Signals that are weaker than the noise in the background cannot be measured by the spectrum analyzer, power levels that are often seen in microwave receivers. These are then converted into a frequency that is selected to a DC level that is measurable.  Special IC chips are integrated to ease up the technology of rf frequency analyzers.  It has the commercial requirement to read range of regions from 50khz to 70 khz, plus the capability to go through VHF and UHF. This is one way to verify the strength and frequency of the signal. These values are then displayed in the CRT, with the signal strength in the y-axis and the frequency in the x-axis. Here, the received signals are measured in decibels rather than voltage because of the low signal strengths that are received and the frequency range of the measurements. 

The question is:  would you rather have a customized assembled rf spectrum analyzer or would you avail commercially available ones?When it comes to rf frequency analyzers, there is no simplicity not directly proportional to the cost. This is because spectrum analyzers are often used in factories and in laboratories. Spectrum analyzers especially the modern ones have a lot of uses.Spectrum analyzers may seem really technical and scientific to the ears.  The varying designs could mean a lot to the convenience of the user as far as function is concerned.  A good one must include the important elements necessary like amplifier, mixers and the visual display. Spectrum analyzers are instruments that is used to receive and select frequency levels based on the superheterodyne principle. It is very sensitive, converting higher frequencies of up to 10s GHZ into something that is measurable. . Another application is the analysis of vector signals as well as the saving, printing and transferring of data. Received frequencies are first put into a series of pre-selected values.  For electronic enthusiasts inclined to this specialized analysis of signals and frequencies, having rf spectum analyzer is one of the most wanted device for collection, just like the need for having oscilloscope for amateur and professional use. This is the reason why spectrum analyzers need the RBW to be able to determine these measurements.

It can also analyze digital modulation measurements especially against industry standards such as GSM and blue-tooth.

The resulting value is on Hertz. It can also provide measurements that are specific to the program or applications being used such as in the case of Adjacent channel power or (ACP) and phase noise.  Spectrum analyzers are also being used to identify and measure interference in signals, which are often needed in site operations of telecom towers, TV stations and the guiding systems of airports. Some spectrum analyzers also have provisions for diagnostics and self-calibration. One of which is as a device frequency response measurements, which is used primarily in measuring amplitude response in dBm in comparison to the frequency of the device. Often the values are converted into the logarithmic scales. Other measurements that the device can handle are measurements of fiber optics return and loss as well as spurious signals; and alignment of satellite antennaRadio frequency analyzer is technically necessary as measuring tool. Another use is as a microwave tower monitor, where its transmitted power and receiver power is measured. Spectrum analyzers also allow you to have remote control over LAN and the Internet as well as update firmware, add new features and fix problems in the program.