Its probably a pretty decent medium gain suburban antenna. Fairly directional, with tight beamwidth and high F/B Ratio except at the very bottom channels of VHF High.
Rando, in my antenna thoughts of late. I think that the AntennaCraft G1483 may be the absolute best set and forget solutino as an antenna for you. The "4 Bay" version at Summit Source. In my studies my esteem for this antenna continues to rise.
What the dimensions are makes it impossible to really evaluate. I suspect those db figures are dbi. A log periodic doesn't generally get much more gain by being longer, but tends to have more elements of more different lengths to cover a wider range of frequencies. My experience with reading about log antennas of this design I think even using dbi, these are slightly exaggerated gain numbers. It's always been the thing to do by companies that want their gain to look as good as possible, use dbi and maybe fudge it a little on the high side.
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The more I understand, the less I know.
You may want to remind readers that there is nothing wrong or deceptive about posting gain in dBi. If you look at the IEEE definitions of gain you will find that it is fundamentally tied to the concept of an isotropic radiator.
Per IEEE definition, the word "gain" only refers to an antennas ability to focus power in a particular direction. It does not include mismatch losses! IEEE "realized gain" however does include mismatch loss.
Strictly speaking, if you only have a "gain" curve, you only know how well an antenna focuses and nothing more. This makes it easy to post a higher number since mismatch losses are left out.
If, in addition to the "gain" curve, you also had a VSWR or Return Loss curve (referred to a particular transmission line impedance) you could compute mismatch loss and subsequently compute "realized gain" for the antenna connected to that line.
All the modern antenna simulators I have used output gain in dBi.
When making measurements in the lab, one might use a calibrated half-wave dipole antenna as a reference and then record gain numbers in dBd. I believe its safe to say that this is the only time most antenna engineers would be thinking about gain in dBd these days.
I hope this might add some clarity for those less familiar with the various antenna terms.
New Antenna Spotted!
Linear Mode
