--- In FT817@y..., "Curtis, Tony" <acurtis@t...> wrote:
Regarding switching power supply noise...
I have been using a small Radio Shack 13.8 VDC 3A regulated
switching power
supply with my '817 with very limited hash problems, none where I
have
wanted to operate. It is catalog number 22-503 at $49.99.
Hi Tony,
This PS was perhaps the first one identified for use with the 817
back last year. The problem found with it was lack of quality
control. Some seem to work well while others (most) generate lots of
trash RF. True of even the same lot. I noted in the FAQ that one
would be well advised to take their 817 to RS and test the PS in the
store until an acceptable one is found.
Switching PS generate noise. No surprise, but how bad it is depends
upon the shielding of the PS. For example, the PS inside my FT-
1000MP is quiet. The IPS CUP36-12-1 works well for me unless I have
a long wire hooked directly to the rig or some other antenna very
proximate to the PS. Since there is a limit to the amount of
shielding that can be done within the size and weight of the CUP36,
there is a low-level RF emission from it. The fact that you hear it
under this situation means that your receiver is doing a good job. :-
) When I use shielded cables to my antenna (say > 10' away), I hear
nothing from the PS. The 817 is nicely shield and doesn't hear it
directly.
My larger 25 A PS for other rigs like the FT-847 are well shielded
and are unheard, but they are a LOT bigger than the CUP36 (that fit
into my shirt pocket with my cell phone to give you some idea of how
small it is). If you look in the Files sections under the
folder "Rig Photos," the first file is a image I made showing the 817
with the RS 22-503 and the CUP36.
72 de Barry - W4WB
