[Elecraft] WA3WSJ: Bead-Wire Antenna

[Ron D'Eau Claire]

Doing the math, a wire self-resonant at 7 MHz exhibits 2:1 SWR limits that
vary with the wire size as follows:

#8 wire = 280 kHz

#12 wire = 270 kHz

#30 wire = 160 kHz

Since the antenna is probably less than self-resonant length (1/2 wave or
1/4 wave over a perfect ground) the bandwidths will be greater than that
owing to the matching network or ground losses. However, these numbers
provide some idea of how the size of the wire affects bandwidth.

The original poster was using a KX1. He didn't say, but I'd assume he's
using an ATU, perhaps the KXAT1 built into the KX1. 

Ron AC7AC



-----Original Message-----
Since the wire is quite thin, the resonant element which results will 
have a rather high-Q and therefore best used for a narrow range (such as 
the CW sub-band). My wife does beading and uses the stuff; it looks to 
me like stranded stainless wire with a nylon jacket.

My guess is that the high Q will win out over the skin effect of the SS. 
Furthermore, although nylon is lossy at RF, that usually applies where 
the tangential electric field is relatively intense, such as when the 
nylon serves as an insulator or a capacitor dielectric, rather than 
merely as a jacket.

I also think Ed will have loads of fun in spite of the losses. :) Stay 
dry, man!

Marshall, WA3VPZ