What is the minimum mghz oscilloscope i should get?

[cjruger]

I can get a 5 mghz o scope for 15 bucks but not sure if thats big enough. I read somewhere no leas that 15 mghz for 11 meter band. Is that a good guidline?

 

[Captain Kilowatt]

11m CB is at 27 MHz. For best accuracy you would want a minimum of 30 MHz. Never heard of a 5 MHz 'scope. Must be REALLY old.

 

[cjruger]

Oh, sovexplain how it works, i know you adjust the dead carrier to be 1 above and 1 below and the modulation willvshow a wave from carrier. So if the scope is not big enough what will happen on the screen, i dont get it. Will you not be able to adjust the carrier into the screen?

 

[Captain Kilowatt]

OH....for simple modulation monitoring you may be fine. The bandwidth of a scope typically defines how high a frequency the vertical amp in it will work with stated accuracy as well as how fast the horizontal sweep will lock. A scope is used to accurately measure the vertical amplitude of a signal as well as other things. If the vertical amplifier circuits cannot pass the signal then the amplitude cannot be accurately displayed on the screen. If all you want is to look at a modulation waveform without regard to how accurate the level is you may be fine. Everything is relative. The carrier value is subject to the same accuracy error as the peak value so even though it is far below what SHOULD be used you may be able to use it for mod. measurements only. I have used my 20 MHz scope to 30 and even 50 MHz for such measurements. I recently obtained a 100 MHz scope so that is no longer an issue.

 

[cjruger]

Ya this is kinda new to me, im atarting with the basics. Not really sure about all that you were talking about, but doing some reading about modulation and what you want to see on a scope for a am signal. I have some small cbs
From years past i want to see if i can learn to tune them

 

[wavrider]

30mhz and at least dual trace, the scope can be used for so much more than modulation and tuning radios.

Inexpensive ones can be had on Ebay.

 

[cjruger]

Ya ive been scowering ebay, what is inexpensive? Not much under 70-100$ what are some of the other things that can be done?

 

[wavrider]

Using The Oscilloscope

might give you some insight to o'scopes

 

[Captain Kilowatt]

30mhz and at least dual trace, the scope can be used for so much more than modulation and tuning radios.

Inexpensive ones can be had on Ebay.

Very much agreed. That's why I said he MIGHT get away with the other one for just modulation measurements. A scope can detect snd measure much lower levels than an RF voltmeter for when tuning and aligning also. I keep my old 20 MHz scope just as a modulation monitor on my outgoing RF and as a RX monitor on my Kenwood TS 820s which has a rx IF port allowing my to see the signals of what I am listening too.