Up the power to 100 W and you’ve got a personal heating appliance. Awesome.
“Without RF, life itself would be impossible.” Wayne ---- elecraft.com > On Jan 22, 2019, at 9:04 PM, David Gilbert <[email protected]> wrote: > > > > Here's another idea. > > Run a wire inside your shirt from one cuff across your back and down to the > other cuff. Wrap loading coils around each arm just above the elbow. Feed > the "dipole" in the center at the back of your neck. > > I did a quick model (assuming your arms are held straight out) with 5.5 feet > total length and 2200 inductive ohms for each coil, with each coil 30% from > their respective ends of the wire. It "resonates" at around 14.15 MHz, but > with only about 0.4 ohms real feedpoint impedance. I assume it would take > some sort of extra matching network to bring that up enough that a KX2 with > the internal tuner could drive it. > > Ignoring the effect of a person's arm, another quick calculation says that > the arm coils would need to be roughly 11 turns of 10 gauge wire 3.5 inches > in diameter ... unless I made a mistake, which is quite possible. > > It would bring new meaning to the term "compromise antenna", but I bet it > would be more effective than a super small loop the size of backpack frame. > > 73, > Dave AB7E > > > >> >> >>> On 1/22/19 12:57 PM, Wayne Burdick wrote: >>> I’ve engaged in plenty of ultralight HF pack operation, with a KX2, AX1 >>> antenna and a dragged counterpoise. In wide open spaces it’s a blast. But >>> urban settings with dogs, wire-eating cacti and overzealous Neighborhood >>> Watchers can distract from one’s radio experience. >>> >>> So, just for grins, I’d like to try something completely incognerdo: no >>> visible antenna. A small remotely tuned loop (say 12” diameter) would seem >>> to be the best choice, as it would fit entirely inside a small backpack. It >>> could have modest efficiency while not requiring a counterpoise wire. >>> Rigid 1” copper pipe formed in a square would be convenient to deploy. >>> >>> The loop would be only 6 to 8” from soft tissue, so you’d want to run QRP, >>> of course. OTOH, we’re talking about HF. A cellphone by your ear is >>> probably worse. >>> >>> Any other antenna suggestions? >>> >>> Wayne >>> N6KR > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
