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## [TowerTalk] Tennadyne T7 DB Gain Question

 To: [TowerTalk] Tennadyne T7 DB Gain Question n3rr@erols.com (Bill Hider) Fri, 13 Jul 2001 17:46:55 +0100
 ```That's right Tom. Since, from the original question, I deduced that the questioner was not that sophisticated, I referred him to the Force12 antenna spec URL which goes into much detail on this. Those of us who have modeled antennas for years and studied this subject will not be confused. You are correct in your comment, but it's all in the Force12 URL, so I gave him the endpoints and referenced it. Bill, N3RR -----Original Message----- From: owner-towertalk@contesting.com [mailto:owner-towertalk@contesting.com]On Behalf Of n4kg@juno.com Sent: Friday, July 13, 2001 6:09 PM To: TOWERTALK@contesting.com Subject: Re: [TowerTalk] Tennadyne T7 DB Gain Question Bill, I feel that your third paragraph is misleading and needs further clarification. Specifically, dBi = dBd + 2.18 dB in FREE SPACE. Over ground, ANY horizontally polarized antenna will pick up 5 to 6 dB GROUND REFLECTION GAIN (6 dB over "perfect ground") which has absolutely NOTHING to do with the gain characteristics of the antenna. This ground reflection gain is at the peak of the first lobe. The peak angle depends of course on height above ground in wavelengths. Tom N4KG On Fri, 13 Jul 2001 "Bill Hider" writes: > > Joe, > > dBd is "gain over a dipole". > > "Real gain", as you call it, has no meaning. Each person defines > "real gain" in their own terms. > > For horizontal antennas, you would ADD approximately 7 - 7.5 dB to > the dBd figure to get dBi, the gain over an isotropic source at the same > height. > > There is an excellent discussion on this subject in the Force12 > catalog> which is downloadable from their website: http://www.force12inc.com/ > > see: http://force12inc.com/F12-ant-specs-r31.htm > > Bill, N3RR > > -----Original Message----- > From: owner-towertalk@contesting.com > [mailto:owner-towertalk@contesting.com]On Behalf Of k0bx@qsl.net > Sent: Friday, July 13, 2001 3:02 PM > To: towertalk@contesting.com > Subject: [TowerTalk] Tennadyne T7 DB Gain Question > > I am looking to replace my Hygain DB10/15 Dualband beam with a > Tennadyne T7 18-33 MHZ log. It would be located under my Hygain > 204BA (20 Meter Monobander). > On the Tennadyne website it give the gain figure as > "6.2 dBd"? I am not sure what dBd is? Should I subtract 3 from > the figure to get the real DB gain? > Anyone have this antenna and have a comment about it? > Thanks > Joe K0BX > ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/tagj. List Sponsor: Are you thinking about installing a tower this summer? Call us for information on our fabulous Trylon Titan self-supporting towers - up to 96-feet for less than \$2000! at 888-833-3104 www.ChampionRadio.com ----- FAQ on WWW: http://www.contesting.com/FAQ/towertalk Submissions: towertalk@contesting.com Administrative requests: towertalk-REQUEST@contesting.com Problems: owner-towertalk@contesting.com List Sponsor: Are you thinking about installing a tower this summer? Call us for information on our fabulous Trylon Titan self-supporting towers - up to 96-feet for less than \$2000! at 888-833-3104 www.ChampionRadio.com ----- FAQ on WWW: http://www.contesting.com/FAQ/towertalk Submissions: towertalk@contesting.com Administrative requests: towertalk-REQUEST@contesting.com Problems: owner-towertalk@contesting.com ```
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