Ham radio has been a fun hobby to add to my belt. As of recent, building my first quarter-wavelength antenna added confidence in answering this question in the Technician Exam.
Here are some photos of my radials for the 1/4 antenna.
T9A08 — Quarter-Wavelength Vertical for 146 MHz
What is the approximate length, in inches, of a quarter-wavelength vertical antenna for 146 MHz?
Answer: 19 inches
Frequencies and the 70cm Band
As a new ham I started to notice a few things that helped me understand the technology — more specifically, frequencies. For example the 70cm band: repeaters using that band usually have a frequency offset of plus or minus 5 MHz. Just like the question in the Technician exam.
What is a common repeater frequency offset in the 70 cm band?
Answer: Plus or minus 5 MHz
A Real-World Snag — Papa 07
Imagine my surprise when I was adding a repeater into my radio and ran into a snag.
The website was missing some details. Notice the red marks I've placed — Papa 07, that frequency 447.840− listed there is just the downlink. Where's the uplink frequency?
Here's another picture from RepeaterBook showing Papa 07 in another format — the downlink and uplink are both there.
Less Is More — Reading the Shorthand
Why is Papa 07 only shown as 447.840− in the previous image? Because less is more.
447.840− is simply saying 447.840 − 5.000, like the exam question above, which puts you at 442.840 MHz as the uplink. That's it. You only need to worry about the PL tones, which are shown on the image.
You only start to realize this when you are constantly exposed to the study material, the radios, and basically messing around in ham tech. There are many examples in the materials that connect the dots — just like the ones above.
Jump in!