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, Bud Hippisley, K2KIR <k2kir@telenet.net> writes >At 04:42 PM 2003-05-05, GI0NWG wrote: >>On the L.B. Cebik W4RNL webpage he shows a nine element log on a 21ft boom >giving gain in the region of 5.63-6.33dBi (3.48-4.18dBd) across its range. >Again I have no reason to >>doubt these figures. >> >>The T10 should therefore fit somewhere in between these figures, which >>would suggest gain in the 6.0-6.6dBi (3.85-4.45dBd) region across its >>range, as opposed to the totally outrageous 8.24dBi quoted on the >>Tennadyne webpage (http://www.tennadyne.com/specs&prices.htm). >> >>Force12 quote the C31XR as having 8.15-9.55dBi (6.0-7.4dBd) gain across >>10/15/20M, or about 2.5db (on average) above the T10. This is a >>substantial difference. > >Yes -- it's interesting, however, that the difference you point out is just >about equal to the difference between Tennadyne's _advertised_ gain and L. B. >Cebik's _calculated_ gain for roughly comparable logs. Could it be that >Force12's gain calculating machine does the same "totally outrageous" thing that >Tennadyne's does? Instead of comparing apples and oranges, what I'd prefer to >see is _L. B. Cebik's_ calculation of the C31XR gain, not Force12's..... Bud, I certainly wouldn't be considered to be one of the F12 'converted' but the one thing I would say is that their gain figures are derived from computer models and are probably not far off the mark. They should be commended for bringing honest gain figures to the market place although I wish they'd drop the silly 'gain @ 74ft' figures. That said, they do give net gain figures too which have more meaning when comparing antennas. Andrew Williamson GI0NWG / AC6WI Homepage = http://www.gi0nwg.freeserve.co.uk/ One of the ZL9CI gang http://www.qsl.net/zl9ci/ -------------------------------------------- Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. Force12 Web Site: http://www.force12inc.com To Submit Message to the List: Force12Talk@qth.com To unsubscribe and view the Message Archive: see http://qth.com/force12/list For problems with the list: contact n4zr@qth.com |