[amsat-bb] Question - Icom IC910-H full duplex operation using the Data jack inputs

N6RFM1 gmail n6rfm1 at gmail.com
Thu Nov 30 14:57:28 UTC 2017

I have an IC-910H question maybe someone can help with? 

Would like to set up mine for full duplex to work Falconsast-3 using the
Data  jacks for TX/RX data jacks for I/O but cannot seem to get the TX input
side working.  I do get RX data out of the radio no problem, so issue seems
isolated to TX input side of the Data jacks.
In brief, I made a cable so that the output of an UZ7HO sound modem will
pass audio into the Data jack input.  The cable ohms out OK, but I do not
seem to be getting the data/audio into the radio via either Data jack.  I
have set the audio going into the data jacks at ~ 0.4 V p-p.  I am aware
that when the rig is in Satellite mode, the Data jacks act in reverse.
To troubleshoot further, I have tried Split mode.  As I understand, this
should leverage the Main Data jack only? With the radio in split FM mode
only, even if I feed a 1k2 tone to the Main or Sub Data jack input and key
the radio (by pushing the front panel TX button), I cannot hear modulation
on a second radio set up to monitor the IC-910H TX frequency.   Have also
tried all sorts of combinations for the Main and Sub Data inputs, but no


Is it required to assert PTT from the Data jack itself?


BYW, I already have 1K2 packet set up for the sound modem using the ACC
jack.  Works FB.  I'd just like to use the Data jacks for 9K2.  
 Any suggestions on how to troubleshoot further?  I will try an even lower
audio input level (as suggested by N8MH), but the TX light is bright with
0.4 V input suggesting that the automatic limiter may not be the problem?  


Hopefully, I have missed something very simple.  Direct email replies OK







n6rfm at gmail.com






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