I thought I would document here the results of a test Ken VE6AGR and Ian VE6IXD did to compare Ken’s inverted-V dipole versus a 1/4 wave vertical with 3 elevated radials made by Ian.
The idea of the vertical antenna was to enhance low-angle radiation compared to the dipole, and so enhance long-distance skip for participation in Trans Atlantic or Pacific SOTA activities.
We ran the experiment for 10 hours on Sat April 24. Both antennas were driven by WSPRlite transmitters providing 200 mW of power on a 30% duty cycle. They were started at the same time, and so transmitted on a pseudo-random sequence that is synchronized between the two units.
This allows direct comparison of signal strength at stations receiving both transmissions in the same time slot.
The overall result was that the two antennas provided essentially the same performance!
1800 (+/-15) spots were received from each unit, 1347 of these spots were received simultaneously by other stations, the average signal strength difference favoured Ken’s dipole by 1 dB which was probably caused by Ian housing his WSPRlite inside and feeding the antenna via an extra 50’ of RG58 co-ax. Examination of signal strength difference by distance of receiving station suggested a slight increase (less than 1 dB) at longer distances by the vertical.
Both stations (located in Calgary) were heard reliably in Hawaii, Alaska and all across continental USA. The vertical managed a single spot in the Canary Islands.
The propagation conditions were not great, so we will probably repeat the experiment from a SOTA hill-top later in the summer when conditions are better.