In a message dated 4/20/2006 1:41:29 AM Eastern Standard Time,
towertalk-request@contesting.com writes:
Message: 2
Date: Wed, 19 Apr 2006 23:02:40 -0600
From: "denis coolican" <coolican@telus.net>
Subject: [TowerTalk] Lightning Bolt Quad
To: <towertalk@contesting.com>
Message-ID: <014f01c66437$a6be3520$8e00a8c0@mycomputer>
Content-Type: text/plain; charset="iso-8859-1"
This four element Lightning Bolt Quad covers 20, 17, 15, 12 and 10 meters. It
is fed by a common balum. (one input PL259 and 5 output pairs of conductors)
Does anyone know what type of balum this is and what would be the replacement
for it?
I imagine the driven elements for each band has an impedance of about 80 to
100 ohms. The feed into the balum is 50 ohms.
If a person provides a 2:1 balum for each feed, would the unused balums be
terminated in 50 ohms or left open?
Any more thoughts on this antenna?
===========================================================
The device feeding the antenna is a BALanced to UN balanced transformer
(BALUN) and usually the Lightning Bolt device had a HI and LO terminal with a
common terminal. The higher frequencies on the HI terminal and lower on the
LOW
terminal. HI terminal nominally would be about 100 ohms plus, and the lower
50 ohms.
I would recommend individual feeds for each band, and a remote switch. Use
odd quarterwave 75 ohm cable to make impedance transformers.
Norm W4QN
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