MEF-530-3K

Description

MEF-530-3K Multi-Band End Fed Half Wave Antenna Transformer 49:1 Ratio (2450:50 Ohms)

 Legal power using as much as 3kW ICAS and 1000W on FT8/ Digital modes

Features massive ferrite core of three (3)stacked  3.1 inches (79mm) in diameter and very low Insertion loss of less than 0.15dB

This is an End-Fed Half-Wave antenna (EFHW) transformer covering 40-10m amateur bands or any frequency 5-30MHz. It transforms high impedance ~2450 Ohms at the end of the half-wave radiator to 50 Ohms and features very low insertion loss. Average insertion loss from 5-30MHz is less than 0.15dB

• NO TUNER needed!
• NO counterpoise is needed! (Grounding recommended)
  • Adding a wire radiator of ~133 feet makes this antenna resonant on 40/30*/20/17/15/12 and 10m.
  • The wire of ~67 feet will give you a low VSWR on 40/20/15 and 10m bands
• Frequency coverage: 5-30MHz
• Power Handling: 3kW I.C.A.S
• FT8/Digital modes at 1000W is continuous!
• Polycarbonate housing
• Hardware: Stainless Steel
• Connector: Silver/Teflon SO-239

 Assembly

Add 1/2 half-wave wire to this transformer and tune the length to your preference. Note that the antenna will be working on multiple frequencies. Half-waves for 40m (~67 feet) will be two half-waves for 20m  If you desire to use it on any frequency between 5-30MHz, just cut the half-wavelength wire for that frequency. The following formulas can calculate the wire length:

• Length (feet)= 468/Frequency (MHz) or
• Length (meters)=142.5/Frequency (MHz)

Always cut the wire a little longer to allow for tuning to your desired frequency. Tuning depends on the height above the ground and the presence of nearby objects. There are numerous ways to install the wire, and your creativity is key. You can position it horizontally, vertically, at an angle, in an inverted “L” shape, in a horizontal “L” shape, or in an inverted “V” shape, among other configurations.

Note: The minimum recommended height for a horizontal portion of the antenna is 0.1 wavelengths above the ground. While it can function at 30 feet above the ground, its efficiency is reduced due to increased ground loss (absorption).

An antenna of this type will not require radials, and in most cases, you won’t need a tuner at all. Embrace your inner HAM radio operator and conduct some experiments! 

It is recommended to ground the lug next to the SO239 connector. Long wires can collect electrostatic charges, especially during stormy weather, which may result in electrostatic discharge (ESD) at the end of your cable, potentially damaging your equipment.