Measuring AC at Radio Frequencies

6f6 · 26th August 2008, 08:32 PM

I'm looking to build a small transmitter (using only"useless" tv tubes) for broadcasting onto antique radios. My question: What equipment would I use to get an accurate measurement of the AC voltage (rms) generated at the local oscillator (Armstrong type) at 8.200 MHZ? I connected a 560 pf cap to the plate and to a 47k resistor and got readings on the order of a few millivolts with my multimeter. Do you this is just typical?

Miles Prower · 26th August 2008, 08:56 PM

Quote:

Originally posted by 6f6
My question: What equipment would I use to get an accurate measurement of the AC voltage (rms) generated at the local oscillator (Armstrong type) at 8.200 MHZ?

An o'scope, and for accuarcy, make sure the BW is 20MHz or better.

nhuwar · 26th August 2008, 09:01 PM

I agree with Miles use an oscope but you could also score an hp rms ac volt meter off ebay. Like a 400e. They can handle a signal of a few mhz's.

Nick

26th August 2008, 08:32 PM	#1
6f6 diyAudio Member Join Date: Oct 2006	Measuring AC at Radio Frequencies I'm looking to build a small transmitter (using only"useless" tv tubes) for broadcasting onto antique radios. My question: What equipment would I use to get an accurate measurement of the AC voltage (rms) generated at the local oscillator (Armstrong type) at 8.200 MHZ? I connected a 560 pf cap to the plate and to a 47k resistor and got readings on the order of a few millivolts with my multimeter. Do you this is just typical?

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26th August 2008, 09:01 PM	#3
nhuwar diyAudio Member Join Date: Jan 2007 Location: Tomball Texas	I agree with Miles use an oscope but you could also score an hp rms ac volt meter off ebay. Like a 400e. They can handle a signal of a few mhz's. Nick

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