Hello All
Thanks for the replys on my questions about the Loop Antenna I put up.
I have a question about RF choke reactance value.
I use a 30 turn coil of 9913F coax wound on a 4.5 inch coil form to act as a
1 to 1 balun. (4 inch pvc pipe)
I got my calculator out tonight and figured the inductance at 32.6uh.
This figures to about 368.5 ohms of inductive reactance at 1.8 mc.
I am sure there is some effect of the wire size as the coax is 1/2 inch in
diameter so I am sure the inductance is more than the formula says. Since
there is no correction for the wire size in the formula I just took the
32.6uh at face value
Is 368.5 ohms of reactance enough to isolate the feed line at 1.8 mc ?
If not how much reactance should I have to isolate the feed line.
Just in case I did my math wrong here is the values I used. I took the
formula out of the ARRL Handbook.
L(uh) = a²n² divided by 9a + 10b
a = coil radius in inches = 2.5 Diameter of coil center to center is 5
inches.
Diameter of 9913F .5 inches
b=coil length in inches = 15
n= number of turns = 30
a coil radius squared is = a² 6.25 x n number of turns squared = n² 900
a coil radius 9 x a2.5 = 22.5 + 10 x b15 = 150
5625 divided by 172.5 = 32.6uh
32.6uh total inductance that equals 368.5 ohms inductave reactance at 1.8
mc.
Thanks for the help
Dan W0VD
w0vd@arrl.net
www.clevengercreations.com/w0vd.htm
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