High VHF Omni-Directional Antenna for 174-216 MHz
Model: PA31-RYFD - High VHF Turnstile Antenna
The PA31-RYFD turnstile antenna is a horizontally polarized antenna covering the high VHF band from 174-216 MHz. The antenna is fine tuned and supplied in 6 MHz increments for any of the high VHF channels from 174-216 MHz. The PA31-RYFD is composed of aluminum and can be installed as a side mount antenna or a top mount antenna. The folded dipole radiating elements are shipped disassembled from the support mount to reduce shipping volume, thus minimal on-site assembly is required.
The antenna has a VSWR of less than 1.15:1 across any of the 6 MHz channels in the high VHF band and can be fine tuned for a VSWR of less than 1.10:1 on channel(s). The addition of multiple antennas stacked vertically (one on top of another) increase overall gain and ERP of the array. For example, four (4) PA31-RYFD antennas stacked vertically on a mast is a 4-bay array with gain being +6 dB higher than a single PA31-RYFD.
The folded dipoles that comprise the antenna are mounted 90 degrees to each other called "turnstile", therefore, an omni-directional coverage pattern is created. The harnesses feeding each dipole are phased in such a way that, at the antenna input connection point, each dipoles' VSWR cancels a large percentage of the other dipoles' VSWR in a quadrature hybrid fashion, creating a very simple antenna that has exceptionally low VSWR. The PA31-RYFD is ideal for low power operators or where the mounting structure cannot handle a larger antenna and higher wind load values.