How are coaxial relays controlled from the computer to allow software like SDR Sharp to collect calibration data vs signal data?

Copy of email sent to me by Ted Cline October 2025:

I suggest batch files (or Linux script files) and a USB Relay controlled by USB via software.

The batch file would change the relay, then run SDR#, change the relay back, then run SDR#.

(But can SDR# terminate automatically ??)

The software to control the relay is described in the

ezCol With A USB Relay Needs Even More Installation

sections near the end of the 2 ezRA installation PDFs,

And with more trouble, for a non-HID relay, try serialSend.exe,

and down below in “Customer questions & answers”,
see “How to set for 7sec on, 3sec off, 20sec on, 1 sec off. (5 series repeat)”
talks of
c:\disp\serialsend.exe /baudrate 9600 /hex “\xA0\x01\x01\xA2”
and
c:\disp\serialsend.exe /baudrate 9600 /hex “\xA0\x01\x00\xA1”
https://batchloaf.wordpress.com/serialsend/
https://batchloaf.wordpress.com/2011/12/05/serialsend-a-windows-program-to-send-a-text-word-via-serial-port/

ezRA’s ezCol Python code can do similar stuff with relays.

Coaxial relays will reduce your signal.

—
Ted Cline N0RQV