On The Assembly Table
10/80 meter multiband antenna
Here is a look at the antenna assembly.
The coil-form is machined from Lexan® (polycarbonate)
The end-caps are machined from Delrin® (acetal homopolymar)
The wire on the coil is 12 gage tinned buss wire
The mast as well as the coil fittings are machined from 304 stainless-steel
The TuneSleeve assembly is a build-up from 16 gage 6061-T6 aluminum
The TuneSleeve has a beryllium copper fingerstock contactor surrounding the top of the TuneSleeve assembly, compressed and contacting the coil.
The photos show the coil positioned in the 80 meter (3700mhz) band. Run the TuneSleeve to the top of the coil and your tuned for the 10 meter band.
The linear actuator that is mounted on this multiband antenna and is attached to the TuneSleeve works extremely well. This style of actuator is ideally suited for this application, as the TuneSleeve requires a smooth linear operation with positional control. The other plus to this actuator is the fact that it has built in limit switches. The actuator is set up so that once the TuneSleeve reaches the 17 meter band (top of the coil), the actuator has reached the end of its travel and the limit switch shuts the actuator down.
While sourcing the linear actuator for this antenna, I was successful in discovering a company that could supply me with a actuator geared with a final drive-ratio that was required for this antenna. In the past I have found the various motorized antennas that I have used to be agonizingly slow when shuffled between the various bands. The problem is eliminated with this antenna as the TuneSleeve moves to either end of the coil (10/80) in under 15 seconds, yet the antenna is very easy to tune.This actuator is proving to be extremelly quiet, with no electrical noise from the motor coming through the receiver of my TS-480 HX while tuning the antenna.
The antenna may also be operated as a manual tune antenna by removing the actuator assembly, and re-installing the locking-knob into the TuneSleeve. Changing over is a simple operation taking only moments to remove the two fasteners securing the actuator in place on the antenna.
It may not be apparent in the photo, however the actuator assembly is insulated from the TS/antenna mast with a non-conductive Delrin® mount.
Hover your mouse over the photo, and select "Original" for a close-in look.