Weigh it. Most small wall warts are also very light. I've got a couple
of heavy larger ones in the junk box and the difference is hard to miss.
The cable from it is the radiator of course, a BC band radio tuned to
a clear spot [preferably at the high end] will usually show a distinct
increase in noise as you move it up the cable.
I was choking a 4 A feed to the wireless equipment and used a couple of
3 1/2" OD [or so] toroids that N6XI gave me. Consulting the K9YC
recipe, I wound 12 turns of Radio Shack red-black pair on one, and as
many turns as I could get in one layer on the other, wired them in
series and then stacked them using zip ties. My theory was that the one
with lots of turns would get the 160-80 m stuff and the 12 turns would
get 40-30-20. They went right at the Chinese RPOJ power supply in the
24 VDC cable. I don't know the mix but I think probably 34 or 43, I
think they were part of a group buy by the contest club.
My experience with the small clamp-ons has been poor, unless you get
several turns of the cable through it, and even then I don't think
there's enough permeability in the magnetic circuit to do much. It's
pretty hard to find linear wall warts these days.
73,
Fred K6DGW
- Northern California Contest Club
- CU in the Cal QSO Party 1-2 Oct 2016
- www.cqp.org
On 3/3/2016 2:53 PM, David Christ wrote:
Is there any way to easily determine if a wall wart is a SMPS? Most
probably are but are there any that are not?
David K0LUM
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