UHF installation/electrical questions

[randybay]

I'm about 3/4 the way through my first DIY mod - I'm putting in a GME XRS-370C UHF radio with a GME Antenna mounted on a Labtronx (https://www.labtronx.com.au/products/aerial-or-sand-flag-bracket) mount.

180463

Like the UHF setup (https://www.aulro.com/afvb/members-rides/225222-scotts-discovery-4-a-8.html#post2483777) in Scott's D4 Build (https://www.aulro.com/afvb/members-rides/225222-scotts-discovery-4-a-8.html) (which has been tremendously helpful in both what to do and how to do it), I've located the box under the passenger seat. But unlike his build, I decided that I wanted to use a fuse tap off of a fuse in the fuse box rather than splice into the rear console cigarette lighter. I've got it working insomuch that I have power to the UHF, but there are a few details that aren't quite right.

Like other threads, I first attempted to tap into one of the cigarette lighter/aux power circuits. Most use fuse 53 - I didn't want that because I use the front lighter ports to power USB adapters. So I tried to use 55 - Aux Power Centre and Rear, but the fuse tap didn't fit. So I used 47 - Sunroof .... which worked and I'm assuming it is unused because I don't have a sunroof. Also, this fuse isn't switched, so maybe that's a bad thing. I'm curious about others' thoughts on this choice of fuse positions. On the one hand, I like that it is (I think) completely unused. I just don't like that it isn't switched.

When I was wiring it all in was that I couldn't find anywhere to earth. I was following this thread (https://www.aulro.com/afvb/l319-discovery-3-and-4-a/267878-dash-cam-install-2014-d4.html?267878=#post2872391) to guide my wiring attempts. Rather than drill a hole to earth, I undid the torx screw that screws into that metal bracket. It must work because the UHF powers up and works. But I'm wondering if there is a "more correct" place do earth?

180462

I can't figure out a way to route the power cable from the UHF to under the plastic door sill cover. I tried removing the big plastic trim piece that runs along the power seat rail, but only got about 1/2 way and got really worried that I wouldn't be able to get it back on. Any suggestions on how to clean this up?


180464


The final issue is with that sill cover (above picture, red arrow). I got it off. Any advice on how to get it back so that it stays in place? Its got these funny plastic tabs that go into slots with clips ... but I can't get them to snap into place. So right now it is held in place by gravity. Not ideal.

The only thing remaining is to dremel out a place in the cupholder for the mic port. Once I get done, I may start my own build thread. [biggrin]

Cheers,

Carl

[kelvo]

I took power from the permanent 12V supply under the seat for the electric seats, no need to worry about getting a cable from the fuse box to under the seat. I fitted an inline fuse between the power seat connection and the UHF.

The door trim plastic tabs push into metal clips. Chances are these metal clips have ended up in the cable duct. You’ll need to find these clips, then fit them to the plastic tabs, then refit the trim.

[randybay]

I took power from the permanent 12V supply under the seat for the electric seats, no need to worry about getting a cable from the fuse box to under the seat. I fitted an inline fuse between the power seat connection and the UHF.

The door trim plastic tabs push into metal clips. Chances are these metal clips have ended up in the cable duct. You’ll need to find these clips, then fit them to the plastic tabs, then refit the trim.

Thanks Kelvo - that does sounds like a pretty solid plan. But I'm already in the fuse box and I've already ran the cables, so I'll leave it there for now. If I can't figure a solution for my power cable, that'll be plan B. The other option would be to come up through the centre console along where I routed the antenna cable.
Regarding that trim ... yup. There's no metal clips on the tabs. Guess I need to go fishing ... [bigwhistle]

I got the rest of the installation done. Not as good of a job as Scott's (https://www.aulro.com/afvb/members-rides/225222-scotts-discovery-4-a-8.html#post2483777). I didn't realise the cupholder only went in one way and of course I went into the wrong side. Oh well ... It works and looks good enough. If it bothers me too much, I'll buy another and do it properly.

180468

Cheers,

Carl

[PerthDisco]

Dumb question probably but could you install the unit in the engine bay and only run the handset lead into the cab? I assume on the removable handset type that is the speaker also?

The void around the brake booster would be ideal.

There a many clever ways to hide it inside the cab but is it absolutely necessary?

[Tombie]

Dumb question probably but could you install the unit in the engine bay and only run the handset lead into the cab? I assume on the removable handset type that is the speaker also?

The void around the brake booster would be ideal.

There a many clever ways to hide it inside the cab but is it absolutely necessary?

They aren’t IP rated so unsuitable for engine bay fitment.

Running headset lead would be much harder than running a single coax.

[LRD414]

Carl, my UHF supply is also switched in that I’ve taken it from my aux battery setup. I prefer this so that it will always work if the vehicle is dead. The risk is forgetting to turn off the UHF when camped for awhile but there’s low voltage cutout protection and I think the UHF would take quite awhile to drain the aux.

Magnet on a flexible handle and some patient fishing should find quite a few of the metal sill clips.

Cheers,
Scott

[Tombie]

I have 2x 25w UHF commercial units on permanent power and always left on.

When in receive mode power consumption is very low, the vehicle sits for days without a problem.

[veebs]

Mine times out if not used for a while. A few beeps for warning, so I can tap the transmit button if I want it on.

Mostly used for chatting with a convoy, so not monitoring the radio after we stop.

[RANDLOVER]

....... I just don't like that it isn't switched.........

If the constant power feed really worries you, try one of these Dashcam Wiring Board - Converts 12v Battery to Igntion Feed + USB-A (powerfuluk.com) (https://www.powerfuluk.com/vehicles/land-rover/discovery-3/interior-accessories/dashcam-wiring-board-converts-12v-battery-to-igntion-feed-usb-a.html)

Cheers,
Randy

[Netorius]

They aren’t IP rated so unsuitable for engine bay fitment.
I have been following thread as I intend to fit a UHF shortly. As stated, under the seat is the ideal place to mount a UHF with remote mic coming up to an accessible place (like between driver and passenger cupholders). But, Tombie raises a good point here. I suddenly thought that having the unit on the floor may lead to damage if you were submerged for some unfortunate reason. The first thing you will lose (at the lowest point in the cab, will be the UHF - your primary means of soliciting help!

I really like the idea of it being concealed, and seems like there are very few real options in the D4. To be honest, I rarely travel alone in remote areas, so not sure how much of an issue this would realistically be, but worth talking it through.

Does anyone have any other good locations that are maybe higher up?

[Tombie]

Behind upper glove box is plenty of room,
Or
Up on firewall above drivers left foot (need to make a bracket)

[Jeffoir]

Behind the Glovebox
Our UHF is mounted behind the glove box, with the handset cabled to a socket in centre console. Neat, dry and not too dusty.
Could I also please say that this is an excellent thread with some great pointers for less experienced people (like me) looking to DIY their UHF. The positive power of the Forum at work. Best wishes, Jeffoir

[BMKal]

Not sure if this is relevant to the Disco's / modern alternators etc - but I learnt the hard way over many radio installations in the past to always source my power for a 2 way radio directly from the battery. This was probably more important with the old style 27MHz CB Radios. If you did not do this, you often had a high pitch static / squealing noise from the radio, the volume and frequency of the noise directly related to engine revs.

Anyway - sounds like this is not a problem these days with the number of recommendations here to source power for UHF directly from piggy-back fuses / cigarette lighter sockets / power sources for heated seats etc. The UHF radio in mine is about the size of a cigarette packet, with all controls and speaker on the microphone (plus I have an aux. speaker mounted above the seatbelt bracket behind my right ear). I have mounted the radio head unit up behind the dash, above the centre console - held in place with a couple of cable ties. Power for the unit comes from my aux. battery (as does my phone charger / mount and a power supply for Laptop / iPad etc so that we can run communications / modem etc at night without drawing from the cranking battery). I have made my own fuse panel which lives above the OBD port to manage accessories power supply from the aux. battery. The relay is switched from a circuit on the main cranking battery so that power to the three fuses on the left end of the box is cut when the ignition is turned off (Hema / tpms & one spare). The other 5 fuse positions are permanently powered. I installed one common earth bus bar so that all accessories can simply be wired directly to this board without having to split wiring and look around for other earthing points.

I'm no electrician - but it works. [biggrin]

181603

I have recently scored this fusebox as well - needs to be mounted on a panel with easy rear access to fuse pins, but is probably a better option than my home-made version. Will have a look at how / where I can install this sometime soon. Maybe in the bottom panel of the dash, so that I don't actually have to drop the panel to change a fuse.

181604 181605 181606

[l00kin4]

I put mine in the rear cubby (where rear aircon lives if fitted) for this exact reason - just to have it that little bit higher…

Thread here: https://www.aulro.com/afvb/l319-discovery-3-and-4-a/224534-icom-ic-450n-installation-plan-4.html

David


I have been following thread as I intend to fit a UHF shortly. As stated, under the seat is the ideal place to mount a UHF with remote mic coming up to an accessible place (like between driver and passenger cupholders). But, Tombie raises a good point here. I suddenly thought that having the unit on the floor may lead to damage if you were submerged for some unfortunate reason. The first thing you will lose (at the lowest point in the cab, will be the UHF - your primary means of soliciting help!

I really like the idea of it being concealed, and seems like there are very few real options in the D4. To be honest, I rarely travel alone in remote areas, so not sure how much of an issue this would realistically be, but worth talking it through.

Does anyone have any other good locations that are maybe higher up?

[randybay]

Not sure if this is relevant to the Disco's / modern alternators etc - but I learnt the hard way over many radio installations in the past to always source my power for a 2 way radio directly from the battery. This was probably more important with the old style 27MHz CB Radios. If you did not do this, you often had a high pitch static / squealing noise from the radio, the volume and frequency of the noise directly related to engine revs.

No, it wasn't a problem on my last few uses.



Anyway - sounds like this is not a problem these days with the number of recommendations here to source power for UHF directly from piggy-back fuses / cigarette lighter sockets / power sources for heated seats etc. The UHF radio in mine is about the size of a cigarette packet, with all controls and speaker on the microphone (plus I have an aux. speaker mounted above the seatbelt bracket behind my right ear). I have mounted the radio head unit up behind the dash, above the centre console - held in place with a couple of cable ties. Power for the unit comes from my aux. battery (as does my phone charger / mount and a power supply for Laptop / iPad etc so that we can run communications / modem etc at night without drawing from the cranking battery). I have made my own fuse panel which lives above the OBD port to manage accessories power supply from the aux. battery. The relay is switched from a circuit on the main cranking battery so that power to the three fuses on the left end of the box is cut when the ignition is turned off (Hema / tpms & one spare). The other 5 fuse positions are permanently powered. I installed one common earth bus bar so that all accessories can simply be wired directly to this board without having to split wiring and look around for other earthing points.

I'm no electrician - but it works. [biggrin]

181603

I have recently scored this fusebox as well - needs to be mounted on a panel with easy rear access to fuse pins, but is probably a better option than my home-made version. Will have a look at how / where I can install this sometime soon. Maybe in the bottom panel of the dash, so that I don't actually have to drop the panel to change a fuse.

181604 181605 181606

I really like that! I may appropriate your ideas if I decide to put in more aftermarket electronics.

Cheers,
Carl

[randybay]

Thanks Scott.

I haven't done the Traxide dual battery setup like you have .... yet [bigwhistle].

Thanks for the tip about getting the metal sill clips out. I'll have to find a day where I've got nothing better to do but to take some valium and settle into it. [bigrolf]

Cheers,

Carl


Carl, my UHF supply is also switched in that I’ve taken it from my aux battery setup. I prefer this so that it will always work if the vehicle is dead. The risk is forgetting to turn off the UHF when camped for awhile but there’s low voltage cutout protection and I think the UHF would take quite awhile to drain the aux.

Magnet on a flexible handle and some patient fishing should find quite a few of the metal sill clips.

Cheers,
Scott