As far as the LDG AT-7000 goes, I can tell you first hand that it does work, and work well mobile. My wife and I have gone cross-country in the US nine times, averaging about 10,000 miles a trip (up & back) using the tuner with my IC-7000. I used an "off-brand" (Shark Mini, as I remember) hamsticks (NOT the original creators of the Hamstick brand). I tried antennas from 80 thru 6 meters, along with a separate 2M/440MHz antenna on a different mount. I used 2 different mag mounts, one, a MFJ triple 5" triangular mag mount, and one a 3" Comtelco commercial mag mount. Everything works great from 40-6M, 2M & 440MHz.
I originally, I started with a single 5" mag mount for the Shark brand hamsticks, and learned the hard way that that wasn't the way to go. I had an 80M antenna on it and was "side drafted" by a 53 foot semi-truck and trailer that may have been speeding, whatever, but it literally blew my 80M antenna/single mag mount over and right off the roof of my mini-van, and it was dangling down on the rear hatch, the antenna's stinger (whip) getting its tip ground down on the concrete surface of the road. As it turned out, I could never get the 80M antenna to resonate properly anyway, and still haven't. I guess you can't win them all. So, 40M is the lowest HF frequency I operate on mobile. I subsequently replaced the single 5" mag mount with the triple 5" mag mount from Universal Radio. I have since redone the cabling, so if that were to ever happen again, which is not likely, won't go too far due to even shorter coax cable lengths. I also heartily recommend using a stainless steel quick disconnect to attach any hamstick type antenna to your mount.Now as for the AT-7000 itself. I ran #8 red/black wire directly from the battery with very heavy duty fuses used typically for mobile sound installations, directly to the radio for maximum power output. All I have to do is push the Tuner/Call button on the IC-7000, and it will immediately seek to find the best/lowest VSWR that it can obtain with the antenna in use. I have found it to work very reliably as long you use good radio installation practices, especially when it comes to really good, tight connections and really solid grounds. Poor ground connections most often (I think) lead to faulty or troublesome mobile operation. Very often, what you may think is a "good" ground, may not be what you think. In vehicles, ground connections are NOT always created equal, so use due diligence when it comes to grounds. Poor power output and/or RF inside your vehicle will let you know right away.
Be sure that you tune your mobile antenna as close to resonance (lowest VSWR) as possible, while it is mounted on the base you will use on the vehicle with an antenna analyzer, (such as a Bird 43 or MFJ 259/269 or a RigXpert analyzer, or equivalent, etc), but NOT using the AT-7000. You need to "start" from a position of knowledge, that is, that the antenna has already been tuned properly to begin with. Tuning it off the vehicle is NOT the same as tuning it ON the vehicle, just the way you are going to use it. I used several different analyzers to just compare and confirm the antenna tuning readings in my vehicle right AT the MALE coax connector that will connect to the AT-7000 FEMALE antenna connector ON the AT-7000 itself. In other words, measure only at the end of the coax that comes from the antenna ONLY, period. (And of course, this "tuning" I've been talking about is actually trimming the length of the stinger (whip) that is adjustable at the top of the hamstick (assuming that is what you plan to use). Then you will know when you use the AT-7000 in the circuit, you should get good results.
Also, be aware that after tuning for best VSWR on the IC-7000 using the Tuner/Call button, you will NOT be able to see VSWR. To display the VSWR
after a tune, select the VSWR indicator scale from the radio’s menu, and transmit a carrier (AM, FM, CW or RTTY). The VSWR will then be displayed on the VSWR scale.
Another great "plus" for using the AT-7000 is the remote-able control head. That is what I am using, and it works great. Also, for a microphone cable extension, I used a FLAT CAT 6 Ethernet cable, one end plugged int the IC-7000 body located under the driver's seat, and the other end right into the underside of the mic which is located in the glove compartment where the remote control head is now mounted.
I know I may have given more information than just that on the AT-7000 tuner, but I've found the more information I can get all of the subject, the happier I am.
If I can answer any other questions, feel free to ask. If I know the answer, I will be happy to share. I hope this has been of some help.
PS I still use my mobile just as described to this day, and it still works great.
I've added some photo's but don't know if this group will allow them or strip them.
73, Alan, AB6C