[TowerTalk] Rai Beam

[thompson@mindspring.com]

The discussion about the Rai Beam has got to be based on real antenna
principles.   N4KG did an excellent presentation about
gain several years ago.   A wide spaced 3 element beam optimized for forward
gain over real earth can be up to 16 Db.   This does not mean that the 3 el
beam had 16DBd or even 16Dbi gain!   A dipole has up to 8Db in the same
model!    A Rai Beam might have 12 or 13 Db in this senario as the Rai Beam
has much less gain than the 3 el wide spaced beam.   The Rai Beam is a 2 el
closed spaced beam and might have 5 dbd at one frequency.  I still say
having good front to back is often confused with playing well and having
gain.

I feel that the 4 el version on 10 can play well and that almost any 2 el
beam is better than a dipole especially if you can get it well up in the
air.    Once you get past the 2 el model (no matter if all elements are
driven or not) the gain is a function of the boom length as I4JMY pointed
out.   W2PV showed us that a optimized 3 or 4 el mono bander can outplay the
4 or 5 el closed spaced yagi especially the old W6SAI design with equal
spacing of all elements.

There is no magic potion to make a beam a super performer except bigger is
better.

73 Dave K4JRB



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