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Questions tagged [spectrum-analyzer]

Questions about the use and theory of spectrum analyzers. For spectrum displays that are not test equipment, use [panadapter-and-waterfall] instead.

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7 votes
3 answers
801 views

What cause the spectrum peak of `center frequency`?

I use gnuradio and fosphor to view the spectrum from USRP B210, default gain set to 34, output looks like concave as below: ...
2 votes
2 answers
152 views

Is the noisy spectrum from 20MHz to 330 MHz normal?

I have recently been testing some VHF/UHF antennas for reception in my Lab, and have noted something I could not explain. Following are the spectrum plots captured on our R&S FSV spectrum analyzer,...
0 votes
1 answer
80 views

Weird looking spectrum. FSK and ASK combo?

Does this look familiar to anyone ?
5 votes
1 answer
679 views

Why would a VNA not make a good Spectrum Analyzer? Or an SDR a good VNA?

Happy to be corrected where I'm wrong in any of this but in broad strokes my understanding is: Spectrum Analyzer measures input signal strength while sweeping across frequencies, measuring RF ...
-2 votes
1 answer
89 views

How to know whether aliasing occurs when observe unknown signal?

Per my good but downvote question,I am hard to set sample rate even to a standard cosine wave. When I observe unkwon signal,how to judge whether aliasing occurs?
8 votes
1 answer
3k views

Why is 9 kHz the lowest frequency for spectrum analyzers?

I researched a number of spectrum analyzers and it seems that the lowest frequency that these operate at is 9 kHz. Why is the lowest frequency supported by spectrum analyzers 9 kHz?
-1 votes
1 answer
88 views

What's the negative float of rtl_power output means?

I got below float numbers after soapy_power -f 80M:100M -B 1000 --output a --format rtl_power: ...
0 votes
1 answer
169 views

Why so high values of noise température of a spectrum analyser?

We know that the displayed average noise level(DANL) and noise figure(NF) of a spectrum analyser is given by the following equation: \begin{equation} NF_{𝑆𝐴} = 𝐿_{𝐷𝐴𝑁L}[dBm] + 174dBm βˆ’10 \cdot ...
2 votes
1 answer
216 views

How the ELF-VLF background noise spectrum looks like?

In the ELF-VLF frequency band,some background noise like Schumann resonances shows in the spectrum analyzer as peaks. I want to have a overview look of the background noise of ELF-VLF frequency band,...
3 votes
3 answers
3k views

How to increase the range of the spectrum analyzer in SDRSharp?

I'm trying to visualize the frequency band utilization during a GSM phone call using SDR. Ideally, I would like to plot the whole 900 MHz range, i.e. 876-959 MHz. However, even setting the zoom to the ...
2 votes
0 answers
173 views

Is this signal BFSK or BPSK?

I'm trying to analyse a signal from a HVAC remote control (864 MHz) with my HackRF, but I'm facing an interrogation about the used modulation: Is it BFSK (frequency modulation) or BPSK (phase ...
1 vote
1 answer
316 views

Looking for a convenient audio frequency spectrum analyzer

I would like to have a convenient tool to measure filters and amplifiers in 20 Hz - 20 kHz frequency range. Currently I'm doing this with a signal generator, an oscilloscope and LibreOffice. It's not ...
1 vote
1 answer
490 views

Retuning 2m Duplexers (Q2330E) with Spectrum Analyzer and Tracking Generator

Yesterday I was trying to tune up the duplexers one can at a time as listed in this Sinclair Youtube Video. After tuning them my receive is awful and my transmit is somewhat not what it used to be. ...
0 votes
1 answer
273 views

What determines the bandwidth of an FM signal?

With an FM signal, it takes up more room in the radio spectrum presumedly because the carrier frequency is changed. On average what's the width of the FM sidebands? Does the deviation from the center ...
0 votes
1 answer
308 views

Most accurate way to measure signal power with (cheap) Spectrum Analyzer

I am using an USRP X310 which is unfortunately not calibrated and the specs given are only very vague. Hence I would want characterize the device with first-order measurements. Unfortunately I only ...
8 votes
1 answer
191 views

Identifying regulations for interfering stations

I'm working on tracking down some 2m repeater interference, and I have identified that the offending signal is a spur transmission on a commercial pager service (that lands right on our repeater input ...
2 votes
2 answers
417 views

Strange Noise Floor observed in UHF Band

I have a tracking station for UHF band satellites which comprises of a cross yagi of 12 dBi and a wideband LNA of 40 dB Power Gain and 1.3 dB Noise Figure. I observe a Noise floor of about 300 kHz ...
5 votes
1 answer
3k views

How to measure gain of an antenna?

I have dual stacked crossed yagi antenna. How can I practically measure the gain of the antenna combination? I know that this can be done in an anechoic chamber. But this is not feasible for me (...
7 votes
3 answers
4k views

Using an RTL-SDR as a spectrum analyzer

I've been trying to get into RF electronics, but one thing that is holding me back is lack of test equipment. I have an old analog oscilloscope, but that doesn't help much for things like verifying ...
1 vote
1 answer
206 views

How to measure the power emitted from an HF antenna in near-field WPT?

I'd like to estimate the power density from a 13.56 MHz power source in a near-field WPT (wireless power transfer) scenario. Using a spectrum analyzer with a receiving antenna will give the E-field ...
1 vote
2 answers
805 views

2,4GHz Spectrum Analyzer with wireless card

I am new in the world of Radio Technology and I would build an idea with Bluetooth 4.0 and want to see the frequency for debugging. So I will need a Spectrum Analyzer, but won't buy one of these. ...
0 votes
1 answer
3k views

Spectrum Analyzer: using "Max hold" for peak detection of a burst signal

TX works at 433 MHz and sends a burst of 64 bytes every second. The burst itself lasts for 102.4 ms. The width of TX signal is 400 kHz. RX is an Spectrum Analyzer (R&S FSL6) with a receiving ...