Is there any way that you can get one of the antennas into a different horizontal plane? i.e. mount the new antenna a few feet lower? Your vertically polarized antenna does not put out much power in the straight down direction, so even 15-20 feet might buy you enough isolation.
This may help: <http://www.repeater-builder.com/antenna/separation.html> Mike At 03:51 PM 6/1/04 +0000, you wrote: >Answering my own questions...on the repeater-builder.com site there >is this great links: > >http://www.decibelproducts.com/collateral/aboutrfcommunications.pdf > >On Page 4-26 there are charts showing the db separation I was looking >for. At a horizontal spacing of just 40 inches it looks like >the 'isolation' will only be 15 db at most. Also I would guess there >will be significant issues regarding the effect upon the radiation >pattern. If I could notice it is another issue. > >Still thinking about the affordable solution..... > >Ron N5IN > >--- In Repeater-Builder@yahoogroups.com, "Ron Stordahl N5IN" ><[EMAIL PROTECTED]> wrote: > > Back to the project...getting a 147.09tx/147.69rx repeater and >144.39 > > APRS on the same antenna...I received many good answers and links >to > > assist me. > > > > HOWEVER...looks like the costs are such that I could consider >another > > route..namely two antennas/transmission lines, one for 144.39 and >the > > other for the 147.09+ repeater. The tower is 200' and we have line > > and antennas available, so cost wise this is a sensible way to go. > > > > My first choice would be to put both antennas one the top, in the > > same horizontal plane. Actually we have to go to the top to get >away > > from a flock of 2.4 GHz 802.11b service antennas. The physical > > separation between out antennas will be the issue..the tower has a > > 40" face, so the simple install would have the two antennas (specs > > claim 6 dbi) 40 inches apart. > > > > Are they any tables someone could point to which would tell me what > > the db separation this would achieve so I could see what might be > > required in cans to make this approach work? > > > > The radios are Motorola Micors which have pretty good filters in >the > > front ends. > > > > Ron N5IN > > > > > > >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: http://docs.yahoo.com/info/terms/
