Amplitude of an FM wave

[unix60959]

Hey everyone, I'm new to this website. I've actually been looking over some things on the main website but this is my first post. Anyway, My question is does anyone know what the peak voltage of an non-amplified FM radio wave is? Maybe at general/average value?

thanks,


Unix60959

 

[JimB]

Your question makes no sense.

Where is this FM wave measured?

At an antenna receiving a weak distant signal - about a micro-volt.

At an antenna right next to a 50kW transmitter - several 100mV

You need to explain you question a lot more.

JimB

 

[MRCecil]

My question is does anyone know what the peak voltage of an non-amplified FM radio wave is? Maybe at general/average value?

That would vary with a number of factors, but primarily with the distance of the receiving antenna from the transmitting antenna. Generally, the signal strength would be in the microvolt range at a nominal distance. The basic consideration is the signal loss over distance.

Given an isotropic (singular point) antenna in free space, the signal loss is 6db for each doubling of distance from a specified referent. That is to say the voltage of the propagated signal is reduced by half by each doubling of the distance from the reference point given no other of a myriad of factors to consider.

 

[RCinFLA]

I have an external antenna at 50 feet for TV reception. Unfortunately there is a commercial FM station about a mile away straight down the boresight of the antenna.

I get 0.1 vrms (100,000 uV's) on this FM station at end of 65 feet RG6 with 75 ohm termination. I have two stage trap to reduce its level to avoid intermod generation on the distribution amplifier.

 

[BrownOut]

I have an external antenna at 50 feet for TV reception. Unfortunately there is a commercial FM station about a mile away straight down the boresight of the antenna.

I get 0.1 vrms (100,000 uV's) on this FM station at end of 65 feet RG6 with 75 ohm termination. I have two stage trap to reduce its level to avoid intermod generation on the distribution amplifier.

You said .1v rms and then 100,000's uV's. Did you mean 100,000's uW?

 

[unix60959]

Thanks a lot guys, that helped a ton!