From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benoit Papillault Date: Tue, 12 Jun 2012 11:50:03 +0200 Subject: [ath9k-devel] TX power and TPC In-Reply-To: References: <4FD70023.1000603@free.fr> Message-ID: <4FD710CB.1080307@free.fr> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ath9k-devel@lists.ath9k.org Le 12/06/2012 11:28, Holger Schurig a ?crit : > To your question 2: are both the spectrum analyzer and the USB power > sensor calibrated? The spectrum analyzer was bought with calibration certifications. The USB power sensor has been Zero Calibrated once before all measures. > Also, do all components have matching impedance? Sure. 50 Ohms here. > > Also, do they all use short coax cable that don't eat up much of the > power? Do you know the cable type? If a cheap cable is used, then > even a short piece of cable or a cheap plug can reduce the signal > considerable at 5 GHz. For example, RG 58 CU (which no one uses for > GHz things) has 100 dB loss for 100 meters at 2 GHz. Aircell 5 has > 81.18 dB loss at 100 meter at 5 GHz. And so on. > The same cable (2m, LMR-200 I guess) was used for both type of measures. No attenuators was used (the SA has some internal attenuators and the power sensor range is up to +20 dBm). Regards, Benoit