Topband: Long sloper

[Gary Smith]

I just installed a replacement wire for 
the 160 sloper. I made it 129' as was the 
earlier one that came down in the winds. I 
have to use a spud gun to get fishing line 
over the tree tops and where the spud 
lands, I connect the wire to the eye 
fastener & reel it to the radial plate. 
This time I had to use a different tree as 
the earlier one came down in the last 
hurricane. 

Now it is resonant at 1.785 and it is not 
a problem at the lower end of 160 but 
higher up it is. My problem is compounded 
in that I also use this antenna for 10M, 
12M and the upper part of 15M. I need to 
shorten it for use on these as well.

It is too far away to shorten the wire and 
solder a new eye on it and now it is too 
cold to play with it on the tree (have 
difficulty walking right now). So being 
too long, capacitance at the feed point 
might be my best answer. I have several 
fixed vacuum & doorknob capacitors of 
small pF to choose from that I can put in 
line. Is there a formula that I might plug 
data into to come up with the needed pF?

Thanks & 73,

Gary
KA1J