Chameleon Antenna: CHA EMCOMM III PORTABLE
The EMCOMM III Portable antenna is a portable High Frequency (HF) antenna specially designed for short to long range portable and man-pack HF communications. The EMCOMM III Portable antenna is ideal for hiking, backpacking, and both tent and Recreational Vehicle (RV) camping. It is also highly suitable for military, government agencies, non- governmental organizations (NGOs), Military Affiliate Radio System (MARS), Civil Air Patrol (CAP), Amateur Radio Emergency Service (ARES) / Radio Amateur Civil Emergency Service (RACES), Salvation Army Team Emergency Radio Network (SATERN), and amateur radio operators (hams) involved in field communication and disaster preparedness.
The EMCOMM III Portable antenna is configurable to facilitate Near-Vertical Incident Sky wave (NVIS) communication and will support most Automatic Link Establishment (ALE), frequency-hopping, and spread- spectrum modes and operations. An antenna tuner or coupler may be required for in some instances. The EMCOMM III Portable antenna can be deployed by the operator in the field in less than 15 minutes, using almost any available support, with no masts or guying required.
The EMCOMM III Portable antenna is comprised of a matching transformer, a 73 foot antenna wire on a line winder, and a 25 foot counterpoise - making a highly portable and effective HF antenna system.
CHA EMCOMM III Portable Specifications:
- Frequency: 10M - 160M
- Power: 100W SSB or 50W CW
- Length: 73' + 25" Copper Clad KEVLAR PTFE (Teflon) (-70°C to 150°C) wire
- Weight: 1.5 Lb.
The antenna system consists of:
- 1 X CHA EMCOMM III matching box
- 1 X 73' Copper Clad KEVLAR Wire (Radiator)
- 1 X 25' Copper Clad KEVLAR Wire (Counterpoise)
Inverted “L” / Sloping Wire Configurations
The EMCOMM III Portable antenna, Inverted “L” and Sloping Wire configurations, see figure (1), are medium to long range HF antennas. They should provide acceptable ground wave and sky wave propagation. The Inverted “L” and Sloping Wire configurations are excellent general-purpose antennas and are a good choice when two supports are available (for the Inverted “L”) or one support (for the Sloping Wire) and there is sufficient time for site selection and installation. Installing the antenna at a height of around 25 feet or higher will provide good performance. These configurations are predominately omnidirectional on lower frequencies, slightly favoring the end of the antenna on upper frequencies.
End-Fed Inverted “V”
The EMCOMM III Portable antenna End-Fed Inverted “V” configuration, see figure (1), is a medium range HF antenna. The End-Fed Inverted “V” is a good compromise between performance and ease of installation since it requires only one center support, has a reasonably small foot-print, and provides good sky wave propagation. The center should be mounted at a height of around 25 feet and when mounted at this height, the antenna will be omnidirectional at lower frequencies and predominately bidirectional broadside to the antenna on upper frequencies.
Horizontal End-Fed (NVIS)
The EMCOMM III Portable antenna Horizontal End-Fed (NVIS) configuration, see figure (3), is a short to medium range HF antenna. The Horizontal End-Fed configuration will provide good NVIS propagation on lower frequencies and medium range sky wave propagation on upper frequencies. It requires two supports and should be mounted at a height of around 25 feet for good overall results. When mounted at this height, the antenna is omni-directional on the lower frequencies and predominantly bidirectional towards the ends of the antenna on the upper frequencies.