[hpsdr] Power Ping RFQ

[Eric Ellison]

Ben/All

Just got off Teamspeak tonight. Scotty and Dan are testing OZY and Janus and
are using PicoPSU's and not having any problems with Janus/Ozy with the PSU
in testing mode! Nothing was said about negative supplies. 60 Watt PSU is
more then enough for janus/ozy. Yep, I would say most neg supplies are a
little lean.

Will post the Teamspeak Audio sometime tomorrow morning. Much discussion
regarding test program for Janus. Verilog guys please listen in!

Thanks
Eric




-----Original Message-----
From: Ben Hall [mailto:kd5byb at bellsouth.net] 
Sent: Friday, April 20, 2007 10:35 PM
To: Eric Ellison
Cc: hpsdr at hpsdr.org
Subject: Re: [hpsdr] Power Ping RFQ

Hey Eric and gang,

I'll chime in quickly - it's getting late for me.

 From the research I've done for Pandora, it seems that the power supply 
requirements right now are very low - under 20 watts for existing Atlas, 
Janus, Ozy, and planned for Penelope and Sasquatch.

With under 20 watts being easily handled by linear supplies, I'm not 
sure that there is a need to use anything besides linear supplies.

One problem I've found with the picoPSU switchers is that they can only 
do 100 mA on the negative supplies.  I know I had to modify my power 
supply tester when I was testing my picoPSU as it was set to draw more 
like 400 mA.

Yet, with linears, portable operation off of a 12 VDC battery becomes 
problematic due to the fact that existing HPSDR boards need the negative 
supplies.  You could use another 12 VDC battery, but that's a lot of weight.

Perhaps the negative voltage draw is low enough that a charge pump 
inverter could be used?

Interesting this came up - was reading about just such a supply in 
Horowitz and Hill "Art of Electronics" at the hospital today.  Seems 50 
to 100 ma is possible?

I will think more about this tomorrow.  I've used some NICE open-frame 
supplies from Lambda/Power One/ACDX/Etc., and some real junk too.

thanks and 73,
b, KD5BYB

Eric Ellison wrote:

> I got an off-list question from a friend who was inquiring about power 
> supplies for Janus/Ozy. 

<snip>

> Obviously most of the Alpha testers, have used regulated bench supplies. 
> Chris AE6VK has used the 60 and 120 W PicoPSU and shown it to work and 
> be pretty 'clean'. (Thanks Chris!)
> 
> Would it be advisable to spend a little more money and go with a 
> Power-One or Lambda multi-voltage linear open frame supply?
> 
>  
> 
> What is the minimum wattage we would need if just these 2 boards?
> 
>  
> 
> Anyone have any suggestions for a good ATX supply? Considerations for 
> selection? Mods? Circuit Protection for Atlas + Projects?
> 
>  
> 
> Personally I am going to take a shot, and have purchased a PicoPSU 120 W 
> 12-32, based on Chris's work, in the absence of any personal experience.
> 
>  
> 
> Also:
> 
>  
> 
>    1. It can be powered by my 12 v. station supply and fused.
>    2. It is small.
>    3. This is the only device anyone has tested.
>    4. I don't feel that I want to invest in a 3 voltage regulated bench
>       supply. (not very portable!)
>    5. It does not require any minimum 'load' modifications to run.
>    6. They come with all connectors.
>    7. They are cute.
> 
>  
> 
>  They are out of 12-32, but have what looks like an equivalent 12-25 in 
> stock.

-- 
Thanks and 73,
Ben, KD5BYB


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