Hi Having worked with such patterns -the result is up to your imagination.
The most commonly used was an omni and yagi. EG:A 6dB omni phased with a yagior corner reflector . This gives you a typical Butternut pattern as viewed from the top. This would be used in a case where a 2-stacked dipole of 3dB gave good all round coverage but a specific direction required additional coverage. The c-450 uhf system used many of these types of patterns to give the highways the best coverage possible. I am surprised many ham repeaters do not do the same.I have been doing some experimentation with cross-field coverage using the same principle. Regards Bradley Glen ZS5WT South Africa --- Thomas Oliver <[EMAIL PROTECTED]> wrote: > I saw an article on something like this myself, > There was this guy that had a tower with very wide > face (20 ft.) and wanted to have an omnidirectional > pattern so he tried the yagi approach and actually > ended up with a great omni pattern but the gain > ended up being unity or slightly above due to the > interaction of all the lobes of the yagis. Anyway > that is how I remember the outcome. > > > tom n8ies > > > ----- Original Message ----- > From: TOM MANNING > To: Repeater-Builder@yahoogroups.com > Sent: 3/29/2005 10:44:00 PM > Subject: Re: [Repeater-Builder] Re: A Good 440 > Antenna > > > Skip > This type antenna setup is of interest to me. > We have our repeater antenna atop a 150 ft water > tank but the cell antennas have taken over. The > owner told us we would have to live with the cell > people as they were paying customers and we aren't. > My idea is that we could use four yogis around the > rails with the power divided into four equal parts > with the yogis fed in phase and get somewhat a round > radiation pattern. Any info as you said would be > greatly appreciated. > Thanks. > de Tom Manning, AF4UG > > skipp025 wrote: > > re: Multiple feed antennas around a tower: > > This type of antenna was written up in Ham Radio > Magazine (rip) some years back. I just thumbed > past it the other day. > > The math and the information to cover around a > large tower with a quasi Joni pattern using > directional antennas was shown. > > If I see it again, I'll scan it and send it > in. I sure miss Ham Radio Magazine... > > skip > > > > Mike Morris WA6ILQ <[EMAIL PROTECTED]> wrote: > Years ago I saw a weird situation - a pair of 4-bays > on opposite sides of the tower, fed by a KM 2-port > power splitter. Later at a different site I saw a > custom > pattern engineered with a 4-port splitter and 4 beam > antennas. > How they kept them from interacting and screwing up > the pattern I'll never know... > > In your case you might be able to mount the dipoles > to the tower leg itself, perhaps with some magic > distances to get an Joni pattern. This would leave > the top of the tower bare ... let the tower itself > be > the lightning rod. > > I'd measure the tower face and make up a drawing > showing the 4 sides (or 3 sides?) of the tower, and > your mounting concept. Then contact the engineer > at the antenna company (via email or phone) and fax > the drawing to him and get his ideas. > > Mike WA6ILQ > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > > > > > Yahoo! Groups Links > > To visit your group on the web, go to: > http://groups.yahoo.com/group/Repeater-Builder/ > > To unsubscribe from this group, send an email to: > [EMAIL PROTECTED] > > Your use of Yahoo! Groups is subject to the Yahoo! > Terms of Service. __________________________________ Do you Yahoo!? Yahoo! Mail - Easier than ever with enhanced search. Learn more. http://info.mail.yahoo.com/mail_250 Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
