[hpsdr] SB104A Power Amp

[Phil Harman]

Hi Jeff, 

A few suggestions regarding interfacing Penelope to an existing PA.  You can use the open collector drivers on Penny J6 to select the LPFs on a band-by-band basis in conjunction with PennyCrtl in PowerSDR.  Use the open drain FET on J6 pin 13 to control the  T/R relay. Place a snubber diode across any relay coils that your connect to.

If your PA needs  1/2w or so to drive it then a direct connection to Penny will work fine. If you need much less power then place an attenuator between the output of Penny and your PA rather than turning the drive level right down.  At low drive levels the S/N performance of Penny will degrade - drive her to about 200mW and you will have a great sounding signal.  

If you need drive in the mW region then remove JP2 and take the drive from pins 1(signal) and 3 (ground) - you need 50ohms at the destination to terminate the LPF correctly

Good luck and be sure to let us know how you go.

73's Phil...VK6APH 

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