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Different Look At 102" Whip Discussion

The following doesn't always get brought up in discussions of the venerable 102" stainless steel whip for use as a high reliability, broad-banded, good working antenna for 10-11-12 meters.

Very common for CB. This antenna will be a full 1/4 wave ground plane.

What is commonly found on many vehicle installations is that you put this whip on by itself and find find that the SWR is not flat in the CB area, say in the middle at channel 20.

Common to find again that with testing it is discovered that the center resonance point is further up the band. The math will show that the center resonance point on 102" is right about at 27.520 mhz or "Channel 52" for you sophisticated raydideo operators. Checkout and save the 1/4 ground plane calculator below.

Amateur Quarter Wave Ground Plane Antenna Calculator


So why is this? Why do they make and market the 102" whip as a ready-for-CB antenna when actually it is not ready for CB (many installations) and has to be lengthened to be resonant square in the CB band, commonly accomplished by adding a 4 inch heavy barrel spring, or by using a solid Shaft Extender?

I don't know. I just know that on my pickup and every vehicle I have ever run one on, and as most of the locals around here find....you must do something to lengthen the 102 to make it flat line the SWRs in the CB band....which is critical when running an amplifier....which is always best run with no or very little SWR.

This is a good lesson for newbies in particular as one might expect to simply go to a CB antenna seller, purchase a made-for-CB antenna, slap it on the car and expect it to work with no tuning or adjustments....and particularly so for the 102 whip that appears to be complete and there isn't anything to adjust anyway.

So most installations require the addition of the 4 inch spring which has a wire running up inside it, which effectively lengthens the whip another 4 inches.

Even that is insufficient on some installations and even more lengthening is required. This was so on my pickup and I had to add 6 more inches to achieve at flat SWR across the CB area. I used a 6 inch Shaft Extender from Monkey Made Antennas for this.

There is another handy solution. MFJ still makes a 108" Stainless Whip which should be just what the doctor ordered and should give excellent resonance on CB by itself. Their part number is MFJ-1966 and they are $26.95 which is a reasonable price. (Their) problem here is - because it is so long it is an oversize package for shipping and the shipping on these costs more than the antenna does....unfortunate.

But still is less than what you would pay for something like a new Wilson 5000 magnet mount.....so cost is relative.

Just something to think about when considering the 102

Again it makes me wonder why all the manufacturers didn't just offer a 108" all along.


Comments?
interview.gif
All springs and whips are not the same length. I have a spring @ 3.940"long/high, another spring @ 3.980"long/high and a third spring @ 4.175" long/high. The length of the whip was 102.500". Using the 4.175" spring attached to the trimmed-down 102.250" stainless steel whip attached to a Breedlove Quick-disconnect Stake Pocket Mount having a total length of 3.500". The 3.500" is from the coax connector below the bed rail to the top of the quick disconnect fitting above the bed rail. The thickness/height of the mounting plate on the stake pocket is .300".
The total overall length from the coax connector under the bedrail to the top of the whip is 110.225". SWR is less than 1.5:1. Note: I removed the whip from the feral by removing the setscrew and trimmed the bottom of the whip in 1/16" increments to obtain a decent / acceptable SWR.
The antenna is installed at the forward left-side stake pocket. President Bill radio with dead-key set @ 2 watts and a RM Italy KL203 Amp.
 
I knew I'd gotten the 103" radials, below my Imax 2000, from somewhere:

1664093814910.png
I substituted the original GPK 6' FG radials for SS 102" whips + adapters.

Likely to the chagrin of others the ground plane placement of my antenna is based at the absolute minimum tuning ring adjustment threading height. I do not include as a portion of radiating antenna from coax attachment, within in aluminum casing, to tuning threads as portion of the radiator.

I've never heard, from Cntl Alabama, Italy before nor Australia so clearly. I believe 103" radials have a 45-60d spread.
Perhaps the closest to a >5/8 (.64) wave 11M dipole.
 
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Somebody throw me the GOLDEN SHOVEL!
Yes this is an old thread but, I am using a very heavy duty barrel spring my Dad bought back in 1967 and it still works perfectly. And, it is very strong. He ran it for yrs and yrs on his 1967 Chevrolet pickup truck and that spring and whip took a beating! As a matter of fact, I'm using his old 102 in whip also.
They talk just as good as the day he bought them.
The "braided" linkage from base of spring to antenna attachment, I've as many as 6 or 7 springs; 2-3 fat whoppers and 4x 4" inches. Granted I've poor eyesight; but, I've personally never seen a one. I expect there may be the potential for a weak link in the more recent renditions. Crappy construction material and shite QC, a given in today's surge for profiteering, but if your 1967 spring is still performing. Accept pre-one-world goobermint 1967 construction for what it once were. Keep on trucking!

You didn't mention spring length?
 
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The "braided" linkage from base of spring to antenna attachment, I've as many as 6 or 7 springs; 2-3 fat whoppers and 4x 4" inches. Granted I've poor eyesight; but, I've personally never seen a one. I expect there may be the potential for a weak link in the more recent renditions. Crappy construction material and shite QC, a given in today's surge for profiteering, but if your 1967 spring is still performing. Accept pre-one-world goobermint 1967 construction for what it once were. Keep on trucking!

You didn't mention spring length?
It's about 4 and 1/8 inches tall.
 
I've personally never seen a one.
If you bend the spring over and look, there is a braid inside the spring that connects the top and bottom.

From the Hustler spec sheet.
:
Hustler Stainless Steel Springs with Coupling Stud

Hustler stainless steel springs with coupling stud are designed to fit the bottom position on vertical masts. They feature protective spring caps, an exclusive hex nut tightening system, and a copper braided center conductor to prevent detuning.

End Quote

73
Jeff
 
If you bend the spring over and look, there is a braid inside the spring that connects the top and bottom.

From the Hustler spec sheet.
:
Hustler Stainless Steel Springs with Coupling Stud

Hustler stainless steel springs with coupling stud are designed to fit the bottom position on vertical masts. They feature protective spring caps, an exclusive hex nut tightening system, and a copper braided center conductor to prevent detuning.

End Quote

73
Jeff
I've tried, AudioShockwav but, it's way too stiff for me to bend. Maybe if I run some bolts in both ends and clamp it in a vice I can bend it far enough to take a good look inside. I haven't tried that yet.
Or, put my SS whip back on on and pull it over sideways and try to see inside.
 
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If you bend the spring over and look, there is a braid inside the spring that connects the top and bottom.

From the Hustler spec sheet.
:
Hustler Stainless Steel Springs with Coupling Stud

Hustler stainless steel springs with coupling stud are designed to fit the bottom position on vertical masts. They feature protective spring caps, an exclusive hex nut tightening system, and a copper braided center conductor to prevent detuning.

End Quote

73
Jeff
Yes, I like the Hustler spring because of the built-in hex nuts. Without those nuts, it is a pain to tighten the spring onto the mount and also a pain to grasp the spring to install and tighten the whip.
 
I've tried, AudioShockwav but, it's way too stiff for me to bend. Maybe if I run some bolts in both ends and clamp it in a vice I can bend it far enough to take a good look inside. I haven't tried that yet.
Or, put my SS whip back on on and pull it over sideways and try to see inside.
If the spring is stainless steel, you can insert a large screwdriver between the coils to see the braided wire. If the spring is not stainless, use a wood wedge to spread the coil because the screwdriver will chip-off the nickel-plating and then comes the rust.
 
If the spring is stainless steel, you can insert a large screwdriver between the coils to see the braided wire. If the spring is not stainless, use a wood wedge to spread the coil because the screwdriver will chip-off the nickel-plating and then comes the rust.
Great idea. I never thought of it but, I will. I have a big screwdriver that will work just fine. Thanks.
 
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The best way to match a 1/4 wave steel whip.

73
Jeff
View attachment 60711
Off topic: My 7 ft skipshooter is a 1.1 on channel 1 and almost 1.5 on channel 40 with the nail all the way down. Would it hurt to spit the coating and snip off a quarter inch or so of the wire on top or, would that completely ruin the antenna. I know a 1.5 isn't bad but, i'd like to match it as close as possible. Thanks in advance.
 
The wire has to be attached to that top brass piece somehow, likely soldered.
You would have to cut the shrink wrap, disconnect the wire, trim it , reattach it and repair the shrink wrap.
Me, I wouldn't unless you are going to do something above the 40 channel band.
Do you have anything under the antenna like a disconnect or spring that is adding length to the antenna?
73
Jeff
 
The wire has to be attached to that top brass piece somehow, likely soldered.
You would have to cut the shrink wrap, disconnect the wire, trim it , reattach it and repair the shrink wrap.
Me, I wouldn't unless you are going to do something above the 40 channel band.
Do you have anything under the antenna like a disconnect or spring that is adding length to the antenna?
73
Jeff
No I don't. It's ok it's just that I like to get it close as possible.
Thanks.
 

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