[Elecraft] Elecraft Digest, Vol 89, Issue 15

[István Szabó]

Alfatronix in UK does make very silent switch mode PS.  This is 
excellent down to 500 kHz w/o any noise.  I use 9A version with the 
K3/10. The 3A version is good only if you do not the second RX. They 
have 20A version for 100W trx as well, but that one a bit expensive.

73, István


On 9/14/2011 11:03 PM, David Dunn wrote:
> Re:] Switch mode PSU
>
> I just read the comments and reply in the message below:
> I have both those PSU, the Sec 1223  is by far the oldest one. It has
> several" birdies"   best described as rather Raucous Crows, which get worse
> as the frequency goes lower. 160m is pretty poor.   I added several devices
> in attempts to quieten same, which was achieved to some degree.  It is
> acceptable on all but 160m,   where it appears in about 3 places across the
> band, (not always the same places)  The Waters and Stanton  Power Mite is
> cheaper device and does much the same  although trips off when the full 20
> amps is drawn quite often. It has similar noises on several bands, which I
> can live with but is about the same as the other on 160. I have not
> attempted to add filters due to the limited success of the other. There is
> little doubt the "proper" transformer PSU's I have are best   but where
> weight is concerned the switch modes units are light and neat for the cost.
> -  Ideal I guess for the VHF folk
>
>    73   David G3SCD / VK3DBD
> _____________________________________________________________________
>
> Message-ID:<C27A8EE8-BD45-4069-A787-D8BBB9D59B3F at Alphadene.co.uk>
>
>
> Iain, I use a Power Mite from Walters&  Stanton when not in the shack - is
> very quiet, both physically and RF wise
> 73 de M0XDF, K3 #174, P3 #108, KX3 #???
>
> -_______________________________________________________________
>
>
> On 10 Sep 2011, at 22:58, Iain Haywood wrote:
>
>> Hi,
>>
>> Has anyone had any bad experiences using a K3 and a switch mode PSU?.
>> The SEC-1223 looks great aware some can cause problems..
>> They say 'Totally noise free', that's some claim..
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