9dB

Last night, far too late in the day, and with some rain showers around, I decided to compare a vertical antenna up on the copper mine 'mini-bog' site against my 3-element LFA Yagi at home, just a few hundred metres away.

Well, I only managed one simultaneous spot from both, such is the paucity of active WSPR stations at 12m. But three spots were obtained within a few minutes of one another, so that gives a slightly better picture.

Beaming North America - against my simple vertical!

 

The single simultaneous spot was to KD2OM.  I have to say I was very surprised to find the difference in favour of the Yagi was only 9dB.  The three spots within much the same period, but not simultaneous, gave 10dB in favour of the Yagi.

Of course, this is a big difference; you get ten times more effective signal from the Yagi than the vertical.  

That said, it will be interesting to now take the vertical to the water's edge and see whether it can erode that advantage.  We'll see if I can make some time this evening.

Whilst the Yagi is a superb performer, it is a relatively complex beast to put up in the air, rotate, maintain and - a big issue here - protect from frequent hurricane-force winds in winter.  All that sometimes causes worry.  To be perfectly honest, whilst putting up a beam is very nice and give a sense of achievement, the hassle of it all for an additional 9dB over a simple vertical is not a favourable equation, at least for me.

In the meantime, for those starting out, or simply curious, here's a sweep of the whole 12m band when using my 1/4 wave vertical with 2 elevated radials at about 1.5m feedpoint height above ground, radials sloping: a flat SWR, for this very narrow band, of just over 1.2:1

Although it's by no means necessary, you can bring the match closer to 1:1 by using a small coil connected between the radiating element and the radial connection, as shown in the image below (it's the orange coil at lower right, used in this case for another antenna experiment):