Martin wrote: I read the manual for the KXAT1 and the advice for antennas states that short whip antennas should only be used in emergencies.
Text of the manual included below. This seems strange because when I read the HFPack yahoo group I can find lots of HAMs who are using the KX1/KXAT1 with various HF whips attached to bicycles with varying degrees of success. Any HF whip connected to a bicycle must be a "short" whip, probably loaded. Anyone have an opinion or personal experience who can shed some light? I'd like to fit the KX1 to my bike! Reply: -------------------------------- What the manual says is correct. Short whips are terrible radiators and they should not be connected directly to the antenna jack, but the reason they should not be connected directly to the antenna jack is *not* because they are terrible radiators. TERRIBLE RADIATOR: Almost anything other than a very well-shielded dummy load will radiate better than a short whip. But they do radiate a little bit. Running a couple of watts with your KX1 you might have an effective radiated power of a few milliwatts. Now, being "terrible" is relative. A few milliwatts can be heard over very long distances under the right conditions, and it can be heard over short distances at any time. The efficiency of an antenna does *not* change linearly with it's size. At very small sizes, a small increase in the size of an antenna can result in a relatively big increase in radiated power. For example, making a very small antenna twice as long doesn't double the effective radiated power, it can make if five or 10 times better! So when you are dealing with a small antenna, don't lose one inch of radiator more than you need to. And when you're dealing with an end-fed antenna, the same is true of the ground. A tiny improvement can make a huge improvement in signal strength at the other end. Still, a short whip is the only thing that fits some applications, such as pedestrian or bike mobile. A lot of operators will attest to having a great deal of fun with them in spite of their abysmal efficiency. DON'T CONNECT TO KX1 ANTENNA JACK: That's a mechanical issue, not a performance issue. The BNC antenna jack on the KX1 is attached to and supported entirely by the printed circuit board. There's no mechanical connection to the case to support the connector, so any strain placed on the connector must be borne by the board. A stiff whip connected directly to the jack that gets bumped could easily shear off the corner of the pc board holding the jack. That's why it that practice is strongly discouraged by Elecraft. Ron AC7AC _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
