Creating A Delta Loop For 440Mhz Band
I like small compact easy to hide antennas...a part of life when living in a apartment. This was my first kick at the can for a delta loop. Delta loops offer a vertical or horizontal polarization (depending on where the coax gets connected). A big plus for the delta loop especially for VHF/UHF is it does not need a ground plane to operate and it gives a low radiation angle. I needed a 440 antenna so I can hit the local 440 repeater that I was having great difficulty getting into on the rubber duckie.
The follow is as such a vertically polarized antenna.
Dimensions are calculated as 1005 / freq in MHZ...to get the length in feet....due to small size I then converted it to inches to help in ease of construction.
The Delta loop is 1 full wavelength long divided almost equally into a triangle shape. I used that calculation and then trimmed it down until I got a dead flat SWR on the frequency I needed. It is quite broad banded and will do the full 440 band with ease. And with the small construction it can easily hide behind a picture frame.
The coax is connected to the antenna 1/4 of a wavelength down from the apex. It doesnt matter which side. The center conductor is connected to the wire going up towards the apex. The shield connectes to the wire leading down to the bottom corner.
I finally settled on the following dimensions