In article om,
"RHF" wrote:

- If your antenna is fed with coax you don't need a balun.
- The 50 ohm coax is close enough to the 70-or-so ohms
- of a plain dipole.
-
- bob
- k5qwg

And . . . That 'plain' Dipole Antenna is by-design
best used for a single specific frequency.

It's pretty much good for a band (1 to 2 MHz wide) cut at the center
frequency not just one channel.

Like most antennas for receiving it will work well at higher frequencies
above the resonant frequency with some exceptions such as 2 times the
fundamental.

Very Good for Amateur Radio single band operation.

Not-So-Good for a Shortwave Listener (SWL) who
intends on using the Dipole Antenna across the
entire Shortwave (HF) Band from 1.8 MHz to 30 MHz.

Well that depends. If you have one resonate at around 1.8 MHz it will
work well up to 30 MHz with a few noted exceptions. You can of course
make the antenna resonant at a frequency so that the even harmonics do
not fall on a broadcast band.

1 - Make the Dipole Antenna into a Windom Antenna
( Off-Center-Fed-Dipole ) for better Multi-Band use from
a single Antenna.

This won't buy you much.

2 - Use a 4:1 Matching Transformer {Balun} for improved
Broad-Band characteristics for Across-the-Band Shortwave
Radio Listening (SWL) at the expense of single frequency
performance.

Wrong, wrong, wrong, just plain wrong.

The "Best" Antenna is not always the 'best' antenna.

Some advise is not always the best advice.

theoretically speaking - it should not work,
but hey... What Works. WORKS ! - iane ~ RHF

Theoretically speaking using the wrong BALUN for an application will not
cause the antenna not to work, just not to work as well as it could.

--
Telamon
Ventura, California