Ford Focus RS Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
102 Posts
Discussion Starter #1
Could not find a thread on any of this.

I'd like to put an APRS digipeater in the car. It will require the following:
  • Dedicated 2-meter antenna.
  • Dedicated power, dual-fused.
  • APRS controller with built-in TNC and transmitter.
  • Industry-standard NMEA-0183 GPS antenna, preferably 5-volt, WAAS enabled, 4800 baud RS-232 serial and SiRFStarIV chipset.
The APRS controller could live in the boot. In a self-contained unit, there is really nothing with which one needs to interact in the cockpit. It needs to turn on and off with the ignition.

APRS-enabled dual-band 2m/70cm >=50-watt transceiver with built-in TNC and either built-in GPS or a port for an external GPS antenna.
  • Dedicated dual-band antenna.
  • Dedicated power, dual-fused.
I was thinking of bringing a dual-fused 4-gauge pair from the battery to a Power Pole block and then running 12-gauge from the block to each unit.
 

·
Registered
Joined
·
1,115 Posts
Not sure what you're looking for, are you needing switched 12v power in the boot? If so, check out my writeup on adding a 12v power socket by the luggage compartment fuse box:


Running antennas should be pretty easy too.
 

·
Registered
Joined
·
102 Posts
Discussion Starter #3
Not sure what you're looking for, are you needing switched 12v power in the boot? If so, check out my writeup on adding a 12v power socket by the luggage compartment fuse box:


Running antennas should be pretty easy too.
Thanks for the link; it helps in that I do need switched power--probably for a relay for the dedicated +12V from the battery. Transceivers are very sensitive to electrical noise, and it's SOP to have dedicated power, preferably shielded and filtered. The unit that would live in the boot (APRS) contains a transceiver that transmits and receives exclusively on 144.390 MHz and transmits at 40 watts (3.3A).

The antenna wire, both for the APRS unit and the transceiver at the front of the vehicle, will be RG8-X or LMR 155 and perhaps short lengths of RG174/RG316. Assuming the antennas will be somewhere near the back of the vehicle, the run for the APRS unit would be rather short. For the dual-band transceiver I will have to get all the way to the dash. So in total, I will have at least one coax for RF and one 12-gauge pair for power running between the front and rear, albeit each for a different transceiver.

I have yet to figure out mounting for the 2-meter antennas. Obviously I don't want a solution that mars the car.

Also, I need a good location for the GPS antenna for the APRS. I could mount it outside the vehicle but am curious as to whether anyone has had success with GPS antennas mounted, say, at the front of the dash or up in front of the rearview mirror.
 

·
Registered
Joined
·
30 Posts
I run a 50w dual band with radio in the back foam. Remote head in the front console. No dedicated power. No issues. Dual band antenna on side of the hatch with thin trunk feed thru coax. Works great.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
102 Posts
Discussion Starter #5 (Edited)
I run a 50w dual band with radio in the back foam. Remote head in the front console. No dedicated power. No issues. Dual band antenna on side of the hatch with thin trunk feed thru coax. Works great.


Sent from my iPhone using Tapatalk
Good to know. At a minimum I'll have a 40w digipeater and a dual-band transceiver. So worst case I am using 50w when the digipeater decides to transmit--for a total of 90w for up to one second. Where are you getting the power?

I want to be able to turn off the APRS at the dash while the car is running, so I might put a switch in the negative side--either of the coil ground (85) of a relay or the lead from the APRS unit itself. So that's at least one wire running to the front along with the separation kit line I had planned to run for the transceiver head. Also, if there's not a good spot for the GPS antenna in the rear window, I will need to route that to the front as well.
 

·
Registered
Joined
·
102 Posts
Discussion Starter #6
Is there a good route to the front of the vehicle excluding the above the headliner?
 

·
Premium Member
Joined
·
488 Posts
You can pull the door seals and route the wires between the body and interior trims easily up to the front.

This is how I wires my rear fog up to a switch up front.

Might not be suited for larger wires or wire bundle though, but real easy to try before you decide on your final routing!
 

·
Registered
Joined
·
102 Posts
Discussion Starter #8
Thanks for the info.

With regard to routing wires to cover up to 2 transceivers and the APRS digipeater, it's going to require:
2 x 8-gauge power wires from a block from the battery to another distribution block in the rear,
2 x separation kit wires from the transceiver bodies to the dash,
2 x microphone extension cables (CAT-6e) because the microphones actually plug into the transceiver bodies in the rear,
1 x 14-gauge wire for a switch for the relay for the APRS in the back to the dash.

This way I don't have to worry about fitting the transceiver bodies and APRS unit in the cockpit and running antenna wire to them.

I'll put the two transceivers on one relay tapped into F43. The APRS will also be on that tap unless I can find another source.
 

·
Registered
Joined
·
102 Posts
Discussion Starter #9
Adding:
  • 1 x audio cable pair (Kenwood) for cockpit-mounted speaker(s),
  • 1 x audio cable pair for additional remote speaker(s).
 

·
Registered
Joined
·
102 Posts
Discussion Starter #10
Three links pertaining to getting power from the battery through the firewall:
 

·
Registered
Joined
·
102 Posts
Discussion Starter #12
Recent work:
336998

Here is the mess I came up with for power in from the battery. I wanted the fused links accessible from underneath the glovebox, without having to remove more than the cover. There are identical inline fuses at the battery as well.
 

·
Registered
Joined
·
102 Posts
Discussion Starter #16
337003

Final destination, almost. I will add a short piece of harness to get the 8AWG to the target area and a Powerwerx PD-75 distribution block. I also have to add the relays. The extra black 12AWG is to connect the APRS switch in the cockpit to the APRS's relay in the boot.
 
1 - 16 of 16 Posts
Top