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Message |
    
Stepchild
Intermediate Member
Username: Stepchild
Post Number: 149
Registered: 11-2002
| | Posted on Wednesday, February 28, 2007 - 3:28 pm: | 
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I have a Stryker antenna (made in OK.city) that I am going to mount on my pu truck.Mounting on a 1 1/2x1 1/2 inch tube behind the cab,from the floor of the bed up.Do I need just the coil above the cab or the whole antenna.The antenna is sort of like a predator 10k.It has a 10 inch shaft,a 9 rap coil and a 46 inch stinger |
Wildrat
Senior Member
Username: Wildrat
Post Number: 1253
Registered: 12-2003
| | Posted on Wednesday, February 28, 2007 - 7:15 pm: |
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if it has the 10 inch shaft I would raise the coil up above the cab at least half way up the shaft. Personally I would put the feed point right at the top of the cab. Others will have other suggestions. That's how I did the Monkey Made I had on my Jeep.
WILDRAT
MARK
27.285MHZ
CEF674
CVC029
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Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2430
Registered: 9-2004
| | Posted on Thursday, March 01, 2007 - 12:09 am: |
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well, i cant say that it will or wont work, but here is my experience with trying to get the feedpoint up high.
i have a 1977 f250 4x4 that i put an alum. truck bed tool box in.
being a CB adict; i knew that i would be using it to mount my antenna projects on, so i bolted it to the bed, making sure it made good ground connection at each bolt.
i mounted two eve mounts to the box right in the middle, facing the tailgate. (the kind used to mount base antenna masts to your roof.)
they held a 5 foot mast to which i connected a luggage rack mount, and put a 102" whip on.
everything was done well, and correctly, and the base of the antenna sat about 6" above the cab.
i thought it was perfect!
nope.
SWR was 3 to 1 across the band; i was bummed.
checked coax, grounds, antenna, everything.
no luck.
i started looking around different forums online to see if others had similar problems, and BINGO!
found a thread about just this subject. (cant remember where now, sorry)
the answer came from an RF engineer, and made alot of sense.
he said, that the antenna needs a ground "plane" to work against. "plane" being the operative word here.
at the base of the antenna, no matter what kind of mobile antenna (boat, and no- ground antennas excluded) the ground needs to be a flat plane extending out perpendicular (90*) to the antenna.
having that groundplane that two or three feet down from my antenna made all the difference in the world.
i went home, drilled four holes in the drivers side of the truck box, as high up the side, and as far towards the back as i could, bolted on the mount, mounted the antenna, and voila!
1.3 to 1 SWR across the band.
the mount was about an inch and a half down from the top of the lid, and about 18" away from the cab.
maybe a bit directional towards the passenger side, but it gets out great, and has never given me a problem.
remember, we are talking about RF ground, completely different beast from DC ground.
good luck,
matt |
Stepchild
Intermediate Member
Username: Stepchild
Post Number: 150
Registered: 11-2002
| | Posted on Friday, March 02, 2007 - 9:30 pm: |
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Thanks guy's.
I'm planning on mounting this in the center of the front of the bed.I've been told that these type antennas radiate from the bottom of the coil and a few others say from the bottom of the antenna.
What if all your "plane"is in front of the antenna?
Would that cause it to be directional toward the front? |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2442
Registered: 9-2004
| | Posted on Saturday, March 03, 2007 - 10:15 pm: |
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yes.
for example, if you mounted your antenna to the tailgate, your maximum signal would be whatever direction the truck is pointing.
whichever direction has more metal, thats your furthest reaching direction.
as for the antenna radiating from the bottom of the coil, i cant say for sure, but i really doubt it.
unless these antennas use some sort of strange feed system that i have never heard of, then where ver the coax feeds in is where the antenna starts radiating from.
i am just allowing for the slight possibility that i might not have heard of something. it has happened on occasion.LOL
ever heard of a stakehole mount?
they are pretty cool.
they allow you to mount an antenna using any of the stakeholes in the bed of your pickup.
these would work quite well for you.
i think firestik makes one.
good luck,
matt |
Stepchild
Intermediate Member
Username: Stepchild
Post Number: 151
Registered: 11-2002
| | Posted on Sunday, March 04, 2007 - 3:02 pm: |
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Yep, antenna feeds in from the bottom. There's really nothing odd about this antenna, I had it mounted on the mirror of my W900L Kenworth and it was just awsome but I mounted it on the left front corner of of my 4 door dually and made the SWR's real mad.LOL.The coil was down behind the cab and the signal had almost no were to go. Yes I have heard and saw the stake hole mounts from firestick. they'er nice mounts but I would still have the coil under the surface of the cab. I should have my mount built by the end of the week and will let yall know how it works out
Thanks
Stepchild
CEF-187 |
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