5 Jul 2015

Big wheel antennas

Next winter I want to replace my hand rotated beams for 70cm and 2m with a big wheel stack for either 2m or 70cm. I was going to erect a 2m big wheel stack (of 2) but looking at the logs it may better to erect one for 70cm which is the more interesting band.

2 big wheels, suitably stacked, should give about 5dBd gain horizontal and need no turning. This is not far off the gain from my 5el yagi in the best direction.  Quite often I work stations off the direction of maximum gain. For my kind of operation (mainly UKAC contests and beacon monitoring) I think a big wheel is well suited.

70cm big wheel stacks are a lot smaller than the 2m versions. The stacking distance is smaller too. Commercial big wheels are available from Wimo in Germany.

See http://www.wimo.de/big-wheel-antennas_e.html .


Jan, OZ9QV said...

I would actually consider making a 4 bay (or maybe 8) stack for 70cm, given the small size of the antennas, if you can find the space.

Roger G3XBM said...

Yes Jan I am definitely considering this. I am lucky that my QTH is on a high spot, so a stack of 4 could do quite well.

Todd Dugdale said...

Always love to hear about 70cm. There's very little activity on 70cm SSB here in the U.S, though there's a whole lot of stories from twenty years ago about activity. I'd love to explore it more, but it takes two to tango, as they say.

Roger G3XBM said...

Activity in the UKAC 70cm activity evenings once a month is HIGH. I usually manage to work 200km with 5W and a hand rotated 5 el beam. I am hopeful that a stack of big wheels will be just as effective.