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 [email protected], "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 <*> 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/
