As this thread has gained some traction since my original query, I thought
I'd post a follow-up, now that I have the Samlex 1235P-M in line. Nice to
have an HRO in town.
My setup is a K3 with a fan dipole for 40-10 on my balcony (pic on qrz.com)
only 15-20 ft away from the "shack." Besides the K3, I connected an MFJ
12V power strip with a bunch of low current peripherals (keyer, antenna
tuner, P3, etc.) I tuned the bands, listened and watched the panadapter on
each of the 4 bands, 40-10. I hear ZERO RFI from the power supply. One
caveat is that I am in an urban setting with a fair amount of external
noise, so there may be some PS RFI I just don't hear.
The only thing I don't like about the Samlex is the DC connections. It has
a + and - terminal on the back with a hole in the center that is tightened
down with a set screw (Allen wrench included). It's recommended not to
insert bare stranded copper into the terminals as some of the strands may
not be held down and splay. So, I tinned the copper ends of both the K3
power cord and the MFJ power strip (rated at 15A). They didn't fit. Sooo,
I cut off the just-tinned ends and used the two included pin terminals. It
was a tight fight, but I got both of the two bare leads of each of the two
power cables into the round end of the pin terminals, then soldered them.
The flat ends are then inserted into the power supplies terminal and the
set screws tightened.
Tnx again for all the replies.
73,
Barry W2UP
On Wed, Nov 13, 2024 at 2:55 PM Drew Vonada-Smith <drew@whisperingwoods.org>
wrote:
> Charlie,
>
> This is not the case. While medical equipment has a more strict rating
> for leakage and other safety issues, it has a LESS stringent rating for EMC
> emissions, unless it is also designated for home use. This is because the
> FCC rating for equipment to be used in homes is more strict than for those
> limited to the hospital setting. It is assumed that interference with
> TV/radio etc. is less an issue in the hospital.
>
> The ratings for EMC susceptibility (can't handle a nearby TX) is the same
> or can be higher in medical equipment, depending on application. But hams
> seldom have that problem with 12 V power supplies.
>
> 73,
> Drew K3PA (Medical Systems Engineer)
>
> -----Original Message-----
>
> ------------------------------
>
> Message: 2
> Date: Tue, 12 Nov 2024 08:33:28 -0500
> From: <charlie@thegallos.com>
> To: "'Barry W2UP'" <w2up.co@gmail.com>
> Cc: <cq-contest@contesting.com>
> Subject: Re: [CQ-Contest] Switching Power Supplies
> Message-ID: <045901db3507$757e0d40$607a27c0$@thegallos.com>
> Content-Type: text/plain; charset="utf-8"
>
> I never had an issue with my Samlex, even the older one, and of course my
> linear Astron works fine, but is bit on the heavy side
>
> If you want to get a really quiet supply, look for one that is rated for
> Hospital Medical Equipment ? there is a EMC requirement that is very strict
>
>
> *****************
>
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> CQ-Contest@contesting.com
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