Hi Paul,
As a rule of thumb, the length of the vertical wire and half of the T top
should be approximately 135 feet total. Your antenna is too short, its probably
resonant at approximately 2.5 MHz.
You can bring it into the 160M band by, in order of preference:
- lengthen the vertical wire to 85 feet, or
- lengthen the vertical wire and the T top so the length of the vertical wire
and half of the T top equals 135 feet.
- lengthen the T-top to 170 feet, or
- change antenna configuration from a T to an inverted-L with a total wire
length of 135 feet
- add a loading coil to the base of the vertical.
73
Frank
W3LPL
---- Original message ----
>Date: Fri, 18 Sep 2009 14:04:14 -0600
>From: WY7I <WY7I@EARTHLINK.NET>
>Subject: Topband: Need assistance with 160m Marconi
>To: topband@contesting.com
>
>Hi Gang,
>I finally have gotten my 160m antenna up and need some assistance on
>what to do next.
>
>It is a T-top Marconi aka a top-loaded vertical wire. The top wire is
>100' long of 12 gauge, the vertical wire bisects at the halfway point
>and is about 50'-60' long. There are right now 24 - 100-ft. radials.
>
>The Palstar analyzer says it is: SWR >10, 0 + j122 at 1.825Mhz. at the
>base of the antenna.
>A. What does this mean and what do I do about it?
>
>At the rig, the SWR shows something like 5:1 at 1.825 and decreasing
>until I run out of band at 1.999.
>
>I have the following:
>Amidon T240-K and T240-77 cores.
>16 gauge Thermalize wire
>Glass tape
>
>What do I do next to get this thing working?
>
>Regards for any advice!
>
>Paul
>WY7I
>
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