What might cause erratic changes in SWR readings?

Erratic changes in Standing Wave Ratio (SWR) readings can be caused by a loose connection in the antenna system or the feedline. SWR is a measure of how efficiently radiofrequency power is being transmitted through the antenna system. A loose connection can lead to intermittent contact, which causes variations in the impedance presented to the transmitter. This affects how much power is reflected back from the antenna system to the transmitter, leading to fluctuating SWR readings.

When connections are not secure, the integrity of the signal path is compromised. This may introduce additional resistance or reactance, resulting in inconsistent readings as the radio waves' transmission characteristics can change based on the quality of the connection. Therefore, ensuring all connections are tight and secure is crucial for maintaining stable SWR readings and optimal performance of the radio setup.

Other factors, such as modulation or interference, do not typically directly cause erratic SWR readings; instead, they may lead to broader issues of signal quality, but not necessarily to fluctuation in SWR, which is specifically a reflection of impedance and matching within the antenna system.