[Elecraft] K2 Power Supply Recommendations

[John Grebenkemper, KI6WX]

A few days ago I posted a message regarding AC power supplies for the K2.  A
summary of the results of the messages I received follows.

Radio Shack makes two 13.8 V 3A supplies.  #22-503 ($50) is a switching
supply and some folks have heard noise from the supply in the receiver.
#22-504 ($40) is a linear supply and runs a K2 with no apparent noise, but
is bigger and heavier than the switching supply.

Mouser (www.mouser.com) has a small 15V 3.4A switching supply.  Again, you
might get some noise from it if your antenna is close to the supply.  The
part number is 552-PSS-45W-150 ($38).  This is clearly the one to get if
small size is important to you.

Finally, the cheapest supply is from http://www.allelectronics.com/.  The
Elpac PS-1242 is $18.  Again this is a switching supply and you may have
trouble with power supply noise getting into the antenna.

Since size was not an issue, I purchased the Radio Shack #22-504 linear
supply.  It is very quiet; an antenna draped across the supply did not pick
up any noise from it.  The supply as delivered provided 13.85 volts output,
which dropped to 13.75 volts at a 3 amp load.  There is a pot on it that can
adjust the supply voltage from 13.1 to 14.2 volts.  The noise on the output
voltage measured 5 mV peak-to-peak with the K2 in receive and increased to
20 mV peak-to-peak with a 3 amp load.

Thanks for all of the suggestions.

-John
 KI6WX