Tk7180h

[ghatchett]

I am installing a TK-7180H Radio in an airplane for use in doing fire patrols. I need to interface the radio with the aircraft audio panel. To do this, I need to know the pinout of the accessory connector. I believe the following pins are used. Pin 1 is speaker out, Pin 18 is power ground, Pin 14 is 12 volt Switched Voltage out, Pin 13 is PTT, Pin 6 is Mic Audio Hi and Pin 25 is Mic Ground. Can you confirm these pins are correct for the functions?
Thanks for your help.

 

[Luis_R]

Pin 1 is wrong it has no connection. You could try to use pin 17, which is filtered RX out - low level - not sure if it would be to low, but you can try. Or just use the 3.5 mm speaker jack on the back of the radio. Your other pins are right, but make sure to program pin 13 for PTT voice ( this is a programmable aux I/O pin ) so no function till programmed.

 

[code3cowboy]

That is a lot of radio for an aircraft, remember to use low power. Luis has it right.

 

[ramal121]

What is the aircrafts audio system. David Clark? You may not be able to use low level audio (pin 17) unless there is some way to crank the gain up. If not that leaves you with speaker audio via the 3.5mm jack as stated.

 

[ghatchett]

tk7180h installation

Since the aircraft audio system is approx 600 ohm impedance and the TK7180H audio out is at 8 ohms, I will use a 8 ohm/600 ohm transformer to match the impedances. Hopefully the audio level will be enough, but if not I will use the 3.5 mm jack on the back.

 

[ghatchett]

Incidentally, the audio will be fed into an Acft Audio Panel, KMA 24 and should work. I guess I will have to take the radio to a radio shop to program the radio to use pin 13 as the key line.

 

[ramal121]

On the 25 pin acc connector, RX audio (pin 17) is low level, about 300mV RMS and is designed to a feed a high impedance input, like 10k or more. It is not 8 ohm speaker source. 600 ohms would load this pin down considerably and I doubt it would work for your unit.

I think the easy way out, since the shop has to prog the PTT pin, have the geek jumper the speaker jack so the internal speaker does not turn off and then use the 3.5 speaker jack. You can then bridge the 4 ohm speaker with the 600 ohm input and the audio PA won't even blink.

Your KMA-24 should also be DC blocked for the input, but for the money, I can't see why they would not provide this.

 

[ghatchett]

Ok, I used pin 6 for mic audio in and the received audio is extremely low. I tried a 8 ohm/600 ohm tranformer and a 600/600 ohm transformer with a 120 ohm resistor in parallel with the primary and 330 ohm resistor in the mic hi side of the transformer and the received audio is still low. Any suggestions?

 

[ramal121]

Confirming your transmit audio is way down in the ditch?

First, toss all the transformers and resistors. If the KMA 24 is a 600 ohm mic output, it will match the radios mic input perfectly.

Two things. First, check the radio programming. Somewhere in there (under FUNCTION PORT I believe) is a window called MODULATION LINE. It needs to be set so external PTT connects MI2 to the transmitter. This is microphone audio and is default programming from factory. If it is set as DI (DI2?), this is data modulation and microphone audio will be very weak if used this way.

Second, and I'm guessing, the KMA 24 will have a balanced output for the mic, which means it has no common ground. Check your installation manual. Mic (mic hi, mic +) would obviously go to pin 6 of the radio. The other side of the balanced output (mic lo, mic -, mic return) would connect to pin 25 mic ground of the radio. If it is not done this way, tx audio will be very low or none existent.

Otherwise, what does the manual say about adjusting the tx audio?

 

[ghatchett]

I took one of the radios to the local wireless place in BHM and the guy came back pointing to pin 13 was updated for ptt low. I don't think he has a clue of setting the port, connecting the external PTT to M12. I have one more source for help tomorrow. I can't see Kenwood setting pin 6 for mic audio in, on the accessory connector and not allowing it to be usable, meaning the tx audio is not usable.

 

[ramal121]

If external PTT (voice) is set for pin 13, use that. It does the same thing no matter what I/O pin it is assigned to.

By default, external PTT (voice) will use MI2 as an audio input, which is pin 6. This could be changed to another source (MI on the front mic jack or the DI pin) Checking the programming is the way to be sure.

Does this help?