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CTU Presents. Station Notebook & Your 2013 Antenna Projects Tim Duffy K3LR. Contest University Update. 7 th year for Dayton CTU 5 years for CTU Italy CTU Finland July 2012 CTU Australia Feb 2013 CTU Brazil April 2013
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CTU Presents Station Notebook & Your 2013 Antenna Projects Tim Duffy K3LR
Contest University Update • 7th year for Dayton CTU • 5 years for CTU Italy • CTU Finland July 2012 • CTU Australia Feb 2013 • CTU Brazil April 2013 • Over 3000 students have now attended CTU • CTU Live Stream • Look for more exciting CTU developments
Montichiari, Italy John, W2GD – aka P40W
CTU Italy 2013 IK2QEI and EA8RM
Getting the most out of CTU 2013 Ask lots of questions this weekend and keep notes – if you are not asking questions you are falling behind! • Meet someone totally new and ask them why they came to CTU • Share some of your “secrets” with others here at CTU • Commit to giving a CTU related talk or write a contesting article - in the next 12 months.
K3LR 2013 Notebook Ahha #1 RX Preamps can be good and can be bad. • Be very careful with preamps around TX RF antennas • Even the best preamps will cause bad IMD and harmonics when close TX overloads • Using protection circuits that turn off (bypass) preamps when TXing - is a good option. • Use BandPass filters when you can. • The KD9SV Front End Saver is a good idea.
K3LR 2013 Notebook Ahha #2 • Trying to RX in the same band you are TX (Field Day for example) is VERY hard to do. • Proper placement of vertical and horizontal antennas (even close spaced) can provide amazing results. • The placement is not super critical – once you know where the null is – and why it is there. • Compromised configurations will reduce the isolation. • This is not a fix all “tool” and your station “system” still needs to be very “tight” for best results.
100 watts is +50 dBm All horizontal antennas at 35 feet. One TX and One RX antenna on 20 meters Case #1 - 2 dipoles, spread 300 feet broadside to each other (worst case) = +17 dBm Case #2 – 2 dipoles, spread 300 feet side to side (both the same direction) so tip to tip = -10 dBm Case #3 – 2 three element Yagi’s spread 300 feet both at 0 degrees (max side isolation) = -20 dBm Case #4 – a dipole and the ¼ wave vertical spaced 75 feet = -160 dBm (the K3LR ahha) Case #5 - The vertical and dipole – 75 feet apart – but off the “tip” of the dipole (worst case) = +13.5 dBm
Your 2013 Antenna Projects • I hope you add to, change or improve your own antenna system this year! • Share your CTU passion with others – help THEM put up or fix an antenna. • Have an open heart to all who are willing to learn – encourage and send congratulations emails. BE AN ELMER! • Be active in your local club – not just Field Day. Join, pay dues and contribute your time experience! • Help at least TWO operators with their antenna systems and be active in your local club = a CTU 2014 discount!