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It is MHz, not mhz. Why is this you might wonder? Hertz is abbreviated to Hz to begin with. Mega = M, Giga = G, Tera = T, hence MHz (10^6 Hz), GHz (10^9 Hz), THz (10^12 Hz). There's also milli = m (10-3), micro = u (10-6) and nano = n (10-9), so 1.3mHz would be 1.3 milli hertz, that's 1.3/1000=0.0013Hz.
Also, there's no 1.3mhz transmitters, there however are 1.3GHz transmitters, please make an effort to get the nomenclature right! Thank you!
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