MEF-130-2K-Plus Multi-Band End Fed Half Wave Antenna Transformer 49:1 Ratio
Features massive ferrite core weighing 1.25 pounds (0.54kg) and very low Insertion loss ~0.5dB
This is an End-Fed Half-Wave antenna (EFHW) transformer covering 160/10m amateur bands or any frequency in between. It transforms high impedance ~2500 Ohms at the end of the half-wave radiator to 50 Ohms and features very low insertion loss. Average insertion loss from 1.8-30 MHz is ~ 0.5 dB
NOTE: for decent efficiency and match the minimum height for a horizontal portion of the antenna is 0.1 wavelength above ground. Also, the wire cut for 1.8-2MHz will not produce harmonics in all the amateur bands up to 30MHz. They are not harmonically related ie 1.8-2MHz times 2,3,4,5,6…
- NO TUNER needed!
- NO counterpoise needed! (Grounding recommended)
- Frequency coverage of the transformer only: 1-30 MHz
- Power Handling: 2kW I.C.A.S
- Polycarbonate housing
- Hardware: Stainless Steel
- Connector: Silver/PTFE (Teflon) SO-239
Just 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-wave for 160m (~259 feet) will be two half-waves on 80m and four (4) half-wave on the 40m band etc. The wire length can be calculated by the following formulas:
- Length (feet)= 468/Frequency (MHz) or
- Length (meters)=142.5/Frequency (MHz)
Always cut a wire a bit longer to allow for tuning to your desired frequency. Tuning depends on height above ground and nearby objects. There are so many ways to install the wire and your imagination is the only limit. You can do it horizontal, vertical, sloping, an inverted “L” shape, Horizontal “L”, in “inverted “V” shape, etc.
Such an antenna will not need radials and in most cases NO Tuner at all. Be a radio amateur and do some experiments.
Grounding at the lug next to the SO239 connector is recommended! Long wires tend to collect electrostatic charges (usually when the weather is stormy) which can produce ESD (electrostatic discharge) at the end of your cable and damage your equipment.