ZL1RS - Antennas
Another stacked array for ZL1SIX 2m WSPR
Another stacked Yagi array for ZL1SIX 2m WSPR
Following the success of the first 2m beacon antenna I decided to make another 4-stack array of 3 element 2m Yagis to beam the 2m WSPR signal in two directions (Australia and the Pacific Islands).
Due to the available materials, the second array has slightly shorter booms and 0.2 dB less gain. However the design still has good F/B and a 50 Ohm feed impedance so simple 'split-dipole' driven elements could be used with 1:1 baluns.
The Yagis were made on 800mm lengths of 25mm square aluminium tube with Stauff clamps to mount the parasitic elements and plastic electrical boxes with cable glands to mount the driven elements. The rear 250mm section of the boom is used for the mast mounting clamp and has a double wall thickness for extra strength (an insert of 22mm diameter tube).
The driven elements are each fed via DG7YBN baluns using LMR-195 coax and ferrite sleeves. The phasing lines are also made from LMR-195 and combined with a power divider made from LMR-400. After some minor adjustments, the overall feedpoint impedance was 53 Ohms with zero reactance (resonant) near the 2m WSPR frequency.