Buddipole 4NEC2 Model Files

I have found a way to post my 4NEC2 Buddipole modeling files on line using Google Documents.

Eventually I will log many of my design files here for anyone to use.

4NEC2 is available at http://home.ict.nl/~arivoors/

Below is a list of the files I have created.

FILE AC_Vbud_40M_09_V01 40m Vertical, (longwhip, 4 dipole arms, red coil)
FILE AC_Vbud_40M_08_V01 40m Vertical, (longwhip, red coil, 4 dipole arms)

Detailed Files:

FILE AC_Vbud_40M_09_V01

Description, LongWhip with RedCoil and 4 Dipole Arms on VersaTee w/ TRSB set to 25ohms (2:1) and 1 8.6m Counterpoise.

This is a new configuration
a) attempting to generate a lower takeoff angle and more gain
b) 40m PSK31 frequency (7.07MHz)
c) Red coil was moved to below the arms and whip
d) Suggested by Ray (K7RFW)

1 fully extended Long Whip
4 22" Dipole Arms
1 RedCoil tapped turns from Bottom
1 Versatee
1 TRSB,(2:1) 25 ohms
1 8.6 (m) Counterpoise

Takeoff angle	30	degrees
Gain	0.0	dBi
SWR	1.6	into 25 ohms

Conclusion:
Moving the red coil to below the dipole arms, resulted in a modest loss of antenna gain from 0.6dBi to 0dBi, the take off angle remained the same at about 30degrees. The inductance needed to maintain the antenna at resonance (7.07MHz) was reduced from 15uH (18 turns form the bottom) to 10uH (25 turns from the bottom). Best case SWR was increased from 1.1 to 1.6 as the impedance of the antenna decreased from 22.5ohms to 15.6ohms.

Overall, I would take from this, that is it better to not have the coil placed adjacent to the feed point.

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FILE AC_Vbud_40M_08_V01

Description, LongWhip with RedCoil and 4 Dipole Arms on Versatee w/ TRSB set to 25ohms (2:1) and 1 8.6m Counterpoise.

This is a new configuration
a) attempting to generate a lower takeoff angle and more gain
b) 40m PSK31 frequency (7.07MHz)

1 fully extended Long Whip
1 RedCoil tapped 18 turns from Bottom
4 22" Dipole Arms
1 Versatee
1 TRSB,(2:1) 25 ohms
1 8.6 (m) Counterpoise

Takeoff angle	30	degrees
Gain	0.63	dBi
SWR	1.11	into 25 ohms

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