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Frequently asked questions and answers about the GB-4000 Frequency Generator and SR-4 Linear Amplifier:


  • Does the GB-4000 output its frequencies digital or analog?
  • Does the GB-4000 use crystal-controlled frequencies for high accuracy?
    Yes, it does for the 3.1 MHz RF carrier frequency. The GB-4000 also goes beyond using crystal-controlled frequencies. In order to output up to 8 individual frequencies simultaneously we use 1) Digital synthesizing processor (or DSP) and 2) Direct digital synthesizers (or DDS) for creating arbitrary waveforms from a single, fixed-frequency reference clock. The Digital synthesizing processor is capable of outputting 1 to 8 individual frequencies simultaneously up to 40,000 Hertz. The 2 Direct digital synthesizers (DDS) are used to output up to 2 frequencies simultaneously from 40,000 Hertz to 20 million Hertz. These frequencies are then summed together so all of these frequencies are at the same power level.
  • How does the GB-4000 frequency Instrument output its frequencies analog when they come from a Digital synthesizing processor (or DSP) and 2 Direct digital synthesizers (or DDS)?
    The GB-4000 uses a DAC (Digital to Analog Converter). This type of electronic circuit is used in all modern analog frequency generators. The frequencies are output from a DSP, (Digital Signal Processor) or DDS, (Direct Digital Synthesizer) for creating arbitrary waveforms and then go through the DAC. From the DAC they go through a low pass or band-pass filter and come out converted to analog. These frequencies are phase-locked-looped for perfect accuracy. They are then output from the GB-4000 with M.O.P.A., or SR-4 15-watt amplifier. By this method we have all the harmonic content of the old antique vacuum tube frequency generators along with the digital accuracy. This method is now the standard in the industry. No old antique frequency generator has the accuracy of today’s modern equipment.
  • Can the GB-4000 frequency machine output RF or Radio Frequencies?
    Yes. The GB-4000 has a frequency range from 1 to 20 million Hertz (20 Megahertz).
  • What is an RF Carrier Frequency?
    Any radio station uses an RF carrier frequency to carry or modulate (piggyback) the audio frequencies, voice or music that is sent out for you to hear on your radio. Modulation is the mixing of the RF carrier frequency with the audio frequencies. So, the RF carrier frequency is the means by which the radio station transmits the signal through the air to you the listener. The GB-4000 goes beyond what most carrier frequencies are designed to do. It produces harmonic sidebands replicating the output of the 1936/1950's, M.O.P.A. style equipment.
  • Why do most frequency generator manufacturers limit their audio frequency modulation to 20,000 Hertz?"
    Most likely they just do not want to spend the money to build their circuit with a higher capability. This is just one of the several differences between the GB-4000 and most of the other frequency generators on the market today. The GB4000 can modulate any frequency from 1 Hertz to 999,999 Hertz on its carrier frequency.
  • What is the main two differences between the GB-4000 and other function generators?
    The GB-4000 is more powerful and can output up to 8 audio frequencies simultaneously up to 40,000 Hertz.
  • What is the highest frequency that the GB-4000 can output?
    20 million Hertz.
  • Most other manufacturers only have a frequency range to 10,000 Hertz. Some go up to 22,000 Hertz. The GB-4000 goes to 20 million Hertz. Why?"
    It is all a matter of what frequency range the manufacturer wants to cover. The higher the frequency range the more versatile the generator will be.
  • How much more powerful is the GB-4000 than other frequency generators?
    Because of the use of an RF carrier frequency the GB-4000 is over 18 times more powerful than most other frequency generators. If the SR-4 15-watt amplifier is connected to the GB-4000 is 75 times more powerful than other frequency generators that do not use an RF carrier frequency.
  • Why should I want the optional Amplifier?
    The GB-4000 can operate in two different modes. 1: RF Mode, which is the higher frequency mode, 2: Audio Mode, which is the lower frequency mode. In RF mode, the GB-4000 has an output of 3.7 watts; however, sometimes more power is wanted. The SR-4 Amplifier boosts the GB-4000 3.7 watts output to 15 watts power output. Also, the Amplifier has three additional sets of outputs for more hookups. The SR-4 is a variable 1 to 15 watts Amplifier and operates in the RF mode only.
  • Why was the GB-4000 built to output up to 8 frequencies simultaneously to 40,000 Hertz while most other instruments only output one frequency at a time?"
    Some of the original 1950's instruments were built to output 10 frequencies simultaneously and this is why we built the GB-4000 with this capability. It was designed to be a time saving feature.
  • Does the GB-4000 show the actual frequency being used on the LCD?
    Yes. The GB-4000 shows the actual frequency on the LCD as long as you are not running multiple frequencies.
  • Some manufacturers build their instruments with built in rechargeable batteries. Why doesn't the GB-4000 have this capability?
    The reason the GB-4000 is not battery operated is because of its power output range. Rechargeable instruments only have 28 volts output. In the audio mode the GB-4000 is variable and has a range from 0 to about 36 volts output or 0.75 watts. In the RF mode the GB-4000 is variable from 0 to over 110 volts output. Because of these capabilities it is not feasible to put batteries into the GB-4000.
  • Does the GB-4000 have programmable channels?
    Yes. It has 2000 programmable channels which can hold up to up 48 frequencies each.
  • What is gating and how does it work?
    Gating is basically an advanced or additional "pulsing" feature. Square wave frequencies naturally pulse but when gating is used with a square wave frequency it creates a second pulse which creates what some call a "pulsating square wave." When used with sine wave or square wave frequencies gating pulses the frequency on and off at the predetermined gate rate set by the user.
  • Why does the GB-4000 have a 10% to 100% duty cycle range?
    All high-quality frequency generators have this capability because different duty cycles are needed in testing.
  • Can the GB-4000 sweep between frequencies like all high-quality frequency generators?
    Yes. One of the great features of the GB-4000 is that it is capable of doing two kinds of sweep functions. 1) SWEEP: Allows you to run a specified frequency range of your choosing, one frequency at a time. The instrument sweeps from your beginning frequency to your ending frequency. 2) CONVERGENCE SWEEP: Allows you to run two frequencies at a time over a specified frequency range of your choosing. The instrument sweeps from your beginning frequency to the ending frequency and at the same time sweeps from the ending frequency to the beginning frequency. The result is that the two frequencies sweep towards each other, then pass each other, one going up and the other going down and each ending where the other frequency began.
  • Why does the GB-4000 have a channel sweep capability which varies the frequency or frequencies from 2 Hertz to 20,000 Hertz?"
    The GB-4000 has the capability to sweep when running any of the 2000 programmable auto channels. The new channel sweep covers a variable range from 2 Hertz to 20,000 Hertz. If you are running a frequency of 2000 Hertz and decide that you want to sweep 1000 Hertz then the sweep will start at 1500 Hertz and will end at 2500 Hertz. This sweep always covers the frequency range chosen with half the frequency range dropping below the targeted frequency or frequencies to half the range going above the targeted frequency or frequencies used. This type of sweep is desirable when you want variability in your frequency or frequencies you are running.
  • Why do you use a membrane type keypad instead of the contact style?
    Durability is the main reason. Membrane keypad switches are the industry standard and have been for many years. Almost all electronic devices that have keypads use them. They are built to last for many years. They replaced the contact style because they have fewer problems. They will generally outlast the electronics. We have had this type of keypad on our instrument for over 18 years under heavy use with very few problems.
  • How long will the GB-4000 last?
    The GB-4000 is built to last a long time and 99.9 % of the instruments sold over the last 18 years are still working. Some manufacturers claim that their instrument will last a lifetime. We cannot and will not make that kind of misleading claim. Any instrument that cannot be repaired, even after years of use, is update to the current model for only $900. No other company that we know of offers this kind of replacement in the industry.
  • Is the GB-4000 easy to use?
    Yes. Programming the GB-4000 is easy. Running an un-programmed frequency is also easy to do. To run a programmed channel all that the user has to do is press the Auto channel button, then enter the auto channel number using the keypad, then press the Run button. The GB-4000 then will run all the frequencies in the channel. To run an individual frequency all you have to do is press enter then put in the frequency you want to use and then press run. Anyone can do this three-step process.
  • Why does the GB-4000 cost less than almost all the other instruments when it has far more features?
    There are no middlemen to make it more expensive. ​
GB4000 and SR-4 Amplifier

Rife Machine Spooky2 PERL M+ TrueRife BCX Ultra Beam Ray

Why should you consider purchasing a GB-4000 Frequency Generator and M.O.P.A. Amplifier?






The M.O.P.A. or Master Oscillator Power Amplifier uses the gas filled plasma tube radiant non-contact method of outputting frequencies from 1 to 20 million Hertz which is the largest frequency range in the industry. Many people ask what are the benefits of the M.O.P.A. over the SR-4 amplifier? First: The M.O.P.A., uses the plasma tube method. The plasma tube method allows for a greater power output of 190 watts compared to the SR-4's 15 watts output. Second: the M.O.P.A., for the first time since the 1930's, allows for the use of high frequencies directly output through the plasma tube. This has been a long sought after feature that many have been asking for. If you are wanting to use the more powerful, versatile 1930's/1950's radiant method, then the M.O.P.A., amplifier is the instrument you will want to own.

When it comes to power the GB-4000, SR-4 and M.O.P.A., should be considered as good, better and best. If your budget only allows for the GB-4000 then you have one of the best frequency generators you can purchase. If your budget allows for the GB-4000 and SR-4 amplifier then you move up to the next level of performance. If you can afford the GB-4000 and M.O.P.A. amplifier then you know you have the very best, highest frequency range, plasma tube system on the market today. You also have a system that can output both the 1930's/1950's frequencies through a plasma tube. Only purchase what you can afford because you can always add the SR-4 or M.O.P.A. amplifier at a later date.

Compare our frequency generator system with others...


Comparison Reports Now Available


We have found repeated misstatements of information by a number of other manufacturers and distributors

of different frequency devices on their websites and in emails received by OUR prospective customers.

If you truly desire to compare real data with factual information about our frequency technology instruments, including links to real time video comparison tests with additional information, then

you'll want to read a comparison paper or report.


Most people who are looking to purchase a frequency generator have in some way or another heard of the work of doctors using them for research back in the 1930s and 1940s. They also want to purchase a frequency generator that can output the frequencies which were discovered back then. The GB-4000 can output all of Dr. Rife's original frequencies. But what most people do not understand is almost all of the frequency generators on the market today, that claim to be of the design and specifications of that era, cannot output any of those higher frequencies. On some of the earlier lab notes from the 1920’s there are frequencies in the 17 million Hertz or cycles per second range. The 1930’s frequencies ranged from 139,200 Hertz or cycles per second to 1,607,450 Hertz. In 1936 those frequencies were multiplied up in harmonic steps to the 3 million Hertz range. This was done because the original 1930’s frequencies were in the AM radio band of frequencies and could interfere with AM radio stations.


You would think that if a company was going to call their machine after a prominent researcher of his day they would at least be able to output the original frequencies he discovered. But this is not the case; most of the instruments sold today only output low audio frequencies below 22,000 Hertz. Because the 1930’s/1950’s original instruments also used low audio frequencies, many manufacturers only use these low audio frequencies without also using the high RF carrier frequency in the 3 million Hertz range. These low audio frequencies were modulated or piggy-backed onto this high RF carrier frequency. When these two frequencies were modulated together they produce many other frequencies known as sideband frequencies. These sideband frequencies were also in the 3 million Hertz range and one of these sideband frequencies would line up with one of the original researched frequencies. It is the combination of the low audio frequency and the high RF carrier frequency that was needed to produce the high RF frequencies.


Because many manufacturers do not understand what we have explained they are only using the low audio frequencies, incorrectly believing they are the researcher's original frequencies. This is why the majority of the machine manufacturers claim they are using the original frequencies when they actually are only using one half of the needed two frequency combination required to produce high RF frequencies.


The GB-4000 is a 20 million Hertz or cycles per second frequency generator which CAN output all of Dr. Rife’s original frequencies including those in the 17 million Hertz range. It can use a 3.1 million Hertz high RF carrier frequency with the low audio frequencies so that the correct sideband frequencies can be produced. It is the only frequency generator capable of outputting 8 audio frequencies simultaneously which makes it 8 times faster to use than any other frequency generator. As a stand-alone machine it has a power output of 4.7 watts and if you purchase the optional SR-4 15-watt amplifier it amplifies the 4.7 watts to 15-watts. Also available is an optional 190-watt ray tube amplifier. The M.O.P.A. has a variable RF carrier frequency range from 2.2 to 3.8 million Hertz. With sideband its frequency range goes from 1.7 to 4.3 million Hertz. It can output all of the frequencies in the 3 million Hertz range and is a replica of the original 1936-39 equipment. The original 1930s/1940s ray tube instrument used a minimum of 50 to 100 watts because anything less than this was considered  to be under powered and not capable of doing the job.


Many frequency technology devices on the market have a frequency range of 100,000 Hertz or less. They do not use any RF carrier frequency. They cannot output any of Dr. Rife’s original frequencies, whereas the GB-4000 can. They are also not capable of using the sideband method used in the original 1930’s equipment so they cannot output any of the sideband frequencies in the 3 million Hertz range.


Usually it is only after people have purchased these other devices that they learn these important facts. At that time, it is usually too late to return the device in order to choose a different one with more capabilities.

M.O.P.A. 20 MHz Sweep/Function Generator GB-4000

"Life's battles don't always go to the stronger or faster man. But sooner or later,

the man who wins is the man who thinks he can."

–Vince Lombardi Jr.

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