To topband from Ed KG4W
Never have used a Inv L on any band. On topband, I've always used a Inv vee
or a Carolina Windom as an Inv vee with apex at 130' with ends up at 75 ft.
Just decided to give the inv L a try. Have done some research via the
archives here on topband & a couple of books etc. I guess what I would like
is some specific info regarding my setup. Looks like my vertical section can
be anything up to about 90 ft. Plan to use #12 wire & design freq of 1.835.
I have seen some comments saying to design the ant for 1.7megs ? I am
interested in acheiving the lowest angle of takeoff as possible, I have
plenty of high angle with the inv-vee hee-hee.
Present plans would have the vertical section located about 50 feet from my
crankup tower at 130 ft. Before you ask, no I don't want to "load this tower
as a qtr wave vertical. This is a "rickedy" 150' crankup tower & is only
used to support the inv vee at 130'. So, I've placed a support rope from top
of tower to top of oak tree about 200 ft away. I can go further from the
tower with the vert section, but the max vert would be less than 90',
conversley I can go closer than the present 50' to the tower & vert section
could be more than 90'. No wire has been placed yet, just the support rope &
all is on pullys & can be easely changed.
So I guess my questions would be -
Would u leave the vertical section at 50' from the tower or move it ?
How long would you make the entire ant ?
Does the compass direction of the horz section have any effect on radiated
pattern ?
I know that the Inv L requires a great ground system & will try to acheive
this.
I probably have a vaccum variable cap suitable for matching.
Use 50 or 75 ohm feedline ?
Looks like feedline will need to be 120-140 ft long, use minimum required or
achieve a special length ie half wave ?
How critical is it for the horz section to be perpendicular (sp) to the
vertical section ?
What 1.8 to 1 bandwith should a properly designed Inv L using #12 wire have
?
Tnx in advance
Ed
KG4W
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