KB6NU's Ham Radio Blog

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Bringing feed lines into the house

Posted: 08 Jun 2020 05:01 PM PDT
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At some point or another, almost all hams face the dilemma of how to bring
antenna feed lines into the house. Heres my solution:



This is the basement window right above my operating position. When I first
got back on the air about 15 years ago, I only used coaxial cable, so all I
needed were the three holes that you see below the window.

I used a 7/8-in. hole cutter to drill a hole in the window frame. Thats
just the right size to allow a PL-259 to fit through it. I was fortunate to
have that much frame to work with. I got the hole plugs from the local Ace
Hardware.

The holes were not a great solution for the ladder line, however. So,
today, I cut a slit in the frame to bring the ladder line through the
window frame as well. You can see that at the bottom right ofÂ* the photo.
Im happy to say that that worked like a charm.

While I was at it, I washed the window, too. Now, I have a nice view out
the window while Im operating.

The post Bringing feed lines into the house appeared first on KB6NUs Ham
Radio Blog.


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IARU voices concern over rising RF noise levels to CISPR

Posted: 08 Jun 2020 10:49 AM PDT
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TheÂ*IARU recently submitted a paper, written by EMC specialists Tore Worren
LA9QLÂ*andÂ*Martin Sach G8KDF, to the International Special Committee on
Radio Interference (CISPR) expressing concern about the problem of
increasing RF noise from digital devices. The paper has been circulated to
the CISPR National Committee for comment, and the IARU hopes that it will
become an official CISPR Report in the future. Ultimately, the IARU hopes
that CISPR will recognise the need to properly consider the cumulative
impact of multiple digital devices on noise levels when developing future
standards.

The paper is titled, Report on long term projects CISPR 1745L, Number of
devices. It notes that sources of electromagnetic interference are more
varied and prevalent than ever, and that RFI is no longer primarily from
electromechanical devices but from their control systems and power supplies.

The paper also reports that the IARU has challenged CISPR on several
occasions, asserting that EMI has worsened over the years, and that the
increased noise levels are linked to the number of devices now potentially
being sources of EMI. In this paper, the authors look at the issues and try
to formulate an approach to assessment and measurement that takes into
account the statistical nature of the large installed base of modern
devices.

They note that for most people, the increase in the number of
electrical/electronical devices over the last twenty years or so is
obvious. Twenty years ago, notepads, laptops and mobile phones were in many
homes but by far not in all homes, and definitely not one per person as has
become the norm. LED luminaires did not exist at that time, nowadays LED
based technology is the main technology for luminaires. At the same time,
there has been a shift from linear power technology to noisier switching
technology, found in switch mode power supplies (SMPS) and inverters which
use similar techniques.

The IARU hopes that a final version of the paper will be released soon.
When it is, it will be available on the IARU Region 1 website.

The post IARU voices concern over rising RF noise levels to CISPR appeared
first on KB6NUs Ham Radio Blog.