[TowerTalk] Antenna Gain Figures

["Dick Green".]

Does anyone know what gain references are used by Hy-Gain, KLM, and Force
12 in their ads and literature? Both Hy-Gain and KLM use "dBd", which the
ARRL antenna book defines as gain over a dipole in free space. The antenna
book also says that a dipole over perfect ground (or salt water) has 6 dBd
of gain due to the sum of direct and reflected radiation.

In the most recent catalogs, the gain claimed by Hy-Gain for the TH7DX is
"6.57 dBd average" (it used to be "9.6 db" in a catalog I have from ten
years ago), and the gain claimed by KLM for the KT-34XA ranges from 8.5 to
11.3 "dBd" (depending on the band.) Since a dipole over perfect ground has
6 dBd of gain, is Hygain saying the TH7DX only has .57 dB more gain? Is KLM
saying the KT-34XA has from 2 to 5 db gain over a TH7DX?

I'm confused. Is anyone else?

73, Dick, WC1M


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