VOR/LOC/GS antenna

[Martin S.]

Evening gents,

considering installation of a GNC 255 to replace antiquated COM/NAV devices. The current KX 175 relies on the depicted antenna + GS receiver (foto 2 - black box)+ coupler (foto 2 - small box lower right corner). My understanding is the GNC 255 will only need the signal from the antenna, and deduce NAV/LOC/GS info from it, without need of the GS receiver and the coupler. Is that right?

Greets,

Martin

[EricJ]

That's correct, that antenna is both the VOR and glide slope antenna.   You may have a diplexer somewhere (it looks just like the coupler in the bottom right of your second pic, if that isn't it), that splits out the VOR and GS signals to separate places if the receivers are separate, which they usually are.

[OR75]

that graph / labels depicted on the small square box (diplexer) should indicate how your signal is split:

one connection goes to the antenna the others are 2 VORs + 1 GS (out of focus picture but it looks like thats what you have)

some diplexers provide 2 VORs and 2 GSs output connection 

[Martin S.]

On 11/20/2023 at 10:56 PM, EricJ said:

That's correct, that antenna is both the VOR and glide slope antenna.   You may have a diplexer somewhere (it looks just like the coupler in the bottom right of your second pic, if that isn't it), that splits out the VOR and GS signals to separate places if the receivers are separate, which they usually are.

Perfect - thanks!

[Aerodon]

On 11/21/2023 at 9:17 AM, OR75 said:

that graph / labels depicted on the small square box (diplexer) should indicate how your signal is split:

one connection goes to the antenna the others are 2 VORs + 1 GS (out of focus picture but it looks like thats what you have)

some diplexers provide 2 VORs and 2 GSs output connection 

It looks more like Ant In, 1 x G/S and 2 X VOR's to me.  You don't want to leave any of these ports open, so looks like you need a new splitter.  Might need antenna in, Nav 1 and Nav 2, or Nav 1, G/S 1 and Nav 2.

Some Nave radios have internal splitters, some have two antenna connection and need an external splitter.

Aerodon