Topband: Choke Baluns etc

[Roger Kennedy]

I think if I had a vertical with just a few Radials lying on the ground, I
wouldn't use a Common Mode Choke either . . . to me, any RF on the outer of
the coax would just mean it acts as another radial.

I've actually NEVER had any issues with RF in the shack . . . I used Dipoles
fed with co-ax on several bands for decades, without any Chokes at the
feedpoint.  However, in an effort to reduce Received Noise, I DID install
decent Ferrite Choke Baluns on my 160m & 80m Dipoles about 4 years ago . . .
however, it made no difference to anything ! (neither the noise level or the
resonant frequency of the antennas)

Here's something else that many people find surprising . . . 

At 3 different QTHs I have had over the decades, it wasn't possible to put
up a Dipole for Top Band . . . so I had an End-Fed Half Wave.  At all 3
locations the shack was in an attic room on the third floor . . . so the end
of the 260ft of wire came into the attic window, straight to an ATU on the
windowsill.  The only ground I had was the Mains Wiring around the house,
plus the central-heating system (copper pipes all over).

Even running an Amplifier, I never had any RF Feedback issues . . . and
those End-Fed Half Waves seemed to work just as well as the Dipoles I used
at other QTHs.

(I do, however, suspect that with all the RF Noise rubbish around these days
that the noise level would be worse than a Dipole!)

73 Roger G3YRO