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How to stack dissimilar VHF & UHF yagis

A few notes from Peter, G3PHO
G3PHO antennas-1

Most of us don’t have the facility of several towers, each with their own yagis. In suburban situations, stacking beams for bands such as 50MHz, 144 and 432 MHz all on one pole can be a problem. How far apart do we have to put them? Is the pole strong enough to carry them, even in high winds. Is the rotator capable of handling the wind load and the weight presented by a stack of beams? I am now very keen on the RSGB UKAC contests series which takes place every Tuesday evening from 8pm to 10.30pm. The bands are rotated around each Tuesday of the month in the following order: 144MHz, 432MHz, 1296MHz and 50MHz. At present, I change the antennas each weekend ready for the following Tuesday’s contest but this is beginning to become a real inconvenience, even though I use a Clarke pump up mast. Can I, I ask myself, have at least two if not three of these antennas on my  mast and turned by my simple TV antenna style rotator, at the same time? It would be great to have my 50MHz 3 element yagi just above the rotator, followed by the 9 element 144MHz just above it and the 432MHz 15 ele at the very top. It’s not wise to have a metal mast running through the yai at 432MHz and is absolutely taboo for 23cm! In any case I can erect the 1296 system elsewhere, at the front of the house, when I need it…. or  go portable to a better location.

The answer to the stacking distance can be gleaned from the following website. Go to it and read and learn! Please come back here when you’ve finished though 🙂

http://www.ifwtech.co.uk/g3sek/stacking/stacking2.htm#5.

http://www.directivesystems.com/STACKING.htm

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