[TenTec] which power supply…station efficiency

[Jim Brown]

Bob,

I have come to realize that bonding the negative 12VDC lead to chassis 
at the power supply is a very bad idea.  The applications note below 
explains why.

k9yc.com/PowerSupplyBondingAndAudioDistortion.pdf

The PSU chassis SHOULD, of course, be bonded to every other chassis in 
the station.

In response to the original question, I am currently using a Powerwerx 
switching supply rated at 20A  to float charge a pair of 6V 220 AH golf 
cart batteries. Before I bought those batteries, I used one of the 
biggest deep cycle batteries that Costco sells. They last at least 3 
years in that sort of service.  I used a float voltage of 13.8VDC with 
them, simply setting the regulator in the PSU to that voltage. The golf 
cart batteries want a higher float voltage.  All of the 12V gear in my 
shack runs off this nominal 12V bus.

The Powerwerx unit is RF quiet. I bought it to take on a DX trip. Before 
that, I used a little 10A regulated switcher that I paid about $10 for 
at the Milwaukee hamfest 10 years ago. It was VERY noisy, so I had to 
add a bunch of ferrite chokes to it, as well as a cap across the AC 
line. But it, combined with the Costco battery, was enough to keep up 
with my rigs, even during heavy contesting.

I replaced the Costco batteries with the golf cart batteries as part of 
a solar rig for the shack. Thanks to the very tall redwoods that hold up 
my wire antennas, the solar panels are useless during the winter, but 
provide good charging during the summer months when my electrical rates 
go sky-high, hence the Powerwerx.

73, Jim K9YC

On 12/8/2013 8:39 AM, Bob McGraw - K4TAX wrote:
> I use exclusively the ASTRON SS-30M at my stations and shop.   
> Actually have 3 of them.  I find them to be reliable, acoustically 
> quiet although I do and can hear the fan switch on and off, and I find 
> they are electrically quiet.
>
> I did add a true GROUND terminal to the rear panel.  Internally I 
> connected the AC ground/green wire to this point and the 12V DC Neg to 
> this point. This point becomes "station ground".
>
> I also put a internal tooth lock washers between the outer shell and 
> the base where the 4 screws attach the outside cover.  This assures 
> the metal parts are electrically bonded and not insulated by a layer 
> of paint as found in many instances with equipment today.
>
> As far as I'm concerned, the SS-30M it is a very good supply for the 
> money.
>
>
> 73
> Bob, K4TAX
>
>
>
>
>
>
> ----- Original Message ----- From: "denton sprague" 
> <denton at oregontrail.net>
> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
> Sent: Sunday, December 08, 2013 10:14 AM
> Subject: [TenTec] which power supply…station efficiency
>
>
> I am upgrading a bit here…
> got a new full sine wave ups coming with two aux battery packs to 
> replace my old cyberpower 3000 ups.
> Ups has AH rating of 336 and each aux battery pack is 864 AH….
> I am also looking at replacing my Astron 35m power supplies with more 
> efficient switching power supplies or running my TT Eagle or my Omni 7 
> and various sundries that use 12 vdc with a battery pack, charger and 
> a battery booster when needed.
> So my question is…what switching power supplies are my fellow hams 
> using and how well do you like them?
> I am aiming for efficiency, rf quietness and flexibility.
> Other than the station, the ups will be used to fire a smaller flat 
> screen tv, satellite receiver, iMax and a lamp….nothing total over 500 
> watts draw…at least to my calculations.
>
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