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108' SS whip

Help with installing an Antenna, or just choosing the right antenna to go with your radio, or your mobile.

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WESTGATE
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108' SS whip

Post by WESTGATE » Thursday, 19 November 2009, 8:32 AM

does anyone know where to find a 108 inch stainless steel mobile whip antenna??any help or posted links would be great, thank u,

randy
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Re: 108' SS whip

Post by Six Liter » Thursday, 19 November 2009, 9:03 AM

Try MFJ Enterprises, have them listed on their website for $26.95, not sure what shipping would be tho.......mabe almost the same!
Whatever goes around, comes back around.......sooner or later.



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Re: 108' SS whip

Post by WESTGATE » Thursday, 19 November 2009, 9:34 AM

sweet man i appreciate it, :icon_e_smile:

randy
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Re: 108' SS whip

Post by WESTGATE » Thursday, 19 November 2009, 9:53 AM

108" SS whip: 38.95 after shipping and handling
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Re: 108' SS whip

Post by Six Liter » Thursday, 19 November 2009, 17:33 PM

That's not too bad.....honestly figured shipping would be around $25......good deal
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Re: 108' SS whip

Post by De_Wildfire » Friday, 20 November 2009, 21:19 PM

Is that 108 inch whip like the old Francis whip they used to screw on the big sticks?

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Re: 108' SS whip

Post by WESTGATE » Friday, 20 November 2009, 23:21 PM

i dunno it didnt have a pic to show me...im guessing its like a 102' but 6 inches longer,

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Re: 108' SS whip

Post by fireman50 » Saturday, 21 November 2009, 18:05 PM

I got my last SS whip at Radio Shack for 19.95 plus tax. 102" and I added a 6" SS spring.

Works great on my Jeep, and the SWR's are 1.2-1.0 overall.

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Re: 108' SS whip

Post by alhefner » Monday, 23 November 2009, 8:01 AM

Yep, got that Rat Shack 102" and 6" spring...works a champ and no shipping charges.



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Re: 108' SS whip

Post by WESTGATE » Monday, 23 November 2009, 9:57 AM

are those springs really 6 inches or just like 4??i figure once u buy the spring and 102" from radioshack, after all the taxes u spend close to 38$$..i figured, might as well just get a real 11 meter quarter wave instead of a 102" with what acts like a loading coil at the bottom, they work good though
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Re: 108' SS whip

Post by 'Doc » Monday, 23 November 2009, 10:59 AM

Two questions:
1. Why would a shorted spring turn into a loading coil?
A. The shorting strap through the center of it is broken.
(I've never seen one broken like that. Doesn't mean it can't be done, but I've never seen one in over 40 years.)

2. How long is a 1/4 wave CB antenna?
A. (234 / f (in Mhz)) = 1/4 wave antenna length.
The antenna length begins where the coax feed line ends, at the bottom of the mount.
(Ch.19 = 27.185 Mhz)
so...
(234/27.185) = 8.6 feet = 103.29" total length.
103.29" - 4" spring = 99.29"
99.29" - 4" ball-mount = 95.29"

Length of 'whip' mounted on ball-mount and spring = 95.29 inches. A 102" whip is 6 and 11/16th inches too long for resonance on channel 19.
Not everyone uses a ball-mount, so change that 4" to whatever height the mount is.
Not everyone uses a spring, so if no spring, don't subtract 4" for the spring height.
-IF- your mount is 1.29" tall, then a 102" whip is just right.
- 'Doc


(I'm using 'Radio Shack' batteries in my calculator so check my math, it may be slightly 'off'. :drunken: , I like that one.)

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Re: 108' SS whip

Post by WESTGATE » Monday, 23 November 2009, 15:13 PM

WOW.....howcome the swr with 102 is high and with 108 is flat???11 meter full wave length is 36 feet....36 feet divided by 4 is 9 feet....108 inches divided by 12 equals 9 feet...which is a full quarter wavelength...i thought that was an easier way of figuring it...ur right i forgot there was a strap inside the spring, so what your saying is im gonna have to cut that 108 down a little but because the antenna starts at the feedline??im not gonna have a ball
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Re: 108' SS whip

Post by Roughneck424 » Monday, 23 November 2009, 15:33 PM

'Doc wrote:Two questions:
1. Why would a shorted spring turn into a loading coil?
A. The shorting strap through the center of it is broken.
(I've never seen one broken like that. Doesn't mean it can't be done, but I've never seen one in over 40 years.)

2. How long is a 1/4 wave CB antenna?
A. (234 / f (in Mhz)) = 1/4 wave antenna length.
The antenna length begins where the coax feed line ends, at the bottom of the mount.
(Ch.19 = 27.185 Mhz)
so...
(234/27.185) = 8.6 feet = 103.29" total length.
103.29" - 4" spring = 99.29"
99.29" - 4" ball-mount = 95.29"

Length of 'whip' mounted on ball-mount and spring = 95.29 inches. A 102" whip is 6 and 11/16th inches too long for resonance on channel 19.
Not everyone uses a ball-mount, so change that 4" to whatever height the mount is.
Not everyone uses a spring, so if no spring, don't subtract 4" for the spring height.
-IF- your mount is 1.29" tall, then a 102" whip is just right. - 'Doc


(I'm using 'Radio Shack' batteries in my calculator so check my math, it may be slightly 'off'. :drunken: , I like that one.)
Well that must be why my 102" screwed into my Predator 10K mount that is about 1.29" tall tunes flat?
Guess I won't mess with a spring
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Re: 108' SS whip

Post by alhefner » Tuesday, 24 November 2009, 18:13 PM

The calculations Doc gave are correct for wave length through the air. To say that a 1/4 wave length for 11 meter band is 9'...is not right on the money.

Through the air wave length will not be the same as the wave length through a the metal of an antenna. RF generally travels a bit faster through metal and the type and size (diameter) of that metal also has an effect. That is why no single "Rule of thumb" calculation will be perfect. The one Doc gave will get you the approximate ideal antenna length to START with. That length will usually be a little long and that is where you start to play with tuning to resonance.

Like I said above, I have a 102" SS whip attached to a 6" spring (with a center strap) and that is attached to a ball mount. Total length is about 109" from where the center conductor of the coax is attached. On my setup, I get SWR of about 1.2:1 to 1.3:1 across the band. In my book, that is pretty darn good!

By all means, buy what gives you the most confidence.



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Re: 108' SS whip

Post by WESTGATE » Tuesday, 24 November 2009, 20:23 PM

i stand corrected :icon_e_sad: :cry: lol
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Re: 108' SS whip

Post by 'Doc » Tuesday, 24 November 2009, 21:20 PM

Ooo, I really hate to say it, but an electron travels faster through a vacuum than through air, and faster through air than metal (or any solid). Since an electron travels faster through a vacuum than air, the length of a wave length in a vacuum is longer than a wave length through air. A wave length through metal/solids is shorter than the wave length through air. So, a fractional wave length through a metal would be shorter than the same fractional wave length through air/vacuum.

To make is even 'nastier', it deals with 'velocity factor', the difference between the speed of an electron through different mediums when compared to a vacuum.

That velocity factor is exactly the inverse of that of sound. Sound is faster through a more denser medium, slower though a less dense medium. (Bad comparison, but I don't know what else to use as a comparison.)

Ain't this _stuff_ fun??
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Re: 108' SS whip

Post by Sporty Mike » Wednesday, 25 November 2009, 0:29 AM

Doc, I love it!! :joker:
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