I have an Icom 706 (original version) and am using the digi-rig cables to connect the ACC and CIV port to my digi-rig. Everything has worked tremendously well so far. Mostly used the rig on FT8 and Winlink.
I am looking to build it out into a rack mounted kit, and one component I may add is the MFJ-1708-SDR switch so that I can use an RSP1A to capture the the whole HF spectrum. Maybe tie into some form of rig control etc.
I am not interested in using the RF Sense functionality as I don’t trust it based on reviews, and would like to have a control line from my 706 to the MFJ-1708. The issue, is the ACC slot is used for the Digirig cables.
I am open to the idea of opening up the ACC 13pin Din cable to splice in another line that goes to the control port on the MFJ-1708. I assume that wouldn’t cause any issues … right?
Does anyone have any alternative suggestions on how to connect the Icom 706 to both the digirig and the MFJ-1708 at the same time?
I’d probably be tapping it on the interface side of Digirig’s cable because 3.5mm TRRS connectors are easier to work with than 13pin MiniDins. You can make a splitter with female TRRS for interface side of the Digirig’s cable that connects all lines to male TRRS connector for Digirig’s audio socket and PTT/GND tail with RCA connector to the switch.
This is incredibly helpful thank you!
Frankly I didn’t know what pin to utilize but that makes sense that it would be the SEND pin.
I wasn’t able to find one, do you have a wiring diagram of the IC-706 cable specifically? Im curious and don’t want to open it up.
Thanks!
Z
Afternoon. I have returned to this project and need more help! Thank you in advance.
Ive purchased an SDRSwitch from Paul N2EME. Very low insertion loss, with some great features. Worth checking out, will be pairing with SDRConsole, OMNI-Rig, WSJTX, N1MM(assuming I can get virtual serial cable duping to work), etc.
Paul has helped me figure out my general signal flow (see overall plan at bottom of post), and mentioned that the IC706 (original model) had a flaw in which its PTT output is capable of only low amperage (fixed on the 2nd and 3rd gens). He expressed concern that if the SDRSwitch should pull current and the Digi-rig ALSO pull current that it may cause issues/damage on the IC706 as its could pull more than its rated for.
His recommendation is to trigger the PTT to the SDRSwitch, and then have its AMP output wired to the digirig to tell the unit that it’s in transmit mode. My concern is getting PTT control of the rig from the PC would no longer be possible.
I ASSUME that the ground between the RCAs are connected, so in theory the Rig_AFOUT and Rig_AFIN would still function to pass audio as the ground is also present with continuity back to the radio? This would get me part of the way there, I think just missing the PTT functionality… I’ve gotta confirm that there is continuity there, but assuming it is, is my understanding correct?
SDRSwitch Wiring:
Alternatively, do you have any experience with the IC706 PTT? Is your recommendation still to do a TRRS Splitter, with the PTT and ground pins being send to an RCA connection to trigger the PTT on the SDRSwitch?
Here is my overall rig plan, apologies for the resolution.
I’m not familiar with the PTT flaw in early IC-706 transceivers. Typically PTT input of the radio is weakly pulled up line which external accessory device grounds to key up the radio. The radio pretty much can expect the PTT connection to be 0 ohm (like when you use the contacts of the relay) and the strength of the pullup in the radio determines how much current that generates. Digirig’s PTT switch is not exactly zero ohm, but it’s close and I haven’t received any reports of the issues with IC-706.
