Joshi

Why when sleeve antennas are used for high frequencies they are superior to single wire or regular whip antennas in both vertical pattern and impedance characteristics. I don't understand when it states the impedance characteristics of a sleeve Antenna can attain satisfactory standing wave ratios over a wider range and radiation at low angles is much greater than a whip?

Why is the dynamic input impedance of an IF amplifier greatly affected by loading and detuning of it's tank circuit when a large resistor is placed in parallel across it, like a large resistive load. And why is it better to use a rf amplifier in this situation?