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Hotwire
Senior Member
Username: Hotwire
Post Number: 1418
Registered: 1-2005
| | Posted on Tuesday, May 30, 2006 - 2:02 pm: | 
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Went to Radio Shack today and bought the last 2 ball mounts they will ever carry anymore. Seems hard to come by these nowadays.
So I'm very interested in testing a 102 inch whip against my Predator and I want to install this thing right.
Lou Franklin states that a 102 inch SS whip if installed correctly is foolproof and swr will be no more than 1.5.
I have the ball mount and will install it on the rear passenger side fender. I also have a spring with the braid in the center to keep swr steady while driving fast.
My question is how critical is the spring. Is the spring necassary and a part of the antenna? 108 inches is 0ne fourth of 36 feet. With the whip and spring together I have 106 inches. Lou Franklin has not said how important the spring is for swr in my book. So what is it? 102 ,106,or 108 inches? Does it matter? I'm thinking possibly that the placement of the whip on the car is gonna determine the swr somewhat. Has anyone ever not used a spring and had good swr? Hopefully whatever the outcome I can get at least below 2.0 swr. Any and all help I am thankful for. How is your ballmount working for you? Did you have trouble? What did you do to solve your problems? Use a spring or not.Anyone have the same wonder about the different lengths of the whip as I do? Will the radio always see the whip as 102 inches or if I add a spring does the radio see a longer whip? I just wanna get my wheels turning before I start drilling holes so I can get the best install and performance possible! thanks
CEF491
Hotwire
Indiana |
Marconi
Advanced Member
Username: Marconi
Post Number: 662
Registered: 11-2001
| | Posted on Tuesday, May 30, 2006 - 2:59 pm: |
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I have found that the 102" whip will work fine in 11 meters if you pay close attention to the ground plane. The ground plane affect is more important in a 1/4 wave setup than precicesly how long the stinger is.
If you can't get the antenna in a 1/4 wave mobile to see a suitable ground plane, one that looks like three or four 1/4 wave radials or longer, then your setup likely won't be very effective. Seeing what the antenna sees in a mobile setup is hard to determine however. |
Navyrebel782003
Intermediate Member
Username: Navyrebel782003
Post Number: 172
Registered: 12-2004
| | Posted on Tuesday, May 30, 2006 - 5:46 pm: |
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Hotwire, when I was in high school I had a 102" whip that I ran on the rear bumper with and without a spring, and I also ran the same setup on the bed rail corner right at the cab, both with and without a spring and never had any problems at all, I only checked swr's once on it when someone brought that to my attention and they were around 1.3 on almost all 40 channels with a undien 66. I think it will depend on your vehicle and all that like Marconi has stated, but good luck, I may be going back to the 102" myself, people keep "removing" my wilson 1000 mag mount and messing up my truck.
James
CEF#590
CVC#49
Va Beach |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1726
Registered: 9-2004
| | Posted on Tuesday, May 30, 2006 - 6:34 pm: |
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what kind of vehicle is it?
sorry if i should know this; cant remember.
i have used two of these in the past on my own vehicles and installed probably another five or so on others vehicles.
here's my findings:
i believe that you should use the spring. i believe that it is designed to work with it.
however, i have seen acceptable SWR without one.
(i looked kinda dumb on that one, because i INSISTED that the guy needed to use a spring)
as marconi said, the groundplane is the most important thing, and to that end; try to get the mount up as high as you can on the vehicle.
try to keep the antenna at least a foot away from surrounding metal.
on my F250, i have a truck box in the bed, and the ball is mounted to that, which is in turn bolted to the bed.
this puts the antenna about a foot away from the cab, maybe a bit more.
SWR on mine is 1.4 to 1 across the band, a bit lower on 20.
i would recommend that you not use the fiberglass whip if you are going to run power.
just FYI, i also bolted eve mounts to the truck box, and drilled a hole in the bed (truck is 1977) just big enough to fit the small end of a mast in it.
i did this so that i could use my A99 on a 10 foot mast from the truck. (worked great!)
i tried mounting the 102" whip on an angle bracket mount up on a 5 foot mast, thinking that getting the base of the antenna above the roof line would be beneficial.
WRONG! SWR was 3 to 1 across the band.
see there was no horizontal groundplane even though the mast was grounded to the bed.
put it back on the side of the truck box, and it works flawlessly.
great antennas!
detail your install ideas for us.
matt |
Hotwire
Senior Member
Username: Hotwire
Post Number: 1420
Registered: 1-2005
| | Posted on Wednesday, May 31, 2006 - 12:58 pm: |
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The mount will be bolted onto the rear passenger side fender panel and up as high as the mount will allow. Its a 93 Chevy Corsica. My other installs have been on the trunk door and with steel sheets layered a qaurter inch thick underneath and swr results have been perfect with all antennas except with the 102 inch whip.I was just using a regular gumdrop style mount with no spring.
Last night I assembled the ball mount. Ok, the whip is 102 inches, my spring is 4 inches, I realized that the ball itself is 2 inches wide! So after all is assembled I will have the 108 inches I was talking about! So as you guys said about my groundplane, if that is good and I install the mount right then all should be perfect!
thanks for the help guys! Once its all installed I will post the results! First its off to the hardware for the bit I need to cut that big 1 inch hole! My car is starting to look like the Bonnie and Clyde car! |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1736
Registered: 9-2004
| | Posted on Wednesday, May 31, 2006 - 11:49 pm: |
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i think that will work great!
nice thing about the ball mount; you can get the antenna to sit vertical even if the body panel is slanted.
remember that a correctly installed 102" whip will have an SWR of 1.3 to 1.5.
thats just the way it is, but thats still way better than 1.1 with a matching coil.
im assuming that your vehicle is already bonded with ground straps, but if not, this 102" whip is really going to be looking for all the groundplane you can give it.
so tie in the trunk lid, the hood, all doors, and whatever else you can think of.
the quote i remember hearing is, "its not about how good of a groundplane your vehicle provides; its about what kind of groundplane you provide the vehicle with".
or something like that.LOL
hopefully you are buying a hole saw instead of a big bit or a paddle bit.
hold that drill tightly, its going to bite big time right before you break through the metal.
and when drilling metal, its better to vary the speed of the drill in unison with the pressure you give the drill.
like push the trigger once while giving a push on the drill.
not too much, just enough to vary the speed around a bit.
this will keep the metal from heating up and tempering. its much harder to cut when tempered. (blued)
you may be way ahead of me here, but at least its in print for those who do need it.
good luck, whatever you do, dont trim that whip.
matt |
Hotwire
Senior Member
Username: Hotwire
Post Number: 1423
Registered: 1-2005
| | Posted on Thursday, June 01, 2006 - 2:04 pm: |
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Matt, I'm going to have cut at work a sort of template out of qaurter inch steel to guide me while cutting so the cutter dont go beserk on me, you know stay in the lines like? I have had good look with my Dremel tool and tungsten steel hi speed cutter bit. Cuts through sheet metal like hot knife though butter! I have also had auto body training so I know what happens if things get to hot! I will be sure to have plenty of ice cold water in a spray bottle if I need it! |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1743
Registered: 9-2004
| | Posted on Thursday, June 01, 2006 - 6:51 pm: |
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thats cool, but wouldnt a hole saw bit be a lot faster, easier, and rounder?
cant cost more than 6-8 bucks for the bit.
you do what you are comfortable with, but i would be afraid of slipping with the dremel.
i realize that you are having a template made, (how much you wanna bet they are using a hole saw to make that hole for you? LOL)
but remember that you still have to hold the template in place on the car, which could be cumbersome, messy, and the template itself could scratch the car.
just me thoughts,
good luck,
matt |
Hotwire
Senior Member
Username: Hotwire
Post Number: 1424
Registered: 1-2005
| | Posted on Friday, June 02, 2006 - 11:30 am: |
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hmmm, a hole saw. Well I could go and buy one. Would look neater than the dremel. Good ideal, why did'nt I think of it? |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1751
Registered: 9-2004
| | Posted on Saturday, June 03, 2006 - 9:14 pm: |
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because you have deep seated subconscious desires to be a dentist. LOL J/K!
good luck,
matt |
Ferd1605
Junior Member
Username: Ferd1605
Post Number: 17
Registered: 1-2005
| | Posted on Sunday, June 04, 2006 - 3:07 am: |
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dentist ? ? ? ok , i be outa here ... them dudes
are NOT on my list to be liked !
On the whip issue , i got really lucky years ago , living in the town of COLLINS radio,s , i found 4 military whips that were made in sections . i found
5 sections were 108 inches , prefect for 11 meters and very broadband too . Got them for 5$ each {10 sections per antenna} from Collins surplus store .
Like said before , groundplane is the key word on 1/4 wave moble antennas .. |
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