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[TowerTalk] 402-CD vs. EF-240X

To: <>
Subject: [TowerTalk] 402-CD vs. EF-240X
From: (Eric Gustafson Courtesy Account)
Date: Mon, 1 Jun 1998 16:39:09 -0700
To: <>
>Date: Mon, 01 Jun 1998 12:32:36 -0700
>From: Fred Roberts <>
>Tom Rauch wrote -snip-
>> My grounded plummer's delight 5 element 20 meter beam was useless
>> during foul weather (it was at 160 feet, the highest antenna on the
>> stack), while lower antennas were pretty quiet. After I installed a
>> tall 2 meter vertical above the yagi, it quieted right down and the
>> vertical was useless. Both were dc grounded.
>I have heard others comment about stacked beams, noting the upper one is
>noisier.  I wonder if this effect is simply static discharge as from a
>spike used for lightning protection.  That is, does an antenna always
>suffer higher noise than when protected by a "spike" mounted above it?
>Fred Roberts, W6TKV
>Riverside, CA

This is why (besides not wanting to be a light source during
transmit) some of the military HF array elements have a smooth
spherical "toilet bowl float" treatment at the open end of the
elements.  Sort of a larger version of the ordinary car antenna
ball.  Probably isn't a bad idea to provide a _different_ place
for corona to form on the tower though.  One that isn't attached
to the receiver feedline.

73, Eric  N7CL

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