I also used a 3db collinear as a TX at the same height as the 4 bay dipole, and noticed quite a bit more isolation just from that antenna. I believe the folded dipoles radiation pattern allows for many more vertical spikes, So you should be in great shape with those station masters and said filtering. In your second question, yes. I was thinking about going down that same road for RX only. If both your receivers have pass cans you may try this. From your dual band RX antenna feedline run a T to you uhf and vhf cavities. Use a UHF ¼ wavelength + velocity factor and coupling loop depth, jumper to connect you VHF pass cavity. Then calculate the save VHF length for the UHF cavity I havent done this yet so let me know how it goes. HiHi Ross kc7rjk -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of kc0mlt Sent: Wednesday, June 02, 2010 10:12 AM To: [email protected] Subject: [Repeater-Builder] Re: Antenna separation question Thansk for the input. That is almost exactly what I'm going to put on the air as far as cans go. I'll have a Hamtronics exciter and receiver amped up by a 110 Watt Micor base amplifier. Just about the same heights too. Antennas are both staion masters. but I like knowing that what I have been thinking about will actually work.
One other question someone may know. Is it possible to run say a VHF and a UHF repeater off a dual band antenna with a diplexer or is there going to be issues. Thanks Wade KC0MLT --- In [email protected] <mailto:Repeater-Builder%40yahoogroups.com> , "Ross Johnson" <kc7...@...> wrote: > > That's exactly what I'm doing. VHF GE mastrII at 100 watts goes through > 2 8" Sinclair pass cavities set at .5db gives 80 watts to the antenna. 4 > bay exposed dipole at 75' The receiver and preamp goes through only one > 8" Wacom also set at .5db then up to the collinear receive antenna at > 100' Very very little desense almost undetectable. Also with the pass > cavity on the receiver side preamps seem to be much more usable and > effective in the real world. This machine hears very very well! More can > be seen from my website. www.kc7rjk.net <http://www.kc7rjk.net/> > > ~Ross > > -----Original Message----- > From: [email protected] <mailto:Repeater-Builder%40yahoogroups.com> > [mailto:[email protected] <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of kc0mlt > Sent: Tuesday, June 01, 2010 10:28 AM > To: [email protected] <mailto:Repeater-Builder%40yahoogroups.com> > Subject: [Repeater-Builder] Antenna separation question > > > Ok just kicking this idea around the other day and the question came up > about antenna separation. I know the basic 2 meter antenna separation is > 50ft. (I am thinking 60ft to be safe) But is it possible to get them > closer if I place some cavities on either the receive or transmit sides. > Sounds dumb from some certian points of view, but I am waiting on the > arrival of a decent duplexer (could be some time out though)so in the > mean time I would like to get this up and going with a split antenna > system for now. I was thinking maybe a 30ft separation... Would this > idea work? If so does it need to be modified from what I was thinking? >
