Hi Lyle,

I was looking at this. I think the files are also in Files > Si570 >
LPT1. This is Guido's (PE1NNZ) parallel interface.

However, I would think a better parallel port interface would employ
opto-isolators. Opto-isolators will prevent a potential source of
ground loops. I took a quick look for opto-isolators and found some
parts that are logic level compatible at the output at-least and fast
enough to handle 400kbps I2C, I think they were from NEC.

Can anyone suggest ideal parts for isolating the parallel port for
Guido's interface?

73's, David

--- In [email protected], "Lyle Koehler, K0LR" <[EMAIL PROTECTED]> 
wrote:
>
> I'm happy to report that my Lite+Xtall v8.3 receiver kit is up and
> running, both with the 12F683 on-board controller and with a
> "modification" to allow parallel-port control. Actually no
> modification to the v8.3 board is required -- the parallel-port
> control interface is on an 8-pin header that gets plugged into the
> socket in place of the 12F683. In addition to the header, the only
> components required are two FETs and a DB25 connector. A schematic of
> the interface is included in Guido's PowerSDR-sr40 Installation Manual
> (http://powersdr-sr40.sourceforge.net/). I used 2N7000 transistors in
> place of the BS170 parts shown in Guido's diagram. The 10k pullup
> resistors R1 and R2 are not required, because there are already
> pullups on the v8.3 board. Here is a verbal description of the
> interface wiring which will have to suffice until I get around to
> posting a diagram to the Files section.
> 
> The source leads of both FETs are tied to ground (pin 8 of the
> header). One FET has its drain connected to pin 2 of the header and
> its gate going to pin 3 of the DB25 connector. The other FET has its
> drain connected to pin 3 of the header and the gate tied to pin 2 of
> the DB25 connector. Pins 12, 13 and 25 of the DB25 connector are
> connected to pin 8 of the header.
> 
> With the 80/40 BPF filter board plugged into the v8.3, I'm able to
> listen anywhere on 80 or 40 and to everything in between, using
> PowerSDR-sr40. In addition, I can check WWV at 10 MHz or listen to the
> stronger AM broadcast stations. So far the 80/40 BPF is the only one
> I've completed, but conditions on all the bands are lousy today anyway1
> 
> Lyle, K0LR
>


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