VLF Transmitter Cutler - Antenna Maintenance

Antenna Maintenance

Antenna maintenance is performed during the summer months. During maintenance periods the station transmits on one array while people work on the other array, which is grounded. This allows continuous transmission, crucial since the Navy closed Annapolis (NSS), the only other East Coast VLF station.

The region where the two arrays come close together, near the transmitter house, is called the "bow-tie area". There are two panels and three towers from each array in this area. The fields on the grounded array are highest in the bow-tie area due to proximity to the active array. The present station operating procedure, based on a past RADHAZ survey, does not allow work on the bow-tie area towers or panels while transmitting on the other array. There is an ongoing tower painting project at Cutler scheduled for completion over the next few years. Under the present station policy, completion of this project would require several months of total downtime, which is unacceptable.

Test transmissions have been arranged, during which only four panels of one array shall be connected to the transmitter. The objective of the four-panel tests was to allow painting and normal maintenance on the bow-tie area towers of an inactive array. A secondary objective of the tests is to determine the antenna operating parameters which had not been measured since changing to 24.0 kHz.