Featured Product Archive
The inventions and products featured on these pages were chosen either for their
uniqueness in the RF engineering realm, or are simply awesome (or ridiculous) enough
to warrant an appearance.
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Realistic (Radio Shack) TRC-409 Portable Citizens Band Radio
It has been a long time since I've had a citizens band (CB) radio in my car.
Back in the 1970s when the CB craze was at its peak, with songs like C.W. McCall's
Casey Kasem's American
Top 40 (AT40) charts, my high school compadres were all installing
23-channel CBs (standard at the time) in their cars and pickups. I joined in with a Radio Shack unit (don't
recall the model number). In those days the FCC required operators to
register and mail a check for a few bucks - same with radio control (R/C)
systems for model airplanes also operating in the same 26-27 MHz radio band
- in return for a "Citizens Radio Station License" document to carry in your
CB channels were spaced at 10 kHz, but the R/C frequencies were
in−between some CB channels spaced at 20 kHz. For instance, my
3-channel OS Digitron R/C system was at 27.195 MHz, which resided
between CB channels 19 (27.185 MHz) and 20 (27.205 MHz). Some electronically
savvy CBers would illegally modify their radios to include operation on
those in−between frequencies (e.g. Ch 19A at 27.195 MHz), thereby creating a
scenario where merely keying up the transmitter could "shoot down" a model
airplane if close enough.
Here are some photos of my late 1980s vintage Archer (Radio Shack) model
TRC−409 portable CB (40 channels). It is in like-new condition since it
rarely got used. I also scanned and posted the user's manual below for
the benefit of anyone looking for one. I see the TRC-409's for sale on eBay
sometimes without the manual. People like to bash Radio Shack, but I got a
lot of good stuff there over the years when ordering online was not an
You can see there are no integrated circuits in the RF and analog sections,
with just a single IC for driving the LED display. I could not find a schematic
for the TRC−409, but it looks from the back side of the PCB that there is no
other DIP footprint that would indicate another IC. The large potted section
appears to be the PLL circuit, where the bottom layer of the PCB being a ground
At some point I'll post my Realistic TRC-474 40-channel CB radio stuff.
Realistic TRC-409 Portable CB Radio User's Manual
*If you've never listened intently enough to pick up all the words, you can
read the lyrics
here... "Well, we shot the line and we went for broke With a thousand screaming
trucks, and eleven long-haired friends of Jesus in a chartreuse microbus."
Posted February 4, 2021