7

So, requirements: runs on OS X and windows easy to work with quicker than "tone and excel" method If you don't like writing software yourself, this should still be pretty doable with just your soundcard and a quick signal flow graph design (in GNU Radio Companion) of your own. So, first off: Exciting with a single tone and stepping through all ...


4

WPT (wireless power transfer) is typically performed using flat, multi-turn coils (inductors) as antennas. In some cases, the coils are self resonant based on their parasitic capacitance and self inductance in order to avoid the losses in a typical matching network. Due to the close proximity of the two coils, the mutual inductance must also be considered. ...


3

It is important to understand that the SA takes some finite time to sweep (calculate the FFT buckets) for the frequency range in question. It is quite possible with a short duration signal that the sweep will catch none or only a small portion of a narrow band signal on a single sweep. On another pass it will potentially catch the peak of the narrow band ...


2

If you have a commercial transceiver you can reasonably assume it's free enough of harmonic distortion. You can then use that as a signal generator or a narrow-band spectrum analyzer to validate your other devices. Besides looking at harmonic frequencies directly, you can perform intermodulation tests to get a sense of linearity without needing a huge ...


2

In principle: yes, that will work. I've never used an RTL dongle without a tuner / bypassing the same; I didn't know that was an option. But yes, as every ADC, you need to sufficiently limit the bandwidth of the signals you digitize in order to avoid aliases. So, you'd be getting into a slight chicken/egg situation here – you need a good filter, but have ...


2

Probably not. Most radio equipment of this sort only gives access to the demodulated-and-decoded signal. The requirements for being an (uncalibrated) spectrum analyzer of this sort are essentially the same as being used for software-defined radio. So if any particular cheap consumer hardware is usable in the way you want, we would have heard of it as ...


2

Measuring received power is pretty straightforward. Set up a receiving antenna some distance away. Make it at least 10 wavelengths, but even farther is better. Make sure the receive antenna has the same polarization. Transmit a carrier at a fixed power. Read the received power at the receive antenna with your spectrum analyzer. If it's more convenient, you ...


2

Your method of measuring the spur signal is perfectly acceptable, and perhaps the best method for this scenario. Search the FCC database for the transmitter owner that you suspect is on the frequency that's causing the problem. Contact them given the information within the database. In my experience, groups are responsive to requests to clear up any ...


2

However, depending on which options I choose on the Spectrum Analyzer, my measurements are different by up to 6-10 dB(!). Using a spectrum analyzer needs a bit of understanding what it does: it sweeps a filter across the spectrum and measures the power passing through that filter. I didn't know how to properly use a spectrum analyzer when I first did, and ...


1

Does the deviation from the center frequency depend on the frequency of the audio/information signal applied to the carrier? No. In FM terminology, the "deviation" is chosen by the designer (or mandated by regulation) and determines the amount by which the carrier itself is modulated at the "peaks" of the input signal. For example, if the deviation is 2.5 ...


1

There is a trick to balance the notch tuning johannsen cap adjustment with the coupling ring loops to meet the required rejection per side with minimum insertion loss. I believe I tuned mine to reject 40-45dB rejection per cavity at max. First, I would get the pass rod approximately at the pass frequency, then tune notch under cap. If too deep or shallow a ...


1

300 kHz channel at 436 MHz sounds a lot like your spectrum analyzer might be seeing that are at twice the frequency – 872 MHz would be a typical 2G cellular network frequency, and 300 kHz might be around the bandwidth of a 2G channel. Try and tune to your SA to 872 MHz.


1

In addition to what AG6YO said in his answer (No, a network card is a network card and is built to find networks, not "spurious" power of another standard) – Bluetooth as is is a protocol especially hard to capture with a spectrum analyzer. The reason is very simple: Bluetooth works by jumping through separate, small 1MHz wide channels within a large ...


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