Andy At the risk of being obtuse, why did you adjust the receive port ? I assume the objective of your adjustment was to match the feeder to an optimised 50 ohm system.
Using Xp and Xs in an L network between the feeder and the circulator as Eric suggests is one method. Another method is to adjust the port 2 (Antenna) matching for minimum tx power at the receive port. However as this is typically a single capacitor, some additional work with a line stretcher on your feeder would be required to obtain a true minimum. Ian Ashford G8PWE www.gb3dx.com ----- Original Message ----- From: "Andy Hearn" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Friday, October 08, 2004 12:20 PM Subject: [Repeater-Builder] Re: Re Circulator > > Andy Hearn wrote: > > > > > > HI > > > I have just changed my 70 cm repeater antenna over to a co-linear > 8 > > > dBd gain, was running 2 full wave dipoles stacked (reason..antenna > > > faults and not able to mount with correct vertical spacing). > > > > > > When I was calibrating the circulator on the bench, all set up > > > perfectly, with the receive port being sharp in its setting. > > > > > > On site since the antenna was running a slightly higher VSWR > > > compared to a dummy load (1.2:1), I thought it might be an idea to > > > just tweak the receive port to optimise the rejection. However I > > > found the tuning to be very flat, question, is this normal or am I > > > missing something? > > > 73 > > > Andy G3UEQ > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > > > > > > > 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/
