Heavy‑Duty Magnetic Ground Plane – GRA‑MAT50 MK2 │ HF Antenna Counterpoise 7–50 MHz │ Portable Copper‑Coated Steel Mat – Fits Magnetic Mounts, 500 W SSB / 200 W FM/CW

Quite functional, works well to adjust a mobile antenna's ground plain and general experimentation. The magnetic pad sticks well to my car for good contact. It's easy to install and remove so it's portable. I've used mine for weeks now and I must say that I have seen changes in signal strength based on frequency and antenna. Do your research first.

I bought a Yaesu ATAS-120A antenna but had problems getting it to work on the 20 meter band when mounted on a mag mount on my van roof. SWR was too high. I bought the GRA-MAT50 MK2 counterpoise magnet mat ground plane and tried it again. My FT-710 tuned on all bands between 40 to 6 meters with a good SWR while testing, I made an SSB phone contact with a POTA activator in Spain on the 10 meter band. Excellent! I'm pleased with this magnet mat ground plane.

I picked up the GRA-MAT50 MK2 Counterpoise Magnet Mat to pair with my magnetic mount and HF antenna, and I’m left with mixed feelings. On the positive side, it’s a clever concept with an interesting form factor that magnetically attaches to the car, making it super easy to use. However, I’m not convinced it actually improves performance, at least on HF frequencies—it just doesn’t seem to make a noticeable difference. Perhaps it might have more impact on VHF or UHF, but for HF use, I’m not seeing much value. While it’s a cute and innovative idea, I can’t justify giving it more than a 3 out of 5.

If you are using a an HF mobile antenna on a car with any kind of mount, the mat will ensure that the ground side of your coax feedline is coupled to the car body. I performed measurement on the capacitive coupling, and the manufacturer's claims of frequency coverage from 7-50 MHz are absolutely correct. The mat, which is magnetic itself, is easy to apply snugly to the car, yet is also easy to remove. This is a nice piece of simple and elegant engineering. Definitely recommended.

Was skeptical about this working for me. I used it on the roof of my truck with the Yaesu ATAS-120a antenna with a triple magnet mount. Since the mag-mount offers no grounding, I bought 2 of them and placed them on opposing sides of the mount and was very happy with their performance. My FT-891 and my FT-710 tuned perfectly from 10-20m. The best I could get out of it on 40m was about 1.8:1 but it didn't stop me from activating POTA across the country during a recent road trip. I did use gorilla tape on the leads between the antenna and the ground plane to keep the wires down while driving. They stayed in place at 80 mph freeway speeds. Before purchasing these I would use alligator clips to a vehicle ground. These tuned the antenna much better.

Not even one year!! I am antenna challenged individual. Long story. So I run a longer piece of coax out of the garage and throw a mag mount Stryker A10 on the car to talk with the group. I never really had any SWR issues but I saw this product and thought it couldn't hurt. It was pretty expensive. It arrived and I in stalled it and sure enough my SWR went down a smidge, great! And it never came off the antenna once installed. But understand this antenna is take off a shelf in high ceiling garage once or twice a week and left overnight on car. The rest of week it is indoors on a high shelf. Also maybe taken mobile up on the "mountain" 3-4 times a year as well. And unfortunately you can see by the photo it less than a year the wire has broken and it almost fully detached. And how I noticed it: all the sudden my SWR's ticked up a bit. Great product, cant hurt, but if it only last less than a year the $$$, I WILL PASS.

Helped my ATAs get 40meters

Looking at this made me think. Could something this simple really solve the noise issue in my mobile setup? It looks well built. Solid connections. It might work. Lets give it a shot... Installation was straightforward and simple enough. Unscrew the antenna, slip the ring connector over the SO-239, screw the antenna back on. OK. Did it work for me? In a word, no. It actually made my SWR and noise floor worse. Unusable. I ended up going from an S5 to an S9+ on all bands with this installed. I got nothing but static and high frequency warbling. It might work for you, but it didn't for me. Sorry.

Great product. I have 3

Great item that arrived in only 7 days from America.

This item flew off my car roof when we were travelling at 45 miles an hour and I haven’t seen it since. It was useful for the 25 minutes I owned it.