[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
California fires: smart speakers and emergency alerts
> On Jul 26, 2018, at 12:09 PM, valdis.kletnieks at vt.edu wrote:
>
> Do those use a frequency band that's suitable for cellphones to monitor (antenna
> size, power, etc)? Because your best chance of getting my attention in an emergency
> is to make my phone start shrieking.
VHF, on 7 frequencies:
162.400
162.425
162.450
162.475
162.500
162.525
162.550
Thatâ??s about 1.85 meter wavelength, so a quarter wave antenna would be pretty large. Iâ??m sure the RF engineers can come up with a way to listen effectively without a huge antenna.
â??Chris