Hi-Z Antennas (tm) Receiving Antenna Comparison Chart

A reasonable way to judge receiving antennas is by RDF factor.

RDF or Relative Directivity Factor seems to have been popularized by W8JI where the Gain in the forward direction is divided by the gain in all other directions.

This is not a new concept as it has been documented in the late 60's by paid government research and coined with the name "SNIF" or

more appropriately Signal to Noise Improvement Factor. Being that as it may we now use the popularized RDF which can be easily calculated by modern antenna

analysis programs. Even RDF can be fraught with problems as it assumes the unwanted noise will be coming from all directions.

 Below are a series of 3D plots that begin to show how acutely different some of the modern antennas are in full pattern that carry

the same RDF value. For instance in early morning when the incoming reception angles are high the antennas with more reception at

high angles may work better than the lower angle antennas. And for long distance signals the antennas with the lower angle reception will dominate.

Also in combination with that the antennas with the higher angle back lobes may be more susceptible to noise than the antennas with low angle side lobes.

The plots and chart below point out that there is no one capture all receiving antenna, only ones that seem to shine

for DX and ones that shine for many purposes. Not all Beverage, loop, or vertical antennas will perform the same. A case in point is to look at the

350 foot BSEF 8 circle as compared to the Hi-Z 8A all active element 8 circle.

Below is a set of tabulated values for antenna comparison as well