MFJ makes a great little multi band, adjustable whip antenna that can be added to your KX2, KX3 or almost any QRP radio. It can be used when the radio is on the table top or even if the radio is used like an HF HT. The compact size of the antenna, along with some ground radials, makes it great for back packers. No trees in site to erect an antenna, pull out your 1899T whip and you are on the air.
For ground radials I use #22 stranded, teflon insulated wire. On Ebay, I found male and female mini banana jacks. They not only fit into the socket on the KX2 but also make for a great inline connection on the ground radials. First I made a 15 meter ground radial. I put a male jack on one end and a female on the other end. I then cut another length of wire, to be added to the 15 meter radial, so the two wires in series would be resonant on 20 meters. I then put a male jack on one end and a female on the other end. So one wire alone will work for 15 meters and then couple the two wires and you are good for 20 meters. Next I cut one more length, to be added to the pair, so I can work 40 meters.
I found that the chart that MFJ provides, for adjusting and using this antenna, is not even close to where the setting should be. To test the antenna, here is what I did.
I made a small table top mount for the antenna and attached an elevated radial. I clamped the mount to a wooden picnic table and attached a short length of coax. I put a #43 ferrite choke on the end of the coax at the feed point of the antenna. I next attached a Rig Expert AA-600 antenna analyzer. Using this method I was not only able to determine that the chart provided by MFJ was not even close to what the setting should be, but was able to develope my own settings and ground radial lengths. Below are my findings.
The telescopic whip measurement was taken from the base of the telescopic whip to the tip, not from the BNC to the top of the whip.
I printed out that above chart, laminated same and take a copy with me when using the MFJ-1899T.
This antenna along with a KX2 or KX3 makes a great little HT to be used on HF.
Shown below in the left picture is the complete assembly. MFJ1899T with mounting plate attached to the tripod. In my back yard I place the assembly on a TV table. You can place this assembly on a picnic table as well as the ground. It does not have to be elevated above ground.
Shown below in the right picture is a closeup view of the actual tripod and the mounting plate. The mount is just a little strip of aluminum I had laying around the house. I used a BNC bulkhead connector. The coax is a short length of RG 174. Take note to the clip on #43 ferrite bead which creates a very effective balun. Without the balun I had a slight SWR issue. I highly suggest using a balun of some kind. You can also see the 20 meter ground radial wire attached to the left hand side of the mounting plate. Since only one ground wire was used to create balance in the assembly, the RF favors in the direction of the radial wire. If you want a uniform pattern, I suggest using four radial wires laid out in an "X" pattern.
The ground radial is 12' 10" long and the tap is in the 20 meter position.
The table top tripod is a Vidpro TT-12. I purchased it from B & H Camera . The overall length of the collapsed tripod is only 8" which makes small enough to carry in your backpack. Each leg telescopes out two places and the mast also extends if needed. This makes is nice for dual purpose, antenna or camera.
If you set up your 1899T antenna, using the above supplied measurements, you should get a low SWR on each band.
Bottom picture shows the SWR curve of the MFJ 1899T on 40 meters.