Copy of email sent to me by Ted Cline October 2025:
How are coaxial relays controlled from the computer to allow software like SDR Sharp to collect calibration data vs signal data?
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,
https://github.com/tedcline/ezRA/blob/master/ezRA/doc/ezRA_20b_Windows_Install.pdf
https://github.com/tedcline/ezRA/blob/master/ezRA/doc/ezRA_20c_Linux_Install.pdf
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