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Author Topic: Spring or NO Spring  (Read 569 times)
K4PVA
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Posts: 7




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« on: December 26, 2003, 10:34:16 PM »

I have a set of Hustler coil for 75-10 meters. I would like to mount the Hustler system on my truck bumper with the 54" mast. In reading one article on mobile operations, I noticed that the author strongly recommended that NO spring be used with mobile antennas. I had a Hustler for 75 meters on my car 20+ years ago and used a bumper mount with a coil and never had a problem. Are there problems using a spring that I should know about? If I decide to use the Hustler short mast with a mag mount and the long whips, is a spring ok?
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OBSERVER11
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Posts: 657




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« Reply #1 on: December 27, 2003, 12:18:05 AM »

biggest problem is that they can become big inductors if the cheap braid jumper inside the spring breaks or corrodes.
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K0BG
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« Reply #2 on: December 27, 2003, 09:28:30 AM »

Over the years I have used springs on every antenna I ever mounted to a vehicle, and I have never had a failure caused by the internal braid breaking. I have been told by others that it happens, however.

The real reason to use a spring is to protect the mast if the antenna hits a solid object like a tree limb. If the whip is flexible enough, you're probably okay.

In my personal case, the antenna tip is at about 16.5 feet and it quite often hits limbs and a few low hanging wires. If I didn't have the spring, I wouldn't have a quarter panel either!

BTW, forget the mag mount.

Alan, KØBG
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N8EMR
Member

Posts: 235




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« Reply #3 on: December 27, 2003, 10:28:14 AM »

I always use a spring on my HF mobiles antenna whips, I have used 16ft whips, spyder antennas, 102" whips and hustler whips. My truck is to high and the branches are to low not to have a spring to help with some of the shock and viberation. What I did find was to run a Thick braded wire around the spring to help with corrosion isseu within the spring. It also helps if you get a "GOOD" spring, Hustler or motorla are better quality than the cheaper radioshack units.
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AA4PB
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Posts: 12899




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« Reply #4 on: December 27, 2003, 10:22:17 PM »

The spring shouldn't cause any electrical problems. A 75M Hustler resonator however has a lot of wind resistance. When I tried it with the Newtronics spring that came with the ball mount, the mast "whipped" all over the place in the wind when the vehicle was moving so I had to remove it. You definately should use the small spring between the mast and the resonator however. This allows the resonator to tilt back if you hit something with it.
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KA0MR
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Posts: 221




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« Reply #5 on: January 02, 2004, 07:30:25 PM »

The spring adds 6 inches to the electrical length of the antenna. With the Hustler Resonator type antennas the 54 inch mast is an integral part of the antenna and the steel rod at the end of the antenna is a tuning rod and if you add a 6 inch spring it will affect the tuning of the resonator. You may or may not be able to tune it to take into account of the spring so be prepared to retune the resonators when you add the spring.

Bob KAØMR
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XE1UFO
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« Reply #6 on: January 04, 2004, 02:39:03 AM »

Move the spring to the TOP of the mast, under the coil. With big coils (80, 40) it works better.
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KA5S
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Posts: 229




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« Reply #7 on: January 05, 2004, 03:44:26 AM »

It depends.

I rely on a spring to protect the antenna, the mount and the car roof. I want it to bend when I meet an immovable object, and not to bend the rest of the time. The ONLY spring I've found that can do this well (and with up to a 75-meter Texas Bug Catcher with 6 inch coil and a top hat, too) is the base assembly sold for the Outbacker -- for which it is substantial overkill.

A full sized Hustler HF antenma will NOT stand up straight on a >Hustler< spring at more than about 30 mph. Even with the "short" mast it is marginal at 65 or 70.  And with the long mast, the coil mass can overcome the spring's restoring force on turns. This is dangerous.


Cheers,

Cortland
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