Iterations on Element Count
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Why? More elements provide higher gain. The returns diminish at some point, however. Let us discover where that point is.

• Antenna: Log Periodic Sawtooth Array
• Frequencies: Elements = 16.2-46 MHz; Range = 17.6-30.4 MHz; Analysis @ 24.89 MHz
• Impedance: 300 Ohms
• Length: 16 m
• Elements: Count = 8-20; LHA^* = 7.8°-16.8°; Diam = 1.628 mm (14 AWG)
• Boom: Spacing = 200 mm, parallel; Diam = 2.588 mm (10 AWG)
• Segments: 120/Lambda
• Analysis: NEC2 via Nec2Go, version 2.1.24
• Quality: 1.00 ≤ AGT ≤ 1.03 @ 20 & 8 element counts
• Download: ZIP Archive All 24 models in each of three formats: NEC, ANT & MAA

^* Leading Half-Angle. Ref. Definition

Ref: How I define saw teeth ☞Link

SWR vs Element Counts

Z_in near 300Ω, 1/𝜏 = 1.06740, LHA = 18.629°

Z_in near 300Ω, 1/𝜏 = 1.05969, LHA = 16.737°

Z_in near 300Ω, 1/𝜏 = 1.05357, LHA = 15.186°

Z_in near 300Ω, 1/𝜏 = 1.04444, LHA = 12.799°

Z_in near 300Ω, 1/𝜏 = 1.03798, LHA = 11.052°

Z_in between 200Ω & 300Ω, 1/𝜏 = 1.03315, LHA = 9.720°

Z_in near 300Ω, 1/𝜏 = 1.02941, LHA = 8.673°

Z_in between 200Ω & 300Ω, 1/𝜏 = 1.02643, LHA = 7.828°

Conclusions: 10 elements provided the smoothest SWR. Gain increased with more elements, but only by a tiny amount. More elements clearly helps out F/R at the bottom-frequency end.

Radiation Patterns @ 24.89MHz vs Element Count

  8 Elements   7.27 dBi Gain

  9 Elements   7.67 dBi Gain

  10 Elements   7.73 dBi Gain

  11 Elements   8.02 dBi Gain

  12 Elements   8.44 dBi Gain

  13 Elements   8.85 dBi Gain

  14 Elements   8.86 dBi Gain

  15 Elements   8.71 dBi Gain

  16 Elements   8.68 dBi Gain

  17 Elements   8.91 dBi Gain

  18 Elements   9.07 dBi Gain

  19 Elements   9.02 dBi Gain

  20 Elements   8.79 dBi Gain

Conclusions: Max gain for 24.89MHz is got with 18 elements. Maybe not enough extra, though, to risk that bump in the SWR chart for 18 elements. Split the difference and go with either 14 or 15?