What is it?

A complete kit to build an antenna trap that can be used in efficient multi-band antennas such as dipoles or end-fed half wave antennas (EFHW). The trap is very lightweight (2.5 grams per trap) and small, which helps quick deployment of the antenna. The trap is rated for 20 watts, hence usable for QRP and slightly above.

This is a kit and needs assembly. You will need to wind the toroid with the supplied magnet wire, solder the toroid and an 0805 sized SMD capacitor to the PCB, adjust the trap to the desired frequency and fix/seal the finished trap with glue or epoxy. Assembly can be challenging as it requires both electronics and mechanical skills and the dimensions of the PCB and capacitor are very small.

The kit contains the following:

1 PCB 1 T50-6 or T50-2 toroid (depending on the desired frequency, see options) 1 SMD 0805 capacitor rated at 500V or more (capacity depending on the desired frequency, see options)

Tuning the trap requires at least a VNA (vector network analyser). If you don't already own one, get one of the clones on Aliexpress or Ebay for ~USD 50, it will be very useful when building and deploying your new antenna (and there are many more use cases).

CAUTION: please take wire diameter and PCB stability into account when using these traps for wire antennas longer than 21 meters. Due to the cable weight you most probably need additional mechanical enforcement to lower strain onto the small trap PCBs.

The antenna wire mounting holes are suitable for wires up to 1.5mm diameter (with insulation). The holes can be extended with a driller for slightly thicker wires.

I also offer suitable tiny kits for dipole and EFHW antennas, that go along with these traps just perfectly. Please have a look at them:

• Tiny EFHW
• Tiny 1:1 Balun for dipole
• Tiny 1:1 Hybrid Balun, combined 1:1 voltage and current baluns on one board

Why did you make it?

Working primarily QRP, often portable I wanted to have a minimal system as lightweight as possible. Often, antennas make up a considerable amount of space and weight of the overall system and I looked into ways to minimize this. Additionally, trapped antenna types are often more efficient than other types of multi-band antennas.

What makes it special?

It's size and simplicity. The resulting antenna is lightweight, compact and can be deployed quickly.