Ham Radio Stray RF Issues?

[WMWHV]

I have seen discussion on here about the technical merits of running dedicated power cables vice using the auxiliary switches to power ham gear. I am well acquainted with the theory behind all of this. What I am looking for is any actual experience anybody has with RF getting into anything on the Jeep and if so, how was the power run? I am particularly interested in anybody running HF and if so, where and how your antenna was mounted when you had the issue. On my LJ, I had a screwdriver mounted on the tire carrier. Ground straps, chokes, etc. I could talk all day on 40, but if I keyed up on 20, the engine shut off. I am hoping to get a sense of any problems people have had and if so, what solutions worked to fix them. I just took delivery of my JT EcoDiesel (yes, I recognize it could have different issues than the gas versions) and am looking at install options for HF/VHF/UHF radios. I run an ICOM 7000 with a High Sierra Sidekick on HF and a variety of radios on the VHF/UHF side. Antenna Options include a mount in the T Slot on my tonneau cover rail near the cab (yes, terrible RF grounding here) and something bolted onto the slider between the rear wheel and the bumper on my Rubicon (yes, poor radiation pattern). Mobile HF is a series of compromises. Thanks in advance and 73.

DE KA5YYD.

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[KHam]

I have seen discussion on here about the technical merits of running dedicated power cables vice using the auxiliary switches to power ham gear. I am well acquainted with the theory behind all of this. What I am looking for is any actual experience anybody has with RF getting into anything on the Jeep and if so, how was the power run? I am particularly interested in anybody running HF and if so, where and how your antenna was mounted when you had the issue. On my LJ, I had a screwdriver mounted on the tire carrier. Ground straps, chokes, etc. I could talk all day on 40, but if I keyed up on 20, the engine shut off. I am hoping to get a sense of any problems people have had and if so, what solutions worked to fix them. I just took delivery of my JT EcoDiesel (yes, I recognize it could have different issues than the gas versions) and am looking at install options for HF/VHF/UHF radios. I run an ICOM 7000 with a High Sierra Sidekick on HF and a variety of radios on the VHF/UHF side. Antenna Options include a mount in the T Slot on my tonneau cover rail near the cab (yes, terrible RF grounding here) and something bolted onto the slider between the rear wheel and the bumper on my Rubicon (yes, poor radiation pattern). Mobile HF is a series of compromises. Thanks in advance and 73.

DE KA5YYD.

I have a similar setup to yours including my favorite radio, the ICOM 7000. I mounted the radios under the rear seat with a minimal clutter up front. I am running a Tarheel screwdriver antenna with short mast on my Gladiator, and I ran a 3 foot mast Tarheel on my JK Rubicon. The only time I have ever had any issues is if I'm out of tune on the antenna where there's a lot of the signal returning. You should always tune your antenna with no more than about 3-5 watts to find your spot, then I go to about 35 watts (I use CW mode for a continuous tone) to double check, then one last check at full power. In my Gladiator I'm am almost dead flat on SWR at 1:1 on 20 meters which is where I am most of the time. If you're getting high SWR, you will have to use a shunt coil to tune capacitance to match your ground plane. I had to do this on my JK. Tarheel has instructions on their site which should be pretty much the same for all screwdriver antennas. I've talked all over the world from my Jeep and I've never had an issue.

I posted some pics of my build in another HAM thread... https://www.jeepgladiatorforum.com/forum/threads/ham-radio-install.32973/page-3

 

[sarguy1941]

Only issue I found was aftermarket LED lights. I grabbeda set for our JK and if they are on my 2M/440 Kenwood is useless. I am wired direct to battery and have traced it directly to the LED. At this point we only use it rarely at night so it is what it is, but i'll eventually try different lights. On my JT both ham and LMR are fine.

 

[KHam]

That's interesting. I haven't noticed any real noise coming from the vehicle to the radio. Just some very mild ignition ticks that the noise blanker is masking nicely.

Only thing I can stress is grounding. Power for my radios come via 6 awg marine cable directly from the battery. Positive is direct to battery but negative comes from the same body ground point that the battery connects. (Do not connect ground directly to the battery as you can cause a ground loop.) At the back where the radios are, the negative from the radio connects to the 6 awg ground wire, which has a short ground strap back to the body again at that point. Antennas are grounded to my all-metal tonneau cover, which is ground strapped to the bed. So far I don't appear to need any additional ground strapping and I'm getting outstanding SWR ratios and little to no noise.
On my JKU the antenna mast connected to the all-metal rear bumper, which was ground strapped to the frame, the body was ground strapped to the frame, and the hood and doors were all ground strapped to the body. That worked well.

And remember, RF grounding isn't the same as power grounding. For RF it's the size of the path that matters. Use wide flat braided straps for grounding.

 

[WMWHV]

I think the absence of reports of stray RF getting into the vehicle systems is a good sign. I toyed with the idea of running power to my rigs via one of the auxiliary switches, but in addition to all the other reasons not to do that, when I looked at the wire, it is way too skinny for even 20 amps, at least with no significant voltage drop. My Kenwood 710G in particular is very voltage sensitive and generally will not transmit on high power without the engine running on my truck. I may go with a heavy gauge wire like KHam did, but am also toying with the idea of a voltage booster like the N8XJK unit so that I don't have to worry about voltage drop, even when the Jeep is off. The down side is more money, another piece of equipment to break, generate heat and consume power. I am figuring the wire run from the battery to the spot behind the rear seat on the driver's side where I intend to install stuff is around 15 feet.

 

[sarguy1941]

I ran my GMRS and CB off the AUX wiring inside the cab, but my APX8500 is going to the battery block directly. Any low power units such as CB and GMRS is fine on the inside power. For anything more I'd run a new cable. It doesn't take long at all depending on the route you pick. Mine actually goes out a grommet under the back seat along the frame to the Battery. I did upsize in case I wanted to upgrade the 8500 to a HP but the MidPower is fine at this point.

 

[WMWHV]

I ran my GMRS and CB off the AUX wiring inside the cab, but my APX8500 is going to the battery block directly. Any low power units such as CB and GMRS is fine on the inside power. For anything more I'd run a new cable. It doesn't take long at all depending on the route you pick. Mine actually goes out a grommet under the back seat along the frame to the Battery. I did upsize in case I wanted to upgrade the 8500 to a HP but the MidPower is fine at this point.

I am going to follow that same path. I am going to use 10ga. even though some might think that a bit light for full power on the HF rig. However, it should be sufficient if the engine is running. If the engine is off, even the biggest gauge wire is not likely to make voltage sensitive radios happy. The only way I see high duty cycle operations on HF would be if I were doing something digital and if that is in the cards, I can just fire up the engine. I have figured out where the speakers are going and (hopefully) all the other variables and will probably do the wire running this weekend.

 

[Radio Guy]

I've got a Gladiator Mojave on order and will be filling it with various ham radios. I'm really hoping there is no excessive ignition noise on HF as I haven't read anything too concerning about that yet.

My current vehicle is a 2008 Tundra which has zero ignition noise and worked fine with all my HF/VHF/UHF radios until I installed the 500w HF amp. The dash lit up like disco lights when I transmitted with that thing and the engine would nearly shut off.

My installation had about 18ft of 4ga wire from the battery to under the rear seat, both hot and ground, then the HF amp and negative lead from the battery grounded to a big bolt under the rear seat. That run of wire is a little small for a 500w amp and it appeared most of my RFI problem was RF getting into the 12V power system via those wires. After a lot of troubleshooting I found sticking a big gel cell battery right at the amplifier would fix the problem and it also helped power the amp better on voice peaks and everything worked great except for the two batteries fighting each other when charging.

I eventually swapped the big battery out for a 15 Farad capacitor that was small and lightweight and that snuffed out the RF on the big power leads and also dumped in some current on voice peaks and worked about the same as the 100AH gel cell.

I'll be installing the same type of wire to under the rear seat in my new Gladiator and will also put the remote controlled HF and VHF/UHF rigs under the rear seat. I'm not installing the 500w amp permanently but will leave a 175A Anderson Power Pole connector under the seat for temporary connection of the amp.

It will be interesting to see if the radios interfere with the vehicle or vice versa and I'm hoping there is no high tech current sensing off the battery for the vehicle computer that my high current wiring will cause problems with.

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