Update: the issue was resolved; it was just connector mis-alignment.
This should be a very useful data point for people who have the KX radio and who want 8.33 with minimal hassle.
I have just heard from someone who successfully installed a KX165A/8.33 in place of a KX155, as described above. No problems.
Well, some issue with VOR mode which is probably specific to the aircraft, which uses a KN72 for decoding the composite nav signal from the radio, and which uses the ILS ENERGISE signal from the radio to select the mode. But it could be the KN72. Back when I used to have one, that never worked on VOR but was fine on LOC…
Airborne_Again wrote:
Pin J shouldn’t be connected to ground but to the MIC KEY input of the other transceiver. It will then be grounded when you press the transmit key and the other transceiver is selected for transmission. If you connect pin J to ground you will permanently desensitise the transceiver which is probably
The problem was that… if you have a KX155 installed the pin J doesn´t exist and you have to install. We have 25 aircrafts A109E and some have KX155 and anothers KX165.
Thanks
Airborne_Again wrote:
ground but to the MIC KEY input of the other transceiver. It will then be grounded when you press the transmit key and the other transceiver is selected for transmission. If you connect pin J to ground you will permanently desensitise the transceiver which is probably not what
Correct.
I finish the correct installation. On my aircraft the pin J goes to a TB (To the MIC KEY) and the other radio to another terminal block.
Funcional test y operational test is ok!!!
Thanks a lot. If you dont say me that….probably I will need more days to investigate….
:)
landete wrote:
I removal the kx 165A and I see that the PIN J isn´t wired. Thanks a lot. I go to do the installation to ground
Pin J shouldn’t be connected to ground but to the MIC KEY input of the other transceiver. It will then be grounded when you press the transmit key and the other transceiver is selected for transmission. If you connect pin J to ground you will permanently desensitise the transceiver which is probably not what you want!
I removal the kx 165A and I see that the PIN J isn´t wired. Thanks a lot. I go to do the installation to ground
THANKS!!!!!!!!
Airborne_Again wrote:
noise. I change the frequencies and do the same.
It would seem to be a problem with your installation. There is a function of the KX165A to prevent this from happening. If this wasn’t properly wired when your new radio was installed, you would get this problem. I quote from the installation manual:
TRANSMIT INTERLOCK
The KX 155A/165A includes a TRANSMIT INTERLOCK (P155A1-J/165A1-J) input which should be connected to the MIC KEY input of the other COMM transceiver in the aircraft. When this input is grounded, the KX 155A/165A desensitizes its receiver by approximately 13 dB, reducing the likelihood of its squelch breaking while another COMM in the aircraft is transmitting. It is highly recommended to use this feature on all COMMs in the aircraft which include such an interlock feature. If TRANSMIT INTERLOCK is used in installations that employ a KX155A/165A with a KMA26
The pin J is on ground!!
Airborne_Again wrote:
Airborne_Again29-Mar-18 10:02
#39
landete wrote:
I have a problem with the new radio kx165A with PN: 069-01033-0201 (8.33Khz)
The problem is that when i transmit with the com #1 in any frequency the other radio kx165A (com #2) open the squelch and I have a noise. I change the frequencies and do the same.
It would seem to be a problem with your installation. There is a function of the KX165A to prevent this from happening. If this wasn’t properly wired when your new radio was installed, you would get this problem. I quote from the installation manual:
TRANSMIT INTERLOCK
The KX 155A/165A includes a TRANSMIT INTERLOCK (P155A1-J/165A1-J) input which should be connected to the MIC KEY input of the other COMM transceiver in the aircraft. When this input is grounded, the KX 155A/165A desensitizes its receiver by approximately 13 dB, reducing the likelihood of its squelch breaking while another COMM in the aircraft is transmitting. It is highly recommended to use this feature on all COMMs in the aircraft which include such an interlock feature. If TRANSMIT INTERLOCK is used in installations that employ a KX155A/165A with a KMA26 (or other audio panel that pulls the MIC KEY line above 11 Volts), isolation diodes will need to be installed between P155A1/165A1, pin J and the MIC KEY line
In bell 407 i install the diode for kma24h but on agusta a109e are installed GEMELLI audio control panel and it´s no neccesary the diode. I have to see the interlock wiring and test it.
Thanks
landete wrote:
I have a problem with the new radio kx165A with PN: 069-01033-0201 (8.33Khz)The problem is that when i transmit with the com #1 in any frequency the other radio kx165A (com #2) open the squelch and I have a noise. I change the frequencies and do the same.
It would seem to be a problem with your installation. There is a function of the KX165A to prevent this from happening. If this wasn’t properly wired when your new radio was installed, you would get this problem. I quote from the installation manual:
TRANSMIT INTERLOCK
The KX 155A/165A includes a TRANSMIT INTERLOCK (P155A1-J/165A1-J) input which should be connected to the MIC KEY input of the other COMM transceiver in the aircraft. When this input is grounded, the KX 155A/165A desensitizes its receiver by approximately 13 dB, reducing the likelihood of its squelch breaking while another COMM in the aircraft is transmitting. It is highly recommended to use this feature on all COMMs in the aircraft which include such an interlock feature. If TRANSMIT INTERLOCK is used in installations that employ a KX155A/165A with a KMA26 (or other audio panel that pulls the MIC KEY line above 11 Volts), isolation diodes will need to be installed between P155A1/165A1, pin J and the MIC KEY line. Refer to Installation Bulletin 407 for details.
The person here with knowledge of this kit is @wigglyamp
However, as I see, it, if a transmission on one radio opens the squelch on the other radio, that should not matter because the other radio’s audio output is not selected on the intercom (audio panel).
