While some festivals might have their own radios and license, many more, now days, go to a third party that leases radios, and applies for a temporary license. An example is WQXT583. They have 13 frequencies, 850 units, and will be using DMR digital radios. This is very common, as to radio type, and size of the event. So, to find the security frequency, out of all of those, can be very hard to find, and would require extensive listening to figure what each frequency is being used for. The event won't tell you.

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