[hpsdr] Hermes schematics

[Lyle Johnson]

A couple of comments/questions:

1) On Magister we added an STMicro DVIULC6 (Digikey 497-5237-1-ND) 
transient suppression diode network on the USB -D and +D lines to help 
protect the FX2.  Might be worth considering.

2) I see a pair of LM317 in series to drop +12V to +5V.  I assume this 
is for heat purposes.  It'd sure be nice to get away from linear 
regulators going from +12V all the way down to +1.2V.  I understand the 
concern about switching regulator noise.

3) The cascaded OPA amplifiers for Penny I presume are to enable 0.5w 
output with low IMD especially at 6m.  But I see no means to reduce 
power output, except via the TxDAC.  Is the intent that power control be 
handled by an off-board attenuator or somehow managed in the add-on 
amplifier? 

Looks like a very exciting project!

73,

Lyle KK7P


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