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PostPosted: Tue Nov 27, 2012 10:11 am 
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Joined: Fri Aug 03, 2012 5:35 pm
Posts: 36
I'm a little confused about the control connections to the PA board. What signals do Pin 3 (DT_RLY) and Pin 4 (TX_RLY) connect to on the DSP-610 main board?

Where does PA_Bias come from?

I haven't found a source for PA-Bias on the main board or on the PA board.

Thanks in advance.


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PostPosted: Tue Nov 27, 2012 10:43 am 
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Joined: Mon Jul 23, 2012 6:25 am
Posts: 1143
DT_RLY switches in a 1500PF NPO cap on 10 Meters so it goes to TX_10 on the main board.

TX_RLY is the T/R switch for the PA the PA_BIAS can drive this signal as well.

PA_BIAS is the switched 5V that biases the MOSFETS it comes from the output of U6 on the main board.

The updated schematic on the wiki shows all of the connections:

https://docs.google.com/viewer?a=v&pid= ... E1ZWY1NzEz

Pae 3 says PA_BIAS goes to PIN 3 and 5 on the new PA board but I think it should say Pins 4 and 5

73's
Jim.


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PostPosted: Tue Dec 04, 2012 12:18 pm 
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Joined: Fri Aug 03, 2012 5:35 pm
Posts: 36
Jim:

Page 2 of the DSP-610 OBPA schematic shows Control Pin 2 of the PA Board connected to the main board TX_6 signal (at R103), which allows 6 meter transmitting only.

Instead, perhaps Control Pin 2 of the PA Board should be connected to the main board 6M signal (pin 16 of the PIC18), to allow 6 meter transmitting and receiving, too.


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PostPosted: Tue Dec 04, 2012 9:00 pm 
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Joined: Mon Jul 23, 2012 6:25 am
Posts: 1143
Yes good point otherwise the RX signal will end up going through the 10 LPF, very bad!


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