You're not going to need 15 dBi. Link budgets are way different at VHF than Microwave.
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Mike Hammett Sent: Monday, April 05, 2010 12:46 PM To: WISPA General List Subject: Re: [WISPA] WISPA TV Whitespaces Meeting with the FCC My experience is mostly limited to the WISP market (though I'm not completely ignorant of other markets). Innovation is always welcome, but any sector that delivers approximately 90 degrees and 15 dBi performance is going to be huge. ----- Mike Hammett Intelligent Computing Solutions http://www.ics-il.com -------------------------------------------------- From: "Mike" <[email protected]> Sent: Monday, April 05, 2010 12:39 PM To: "'WISPA General List'" <[email protected]> Subject: Re: [WISPA] WISPA TV Whitespaces Meeting with the FCC > Have you ever taken a really good look at an FM broadcast antenna? Most > are > circularly polarized so they can be received by both horizontal and > vertical > receive antennas. Even at 90 MHz they aren't that large either. My > choice > of sector would be something like that, and would be made of aluminum > parts, > not panels like we are used to using now. I predict circular polarity > will > be the norm. Why? Because theoretically, a receive antenna of opposite > circular sense exhibits infinite loss. My experiments have shown that > reality is less, but you CAN expect at least 30 to 40 dB of isolation. > The > same 6 MHz segment could be reused on the same tower. The phasing harness > on the CPE antenna would have to set to either left hand or right hand > circular polarization. > > Friendly Regards, > > Mike > > Mike Gilchrist > Disruptive Technologist > Advanced Wireless Express > P.O. Box 255 > Toledo, IA 52342 > 239.770.6203 > [email protected] > > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Mike Hammett > Sent: Monday, April 05, 2010 12:23 PM > To: WISPA General List > Subject: Re: [WISPA] WISPA TV Whitespaces Meeting with the FCC > > Then the problem arises of frequency reuse if we have such low gain > antenna > all over the place... and the size of a sector antenna for towers. > > > ----- > Mike Hammett > Intelligent Computing Solutions > http://www.ics-il.com > > > > -------------------------------------------------- > From: "Mike" <[email protected]> > Sent: Monday, April 05, 2010 11:59 AM > To: "'WISPA General List'" <[email protected]> > Subject: Re: [WISPA] WISPA TV Whitespaces Meeting with the FCC > >> Just for discussion, let's say a TV LPDA has a gain of 8 dBi. It will >> cover >> the entire VHF TV band, and by superimposing a UHF LPDA on the same mast, >> can cover the entire UHF TV band with similar gain figures. >> >> I'd make this challenge: >> >> I could TRY to hide a TV band LPDA on my property and beg you to find it. >> Even well hidden, you would. Now, give me a few hours to build a narrow >> band antenna with similar gain in ANY 6 MHz segment of the same bands, >> and >> let me try to hide it. Do you think I could hide it well enough you >> wouldn't find it? I know I can. >> >> My point is, the antenna which will be needed for any segment of the >> whitespace will be much less intrusive than the LPDA (or Yagi) being used >> for comparison. >> >> This is great dialogue. I hope we are faced with the challenge of >> deploying >> in these bands. >> >> Mike >> >> >> >> >> > ---------------------------------------------------------------------------- > ---- >> WISPA Wants You! 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