[hpsdr] Power supply filtering

Thu Jun 28 21:37:27 PDT 2007

Hi All, Andreas, Jeroen,

Good observation, I agree with you that nothing requiring high power should
go on ATLAS.
And that maybe ATLAS is not intended/designed for this?

Maybe one of any new 2- or 3-slot ATLAS designs could be made to fulfill
these new requirements?
(And some way of coupling ATLAS boards)

On the other hand I think the discussion about power supplies should not be
limited to power for ATLAS mounted boards only, but for a complete setup of
a complete HPSDR receiver, -transmitter or -transceiver.

If this is included, then higher currents and extra voltages than just those
required for the ATLAS mounted boards may be part of the total power supply
requirements.
Also mobile/emergency use of a HPSDR I think should be part of the
discussion, as well as the "green" aspects of power usage.
If these are included, then power efficiency, -scalability, -modularity and
flexibility come into the discussion.

I for one am planning for a standalone (with a small mini-ATX PC and a flat
panel display included), mobile 10-14 Volt operated, 10 Watts or so PA,
HPSDR.

So for this setup I would require:
- A 10 - 14 Volt input SMPS main power supply (energy efficient, generation
of negative voltages)
  (Don't like them, but need them)
- Extra voltages (3,3 Volt supply for PC, ?? Volt for display)
- Extra current (12 Volts @ 5 Amps for PA, 3.3 Volts @ ?? Amps for mini-ATX
PC)

Somebody else will have a different set of requirements.
It would of course be nice if I could use (some of-) the DEMETER
functionality.

For that I think it would be a good thing if DEMETER could provide solutions
for more setups of a HPSDR.

Just my 2 cents.

73's,

Henry.

> -----Original Message-----
> From: hpsdr-bounces at hpsdr.org 
> [mailto:hpsdr-bounces at hpsdr.org] On Behalf Of Andreas Troschka
> Sent: vrijdag 29 juni 2007 1:12
> To: hpsdr at hpsdr.org
> Subject: Re: [hpsdr] Power supply filtering
> 
> 
> ***** High Performance Software Defined Radio Discussion List *****
> 
> Getting a look at the dimensions of the power supply 
> lines/planes and contacts of connectors! on the Atlas 
> Backplane, common sense suggests to forget PAs over say 6-8W 
> rf, continuous wave.
> 
> I would charge no more than 36W on the 12V line and less on 
> the over voltage-lines (don't forget we've one 0V return line only).
> 
> If you really need more power from the PA, then separate 
> supply has to be provided to that board even if we are used 
> to have external PAs so I don't see any requirement for rf 
> power-blasters on the HPSDR.
> 
> Apart from this considerations, if memory helps, the use of 
> FPGAs, quick ADCs and the like is announcing a consumption of 
> a lot of power.
> 
> As project manager of the ATLAS board Phil N8VB should give 
> some indications on the power limits of the various 
> power-lines of the backplane.
> 
> A study should be made and maintained up-to-date to verify 
> what board combinations fullfill the ATLAS power maximum ratings.
> 
> This study should also provide a table containing the current 
> drains (or power requests) of every HPSDR board in its 
> various function modes (or at least the max power consumptions).
> 
> I hope we aren't running low from the beginning. In that case 
> solutions can be studied as modifications to the existing 
> ATLAS backplanes and to its layout (and alternate power lines 
> included) for future production lots.
> 
> 
> vy 73s de IK2WQI - Andreas
> 
> 
> Jeroen Bastemeijer wrote:
> > ***** High Performance Software Defined Radio Discussion List *****
> > 
> > Dear All,
> > 
> > Thanks for the link, N0UU. I downloaded the document. 
> Allthough general 
> > principles still apply, I noticed the AN is quite old (1986!).
> > 
> > Michael Ardai gave a few good suggestions for the 
> supporting electronics 
> > of Demeter (like the ADC etc.).
> > 
> > Andreas Troschka and Tony Langdon send mails with regard to 
> the EMI of 
> > switchers. On this point I would like to add the following:
> > 
> > Designing a "quiet" switcher is not as easy as building a 
> "quiet" linear 
> > supply. However, it is my strong belief that it can be 
> done. By using 
> > proper grounding, effective filtering and a proper lay-out 
> of the PCB. 
> > The main advantage of a switcher will be the lower power 
> consumption and 
> > less heat.
> > Some other words about EMI: We shouldn't panic too much 
> about the noise 
> > which is generated in Demeter. The whole HPSDR is filled 
> with all kind 
> > of sources for EMI (e.g. clock-oscillators and 
> data-busses). One might 
> > argue that the power in Demeter is higher, but this doesn't mean 
> > necesseraly that the noise induced in the SDR will be 
> bigger. Some times 
> > there is a stronger electric coupling (E-field) instead of 
> a magnetic 
> > coupling. So a small signal clock line close to a sensitive 
> input could 
> > cause more noise than a "heavy" switcher at couple of 
> inches away....
> > 
> > I'm certainly willing to make some experiments with 
> switchers and see 
> > how quiet they can get.
> > 
> > Tony wrote: " I would consider a low current linear supply for 
> > everything except the PA. "
> > 
> > Thsi brings me to the point: How much power do we need? I made an 
> > assumtion, based on some measurments (from the Jnaus/Ozy 
> combo), but the 
> > rest of the power consumption is still a mystery....
> > 
> > Next step has to be to mak an inventory of all the 
> "power-hungry" cards 
> > which will populate the HPSDR. Is this a nice task for 
> Phil? Are you 
> > willing to do that? Otherwise, I will contact each 
> project-leader myself 
> > and ask the about real life numbers or good approximations 
> of the power 
> > needed.
> > 
> > Thank you,  73 Jeroen PE1RGE
> > 
> > stoskopf at tri.net wrote:
> > 
> >> ***** High Performance Software Defined Radio Discussion List *****
> >>
> >> For a good discussion of output filtering on switcher supplies see:
> >>
> >> http://www.linear.com/pc/downloadDocument.do?id=4176
> >>
> >> starting at p. 59 of AN19.  Be sure to read the final 
> comments at the end.
> >> Great sense of humor.
> >>
> >> I still haven't figured out the proper source/loads for 
> modeling in say,
> >> SwitcherCad.
> >>
> >> N0UU
> >>
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> >>
> >>
> >>  
> >>
> > 
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