Re: [wsjt-devel] A bit of help and T/R control

[Bill S. <g4...@cl...>]

On 18/03/2019 05:10, lst...@co... wrote:
>
> I have a OSA103M transceiver that I want to try on 630M.  Using HDSDR 
> for control and of course WSJT for the coding/decoding.
>
> So all  I need is a PTT line and audio in/out for the Windows machine.
>
> Before I try to reinvent the wheel, anyone have a suggestion of a 
> simple way to do this.  I can build a board as needed.
>
> The OSA103M is only 8 bit AD on RX and uses a R derived TX, but should 
> be a decent start.  Sounds good on normal use.
>
Hi OM,

from this diagram:

it seems you will need some external T/R switching as well as PTT. One 
common option is to use a serial port, perhaps a USB<->serial adapter, 
and use either the RTS or the DTR signal line to switch PTT. The PTT 
circuit above can be implemented without a separate power supply by 
using both signals, one for power and the other for PTT. WSJT-X supports 
such connections, you should add a diode to the +B line. If you are 
adding a T/R relay for aerial and Tx audio source then you will need 
external power so there I would use that for the PTT switch +B as well.

73
Bill
G4WJS.