Thursday, February 21, 2013

Titan DX part 2

I have been toiling over the models for the Titan for some time now.  I promised some results here but I am not willing to release what I have learned until I am sure of the accuracy.  Currently the models show some real promise but are not yet verified.  I am still unable to simulate the 80 meter operation of this antenna which disappoints me a great deal. 

The primary problem in modeling this antenna is the feed method.  The coaxial cable supplied by Gap runs the length of the antenna but the shield is split at the "gap" to provide the feed.  The 80 meter tuning capacitor is connected between the center conductor and shield at the very top of the antenna. The center conductor then ties to the very top of the antenna.  I have been using the capacitance of the coaxial cable in series with the feed point to complete the feed connection.  At this point, I see a number of VSWR nulls at approximately the correct frequencies (within 1 to 2 MHz) but no null for the 80 meter band.   I am still working on the models to improve the results. 

The 3D antenna patterns at the VSWR nulls are not bad at the higher frequencies.  The gains are roughly 2.6dBi for 10, 12,and 15 meters in the models current state.  The remaining bands display either 0 or negative gains at this point and that is the reason for the questioning the accuracy of the model. 

I will continue to explore and hopefully report results very soon.

Until next time

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