Modification to use a TiltPlate on a tower with a high pivot point

If the tower pivot point is significantly above the base (e.g. 20 feet up instead of 2-5 feet) the tower must pivot beyond horizontal (90 degrees) to bring the antenna all the way to the ground.   The tilting section of the tower will pivot to about 140 degrees.  This means the TiltPlate must open to about 130 degrees.   The exact amounts will vary depending on the model, height, and pivot point of the specific tower.  The standard TiltPlate opens to only about 110 degrees for the STANDARD miodel and 90 degrees for the MONSTER model.  A simple modification will allow the TiltPlate to open to about 140 - 160 degrees.   The addition of 2 bearing blocks 1/2 inch thick are required to allow the plates to open wider and  will be provided at no extra cost when orderend with a TiltPlate.  If ordered seperately they will be provided with a set of longer bolts for a nominal price.  If your TiltPlate is to be configured as a stackable model it requires some additional machining which must be done when originally ordered.

The Rohn 25 with their tiltover option is typical of a design with a "high pivot point."  See picture below. 

Caution: The Rohn foldover option is not currently being sold.   One reason is  (without a TiltPlate) the antenna is still fairly high off the ground.  In addition it is only recommended for fairly light (around 100 lbs) antennas.   Based on user forum notes (see eHam Tower Talk)  it is only recommended for towers in the 40-50 foot range or less.    With a TiltPlate the primary objection of getting the antenna down closer to the ground is removed.  This setup can be a viable option if your application meets these requirements.  

Notes:

- This modification is designed for a single yagi or LPDA antenna.  You MAY be able to mount another small antenna above the TiltPlate using the stackable configuration.    However the top antenna or mast may prevent the tower from tilting all the way if the mast is too long or the antenna is too large.   See Diagram below for the STACKABLE setup. 

- Some antennas like the the SteppIRs with the trombone for the center element will not work.    The trombone will interfere as the tower tilted past 90 degrees.   If the trombone is off to the side of the mast then it will work.   

This antenna will work....

This antenna will NOT work....

SINGLE Yagi on a TiltPlate in the non-Stackable configuration

Diagrams showing a typical application with the pivot point at 20 feet.   

Mike / KM4H installation - SteppIR 4el and Rohn 25 foldover - non-stackable configuration

Non-Stackable version TiltPlate with spacer blocks

TiltPlate with 1/2 inch bearing block installed (between bearing and moveable plate)

TiltPlate open to about 130 degrees 

TiltPlate open to about 160 degrees 

STACKABLE configuration with a small 2M yagi mounted above on the main mast.

STACKABLE version TiltPlate modifications and spacer block

Note the STACKABLE version requires a 3 inch diameter cut to allow extra room for the mast. 

First picture is the view from the top when the TiltPlate is open to about 140 degrees and the mast is extended thru the cutout.

The picture below is when the plates are closed and the mast is on the underside.