A Mini-Whip antenna's DXCC score

Pieter-Tjerk de Boer, PA3FWM pa3fwm@amsat.org

(This is an adapted version of part of an article I wrote for the Dutch amateur radio magazine Electron, January 2018.)

Since July 2012, the Twente WebSDR uses a MiniWhip active antenna. This is a simple active antenna based on a design by PA0RDT, consisting of a metal plate of about 5 by 10 cm and a buffer amplifier; see my previous writings about it here and here.

To judge the performance of such an antenna, one can resort to measurements, e.g. of the noise level, sensitivity and large-signal behaviour. But one can of course also very practically observe what signals one can receive with it.

Since almost the beginning, the WebSDR has a logbook facility, in which users can enter stations they hear. This is totally voluntary, and not a very prominent feature, but in the course of the five years since the WebSDR got its current antenna, some 170000 logbook entries have been made. For each entry the corresponding DXCC entity is automatically looked up, leading to a present count of 304 countries. Surely not a bad score, as there are only 339 in total.

Out of those 304 entities, 41 have been logged less than 10 times. I checked these manually, causing 11 entities to be removed because none of the callsigns logged for them were plausible. E.g., I couldn't find the callsign on the Internet; so these are probably typos or were copied incorrectly. None of the entities that were logged between 6 and 9 times, were removed by this check; therefore I assume that the entities that were logged 10 times or more, are correct too.

Thus, 293 entities remain; still a nice score, and a sign that with such a simple antenna, even at a somewhat industrial location as our university campus, one can still hear quite a lot. But working them is of course quite a different challenge...

I don't really follow the world of DX-peditions, but was surprised that in just five years such a large part of all DXCC entities is activated at least once.

Text and pictures on this page are copyright 2017, P.T. de Boer, pa3fwm@amsat.org .
Republication is only allowed with my explicit permission.