Κάθετη κεραία AM 1610 khz

A.M. Broadcast Antennas

by W5CDT

Shown below is my 1^st prototype of an A.M. broadcast antenna for 1610KHz.

Don't laugh!!!….it's resonant, has a 1.1:1 VSWR, and works AMAZINGLY well.

The goal was to keep it under 9.8 feet in length to comply with FCC part 15.219.

Tuning is very touchy and bandwidth is always narrow for such short antennas for

1.6MHz operation. The capacitive "hat" (a pieplate) was my lazy way of lowering

the frequency by adding capacitance. To be strictly FCC legal you should

resonate your antenna without the capacitive "hat".

Shown Below is my 2^nd prototype with tuneable loading coil

Below is a close up of the tapped loading coil and tuning capacitor arrangement

 electrical model

 construction details

 3D simulation of antenna radiation pattern 

 cross sectional power plot relative to 1/4 wave antenna

After getting it all working I weatherproofed the air variable

capacitor in a nice box as shown below in the two photos...

it's hard to see the box in the right photo but it IS there.

 

Updated 12/3/1999