--- On Thu, 2/16/12, Roger <[email protected]> wrote: > CB uses vertical beams...the difficulty is that they have to have > a non metallic mounting pole extending into the beam or be end > mounted (think torque)
The mounting pole may contribute some capacitive or inductive loading effects on the elements adjacent to it, but a smart antenna designer can modify the antenna's element lengths to compensate for these effects. The pole itself will have a negligible effect on antenna performance, unless it happens to be resonant (or very close to resonant) at the operating frequency. Otherwise, it's essentially transparent. > On 2/16/2012 12:18 AM, Bob Bruninga wrote: > > Just wondering if anyone has a vertical beam. If the signal is strong enough (and/or the receiver sensitive enough), an electrically small loop antenna can be used for 28 MHz radio direction finding purposes. A vertically oriented loop will respond to vertically polarized RF. (In reality, it's responding to the horizontally polarized H-field). The ARRL Handbooks and Antenna Books have carried designs regarding 28 MHz RDF antenna for many decades. 73, de John, KD2BD _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
