[Premium-Rx] B&W Antenna for sale

[Thomas Adams]

At 17:15 03-05-11, George Georgevits wrote:


>That little item in the centre of the dipole at the top - that wouldn't
>happen to be a rather large resistor would it?
>
>Also, did you ever happen to compare the performance of this antenna to that
>of a straight tuned dipole? Just wondering if there was much difference.
>
>Cheers,
>George Georgevits
>Sydney, Oz
>
>VK2KGG

Yep...   the center housing contains a resistor and a balun. The B&W 
antenna is a rather
badly designed T2FD, combined with some rather shaky marketing claims.

I'm a bit of a T2FD buff here, and for me the B&W specs are a joke.

Sure, a T2FD design may well show a low VSWR over 1.8 - 30 MHz, or an 
even WIDER
range...  but once you exceed perhaps 4 octaves, as you go higher in 
frequency the
radiation pattern with ANY T2FD variant turns into garbage; a ton of 
high angle minor
lobes, and NO major lobes to speak of.

Here, I cover HF with TWO T2FDs; the low one is cut to cover 1.750 - 
7.0 MHz, and the high
one goes 7.0 - 28 MHz.

To those who argue that the T2FD is nothing more than a dummy load 
because of the resistor;
the argument tells me a number of things about them.

The first is that they've never actually USED a T2FD. It's an 
effective antenna, if used intelligently.

The second thing is that they haven't figured out that EVERY antenna 
design is a trade-off. Sure,
some of your transmitter power just heats up the resistor... but 
you're trading off radiation
efficiency at discreet frequencies for reasonable performance across 
wide bandwidths.

To get BOTH on HF, the only design I know of that will do it is a 
discone. Anybody got a 100 foot
tower and maybe a half mile of #12 wire laying around?  'Cause that's 
what it would take to erect
one...   not to mention a sizable chunk of real estate.

Well...   lemme get off of my soapbox.


Mr. T.   W9LBB