This is Wes agreeing with Wes re the "too much loss in the system". In an
efficient system on 160 the SWR curve should not be so broad.
Years ago I had an Inverted L configured like what you have, with the
vertical wire going up about 65' spaced about 18" off the tower. The SWR
was broad. I think what happens is that there is a lot of coupling between
the vertical wire and the tower/antenna system.
I worked a lot of DX with this set up but after I took that system down and
put up an inverted L hanging from a high limb on a large Pine tree the
system was better, at least from an SWR standpoint. The SWR curve was
sharper. However, as has been recently discussed in this forum, the tree
was imposing its own influence.
The SWR curve was still broad, but nowhere near as broad as with the wire
next to the tower.
I don't know how much this kind of situation affects your transmitted signal
strength. Possibly, not very much, depending on your ground radial system.
In any event, the antenna worked well enough to get me to the point that
most other 160 ops get to, and that is the point at which you could work
more DX if you could just hear it. That is when you have to start working
on your RX antennas and stop worrying too much about your TX antenna.
-------------------
Wes Attaway (N5WA)
(318) 393-3289 - Shreveport, LA
Computer/Cellphone Forensics
AttawayForensics.com
-------------------
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Bill
via TowerTalk
Sent: Saturday, February 10, 2018 3:28 AM
To: TOWERTALK@contesting.com
Cc: topband@contesting.com
Subject: [TowerTalk] 160 vertical advice
First, I want to say thank you to all who responded to my post about a top
loaded vertical for 160.
The antenna I wound up with was quite different than the one I proposed.
Basically, it is about 132 feet of wire. The top "bent" part (65 feet) is
carried by a piece of thin Phillystran stretched out from the 84 foot level
on my tower out to around 350 feet to a "borrowed" neighbors property.
Luckily the property also rises in slope about 25 feet, giving me a little
extra height. The remaining 67 feet is dropped straight down to the ground.
I currently have around 40 radials laying on the ground, not buried yet.
Another 20 or so to come. Some of the radials from the 160 vertical overlap
the ones from my 4 square for 80
The antenna is directly fed with 50 ohm cable and the SWR is 1:1 at 1825
and is less than 1.3:1 across 1800-1900 kHz. It looks into the tower in the
direction of North America.
I gave the antenna its first workout tonight and it is a winner. Worked all
over the US and had about ten EU call in. Copy was tough on this end as QRN
was quite bad on the shared apex rx antenna.
Thanks again to all who helped me find a solution to my 160 antenna.
Bill KH7XS/K4XS
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