Anyone have a VHF/UHF transceiver in their car? If so, any RFI problems?

[VerityZooms]

Hoping someday soon to add a DStar ID 5100A to my rig when delivered. The radio is sitting in the garage waiting for the X to show up.

I found a $$ Larsen Glass Mount antenna -- but wonder what you think about attaching it to the glass atop one of the FWDoors?
If that's problematic, is there room on the oversized front windshield to mount it?
And then there's the other question of any coatings that would interfere w/ the transmission on the glass. If you have input or thought, that would be really helpful.

I've got a wide-band scanner antenna mounted to the tiny side-window directly behind the FWDs. Anecdotally, the performance at least beats using a rubber-duck inside the cabin, by a mile … but that's not saying much. As to whether there's much loss in reception compared to that same glass-mount on non-metallized windows … I can't say for sure, but I strongly suspect there is loss.

That said, I suspect transmission would be terrible. On that (admittedly wide-band) antenna, I scanned up and down the spectrum, but never saw an SWR lower than 1:10 — I feel it's likely to burn out your fancy ICOM; I definitely wouldn't risk my 7100 on a through-glass stickietenna. Just get a frunk-lip mount!

 

[TechVP]

Follow up from my post in January. So... everybody told me that factory tint on windows would affect SWR through glass.

Had to see that for myself. And now that the X is here... I did perform a test install of a 20 year old glass mount antenna I had sitting in a box.
Results?


Positioning the antenna on the glass of the 3rd pillar window I achieved a 1:1 match in the middle of the 2M band. I simply used the tuning wand and dialed it in. Took maybe 20 min for installation and tuning.
On this old antenna that wasn't designed specifically for 70 cm, it still came in at about 1:1.2 -- perfect for a first try.

Since I had such good luck on the first try, maybe I will experiment w/ a location on the rear window, in between the defroster lines.
For now though... it doesn't look too bad & is easy to adjust or take off. The antenna easily unscrews from the 3M mount.

Hope this gives a prospective X owner some hints on how to mount an antenna on an X, without altering the car body.

And to address the original poster, I, as of yet, have not seen adverse RFI car operation to transmitting 50W on 2 Meters.

 

[TechVP]

In case anyone is wondering where do you tie in for 12V power on the X?

It's easy if you ordered the Tow Package. The tow package comes with a pigtail plug in for a powered brake.
No need to tow everyday, so it's a circuit that can be reused.
The powered brake circuit is rated at 20A -- which you have to locate under the driver footwell. The power plug is perfect for a ~10A communications radio.
I believe I had the radio DC line together in just over 30 min. Even w/o the tow package, the proper plug can probably be ordered. Maybe I saw it in a forum thread somewhere before. The 12v circuit is live all the time, and does not shut off w/ the car.
For a reference / planning / help, send me a message.

 

[Barry]

Positioning the antenna on the glass of the 3rd pillar window I achieved a 1:1 match in the middle of the 2M band.

You mention your antenna is 20 years old. As coax ages, it becomes lossy, particularly at VHF/UHF. Lossy coax blunts the SWR curve, so you may be getting a falsely low reading.
.-- ..--- ..- .--.

 

[TechVP]

Interesting observation. Thanks for the note. Once I identify the connector on the antenna end, I'll upgrade the line and cut it to fit.

 

[TechVP]

You mention your antenna is 20 years old. As coax ages, it becomes lossy, particularly at VHF/UHF. Lossy coax blunts the SWR curve, so you may be getting a falsely low reading.

Follow up to the comment about lossy coax. I have now replaced all of the the coax and connectors with hand assembled in USA RG8x and made it to fit the installation. SWR ratio remains 1:1 in the middle of the 2 meter band. And a respectable 1:1.4 in the middle of the 70 cm band.
I conclude the install is good, unless you think I missed something.

The take-away here is that a glass antenna mounted on the Model X 3rd pillar window appears not to be impeded by the factory tint & show no signs of signal degradation.

 

[Barry]

Sounds good. Glad it's working for you.

 

[wooter]

Hi everyone! I just set up my Hytera MD655 UHF in my Model X but in a temporary setup. Anyone have a clue how to get a wire from the front trunk to the passenger cabin, so I can tap continuous 12V from the contact points up front? Or any good continuous 12V in the back? I have the towing package.

The Hytera MD655 is just lying around in the bottom trunk, and I have a microphone hooked up to it with 20 feet of cable. I use a Panorama antenna with trunk lip mount, but without the screws, around the window of the trunk lid.

 

[TechVP]

Anyone have a clue how to get a wire from the front trunk to the passenger cabin, so I can tap continuous 12V from the contact points up front?

Yes, 20 amps continuous available from the tow brake connection point. See my post #43 in this thread. PM me if you want more details.

 

[Roberta’s]

Have followed several threads on ham radio installations in Teslas. We have a 2019 model 3 and now a 2020 model S which will replace my primary vehicle 2004 Volvo which is my go to dog and ham radio emergency services car. I ordered a Kenwood TN 710GA which has APRS, GPS, packet and is Echolink capable. I am worried about interference with the car’s electronics and haven’t seen any recent posts (since 2017 or so) about 50 watt dual band transmission and interference. My plan is to keep it a portable unit, able to remove it from the Tesla and hook up portable as needed for emergency deployment. I’d really like to be able to use it in the vehicle as well. Any updates on this from older or more recent installs? I think I have the trunk lip mount and antenna figured out but am afraid to do The full install and fire it up while driving having read a few reports of interference problems. Thanks!

 

[TechVP]

Have followed several threads on ham radio installations in Teslas. We have a 2019 model 3 and now a 2020 model S which will replace my primary vehicle 2004 Volvo which is my go to dog and ham radio emergency services car. I ordered a Kenwood TN 710GA which has APRS, GPS, packet and is Echolink capable. I am worried about interference with the car’s electronics and haven’t seen any recent posts (since 2017 or so) about 50 watt dual band transmission and interference. My plan is to keep it a portable unit, able to remove it from the Tesla and hook up portable as needed for emergency deployment. I’d really like to be able to use it in the vehicle as well. Any updates on this from older or more recent installs? I think I have the trunk lip mount and antenna figured out but am afraid to do The full install and fire it up while driving having read a few reports of interference problems. Thanks!

It's been 4 years now since the prior post above. I haven't used my ID-5100 too much while driving, but last year around December I made a very important call into a fringe / distant repeater. The QSO lasted a couple hours. The rig and antenna held up fine. No adverse effects to either the X or the radio. My rig saved the day, when no other good options were available. The rig is still my go-to when out of Cell coverage area.

I suggest you go for it... it should work out as long as you are in the 50w range.
73 -TechVP

 

[hiroshiy]

Bumping an old thread - did anybody try an antenna mount on the trunk of Model X? I purchased this mount to try out.

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Mount K401

I think it would fit here...

I plan to mount a wide band antenna covering 2m and 70cm bands, a length of about 1m.

 

[wooter]

This should work if the trunk lid has a lip around it.

Be cautious though, I had a similar compact mount on my old BMW and the length of the 1 meter long antenna was enough to slightly bend the trunk lid on the area the mount was placed on.

 

[hiroshiy]

This should work if the trunk lid has a lip around it.

Be cautious though, I had a similar compact mount on my old BMW and the length of the 1 meter long antenna was enough to slightly bend the trunk lid on the area the mount was placed on.

Thanks. I did not really understand what the lip was. The trunk has only metal on the outer side, and there's a plastic part on the inner side.

 

[wooter]

If you want to determine if it will fit on your X, you need to open the trunk and see if the trunk has enough space under the bodywork to fit the clap on.

On top of that, you need to be sure that there is enough space between the trunk lid and the trunk opening (the so-called panel gap) to fir the mount clamp through).

My argument is that the limited footprint of this K401 together with a 1 meter long antenna will perform a lot of forces on this small footprint, and will cause the trunk lid to bend. The solutions are a bigger footprint, or a smaller antenna, to limit forces.

In a way this clamp is not much different than the one I use for my UHF antenna, but obviously my antenna is not longer than 20cm and therefore doesn't apply as much forces on the glas paneling of the roof. But obviously, 2m needs a longer antenna than UHF.

 

[hiroshiy]

@wooter Thank you for your advice! OK, if the 1m antenna is too heavy... maybe I need to consider K416 (width 56mm instead of 29mm). I emailed Diamond (the manufacturer) for more information about the suggested weight limit. If I get the answer, I will post it.

 

[reddy]

I am using the Diamond K400C on my Model S, with a Diamond AZ507RSP antenna which is about 70cm long. I was having trouble with long antennae hitting my overhead garage door when I opened the hatch of my Model S inside the garage.

No problem with any metal deformation after a 4500 mile road trip from Texas to British Columbia and back.

There may be a little abrasion from dirt under the mount on the clear coat. I have a ceramic coating and after cleaning the hatch I couldn't see where the mount had been.

I have not seen a Diamond K401 in the US, perhaps it is the same as our K400 ?

 

[hiroshiy]

I am using the Diamond K400C on my Model S, with a Diamond AZ507RSP antenna which is about 70cm long. I was having trouble with long antennae hitting my overhead garage door when I opened the hatch of my Model S inside the garage.

No problem with any metal deformation after a 4500 mile road trip from Texas to British Columbia and back.

There may be a little abrasion from dirt under the mount on the clear coat. I have a ceramic coating and after cleaning the hatch I couldn't see where the mount had been.

I have not seen a Diamond K401 in the US, perhaps it is the same as our K400 ?

Thank you for the information. K400 is 100mm wide, whereas K401 is 29mm, so the K100 looks perfect for long antennas.

I will get both 29mm and 56mm tomorrow, so I can report a few days later.

Where did you install the K100 on your Model S? I'm surprised that the Model S had 100mm of the straight area to attach the K400.

 

[reddy]

Thank you for the information. K400 is 100mm wide, whereas K401 is 29mm, so the K100 looks perfect for long antennas.

I will get both 29mm and 56mm tomorrow, so I can report a few days later.

Where did you install the K100 on your Model S? I'm surprised that the Model S had 100mm of the straight area to attach the K400.

 

[hiroshiy]

View attachment 917890

Thank you for the photo!

I tried to install K416 to my Model X, but I couldn't because the tailgate panel was thicker than the antenna base. I tried three locations.

1. Your location is the best because my base K416 can snugly attach to the rear tailgate. However, the base has an aluminum plate between the screws and the tailgate, and there is not enough space to insert the plate.
2. The rear end of the tailgate and the frontmost hinge area of the tailgate has plastic parts on the back, so I could not insert the base thoroughly.

So now I'm asking Diamond if they have bases for thicker body panels.