1708B-SDR." I'm sorry I've read this sentence in every way I can and it doesn't make any sense. Is the CTRL connected to the amp and is used to key the amp? Then the manual states"If a linear is used then connect the AUX output to the jack that keys the transmitter." HUH!? Connect the AUX jack to the jack that keys the transmitter? I read tech manuals every day and it's been a while since I've read stuff the vague. Anyway, someone please streighten me out on how I need to connect the MFJ-1708 up so when I key the transmitter it will actuate the MFJ box AND key the Linear amp? I appreciate your help.
The AUX is just a relay that can be used to trigger other devices, it has 2 settings.
See page 4 of the manual, the AUX is set to NO or NC depending on jumper1.
In short, CTRL is the RX/TX control line coming out of the ACC connector of your tranceiver.
With AUX you can trigger the Amplifier to TX-mode or some other device, but it's just a relay contact, there is no current.
Reason: No reason
I would like to figure out how to mute the RSP1A on transmit. I see what you are saying about the AUX just being just that. An auxiliary contact for other uses.
I hope this information can help someone else.