Questions tagged [snr]

Signal to Noise Ratio - any questions about improving or detecting an SNR or lowering your noise floor.

13 questions
Filter by
Sorted by
Tagged with
63 views

What would the Signal to noise ratio be for SSB under normally (just) readable conditions?

I want to estimate an upper limit for the data that can be sent over single side band. The upper limit can be determined using Shannon-Hartley theory. The Shannon-Hartley theorem is given by: C = B \...
• 101
1 vote
61 views

What is the point of using LNA if the SDR can increase the gain itself [duplicate]

Usually there is a LNA next to antenna, while SDR devices also have gain setting so we can increase the gain. As i know LNAs are amplifying all signals with same gain (Am I right?) So i wonder what is ...
• 143
391 views

SNR measurement for a BPSK/QPSK signal

I have created a software (gnuradio) that performs modulation/demodulation and supports a number of modulation schemes and error correcting codes. I'm in the process of evaluating the BER vs SNR for ...
216 views

Are there any terrestrial timecode signals receivable in Boston Massachusetts?

I'm looking for any timecode station (like WWV/B, CHU, etc.) with an SNR > 0 dB that I should be able to receive in Boston Mass. WWVB at 60 kHz has a phase modulation that one can apparently receive ...
305 views

Use noise figure and gain to calculate weakest signal radio can receive?

An FM radio receiver, using a 1 kHz tone at 3 kHz deviation has a 12 dB SINAD (Signal To Noise and Distortion) of -116 dBm. I would like to increase the 12 dB SINAD sensitivity of the receiver to at ...
• 7,620
167 views

Is the error rate for QPSK31 in a white noise channel worse than BPSK31?

I've read in a couple sources that in a channel consisting of only additive white Gaussian noise (AWGN), at low SNR, QPSK31 is actually worse than BPSK31. http://www.arrl.org/psk31-spec, probably ...
• 51.9k
544 views

How big is a decibel?

Say I've calculated that my feedline losses are 3dB, or I'm considering an antenna with 10dB gain, or trying to decide between a transmitter with 10dBm output power versus 16dBm (6dB difference). I ...
• 51.9k
102 views

Link margin calculations with two antennas and two low noise preamplifiers

Background - UHF - 434-438MHz Two identical crossed Yagi's mounted on rotator. Currently, I have a low noise preamplifier after combining cables from the two antennas (T connector + matching stub). ...
• 201
196 views

FSK real world application BER

I have designed a receiver for FSK reception in 434 MHz ISM band. For this I used USRP1 and GNU Radio. Now, I would like to measure performances of my receiver. For this purposes I did following: I ...
• 241
123 views

Preferred signal report format for Digital Voice?

When using FreeDV or other digital voice modes, what's the preferred signal report? The software has a single SNR number, but that fluctuates quickly. Since it's a digital mode, you either get the ...
• 1,125
6k views

Is a vertical noisier than a dipole, and if so, why?

I've had people tell me, anecdotally, that a vertical is noisier than a dipole. Is this true, and if so, why? If it is true: Is this additional noise, such that SNR is degraded, or is the vertical ...
• 51.9k
41k views

Can I reduce RFI/noise at the antenna?

Recently, the power was out in my neighborhood for an extended period of time. I fired up my HF rig using battery power and was amazed at the lack of noise across the HF bands. When the power grid ...
• 413