This outfit sells AC-DC linear wall warts:
https://www.acdcpowershack.com/collections/ac-dc-linear-power-supply
I recently procured one to replace the Jameco wall-wart for my SAL-30
receive antenna. When listening on the SAL-30, I found that strong
stations had sidebands something like 1 KHz away (I don't recall the
exact offset, but it rendered the antenna virtually useless when the
band was crowded with strong signals). Switching to my Astron variable
linear supply cured the problem. When I looked at the output of the
Jameco wall-wart on an oscilloscope it was making several volts of
ripple, so I chucked it and I got the 15V DC @ 1000mA supply with 2.5 x
5.5mm (+) center polarity connector from the ACDC Powershack. It is
unregulated so the open-circuit output voltage was 19.6 Vdc, but under
load the output of the SAL-30 bias-tee is around 12.5 Vdc. As far as I
can tell, the SAL-30 is just as quiet on the new linear wall-wart as it
was on the Astron.
73, Mike W4EF..................
On 2/17/2025 5:08 PM, Joe Subich, W4TV wrote:
Having just begun a noise mitigation project, I've found
two of the biggest sources to be a pair of wall warts for
the USB hubs attached to my radio and office computers.
Removing them dropped the noise floor by 20 dB on both
160/80 (and by about 10 dB on the other bands).
Does anyone have a recommendation for a source of *quiet*
replacements (preferably with 3.5 x 1.35 mm coaxial plug)?
73,
... Joe, W4TV
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