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

300+ attended CTU Italy 2013

CTU Italy 2013

IK2QEI and EA8RM

2013 Wyong CTU Australia

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

  

It’s 2359 Zulu – Are you worried about your connectors?

Use the best connectors possible – here is a premade cable

See Article in November 2012 QST

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!