So is there something similar to the Friis formula you can lay on us that takes thermal and interference into account and gives minimum RX levels needed?
From: Chuck Macenski Sent: Tuesday, January 13, 2015 8:25 AM To: [email protected] Subject: Re: [AFMUG] Af5 The clean noise floor number is the thermal noise floor... On Tue, Jan 13, 2015 at 9:06 AM, Chuck Macenski <[email protected]> wrote: Hi, I should learn to sleep at night and email during the day. The tl;dr should have read: Sensitivity for a Modulation Rate at a given bandwidth (from the spec sheet) minus the clean noise floor for that bandwidth (see below) equals the signal needed over the actual noise floor for a given modulation. A rough estimate for the clean noise floor would be (50MHz=-97dBm, 40=-98dBm, 30=-99dBm, 20=-101dBm, 10=-104dBm). Chuck On Tue, Jan 13, 2015 at 8:39 AM, Chuck McCown <[email protected]> wrote: Noodling around with Chucks info: Noise floor = –80 Sensitivity = –82 -80 – (-82) = 2 dB RX signal required –80 + 2 = –78 dBm Noise floor = –40 Sensitivity = –82 -40 – (-82) =42 dB -40 + 42 = +2dBm (Not sure I want to stand in front of the transmitter) Some simple algebra: Required RX signal =Noise floor + (Noise Floor – Sensitivity) - simplifying - RX signal = (2 * Noise floor )-Sensitivity So, every dB of noise floor == 2dB of RX signal. Have I got this right Chuck? From: Chuck Macenski Sent: Monday, January 12, 2015 11:25 PM To: [email protected] Subject: Re: [AFMUG] Af5 tl;dr...the natural noise floor for the band minus the sensitivity of that band for a given modulation equals the signal needed over the noise floor for a given modulation.
