[hpsdr] Penny audio and Hermes

[Kevin Wheatley]

Hi Francis

While developing the layout for Hermes a lot of consideration has done  
around the thermal issues, to aid dissipation maximum copper pours  
have been deployed and we have moved to a 6 layer board to increase  
the copper (and signal integrity on some of the tracks). How this  
ultimately works, will be demonstrated / proven by the Alpha builds :)  
Let's hope we've got it right!

73's
Kevin - M0KHZ

On 13 Oct 2009, at 00:40, FRANCIS CARCIA wrote:

> ***** High Performance Software Defined Radio Discussion List *****
>
> Penny,
> I usually run the gain around 10 using an EV664 with 3 or 4 db of  
> comression. You can dial in the response with the 10 band TX EQ. I  
> did not modify the software. It is easy to over drive the audio. Use  
> a scope to see where you compress. I would like to run higher  
> positive peaks but software seems to limit around 100 % positive. I  
> would like to hit 150% positive and 95% negative.
>
> Hermes layout looks better withough a 15 watt linear living on the  
> board. I have done susceptibility tests with a 1/2 inch loop and  
> have given low voltage logic fits with a couple watts.
> Please use plenty of ground to heat sink the A/D. I'll solder a  
> brass spacer to the bottom and heat sink to the chassis if there  
> needs to be better heat transfer. That board would drop right into  
> my desk top final project
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