What's New?



Blue Ridge Amateur Radio and TrueLadderLine.com are now collaborating on several new remote and shack mounted automatic antenna tuners. Stay tuned for additional details.


The ATU4K automatic antenna tuner has been launched. This new industrial strength antenna tuner is designed to be mounted remotely with the antenna system. The system is controlled the Stepper Tune controller head unit, that resides in the shack with the operator.

This new tuner is brought to you through a collaboration between Blue Ridge Amateur Radio and TrueLadderLine.com

ATU4K Automatic Antenna Tuner


Our second generation vernier reduction drive is now available. This new 2nd generation design significantly shortens the body of the drive, which improves the ability to fit this drive into tight spaces. Same 4.5:1 gear ratio in a smaller package.

In the picture below the 2nd gen drive is on the left and the 1st generation drive is on the right, for comparison.


Oops! Looks like HamCation for 2021 has been cancelled. Well, at least we will have plenty of time to prepare for 2022. In the mean time, we're pretty
well covered up with existing customer work. This will take a bit of the pressure off.


Finally got our silk screening solution up and running. Here's a picture of our latest tuner with silk screened front and rear panels. This one is going to it's new home in Oregon, today.

Front panel

Note the speed handle on the inductor drive.

Rear panel


We've added a progressive shorting wafer switch to our product line. We needed a progressive shorting switch in order to add additional fixed capacitance into the tune when working with "short" antennas. The availability of progressive shorting wafer switches is non-existent these days and I suspect most manufactures that use these types of switches are building their own. We decided to build our own switch as well. The design of our switch includes isolation for 5kv of dielectric strength. This is done by simply keeping the contacts separated by a fixed distance and using the dielectric constant of dry air as our unit of measure. The contactor "wafer" is made of phosphor bronze and the contacts are made of nickel-silver. These are the same materials that we use in our roller inductor and capacitor contactors. The body of the switch is made of plexiglass, which has a massive dielectric strength of 600kv / inch, which is more than enough to allow for the switch to be installed in a tight space without having to worry about arc-over. The switch in the following pictures has 1 pole and 2 terminals. In position #1 the pole and terminals are disconnected. In position #2 the pole and terminal #1 are shorted together. In position #3 the pole, terminal #1 and terminal #2 are shorted together. Additional terminals can be added to the switch if required. The switch also has a positive detent system, which consists of a spring loaded pin that contacts the "resistance wheel". This gives the switch a good solid "click" when turning the switch to each position. The resistance wheel is used to impart a smooth and firm feel to the switch. Here are some additional pics of the new switch.

For more information on the new wafer switch, see this section of the site: Wafer Switch

Contacts and contactor wheel

Positive detent mechanism

Switch body

Switch with RF isolator


We've added a crank to our roller inductor knob. Simple design, looks great and has a very nice solid feel. It should, it's a solid aluminum knob with a real brass crank handle.


Our turns counter is now fully geared! Previously our turns counter used a set of belts to transfer power from one pulley to the next. While this does work, it is prone to slip if there's any resistance to turning. The new turns counter now uses gears, which eliminates slippage altogether. We now make our own gears for our turns counter. This involved acquiring a new set of gear cutting tools and developing the expertise required to cut gears. Our gears have a diametral pitch of 48, with a pressure angle of 14.5 degrees. There are 90 teeth on the big gears and 18 teeth on the smaller gears. Our rotary table has a reduction ratio of 90:1, which was very fortunate as it meant that we could cut our gears using full turns of the rotary table instead of partial turns.

Geared Turns Counter

In this view you can see the brass input shaft and the aluminum output shaft. The output shaft connects to a dial skirt for keeping track of roller inductor position.

Geared Turns Counter

In this view you can see how the gears mesh together to turn the coaxial output shaft.

90 Tooth Gear

Here's a view of one of the larger gears. The gears are held onto the input and output shafts through an interference fit. No need for keyways.