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Re: [Xylo-SDR] RFC - Powers
Phil
Sorry we missed you on Teamspeak tonight! Great session and I botched the
Audio. I'll back up the source file before I try this again!
Thanks also for your project plan. As a team, this is a great project! I
know that we can do it! You 'called the ball' in the first sentence, is that
this is modular in the entire plan so that the 'product' in the end could be
as simple as supplying a 'neat enclosure' to the general public, to
combining 'experiments' that we do and enclosing it in the same enclosure as
a different project/product. I guess you could tell from my comments, that I
am rooting for you/us with your SDR!
--------------------------------------------------------------
Yep, it has been my sad experience that computer power supplies do need a
minimum load to start, and I don't know what that is? Also they need a
'cold contact' to firmware to turn them on. So we are going to have to
figgre that out. They are available in quantity at any landfill so shouldn't
cost much. If you got really sharp eyes, you can catch them at the end of
any driveway on garbage day!
I think we only really need the +/- 12, +5 and ground.
Yes, I think a pass through to the back panel, using a common molex 4 pin
connector should work..
Let's ask Phil - VK6APH, "If Phil likes it everybody likes it!"
Eric
-----Original Message-----
From: xylo-sdr-bounces@lists.ae5k.us [mailto:xylo-sdr-bounces@lists.ae5k.us]
On Behalf Of Philip Covington
Sent: Tuesday, January 17, 2006 10:33 PM
To: Xylo-SDR Discussion
Subject: Re: [Xylo-SDR] RFC - Powers
Phil, eric, all
Don't PC power supplies require some minimal load on each line? And
if so, how much? How are they for noise and ripple? It would be nice
to use them since they are cheap compared to the alternative...
Would you use the ATX style supply and connector or the older PC style?
Maybe if we went with the motherboard mounted on stand-offs to the
back panel, we could arrange for the power connector to be soldered on
the bottom side of the motherboard... and the stand-off spacing could
be adjusted to allow the connector to pass through an opening in the
back panel... kind of like the front panel component idea?
73 de Phil N8VB
On 1/16/06, Phil Harman <pvharman@arach.net.au> wrote:
> All,
>
> At work I've built a number of commercial projects built around PC power
> supplies. They give +/-12/5/3.3v etc at high currents and are very low
cost
> and very small. For 9-15v input you can get DC to DC PC power supplies
> with the same voltages from Taiwan that are again small, low cost and
highly
> efficient.
>
> If we base our rear panel power connector on PC power sockets then we have
> 1000's of potential power supplies to choose from. I had one made
specially
> for me in Taiwan recently and it has low EMC and not much more expensive
> than an off the shelf unit.
>
> For shack use they come free from junked PC's! My 100w PA uses one that
I
> rewound the transformer to give 13.5v @ 20A and it's been working for
years.
>
> Phil...VK6APH
>
>
>
>
> ----- Original Message -----
> From: "Eric Ellison" <ecellison@comcast.net>
> To: "'Xylo-SDR Discussion'" <xylo-sdr@lists.ae5k.us>
> Sent: Monday, January 16, 2006 7:06 PM
> Subject: Re: [Xylo-SDR] RFC - Powers
>
>
> > Guys
> >
> > Thanks for all the comments re power.
> >
> > I am in favor of single 11-14 volt input to the back of the radio.
> >
> > However, I do realize that, due to heat, noise, etc. this might not be
> > do-able.
> >
> > Possibly an external computer power supply? I think all the voltages we
> > might need are present except for perhaps the - voltage.
> >
> > There are quite a few DC-DC converters available, in chip-dip,
fractional
> > brick etc, but I have not Googled much.
> >
> > Eric
> >
> >
> > -----Original Message-----
> > From: xylo-sdr-bounces@lists.ae5k.us
> > [mailto:xylo-sdr-bounces@lists.ae5k.us]
> > On Behalf Of Ahti Aintila
> > Sent: Monday, January 16, 2006 2:22 AM
> > To: Xylo-SDR Discussion
> > Subject: Re: [Xylo-SDR] RFC - Powers
> >
> > Due to the international electrical safety and electromagnetic
> > compatibility regulations (UL, UR, CE, FCC, etc.) I prefer 13.8 V DC and
> > a separate UL/CE approved power supply for the 100 - 240 V, 50 - 60 Hz
> > wall outlet connections. Only very quiet switching power supplies are
> > acceptable, otherwise use bulky linear regulated equipment.
> >
> > Be extremely careful with shielding and filtering, if you have to use
> > switching regulators inside the box. Leon is right, generating the low
> > voltage logic power directly with linear regulators from 13.8 V DC
> > certainly will heat up the small box too much.
> >
> > 73, Ahti OH2RZ
> >
> >
> > ----- Original Message -----
> > From: "KD5NWA" <kd5nwa@cox.net>
> > To: "Xylo-SDR Discussion" <xylo-sdr@lists.ae5k.us>
> > Sent: Monday, January 16, 2006 2:15 AM
> > Subject: Re: [Xylo-SDR] RFC - Powers
> >
> >
> > +5V, +- 13.8V
> >
> > Three scenarios, #1 is the most practical, when
> > you try to do too many things it cost too much.
> >
> > Scenario 1
> >
> > Input power source is either 13.8V or 110V-220V
> > power cord, using a switcher to generate all power.
> >
> > The +5 at 5 to 8 amps, logic power, can be used
> > in a card when 3.3V is required.
> > The +13.8 2 to 3 amps used with local regulation
> > for op-amps. Raw power for a modest amplifier.
> > The -13.8 at .5A or less, very little power
> > needed, used mostly with op-amps that use +-
> > power, local regulated to a lower voltage for noise consideration.
> >
> > Scenario 2
> >
> > +13.8 is the input power source, desire to have
> > fairly high power out from an amplifier.
> >
> > The +5 at 5 to 10 amps, logic power, can be used
> > in a card when 3.3V is required.
> > The +13.8 5 to 10 amps used with local regulation
> > for op-amps. Raw power for a amplifier.
> > The -13.8 at .5A or less, is derived from the
> > +13.8, very little power needed, used mostly with
> > op-amps that use +- power, local regulated to a
> > lower voltage for noise consideration.
> >
> > Scenario 3
> >
> > Power supplied by wall outlet (110V-220V) using a switching power
> > supply.
> >
> > High fidelity audio modes desired, running RF final at 28Volts.
> >
> > The +5 at 5 to 10 amps, logic power, can be used
> > in a card when 3.3V is required.
> > The +13.8 5 amps. Used to power op-amps with
> > local regulation, raw power for power amplifier.
> > The -13.8 at 5 amps , very little power needed,
> > used for op-amps that use +- power, local
> > regulated to a lower voltage for noise
> > consideration. Used for power output stage to run
> > on 28V for higher efficiency, better quality RF in voice modes.
> >
> >
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