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Reviews For: NN4ZZ KARlock

Category: Antenna Rotators & Accessories

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Review Summary For : NN4ZZ KARlock
Reviews: 6MSRP: 190.00
The KARlock is an optional locking device for your TiltPlate. If you live in a high wind area or just feel more comfortable with a device to prevent the antenna from lifting in high winds, you may want to consider a KARlock for your Tiltplate.
Product is in production
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# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
KO4XJ Rating: 2012-08-08
Great Peace of mind!! Time Owned: 6 to 12 months.
After lose of a tower and a Pro-57 in 2011 from 65mph+ winds I went back up with a TX-455 and a 4L Steppir. Knowing that there is considerable more maintenance with a Steppir I wanted the NN4ZZ Tilt Plate and found a "almost" new one at a discounted price. Within a few weeks of installation we had some 30-40 mph winds and after watching the Steppir go vertical I decided to get the Karlock to ease my mind. I found one, again used but never installed and could not be happier. Goto NN4ZZ's YouTube page and see my Steppir tilting in the wind BEFORE the KARlock was installed at
One morning before the KARlock was installed I woke up and the antenna was stuck in the verticle posistion, a little turn of the rotor and it fell slowly into place. You may not really need a KARlock with the Tiltplate but I sure feel much better having it
K8RA Rating: 2012-08-08
Absolute Necessity Time Owned: 3 to 6 months.
It is expensive but necessary in my opinion to sleep at night. Everyone occasionally has a big wind come through and with the expense of towers and antennas it is crazy to not spend the $190! I had no problems putting it on the tilt plate and aligning it. Just be sure to do it before you install any antennas on the tilt plate because you have to clamp the tilt plate together as if it was vertical to set the U-clamp on the Karlock at the correct position.
K3BZ Rating: 2011-12-10
In Service 3+ years and still OUTSTANDING !! Time Owned: more than 12 months.
It's now been more than 3 years since I installed the KARLock, and it continues to perform flawlessly. I installed according to the instructions, and it worked right away to keep my SteppIR 4-element yagi from moving in the wind. It's been through several high-wind events that knocked over many trees in my vicinity, without a hitch. It works exactly like it's shown on the NN4ZZ website. One hopes for products that live up to descriptions, but too many of them fall short of expectations. It's refreshing to find one that just plain works like it's supposed to. It's a brilliantly simple design, and it hasn't required a bit of attention over these years. As another reviewer said so well, the KARLock "completes the TiltPlate" concept.

Earlier 5-star review posted by K3BZ on 2009-01-12

I installed the NN4ZZ TiltPlate on my tilt-over tower for reasons of safety and convenience.... it's a "peace of mind" thing, so I don't have to worry about climbing or the falls that can result. I don't relish the idea of a broken leg or hip or worse to mar the enjoyment of my ham radio hobby. The KarLock is just the "frosting on the cake" to prevent the antenna tipping in high winds...more peace of mind... built with the same over-engineering as the TiltPlate, real solid. I had to wait for those high winds before seeing the KarLock in action, but last week we had 50 mph+ winds here and sure enough, the KarLock worked just as advertised. Glad I've got it.
W6LQP Rating: 2011-02-26
caution on purchase... Time Owned: 0 to 3 months.
Intended for use with NN4ZZ tilt plate(which needs better installation instructions in its own right).

When KARlock device is installed according to instructions, locking device/arm hangs up when tower and antenna are being lowered. Reason? - tower and heavy antenna flexing swings locking arm during lowering procedure and it hooks on the way down instead of swinging free.

On the other hand, if KARlock is not installed precisely as noted in instructions, it will not grab tilt plate as designed for in the upright position.

A novel idea but as an expensive gadget it would be worth the price if it worked better in a live environment with flexing tower and heavy antenna being lowered.

A redesign to eliminate this problem is highly recommended before I would recommend its purchase.
W8TRN Rating: 2010-12-10
No Anxiety Attacks in High Winds Time Owned: N.A.
Without this ingenious accessory, the beam will approach vertical position in 30+ MPH winds. Talk about an anxiety attack. Although this is my hypothesis, without this locking mechanism, your beam will, in high winds, will tilt at least 30 or more degrees, and possibly slam back in to the horizontal position if the wind suddenly decreases. I guess what I am trying to say is gusty winds, i.e. 25 gusting 40 or miles per hour.
The downside: The mounting holes for the U bolts almost intefere with other hardware making installation a b**ch. Perhanps I installed it incorrectly. Just be prepared for some tight spaces.
K6KAR Rating: 2008-11-11
Outstanding Product Time Owned: 0 to 3 months.
The KARlock is simple, elegant and "gravity powered." It's made up of only three components: the pivot block, the catch rod, and the catch plate. The pivot block attaches to the moveable TiltPlate. The pivot block is machined from a single block aluminum and attached with set screws. The catch rod is shaped to catch the latch and pull tight when the moveable plate lifts due to high wind. It is cut from 1/2 inch aluminum plate for high strength and low weight. The catch plate is 1/2 in thick aluminum plate. It is secured to the mast using 2 inch (or 2 1/2 inch)DX Engineering U-bolts . A heavy duty stainless steel catch bolt is mounted on the plate. In the normal operational position the catch rod swings freely about 1/4 inch below the catch bolt. When tilting the tower over for maintenance the catch rod pivots clear of the catch bolt well in advance of any movement or separation of the Tiltplates. In the event of high winds, as the moveable plate lifts, the catch rod engages the catch bolt. The lifting motion is stopped. The KARlock doesn't require the user to climb the tower to lock or unlock in normal use. It does not require cables, poles or other attachments to lock or unlock in normal use. The KARlock does not add additional wind load. The design is simple, reliable, and weighs less than 5 pounds. It uses top quality parts consistent with the TiltPlate itself. The KARlock prevents antenna lifting in any wind speed.
Many thanks to Al, NN4ZZ for the creative and masterful engineering that has gone into the KARlock.