Friday 26 July 2013

Rotatable dipoles



I feel compelled to write about how pleased I am with the effectiveness of my simple homebuilt 10m band rotatable dipole.

I think we are all guilty of underestimating the performance of a simple dipole. If the dipole is mounted a few metres clear of the building (ideally at ½ a wavelength or more agl) and made to be as it was meant to be i.e. flat, preferably rotatable then the performance might give very respectable results.

This might just be the antenna to use if you do not have a tower at your disposal.

There are many advantages:

Light weight.
Easy to construct.
Full size without any lossy loading coils.
No lossy traps.
No impedance matching issues.
Can run full legal power.
Several dipoles could be parasitically coupled, resulting in multiband operation with a single feed line.

The wing span can be reduced if required by using droppers at each end. Cebik W4RNL (SK) had written an article on this idea “portable/field antenna”. I wish I could find the article in question.

I see at least one commercial antenna manufacturer is now selling such an antenna based on this idea.




3 comments:

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  2. HelloPiere, for years I use an inverted vee. It works good enough for me. I guess that I would not notice any difference with a rotary dipole except for directivity. Thanks for the entry. 73 Bert

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  3. Greetings - you left out one important advantage of a rotatable dipole - it only requires a single support. This is a huge advantage for people with small, short lots or lots which lack natural supports like trees.

    Happy days.l K8JHR

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