[Top] [All Lists]

[CQ-Contest] Sloper tuning

To: <cq-contest@contesting.com>
Subject: [CQ-Contest] Sloper tuning
From: "Marco Spalluzzi" <marco.spalluzzi@orobiacom.it>
Reply-to: marco.spalluzzi@orobiacom.it
Date: Mon, 25 Oct 2004 16:07:50 +0200
List-post: <mailto:cq-contest@contesting.com>
Hi guys, I installed a 40/80 sloper last week end.
On the roof, I've got a grounded mast supporting a 10-15-20 quad, with 3
separate feedlines.
The sloper consists of 2 wires, spaced about 45-60 degress apart, sloping
down from the mast, starting from about 12 meters from the street, just
below the quad, to let it turn.
One is tuned for 80 (it should be...) and another is for 40, 1/4 wl each.
They are connected to the central wire of the coax (rg213) feeding them,
while the shield is connected to the mast with a wire as short as possible.
At the beginning, the ground wire was a few meters long, going down under
the roof, where there's is the "ground point" of the mast (big wire down to
the ground rods), but I had very high swr on both bands, then I replaced it
with another one just a few inches b4 reach the mast, and now is better.
When I start measure the swr, I noticed that there was a big difference, if
I connected the feeding of the quad to the antenna switch, where also the
sloper feedline is connected.
To keep the swr lower, I must connect them.
1) Technically speaking, is it better (and right) operate with the quad
still connected, or not?
2) According to what I remember, resonance frequency of the sloper is not
varying connecting the quad or not, so I think the quad
   feed is not radiating; why is the swr varying? Am I providing a better
path to ground if I connect the quad to the antenna switch?
3) Will the feeding quad pick up some rf, that could cause trouble in the
4) So, if it were you, will you first tune (and then operate) the sloper
with the quad connected or not?
Thanks in advance.
Marco - IK2XSL.

CQ-Contest mailing list

<Prev in Thread] Current Thread [Next in Thread>