This week in the Amateur Extra spectrum, we’ll look at a question from the “band plan” area of the exam [E2C06]
During a VHF/UHF contest, in which band segment would you expect to find the highest level of activity?
A. At the top of each band, usually in a segment reserved for contests
B. In the middle of each band, usually on the national calling frequency
C. In the weak signal segment of the band, with most of the activity near the calling frequency
D. In the middle of the band, usually 25 kHz above the national calling frequency
We’ll look at the incorrect answers first, and explain why they’re wrong. This is often the best approach to the exam questions, as the incorrect answers will be blatantly incorrect.
It’s not A. At the top of each band, usually in a segment reserved for contests. This is because there is no section of the band (any band actually) reserved for contests. It’s up to the operator to stick to the band plan for your area, but there isn’t a “contest only” section.
B. In the middle of each band, usually on the national calling frequency? They’re trying to trick you now, you see. The calling frequency shouldn’t be used to conduct QSO’s of any kind, really. It’s called the “calling frequency” for a reason. You make an initial contact, and then agree to move to a different frequency (or QSY) after that, freeing up the calling frequency for more “callers” as it were.
Is it D. In the middle of the band, usually 25 kHz above the national calling frequency? Well, we’re getting warmer, but still no dice. While we’re not sitting on the calling frequency, its still close enough that a strong FM signal could drown everyone out. Plus, “the middle of the band” is pretty vague.
The remaining answer, C. In the weak signal segment of the band, with most of the activity near the calling frequency is correct. But why? Didn’t we just say we didn’t want to be near the calling frequency? and that there is no “reserved” portion of the band?
It’s true there isn’t a “contest only” section of the bands. However, there are plenty of conventions that are used. One of them being that the weak signal part of VHF/UHF should be used for contests. Primarily since (unless you’ve got an absolutely killer station, or the propagation gods are smiling) those VHF/UHF signals will be weak signals, and you’ll probably be working sideband (SSB) anyway. Maybe not, depends on the particular contest and its rules I suppose. Again, the conventional, agreed upon band plan for VHF, 2m in particular, puts the weak signal section (144.1 MHz – 144.2 MHz) directly below the SSB calling frequency (144.2 MHz), not above.