SOTA Dipole 2004 - 2013

With the 2m SOTA Beam available for VHF, but not a lot of activity on this band around here ... I decided to start building a Portable Dipole, based on the mounting principles of the SOTA Beam. 40 and 20m seemed to be the Bands of choice on SOTA, so off I went with a prototype made from some plastic which didn't make it to the Summit so a re-think was in-order. The new design is based on the familiar 20mm PVC Conduit, much like the SOTA Beam.


Centre Fed Inverted V Dipole

Parts

1 x 250mm Length 20mm Conduit
1 x 20mm Conduit Clip
2 x 4mm Bolt - Flat Head
2 x 4mm Wing Nut
1 x 12m Length RG-58 Co-ax
2 x Flat Slide Connector
2 x 5.6m Length 0.16/24 Stranded Wire
1 x Ferrite Choke

The Feed point BALUN is provided by the Ferrite snap-on being used as a choke.


Assembled on a SOTA Pole and Tuned via MFJ Tuner - 5 9 into Sweden using 35w - Inverted V layout, E/W Arrangement at home QTH. Next stage to Tune to the Mid Band Point for 14Mhz and 7.0 Mhz



The elements tuned successfully for the 20 m Band, with a Flat SWR over most of the band, from 14.000 to 14.220, with an Elevated SWR out to 14.350. Element lengths required about 200mm trimmed from each, from what was originally calculated.

Used in the 2005 ARI International DX Contest, handled 100w without any signs of distress, or high SWR.

 

EZNEC Plot

This antenna is used on a regular basis for SOTA and other portable operations on 20m. Several years later, and it's still going strong.

 

AIM 4170C Plots

20m Band


12 Mhz - 16Mhz Sweep