[Elecraft] Silent power supply for a K3s

[Jim Brown]

On 6/9/2019 7:52 AM, Peter Dougherty wrote:
> Any suggestions? Within reason, cost isn't a
> major issue.

Sure. Another linear Astron, maybe bigger, higher power rated. I don't 
know how common the buzzing problem is. As Lee suggested, tighten screws 
and bolts on the one you have if you still have it.

Another important thing with Astrons is to fix their bonding problem, as 
described in this link. 
http://k9yc.com/PowerSupplyBondingAndAudioDistortion.pdf

BTW -- I still do the big float-charged battery thing, but it's now a 
100Ah Bioenne Power LiFePO4, and the charger is a spare power supply for 
one of my Thinkpads, using a  Genasun solar charge controller.  That's 
not an inexpensive solution, but it IS a very good UPS for the radios, 
AND the supply voltage stays above 13.2V under load as measured within 
the K3, there's less IMD on TX. The Genasun controller is RF quiet, and 
allows the Thinkpad PSU to charge the battery at about 7.5A. Make sure 
that you buy the 14.2V version for LiFePO4 chemistry.

https://www.amazon.com/Genasun-GV-10-Li-14-2V-Controller-Lithium-Batteries/dp/B01N6AXQZH/ref=asc_df_B01N6AXQZH/?tag=hyprod-20&linkCode=df0&hvadid=198068984819&hvpos=1o4&hvnetw=g&hvrand=17014603795544971507&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032155&hvtargid=pla-354296381972&psc=1

I use a separate sealed lead-acid battery to run the other 12V stuff, 
which includes antenna switching relays, LED lighting, three LCD 
monitors, and several accessories. It's charged by another Thinkpad PSU 
with a lead-acid version of the same Genasun controller.  I do, of 
course, have multi-turn ferrite chokes on the chargers and on the LCD 
monitor power and video lines.

For about half of my contesting, my K3s run at about 50W driving an 87A 
or 25W driving a KPA500, and this DC power arrangement has no trouble 
keeping up.

73, Jim K9YC