[Elecraft] Switching power supplies...yet another comment

[Alan Bloom]

I can second that.  With no antenna connected I can hear some spurs on
the lower bands, mainly 160 meters and a little on the other low bands,
but with the antenna connected, band noise covers them up completely.

The only complaint I have heard about the MFJ-4125 is that, while it is
electrically quiet, acoustical noise is another matter.  The internal
fan is rather noisy.  I designed a proportional fan controller to slow
the fan down under normal operation and speed it back up again if the
supply gets hot (say for continuous-duty RTTY operation).  The article
was in February 2010 QST.

Al N1AL


On Sat, 2010-07-17 at 20:25 -0500, Edwin Johnson wrote:
> Guess I have to add to the mix by saying I bought several years ago an 
> MFJ-4125 25 amp switching power supply (the one without the meters and about 
> 6"x6"x2", or so) for portable use. I did a bit of research and at the time I 
> bought it, the hash and output was smoother than anything on the market. (That 
> sounds hard to believe, doesn't it? hi)
> 
> At any rate, absolutely no noise nor hash of any kind and I usually use random 
> wire or end fed zepps for portable.
> 
> There have been some new introductions since then to the market which may have 
> other advantages, but I will say this is an excellent choice at a fair price.