Topband: Inverted-L Summary

[i4jmy at iol.it]

10 pieces in parallel, each one 3.3ft long, will better approximate a capacitor than a 33ft long single run of coaxial cable, at least at 2Mhz. All shields togheter, one side, all inners togheter the other end, capacitor terminals will be on opposite ends of coax.
But if I have to use for myself, anyway, I'do go for a real capacitor, air or vacuum.

73,
Mauri I4JMY

> 
> The working capacitance is NOT the capacitance per foot of the cable unless
> the cable is only a few degrees long. In this example 10 meters of RG-8
> cable is the equivalent of 1100pF on 160 meters, but using the
> capacitance-per-foot might make us think it is only 970pF.
> 
> 
> Coaxial cables work, but they generally are poor capacitors compared to
> other choices. They are really open transmission lines operating with
> near-infinite SWR, not capacitors.
> 
> This is why some commercial amateur antennas that use coaxial cables as
> capacitors have failure problems in the coax. I'm sure some people have
> experienced this effect. They should never be used in high current or high
> voltage applications, but probably are OK with an inverted L.
> 
> 73 Tom