Nat SM05, Installation And Operation Manual

Page: 15 / 56

VHF Transceiver Manual SM05 Rev 4.00
Nov 26, 2003 Page 1-5
ENG-FORM: 800-0107.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.3.5 Antenna Selection Guide
This guide shows some industry standard antennas which can be used with NAT NT-
Series Transceivers, and gives a range of mechanical choices where possible.
2.3.5.1
VHF Lo-Band Antennas 30-50 MHz Range
Transceiver
Tryvec/Avant Comant Foxtronics Type
NT30A/B
AV224 (-15 to -6dBi) Bent blade
AV402 (-10 to -4dBi) Whip
AV404 (-3dBi avg.) Whip
AV430 (-8 to -4dBi) Whip
AV504 (-3dBi avg.) Bent whip
CI-233 Whip
FLX-3050B
Active*
*The Foxtronics antenna will tune all channels with relatively low losses. An
external coupler (Foxtronics) is required, along with an interface adapter from
NAT (RS12-020).
Antennas with losses of over -6dBi (dB with respect to isotropic source) will dramatically
reduce transmit power and receive sensitivity. Special order, fixed tuned, narrow
bandwidth, single frequency whips are available from Comant. Spiral wound aircraft CB
whip antennas (Antenna Specialist, etc.) can also be cut down in length to produce
resonant antennas with very low losses for frequencies in the higher 30-50 MHz range.
Note that these will be very narrow in bandwidth, and must be tuned (by cutting) very
carefully.
Substantial ground plane area is required in this band split, and poor antenna locations
may produce very large mismatch losses at different frequencies.
2.3.5.2
VHF Hi-Band Antennas 136-174 MHz Range
Transceiver
Comant D&M Type
NT136 C-63-4 Whip
CI-177-1
Whip
NT150 CI-292-4
C63-4/A Whip
CI-292-3 C63-3/A Bent Whip
CI-145 Blade
CI-177 Whip