensive." Yes, it might apply to
giant scale, competition models, and jets, but when adjusted for inflation, the
cost of an entry level radio controlled airplane (or helicopter for that matter)
is dirt cheap. You can but a ready-to-fly trainer with airplane, motor, battery,
charger, and radio system for under $100 ($11.82 in 1968 money per the
BLS Inflation Calculator). With so much stuff being built by
Uyghur slave
labor and other virtual slave labor in China where hopeless people
commit suicide by
jumping off production plant buildings, combined with a trade policy that
includes undercutting American product prices, modeling has never been easier to
get into.
Editorial
(R/C models today are just too expensive - in both monetary value and in the
time invested - to risk their being wrecked by some idiot bootlegger.)
It has been something of a surprise to us to find that many flyers who operate
(most of them legally!) on the amateur 50-54 MHz band don't know that there is a
group of recommended spot frequencies set up by the AMA for such use - others may
have heard about these spots but don't know what they are. Though they have been
mentioned in this and other magazines before these are the spots and the ribbon
colors to go with them: 53.10 MHz (black-brown); 53.20 MHz (black-red); 53.30 MHz
(black-orange); 53.40 MHz (black-yellow); 53.50 MHz (black-green); 51.20 MHz (black-light
blue); 52.04 MHz (black-violet).
The first five spots are for exclusive superheterodyne use, the last two for
exclusive superregen use. This is the only R/C band where there is enough room to
operate both hets and regens together (latter not allowed on 72 MHz). It should
be evident that the significant feature of all the 50 mc ribbons is black. This
is the "band designator," just as a white ribbon is utilized with certain ribbon
colors to show specific spot frequencies on the 72-76 MHz band. You'll note the
color sequence is the same as on 27 and 72; it starts with brown and follows the
resistor color code thereafter. It was felt best to deviate a bit from the general
scheme of employing brown for the lowest spot frequency, as has been done on both
27 and 72, to emphasize the fact that on 50, the two lowest spots are for regens
only.
Some may ask why were these rather odd spots chosen. And why we can't use all
the rest of that space in the 50 MHz band for R/C too. The AMA Frequency Committee
spent much time weighing all the factors involved. These include harmonics from
the 27-mc spots, image frequency spots of receivers, and other subtle matters we
won't go into now. Just on the matter of images, most R/Cers don't know that their
supposedly extremely-sharp-tuning superhet receiver can operate within a reasonable
number of megahertz from adjacent spot frequencies - but that it is relatively wide
open to a frequency two times the intermediate frequency of the receiver (generally
about 900 KHz, and generally lower than the nominal receiver frequency) away. For
example, a receiver on 53.10 would be vulnerable to a strong signal on about 52.20
MHz. But the AMA-suggested spots have taken this into account, and all the R/C spots
are safe from interference of other nearby R/C transmitters.
As for using more space on the 50 MHz band - makers of 50 MHz gear now have to
stock crystals for at least the five superhet spots - in addition to what they must
carry for 27 and 72 MHz. Let's not ask them to stock a larger number! As for the
flyers themselves, we have five spots on 27 MHz (six, if you count 27.255, which
is not in very wide use for R/C), seven on 50 MHz, and five more on 72 - how many
planes can you put in the air at one time, at anyone field?
So we do have recommended 50 MHz spots. Do you have to use them? No you don't.
They are not required by the FCC, as are the spots on 27 and 72. But - you stand
a darn good chance of shooting down a fellow modeler, if you use other spots. Similarly
you stand just as good a chance of getting shot down yourself ... dig? The old-time
users of 50 MHz have become used to checking other users of this band for frequency
before turning on a transmitter. Many new-comers to 50 MHz just aren't that careful.
But with ribbons and the recommended spots in use, things will be much safer all
around.
While the 50 MHz spots aren't required by the FCC, they probably will be mandatory
at AMA-sanctioned meets, since operation of two or more flight lines simultaneously
makes precise frequency control necessary. Oddball frequencies won't do any more
- as this writer learned to his sorrow last summer! Since they'll be mandatory at
meets, we feel every R/C club should stress their use at club fields - where three
or four 50-MHz transmitters can be in use at one time.
One last point on the use of 50 MHz RIC frequencies in general. Note that an
FCC license is needed for such use-despite what you might hear from scofflaws (some
of whom won't bother to obtain an FCC license for any frequencies). Perhaps we'll
always have such bootleggers with us, but the FCC is cracking down harder and harder
on unlicensed operations on the Citizen's Band spots. And they can (and do) monitor
the ham bands as well. These stupid non-licensed operators - regardless of band
- simply serve to give all R/Cers a bad name, and could lead to loss of R/C frequencies
- to say nothing of their chances of a heavy fine or even a sojourn in jail. R/C
models today are just too expensive - in both monetary value and in the time the
builder invests in them - to risk their being wrecked by some idiot bootlegger,
who is likely on an oddball frequency!
Posted January 21, 2023
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