Installing flags on antennas will alter the characteristics of the antenna. If a flag is installed on any antenna that was previously tuned, the SWR must be rechecked and the antenna retuned. Likewise, if the antenna was tuned with a flag in place and that flag is removed, the SWR must be rechecked and the antenna retuned. There is a possibility that adding a flag to an antenna may change the environment enough that the antenna may no longer function properly with the transmitter. Any time the environment around the antenna is changed, it is imparative that the SWR be retested. High SWR, typically 3.0:1 or higher, can cause damage to the transmitters circuitry.
Updated Dec. 15, 2011