[Antennas] RE: Loading a 90 foot wire on 160M w/added inductance

Wed, 22 May 2002 12:06:45 -0400

Tim, the ARRL Antenna Handbook, my edition is the 18th, gives a chart in
Chapter 6 [Page 6-25 Figure 49] that gives the inductive reactance as a
function of antenna length and planned inductor [loading coil] location
for shortened antennas. It's very easy to use.

The amount of loading coil, inductance, is a function of antenna length
and coil location as percentages based on a half wave equaling 100%.

Back in the 'olden days', 1958, I would have been able to calculate the
value but 43 years after graduation I use charts, it's easier and
faster!

Deacon Dave, W1MCE

> 
> I've been following this thread with some interest. Most of my
> antenna construction has been building various wire antennas or using
> published plans and essentially "following the instructions."
> 
> How do you determine the amount of inductance needed to electrically
> shorten a wire antenna? For example, if I know that ideally I needed
> a 50 foot wire but I only have 40 feet of space how do I calculate
> the size of the inductor I need?
> 
> I haven't done a lot of research on this yet but my first pass
> through the current handbook hasn't provided the information so far.
> 
> Tim  N9PUZ
> 
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> 
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