On 9/13/2014 7:55 PM, Bob McGraw - K4TAX wrote:
I been puzzled by the most frequent and most common uses of the 4:1
balun. It seems that hams believe necessary to use a balanced feed
system, open wire line and such that they must employee a 4:1 balun.
Most oversight is that we are not matching the line but matching the
load.
Hi Bob,
For the record, I have a doublet that is in the inverted vee
configuration, cut to 100 feet per side. It is feed via open wire (~600
Ohm) parallel line (nominally balanced) down the tower and to the eaves,
with a shorter run of window line (~400 Ohms) under the eves to a DXE
1:1 current balun (I prefer to call it a choke) at the back of the
house. There is then an eight foot run of RG213 coax into the
basement-located shack to an Elecraft KAT500 auto tuner. I use this on
all bands from 80m to 20m. It can tune up through 6m, but I have other
antennas for those bands. And I shunt feed my tower for 160m ops.
I don't normally use a 4:1 or 1:4 balun, and was only responding to your
question about semantics in my previous post. Elecraft sells a nice
low-power balun that is switchable as 1:1 or 4:1. I have used it for
field/portable ops, but it's usually set to 1:1 for the antennas I use
(44' or 88' doublet).
73,
Gus
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