Cheap spectrum analyzer

Cheap spectrum analyzer


  • Handheld Spectrum Analyzers
  • RATIONAL WAVES -- Low-cost, RF Spectrum Analyzer Software
  • RF Mapping is now available in Spike
  • New Low-Cost Spectrum Analyzer
  • Tektronix announces affordable portable spectrum analyzer
  • A dirt cheap “spectrum analyzer” with an RTL-SDR dongle.
  • Best Spectrum Analyzer Reviews
  • Handheld Spectrum Analyzers

    Update: There used to be an error in the schematic, R2 was missing. It is needed to work correctly. An alternative is to hook up an RF signal generator, measure the output power of the filter with a power meter at multiple frequencies, and plot the result manually.

    Or a power meter. Fortunately I found a way that works reasonably well, and cost me nothing. However, what you can do is to make the dongle hop from one frequency to the next, and make a composite spectrum. There is software that does just that: rtlsdr-scanner. If only I had a transmitter that transmits at every frequency: I could pass it through the filter and see what remains at the other side!

    Something like a wideband noise generator. After asking Google, it turns out that generating such noise is quite easy: a diode, when operating at the reverse breakdown voltage, generates a fair amount of noise, hundreds of megahertz wide! Not ideal, because there are lots of other signals picked up too, but changing a slider in software is much less work than making a wideband amplifier.

    A current source D1, D2, R1 and Q1 feeding a zener diode. Any diode will do really, just make sure the breakdown voltage is reached. R2 value is not critical, 10kk is fine.

    The setup is now ready for prime time. When I turn on the noise generator, the noise floor of the dongle increases by 30dB around MHz. So far so good. I set the start- and stopfrequencies to MHz and MHz, and do a sweep. I repeat the measurement with the filter in between, and save both sweeps.

    This sets the noise level as the 0dB reference. Apart from the spurs, the technique works quite well! It sure has limitations, but so does a professional spectrum analyzer. The difference is that with this dongle, you bump into them a lot sooner.

    Well, ok, almost immediately. The biggest problem is the dynamic range. If your dongle measures 30dB of noise from the noise source, it means that after 30dB of attenuation, you have nothing left to measure. So while you can get accurate readings of the filter loss at the passband 2.

    Even if you can increase the noise level, you are limited by this 48dB. Maybe this could improve the range, maybe it will block the receiver.

    In any case, the first improvement should be to make the noise source better. Both the amplitude and the frequency range. If you have a dongle you can see the bumps yourself by setting full LNA gain and doing a large sweep with no antenna connected. So just make yourself a noise source and start playing! With these receivers it really helps a lot when the strong signals at other frequencies are removed first.

    RATIONAL WAVES -- Low-cost, RF Spectrum Analyzer Software

    It operates both as a standalone, handheld RF spectrum analyzer and also interfaces with a PC running more sophisticated data analysis software. Don''t let the price fool you -- the performance of these small, affordable devices compares favorably to more expensive and bulky test equipment.

    Nuts About Nets is a software company that develops diagnostic tools for troubleshooting RF and wireless issues. An RF spectrum analyzer measures the raw RF energy of transmitted radio frequency signals and aids the user by providing a view into the local RF environment.

    This RF view can be used to help detect the presence of RF transmissions that are the source of interference. Armed with this information you can either attempt to track down and eliminate the source of RF interference or choose to re-configure your own wireless gear to operate in a different freqency range of the RF spectrum that is less prone to RF interference. The combination of standalone, handheld operation and PC-based, data acquisition and analysis are unique in the market place.

    The RF Explorer team's commitment to quality and low-cost are unmatched -- you'll wonder how you ever got along without this device. Several models to choose from that differ in the frequency range they support.

    Portable Device Light-weight and small in size, can operate as a stand-alone, handheld device. Performance Comparable to RF spectrum analyzers that cost many times more. Excellent dynamic range, sensitivity, and resolution bandwidth. Rational Waves' software features include: Spectrum Trace In the 'Spectrum Trace' view the signal strength data in dBm is displayed as a function of frequency.

    Density Chart Displays accumulated RF energy as a function of frequency. Threshold Chart This view highlights with a yellow box those frequencies whose signal strength exceeds a user-defined threshold.

    Delta Chart Used to view small or large changes in the RF spectrum over time. Monitored Frequencies Allows you to monitor specific frequencies.

    Monitored Bands Allows you to monitor specific frequency bands. Export Data.

    RF Mapping is now available in Spike

    The gain can be Since the screen is limited in space, therefore, a logarithmic scale is required. Unlike the oscilloscope that utilizes a linear scale in both its X and Y axis, the spectrum analyzer uses a logarithmic scale in its Y-axis only, the X-axis is linearly in Hz.

    This Y scale is expressed in dB or Watt. We believe that you have understood the dB. When the analyzer provides the Y-axis reading in dBm, it means that the decibel is referenced to 1 mW.

    If the peak signal reaches 0 dBm, it means the power is 1 mW.

    New Low-Cost Spectrum Analyzer

    If you are measuring a high power signal, you have to get the analyzer with certain maximum amplitude. For example, you are going to measure radio signals, then the maximum amplitude of 20 dBm should be more than enough for that kind of task.

    However, try to be reasonable with your project to save the cost. Resolution Bandwidth The resolution bandwidth is a selective frequency range that sweeps across the input signal. This selective frequency is surely shorter than the span. It functions to carefully detect the signals and display them clearly. However, the more careful it is to sweep, the more time needed. Therefore, narrow bandwidth charges more sweep time.

    The resolution bandwidth is like a filter. By reducing narrowing the resolution bandwidth, expressed in Hz unit, two closely spaced signals can be easily separated and further clearly easy to observe. In addition to the impact of the resolution bandwidth, it reduces the noise floor. If you are looking for the sideband signal, the key is at this resolution bandwidth and the span as well. When it comes to picking the right spectrum analyzer, getting the one with a good resolution bandwidth can help you find the hidden signals which have close frequencies.

    Video Bandwidth To smooth up the noise that shows on the screen, you could reduce the video bandwidth. When the analyzer displays a certain range of frequencies, the noise may be too large.

    This can cause small signals not easy to observe.

    Tektronix announces affordable portable spectrum analyzer

    Smoothing the noise can help you observe the signals clearly. Reducing the video bandwidth does nothing with the resolution or other measurement readings, but it impacts sweep time. And reducing the video bandwidth causes the sweep time to increase. Type of Analyzers The most expensive model is the benchtop models. This model is great to use for labs or stationary locations.

    If you tend to carry the analyzers anywhere you want, then choose from the portable options. The handheld one is more affordable and portable but the functions are limited. This factor may not critical but determines the convenience of your work.

    Conclusion: Last Thoughts Buying a spectrum analyzer can be highly challenging, even for the experts. There are actually a lot of things to consider.

    A dirt cheap “spectrum analyzer” with an RTL-SDR dongle.

    Since the price is fairly expensive, spending a great amount of time may be required to get the best one. In addition, currently, the options to buy the best spectrum analyzer on the market is limited. There are only several products available. You might end up having no great options to choose from. On this page, we are collecting and reviewing 10 products of the spectrum analyzer test instrument.

    There are several models that we review. Picking the best one must consider the condition and needs you are handling. There is no one product that matches all needs especially because each product comes with a different frequency measurement range capability. It comes affordable and covers a greater frequency range. Our selection of the top 10 spectrum analyzers above is hopefully getting into your consideration.

    Reading them carefully can benefit you to get the ideas of the product capability. Decimator D4 is a fourth-generation product that builds upon the capabilities of the popular Decimator D3. Teleports Decimator D4 provides Teleport operators with remote access to spectral analysis along with real-time carrier monitoring of all signals ranging from 5 MHz to 6.

    Best Spectrum Analyzer Reviews

    User defined signal threshold parameters allow instant notification to any number of users when signal parameters fall below or rise above thresholds. Available as a 1RU rack mount, up to 10 simultaneous users can access the spectrum analyzer from any web browser or via the publically available API protocol.

    D4 can be used to line-up and acquire the satellite signal, peak the antenna and monitor signal performance. Operations center-based technical support can remotely access the remote spectrum analyzer to provide further support when needed.


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