Radio attenuation with resistors

[Andrew Howard]

I was just wondering, if you have a high frequency radio with an
antenna, what would happen if you put a resistor before the antenna (in
parallel and/or series with).
Would it just attenuate it, or are there other effects as well?
Would doing the reverse (removing a resistor) stuff any thing up?

Thanks
Andrew Howard

 

[Andrew Holme]

I was just wondering, if you have a high frequency radio with an
antenna, what would happen if you put a resistor before the antenna
(in parallel and/or series with).
Would it just attenuate it, or are there other effects as well?

Yes, a large resistor in series, or a small resistor in parallel, would
attenuate the signal. Small / large in this context is relative to antenna
impendance which is normally pretty low e.g. 50 ohms.

Would doing the reverse (removing a resistor) stuff any thing up?

It depends. If the resistor is acting as an attenuator, then removal might
cause overload.
If the resistor was biasing the gate of a JFET pre-amp then removal would
stop if from working.

 

[Andrew Howard]

Yes, a large resistor in series, or a small resistor in parallel, would
attenuate the signal. Small / large in this context is relative to
antenna
impendance which is normally pretty low e.g. 50 ohms.


It depends. If the resistor is acting as an attenuator, then removal
might
cause overload.
If the resistor was biasing the gate of a JFET pre-amp then removal would
stop if from working.

Thanks for the info.

Andrew Howard