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RF signal generator 3 Mhz up to 30 Mhz

Mori

New Member
Hi everybody
I need to generate mhz range RF signal generator , 3 mhz up to 30 mhz please help me.
 

atferrari

Well-Known Member
You mean miliHertz or MegaHertz actually?

Buy or build?

Sending a letter to Google is an option to you?
 

RadioRon

Well-Known Member
If you only need an unmodulated sine wave, consider also looking for "Function Generator". Many of the better ones can generate up to 30 MHz. Function Generators are not as stable or low noise as an RF signal generator, and often the RF signal generator has a better variable attenuator.

For an RF signal generator, consider something like this:
 

RadioRon

Well-Known Member
I endorse the circuit linked by Nigel. It looks like a good basis for a project. For those more ambitious, using a DDS with a controller IC will be more flexible, but also more difficult to build. Example: AD9834 DDS chip.
 

unclejed613

Well-Known Member
Most Helpful Member
with a standard oscillator like a Colpitts or Hartley, you will need a bandswitch and a few sets of coils because a tuning capacitor doesn't have the range to cover the whole decade of the HF spectrum. you may notice that Ron's signal generator dial has several frequency scales, and the knob to the right of the frequency dial is a 6 position rotary switch to select the bands shown on the dial.
 

RadioRon

Well-Known Member
To design an oscillator that can cover the entire range with one coil, you design an oscillator that varies from, for example, 123 to 150 MHz (which can be done with one coil), and follow that with a mixer with 120 MHz local oscillator and follow that with a 40MHz low pass filter. This is, unfortunately, more complicated than using band-switching.
 

atferrari

Well-Known Member
I endorse the circuit linked by Nigel. It looks like a good basis for a project. For those more ambitious, using a DDS with a controller IC will be more flexible, but also more difficult to build. Example: AD9834 DDS chip.
I even bought one of these but found the filter at the output (to cover the whole range) very hard (for me) to calculate, build and test.
I ended buying a SIGLENT ????10, which I pretty much suspect is built with one of them inside. Their sweeping capability in both channels is extremely useful.
 

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