I have two old MFJ-949 antenna tuners in the shack, they have been good tuners over the years but are starting to show signs of age. Most
notably arcing in the caps and rough tuning across the bands on my 135' Inverted Vee.
I made the decision to replace them and with a limited budget decided on the MFJ-986 Differential-T tuner, I wanted the Palstar AT1500HB but it was out of my price range. I choose a differential-T tuner because of lower loss and ease of tuning. The MFJ-986 uses a true current balun to force equal currents in the two antenna halves even if the antenna is not perfectly balanced! The MFJ TrueCurrentBalun gives superior balance over voltage baluns and minimizes unbalanced current. This reduces field pattern distortion, concentrates your power for a stronger signal plus it reduces TVI and RF in your shack caused by feedline radiation.
Here it is out of the box.
Rear view of the tuner.
Open view showing the roller inductor and capacitor.
Good view showing the size of the capacitor.
This view shows the current balun and the circuit for the peak reading meter.
Last view showing a view from the back.
The old MFJ-949 ready to be taken out of service.
First step is to connect a heavy gauge jumper wire for using ladder line attached to my 135' Inverted-Vee.
All the antennas attached, the Vee, vertical, tribander, and a cantenna dummy load.
Here it is installed and working great! Now to go through all the bands with the Inverted-Vee and make a tuning chart to preset what band I want to work.
I made the chart for tuning up my 135' Inverted-Vee and I am very pleased with the results. I can get the SWR flat across all bands and when switching back to another band, my chart is spot on! It has made a noticeable improvement with the antenna and I've been working DX into EU on 40M and 80M with a lot more ease.