[TowerTalk] Inverted L SWR High

[Ken Hirschberg]

Hello, Jack -
Among other things (and there are plenty), check out John Belrose's technical
corresondence, Oct., 2000, QST, page 81, relating to decoupling 160m inverted L's
from towers.
73, Ken, K6HPX

W4nf@aol.com wrote:

> I have an Inverted L up on 160 that runs up next to my tower for 75'.  It is
> stood off from the tower about 3' at the top, supported by a piece of anlge
> iron and an insulator (ceramic about 4") then goes out to a tree.  The bottom
> of the L is about 8' from the tower base.  I have a LJE radial hub that I tie
> the radials into and have 16 radials that are about 60' long and another 16
> that are 120' long.  On the feed lne coming into the radial hub I have 50
> ferrite cores over the coax (bought as a choke kit from one of the coax
> vendors).  The problem is that I can't seem to get the SWR below 2:1.  It
> does have a nice dip at 1.830 but as I said it just won't go below a 2:1.  I
> also had an 80 meter vertical tied into the same point at the base and
> thought that it may be detuning the 160 L so I removed it.  No change.  The
> tuner on the 1000MP brings it right down but I try to make my antennas as
> resonate as possible.  The bandwidth is pretty narrow, probably about 30 kHz
> either side of the dip, where it goes to a 3:1 and then higher beyond.  I
> know some of you are going to say to shunt feed the tower but I haven't found
> a check source of vacuum variables yet and I would like to have this one play
> better.  It used to have a lower SWR before I put the LJE Radial Bus in and
> the metal angle standoff at the top of the tower but I can't figure how that
> would affect anything but in a positive way.  Any comments would be
> appreciated.  Thanks and 73, Jack W4NF
>
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