Hiding Frequencies for “Operational Security”

Recently, I have heard people in the amateur radio community – especially in emergency communications circles – discussing the idea of using channel names or designators instead of frequency.

To illustrate, here’s an example that you might see:

Designator Frequency Offset Tone Note
A1 146.760 -0.600 110.9 Primary Repeater
A2 146.940 -0.600 110.9 Secondary Repeater
B1 147.015 +0.600 110.9 Operations

The idea behind this is that if everyone has radios programmed with the same names for the same channels, frequencies would never need to be given over the air, and this would provide protection from would-be jammers.  If someone starts jamming your primary repeater, the net control can ask everyone to simply “go to channel A2.”  The jammer doesn’t necessarily know what channel A2 is, so now you’ve solved your problem, right?  Wrong.

There are a couple of major flaws in this logic.  First, chances are that channel A2 is going to be a frequency in the 2 meter or 70 centimeter band.  That’s a total of 24MHz (not counting 420-430 since I am above Line A).  Any scanner made in the last thirty years can scan that entire frequency range in seconds.  Most repeaters use standard offsets and transmit the same PL/DPL as they receive, making it trivial for the jammer to find you again.

The second problem is that this is illegal. Part 97.113(a)(4) states (emphasis mine):

(a) No amateur station shall transmit:

(4) […] messages encoded for the purpose of obscuring their meaning,  […]

 

If you use channel designators or names for the purpose of obscuring the frequency, you are in violation of 97.113(a)(4).

The next time you consider obscuring frequencies for the purpose of “operational security,” think about what I have said here – chances are, you will agree that it makes no sense.

Hiding Frequencies for “Operational Security”
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