[hpsdr] [Fwd: Re: Tiny Demeter]

[Greg - ZL3IX]

Hi folks,

Phil VK6APH asked me to comment on the proposal for Tiny Demeter.  My 
comments and his reply copied below.

73, Greg, ZL3IX

-------- Original Message --------
Subject: 	Re: Tiny Demeter
Date: 	Sun, 15 Jun 2008 13:13:49 +0800
From: 	Phil Harman <phil at pharman.org>
To: 	Greg - ZL3IX <zl3ix at inet.net.nz>
References: 	<48541C31.9050704 at inet.net.nz>



Hi Greg,

Agree with your comments - we may want to have the GPS power on at all times 
to lock the associated xtal.  Suggest we have this discussion on the forum 
so that others can join in on the suggestions. Would you like to move you 
comments overthere.

Thanks

Phil...
----- Original Message ----- 
From: "Greg - ZL3IX" <zl3ix at inet.net.nz>
To: "Phil Harman" <phil at pharman.org>
Sent: Sunday, June 15, 2008 3:29 AM
Subject: Tiny Demeter


> Hi Phil,
>
> I had a look at this as you asked.  Just two comments.
>
> 1)  I would use the DC/DC converter to pre-reg the 5V supply to, say
> 6V.  As it is, that series pass transistor is dissipating over 12 W at
> 1.5A output.  The -12V can then be taken from a flyback winding or
> something like that.
> 2) The original Demeter spec talks about a supply for a GPS module.
> Many of these require 3V3 today.  Not sure if Tiny is also supposed to
> power a GPS module, but if so, this should be taken into account.  Could
> be a linear reg from the 6V, as these modules don't draw a lot of current.
>
> My 2 cents.
>
> 73, Greg


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