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In article fxzdc.143$cD2.12959@attbi_s51,
Dave Shrader wrote: IMO applying the word 'Gain' to an antenna is misuse of the word 'gain'. Since this particular terminology has been used in this way in both amateur and professional antenna literature for more decades than I've been alive (I'm pushing 50) I think you're tilting at windmills to try to eliminate it, or to declare it "misuse". I personally prefer to refer to what an antenna delivers as "directional gain", to distinguish it from the sort of "more RF out than RF in" power gain that an amplifier delivers. From the point of view of someone trying to deliver a specified amount of power to a receiver in a specified direction, the two types of "gain" can be interchanged to a large degree. Yes, they're distinct, and we need to remember the distinctions, but they can be traded-off against one another in many common sorts of calculations. [At the risk of re-opening a topic of contention, I'll posit that the use of the term "gain" to refer to both amplifier power gain and to antenna directional gain is somewhat similar in spirit to the use of the term "resistance" to refer to both dissipative and nondissipative impedances. Each is a single term, referring to two different phenomena which can under many circumstances behave in ways which can look equivalent from a particular point of view.] Next question: where do I get a 160 meter 1/2 wavelength 50 ohm slotted line? Go down to your nearest abandoned rust-belt factory that has a large brick or concrete chimney, wrap the chimney with sheet tin (leaving a slot), and drop a suitable-sized silver-plated cast-iron sewer pipe down the center. Run your probe up and down the chimney on a huge pulley. It'll probably be tricky to couple this to the antenna and feedline, though. I don't think even Andrews makes a heliax connector quite this large. grin -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
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