Loops are amazing antennas and are very very quiet for receiving. They do null off signals on either side and give a low radiation pattern off each end. Although loops are used more so for receiving than transmitting this design takes into account both. Enter the frequency and velocity factor of the 75Ohm cable to be used and hit calculate. It will spit out the results of how long the circumference of the loop should be as well as the length of 75 Ohm cable. Its very important to know the velocity factor of the 75 Ohm cable without it the matching section will not come out properly and trying to get a good 50 Ohm match into the antenna will be more difficult.

Creating a multi-element antenna from this should be simple. Take the circumference of the radiating element and multiply by 5 percent. Vary the length from the radiating element to give the front to back ratio your looking for. However make sure before you attempt to add a reflector to have the loop perfectly tuned.

You might want to download my Coax Cable Chart to go by for information on the velocity factors of your coax cable if you do not know yours

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