Posted by
k6dgw on
Jul 16, 2020; 9:41pm
URL: http://elecraft.85.s1.nabble.com/KPA1500-in-the-IARU-Contest-Last-weekend-tp7663146p7663233.html
Indeed! Probably the least unbalanced of "balanced" antenna systems
that ever existed were the HF point-to-point rhombics and V-beams at the
RCA, Mackay, and Marconi shore stations in the first 60 or so years of
the 20th century. Despite very precise engineering to make them
balanced, the RF currents in each side of the open feeders were never
exactly the same.
As a teenage ham, I tended to think in absolutes and exactitudes. If my
Heath MM-1 multimeter said the screen voltage was 176.5 V, I believed it
was, exactly, and if the spec said 177.5 V, I needed to do something to
"fix" it. If the ARRL Handbook said the two halves of my 40 meter
dipole needed to be exactly 32.9114 feet, I believed that the antenna
would not work if I didn't assure my dipole was exactly 32.9114 on each
side. As I grew older, both in age and ham longevity, I realized my
Elmer was right when reminded me on multiple occasions, "We're
amateurs. Most often, 'close' is good enough."
Seems like many today are convinced that 32.9114 ft will work but
32.9000 ft won't.
73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County
On 7/16/2020 1:00 PM, Jim Brown wrote:
> On 7/16/2020 1:14 AM, Victor Rosenthal 4X6GP wrote:
>> If the antenna is well-balanced and fed via a true balanced antenna
>> tuner (preferably link-coupled) then there shouldn't be a problem
>> with common mode currents.
>
> Few ham antennas are perfectly balanced -- they are often unbalanced
> by their surroundings. For example, ground slope, unequal heights of
> the two halves, other conductors around the antenna, even vegetation.
> And yes, all elements of the antenna system, including the feedline,
> the antenna, and matching at both ends, contribute to the balance of
> the SYSTEM.
>
> THAT'S why it's wrong to talk about "balanced line," using "parallel
> wire" or 2-wire" line instead.
>
> 73, Jim K9YC
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