In fear of moving off topic... I'd like to ask how one can determine the electrical downtilt of an antenna?
I just put into service a RSF/Celwave Super StationmasterR Model 10017-6 that is designed for 925-960 MHz on my 927.5250 repeater. The added gain factor of the antenna (an additional 4dBd over what was previously in place - a Decibel DB586-Y) does not seem to benefit the receive (at 902 MHz). I gained what seems like a little extra receive range, but not equal to what I seem to have gained in transmit coverage. This discussion thread leads me to wonder if maybe some electrical downtilt may be affecting the receive frequency? Is this possible? Antennas are not my strong point. ;-) Thanks, Mark - N9WYS -----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Friday, June 06, 2008 11:19 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: antenna suggestions for 440mhz At 6/6/2008 19:22, you wrote: >The series-fed types (usually fiberglass at these frequencies) *will* >tilt their patterns when moving away from their design frequency. > >Laryn K8TVZ The good news is that the pattern tilts down when used at frequencies below the design frequency. The big question is by how much. Would be easy to calculate in NECWin if I could only get a good NEC model for the coaxial colinear array. I'm not quite expert enough in NEC to figure out how to create that model. Bob NO6B
