K30 Magnet Mount Antenna Review
As many hard core CB operators will tell you, a small magnet mount antenna should only be used when you can’t do a permanent install of a full length antenna.
For most cases I would agree thoroughly with this opinion. There really is nothing that can compensate for a full size antenna.
That being said, there are many times when a magnet mount antenna comes in handy, especially in temporary installs, rental cars, or with cars that don’t have a good place to out a hard mount antenna.
First choice for a magnet mount antennas would always go to the Wilson 1000 and Wilson 5000 models as they are the best performing and have the longest whip element of any of the magnet mounts.
But there are cases where you might want something smaller and easier to manage.
About a year ago I wanted to put a small antenna on our commuter car (also my wife’s main vehicle). Because I didn’t want to leave my radio in this vehicle all the time I set it up to run off of the cigarette lighter plug and made a special mount that could be easily installed and removed in a matter of minutes. To go along with this setup I wanted a small antenna that would still give me fair results but wouldn’t be very conspicuous.
My choice was the K30 antenna manufactured by the K40 Corporation. I purchased the antenna off of eBay for $19.99 and $6 shipping. The antenna/whip comes packaged together on a cardboard piece with plastic wrap all very professionally sealed.
The antenna itself consists of the 36” stainless steel whip element, a small metal cone piece that screws onto the top of the plastic base, and the plastic base that has the coil inside. The antenna comes with 15 ft of pre-wired RG-58 coax.
The steel whip is held in position by a small set screw and the first thing I noticed when I went to put the antenna together was that the hole in the metal cone piece that the set screw goes into had no threads. This was a big problem because without any thread the set screw had nothing to screw into and the whip would not be held properly in place. I called the K40 Corporation to find out if they could replace the metal cone piece because I obviously had a defective one. K40 themselves aren’t actually the company selling the antennas anymore and the antennas are now distributed by a company out of Pennsylvania. I called and talked to the owner and he sent me a new cone piece at no cost. He was very nice and gave excellent customer service.
Once I got my new piece I put this small antenna together and slapped the magnet mount on the trunk of our Chevy Cavalier. The antenna was paired with a Cobra 21 GTL radio which had a maximum peak output of around 12 watts.
The antenna’s SWR was a little high initially and I had to cut off about a half inch to get the SWR where I wanted it. Once tuned I had a flat SWR on channel 20 and a 1.3 on channel 1 and a 1.4 on channel 40. Those aren’t as low as I had wanted but for a small antenna with a small coil I didn’t expect it to be very broad banded so the SWR range fell into the acceptable range.
The first thing I noticed during use was that although the local signals were the same loudness as when receiving with my other vehicle the static level was very low with this antenna. This could be because the antenna was mounted near the rear of the vehicle while on my other car the antenna is mounted closer to the engine, but I was still very impressed with the lack of static noise.
The receive was very good and I had no trouble hearing any of the locals located anywhere from 5-25 miles away. That evening I was also able to hear and have a conversation with a station located across the channel about 100 miles away. Many of the stations I talked to locally said I was a little quieter than normal, but that I still sounded very clear and loud. None of them believed me when I told them I was using a 20 year old cobra radio and a three foot magnet mount antenna.
I continued to use this same setup for many months on the commuter car, taking the antenna and radio out every weekend and putting it back in during the week. I always had excellent results. Later I installed a General Longstreet radio and was able to talk barefoot on SSB to Australia with around 20 watts using the K30 antenna.
I did try running a small amount of power through this antenna – around 150 watts. The antenna plastic heated up pretty quickly and although it’s rated for 300 watts I would not suggest putting more than 50-100 watts max into this antenna. I think that the small coil had a little trouble dissipating the heat and over time if running any power that could result in possible problems. Of course this antenna isn’t really for people running power.
Overall this is a small magnetic antenna that has excellent quality and better performance than I would have expected from an antenna of its size. It’s not going to beat a Wilson 1000 or a 102” SS whip, but for temporary installs or for vehicles where the other antennas won’t work it’s an excellent alternative.