Ways Through the Firewall

[JohnFromPerth]

I recently installed a Yaesu FT-857 amateur radio tranceiver in my PS. The radio outputs 100 watts of rf and draws 22 amps on transmit, requiring some serious power cabling back to the battery. Also needs two coax cable for the HF and VHF/UHF antennas on the bull bar.

I am reluctant to drill holes in a vehicles firewall as the hole can be the beginning of firewall cracking or corrosion and rust.

Looking on the internet I found some pictures of a PS interior with the dashboard stripped out. See first image.

There are three grommeted holes in the firewall suitable for passing wires through.

One is behind the glove box in the far upper passenger side corner of the firewall. This leads through to an opening above the front wheel arch in the engine compartment opposite the battery. The opening already has a large wiring loom passing through it and is very difficult to get at from inside the vehicle. Not really an option to use.

Another grommeted opening is on the far drivers side of the firewall next to the power brake booster. This is easy to get to, but means any wiring to the battery has a long way to travel.

A third, near central opening, and the one I used, is found on the firewall just to the drivers side of the engine and below the air conditioning pipes. See second image. There is a 4 cm rubber grommet in the firewall which covers a hole that come out on the drivers side of the center console. This hole is unused in my 2017 GLX. Maybe other models use it for something?

Pop out the grommet and poke a screwdriver through the soundproofing felt. Look under the dash on the drivers side and you will see a plastic bracket bolted to the firewall just above the driver's footrest. Above the bracket is where you will find the tip of your screwdriver. This is ideal as it is close to the switch blanks on the console for wiring driving lights.
It also made it easy to get wires to my radio mounted under the glove box.

The size of the hole makes it easy to get cables through, and the rubber grommet can be punched to pass the cables and re-inserted to form a water tight seal again.

The only drawback is the any wiring in the engine compartment will be near to the exhaust manifold, so should be well tied back.

[Gwoolie]

I went the rubber grommet above pedals route. Then pinged the main loom off and taped the wires behind. Can’t see them at all. Yes it was a ball ache using the extra wires. I went through with two wires for spots and added in an extra spare cable.
It’s there so I could A drag more through or it’s there for a live feed if I need an extra.
I sealed the hole with liquid rubber. About 3 coats and silicone on the inside just as an added.
Was easy to go through on my own but an added mate to help would make it even easier.

[kod10]

That is great info, thanks.

[OldEmmGee]

When drilling a new hole, I tend to go in the floor (passenger kick-panel area). Not only easier to access, but easier to seal (horizontal surface).

[RobFrance]

Thanks JohnFromPerth
similar issue vhf/uhf and an HF to follow along g with a uhf CB that the kids can use without accidentally blasting out 25watts
rob vk2qrf

[OzGreg]

Hi John from Perth

How do you setup and use the HF side of the unit?

What ariel did you use for the HF?
For HF do you need a license or an account with someone to get it to work?

I am new to HF but will need it for my offroad/off grid trips, so some advice would be great mate.

Cheers, Greg

[JohnFromPerth]

Hi Greg

There are two ways to get into HF radio for outback trips.

You can join a network such as the VKS-737 Group or the VMD-750 Austravel Safety Net or similar organisations.
You need to purchase an Australian Communications Authority (ACMA) approved radio that is set up with with the radio channels for the network you join. There are two way radio installers who will supply the radio and antenna and install it in your vehicle. Important to get this right or thing will not work properly.
As well as a yearly ACMA license fee there is also an ongoing subscription to the network to pay. You should check these organisatons out on the internet for more details.

The other way is to become a ACMA licensed Amateur Radio operator. To get a license you need to pass an exam on radio technology and regulations. Courses to prepare for the exam are run by a number of radio clubs across Australia. Check out the website of the Wireless Institute of Australia at https://www.wia.org.au/ for more information, and the website of the Australian Maritime College who administer Amateur Radio licensing for the ACMA at https://www.amc.edu.au/industry/amateur-radio.

Which is the better way to go?

The networks cost more to get into as regards radios and fees, but they do have the benefit of set schedules and emergency help. They also connect to the telephone network as well as having message forwarding and other services. If you are not technically inclined this is probably the way to go.

Amateur Radio is cheaper as you do not need type approved commercial radios, however you have to pass an exam to get a license. There are many more frequency bands available to talk on, and you can make contacts locally, across Australia and around the world. There are scheduled traveler's networks but they are not as formally organised as the commercial networks.

Hope this helps.
John

[OzGreg]

Hi Team

If you use the grommet that is on the driver side near the brake booster, ensure that it is totally sealed when finished.

When I had my towpro unit fitted they cut a large slot in the grommet and just ran the wires through leaving a small opening.

If you park you PS at an angle in a carpark or driveway, rainwater will travel down the firewall flow through any holes in the grommet and flood the interior floor.

I had an inch of water on the carpet, always double check any work you have done as there are a lot of installers at there who just don't care.

Cheer, Greg

[OzGreg]

Thanks, John, for the HF radio info.

Have you got any pics of your FT-857 radio and the way you have it setup in your PS mate.

Maybe some pics of the antennas would be helpful as well please.

Cheers, Greg

[JohnFromPerth]

Hi Greg

Here are two pictures of my mobile amateur radio set up. The radio has a detachable faceplate. The body of the radio is mounted on a bracket in the passengers footwell under the glovebox.
The faceplate is mounted on a square of acrylic with velcro. This acrylic square is attached by velcro to the center console over the drink holders. There is also a small box next to the faceplate which has a signal strength meter and switches to select high and low transmit power as well as a tune function for use when adjusting the antenna length. This whole assembly is stored in the center console box away from prying eyes when not in use.

The Yaesu FT-857 will transmit on all amateur bands on HF as well as the amateur vhf and uhf bands on 144-148 MHz and 420-450 Mhz. The radio also will receive across the whole HF band 1.8-30 MHz and vhf/uhf frequencies from 30MHz up to 480 Mhz. Power output is 100 watts on HF, 50 watts on vhf and 20 watts on uhf.

The HF antenna is made by Terlin and is adjustable for each of nine amateur bands by moving the wandering wire and plug to the appropriate socket on the antenna. The antenna stainless steel whip is also adjustable to fine tune the antenna. The antenna covers the nine amateur bands 3 MHz through to 54 MHz on transmit and also allows receive coverage of all the international shortwave bands.
You will see there is also a separate dual band vhf/uhf antenna that covers the 144-146 Mhz and 420-450Mhz amateur bands as well as allowing receive coverage on the air band and FM broadcast band as well as commercial and government frequencies.

Cheers
John

[OzGreg]

Hi John

Thanks for the great info and pics, I would not have thought to use the drink holders in this way, great idea mate.

Cheers, Greg