On 03/08/2016 05:42 PM, Roy Harcup wrote: > Hi Cinaed, > > You really need to read up on dB’s. > > 0dBm = 1mW as you have stated; > 30dBm = 1W; > 40dBm = 10W; > 43dBm = 20W, one more dBm will take that to somewhere around 22W (I haven’t > done the calculation, I’m working from memory).
dB is a ratio - ratios have no units. That is the ratio of 44mW/1mW = 44W/1W, so 10*log_10(44mW/1mW) = 10*log_10(44W/1W) dBm = dBW = 44 dB. If you want to change the reference power in the definition of dBm from 1 mW to 1 W, then that's a different ballgame. > > If you ’smoke’ the RF stage on the HackRF I doubt that you would see anything > usable on the output, indeed you could end up with a really bad source of > interference. > You're probably right - I am trying to do everything I can to keep from smoking it. > Best regards > Roy > Formerly G4GGS > > >> On 9Mar, 2016, at 09:18, Cinaed Simson <[email protected]> wrote: >> >> Hi - I'd like to increase the TX power of the HackRF to 50 mW. >> >> First, I disable TX. >> >> Since the dBm=0, this implies the power output will be on the order of 1 >> mW. >> >> Then I add an external LNA with a gain of 44 dB on the RF band I'm >> transmitting on which raises the TX power of the HackRF to 44 mW. >> >> The antenna has a gain of 6 dB - the cable and connector losses are on >> the order of 1 dB, so the maximum effective power is 49 mW. >> >> I'm assuming this independent of the IF gain. >> >> So I could smoke the TX amplifier on HackRF and still be able to use the >> HackRF to TX at roughly 17 dBm :). >> >> -- Cinaed >> >> _______________________________________________ >> HackRF-dev mailing list >> [email protected] >> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev > > . > _______________________________________________ HackRF-dev mailing list [email protected] https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
