I am getting some strange behavior out of a TK-890H that I have not figured out yet.
I have a TK-890H with a remote basic head. I also have a TK-890 (low power version) with a remote full function head. With the 890H I get low TX volume (hard to hear on the other end). I hooked it up to my service monitor and using a phone app that outputs an audible tone, I output a 1kHz tone and hold it up to the mike and I get a very low deviation. I disconnect the mic head from the mic cable and plug the same mic cable into a RJ45 jig I made up that lets me inject a 1kHz tone from the service monitor. I get near full deviation in that case. The same mic and cable plugged into the TK-890 works just fine with the mic head and the jig. I also tried a different mic/cable on the 890H and it behaved the same.
Here is a little table of the FM deviation from the service monitor:
---------------------------------------------------- 890H -------- 890
Mic + audible 1kHz tone from phone --- 0.8kHz ------ 1.9kHz
1kHz @ 50mV tone into jig/mic cable -- 2.0kHz ------ 2.0kHz
The mic and the jig are using the exact same MIC/MICe wires. The stumper is that since the mic and jig are using the exact same wires, the TX deviation should be the same for the same AF tone/level but it is not. At least not for the 890H (obviously the 890 looks good). I don't think it is the mic/cable because it works on the 890. It may be either the head or the radio itself and I will swap things out to narrow it down. Still, from a technical perspective, I can't think of a reason why the jig works on the 890H but the mic head does not....
The obvious question is, any ideas?
Edit: Oh and I did check the 890H voltage out of the connector using the jig and I got 13.6V.
Thanks
I have a TK-890H with a remote basic head. I also have a TK-890 (low power version) with a remote full function head. With the 890H I get low TX volume (hard to hear on the other end). I hooked it up to my service monitor and using a phone app that outputs an audible tone, I output a 1kHz tone and hold it up to the mike and I get a very low deviation. I disconnect the mic head from the mic cable and plug the same mic cable into a RJ45 jig I made up that lets me inject a 1kHz tone from the service monitor. I get near full deviation in that case. The same mic and cable plugged into the TK-890 works just fine with the mic head and the jig. I also tried a different mic/cable on the 890H and it behaved the same.
Here is a little table of the FM deviation from the service monitor:
---------------------------------------------------- 890H -------- 890
Mic + audible 1kHz tone from phone --- 0.8kHz ------ 1.9kHz
1kHz @ 50mV tone into jig/mic cable -- 2.0kHz ------ 2.0kHz
The mic and the jig are using the exact same MIC/MICe wires. The stumper is that since the mic and jig are using the exact same wires, the TX deviation should be the same for the same AF tone/level but it is not. At least not for the 890H (obviously the 890 looks good). I don't think it is the mic/cable because it works on the 890. It may be either the head or the radio itself and I will swap things out to narrow it down. Still, from a technical perspective, I can't think of a reason why the jig works on the 890H but the mic head does not....
The obvious question is, any ideas?
Edit: Oh and I did check the 890H voltage out of the connector using the jig and I got 13.6V.
Thanks
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