On 12/2/2023 5:48 PM, W2HX wrote:
I then replaced the wall-wart power supply with a 12V battery. And this
is what I saw for BOTH bypass and inline. Clearly the problem.
https://w2hx.com/x/Elecraft/KAT500/Noise-Issue/KAT500-battery.png
using a battery, the noise is about -80 dBm. Using the wall-wart, in some cases
the noise is as high as -60 dBm
My task now is to either leave it on battery or preferably, find a low noise PS.
99.9% of stuff that plugs into the wall has a Switch-mode power supply,
most of which are varying degrees of noisy. They were mandated to save
energy about 20 years ago, but thanks to small government, the FCC has
no money to enforce their Rules that they be quiet. So they aren't.
A typical home has several dozen of them, either in the form of wall
warts and line lumps or built into equipment and appliances. Rather than
buying bigger and better anything for our station, our time and money is
far better spent identifying and replacing as many as possible of these
nasty noise sources.
There's a tutorial on my website, k9yc.com/publish.htm about how to
find and replace them. All of the 12V gear in my shack runs on two big
batteries that are float charged by re-purposed Thinkpad power supplies
using Genasun charge regulators. A 100Ah LiFePO4 runs the rigs, a 100Ah
Sealed Lead Acid runs the rest of the stuff.
73, Jim K9YC
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com
