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Old September 26th 04, 03:38 AM
Steveo
 
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Default Mobile antenna questions

"Noltz" wrote:
My question is this; I'd LIKE to use a thru-the-glass antenna for
simplicity & cost.
Are thru-glass types REALLY bad?

Just yell out the window instead of using a thru glass.
  #2   Report Post  
Old September 26th 04, 02:33 PM
Noltz
 
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Default

-=-=- SNIP -=-=-

Don't confuse "ground plane" with "RF ground". The antenna mount needs
a good RF ground to work well. Just about any part of the body of the
truck will work as an RF ground for an antenna (that's assuming the
body isn't fiberglass).

Yes, I realize the difference between them, and the truck has a metal body
& bedsides. I did make that mistake with my first CB when I was 10, and
smoked the transmitter.

...
Too bad. A 102" whip would give you the best performance of any mobile
antenna, and is usually the cheapest, too. It will hit a few trees,
but you can tie it down with a lanyard while driving around town.

The problem with that is it'll be tied down 99½% of its life. And my
truck is a midsize riding at stock height. I don't want to subject my
neighbours to a 'red-neck' looking truck until it comes home lifted with 33"
tires.

Are thru-glass types REALLY bad?


Yes. -=REALLY=- bad.

That's exactly what I didn't want to hear, but suspected.
....

$120 for a fiberglass whip? Judas H. Priest, is the thing gold-plated?
snip
Through-glass antennas are the worst. Coming in a close second (for
different reasons) are NGP (No-Ground-Plane) antennas. And despite
what faith-based rationale others may offer, mag-mounts are included
in the list of NGP antennas.

No, but it might perform better if it was gold :-) I need EVERYTHING,
from the radio, coax, the mount, the stud, antenna, and SWR meter. My
hangup is the only place to mount a GP style antenna on my vehicle is on the
front fender or roof. I really wanted to keep the height on this thing down
while retaining decent transmit range, but that seems to be a contradiction.

Use a standard 3/8-24 stud-type mount and you can use a wide variety
of antennas both cheap and expensive. You can mount the antenna just
about anywhere, but make sure that the mount has a good connection to
the body/chassis of the truck. Generally, higher is better. The rear
of the bed would be better than mounting it just behind the cab
because you won't have as much reflection/absorbtion from the roof.


I'm definately using a standard mount, and it'd be bolted down near the
tailgate, away from the cab.

So I guess my only question left is tuning. Can I tune a ground-plane
type antenna if there is no ground plane at the back of the truck? If it's
mounted to the edge of the bed, the ground plane would be a 4" by 6 foot
strip of metal, not counting the floor of the box, of course. I've seen
antenna's mounted there before, but I have no idea if they work. Here's my
options;
1) a 2' or 3' whip mounted to the left front fender, using the hood as a
ground plane.
2) a 2' whip mounted to the center of the roof, using that as a ground plane
3) a 4' whip mounted to the edge of the bed at the rear of the truck, with
no effective "ground plane" available.

Which of these will give me the best performance for my money? I will be
buying a SWR meter since 2 or 3 others at the shop will also be installing
radios. I'm looking at FireStik brand kits, as they've been recommended
everywhere and have an easy-to-adjust tip.

Thanks again, Frank.
-Noltez


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Old September 26th 04, 06:24 PM
Landshark
 
Posts: n/a
Default


"Noltz" wrote in message
...
-=-=- SNIP -=-=-

Don't confuse "ground plane" with "RF ground". The antenna mount needs
a good RF ground to work well. Just about any part of the body of the
truck will work as an RF ground for an antenna (that's assuming the
body isn't fiberglass).

Yes, I realize the difference between them, and the truck has a metal

body
& bedsides. I did make that mistake with my first CB when I was 10, and
smoked the transmitter.

...
Too bad. A 102" whip would give you the best performance of any mobile
antenna, and is usually the cheapest, too. It will hit a few trees,
but you can tie it down with a lanyard while driving around town.

The problem with that is it'll be tied down 99½% of its life. And my
truck is a midsize riding at stock height. I don't want to subject my
neighbours to a 'red-neck' looking truck until it comes home lifted with

33"
tires.

Are thru-glass types REALLY bad?


Yes. -=REALLY=- bad.

That's exactly what I didn't want to hear, but suspected.
....

$120 for a fiberglass whip? Judas H. Priest, is the thing gold-plated?
snip
Through-glass antennas are the worst. Coming in a close second (for
different reasons) are NGP (No-Ground-Plane) antennas. And despite
what faith-based rationale others may offer, mag-mounts are included
in the list of NGP antennas.

No, but it might perform better if it was gold :-) I need EVERYTHING,
from the radio, coax, the mount, the stud, antenna, and SWR meter. My
hangup is the only place to mount a GP style antenna on my vehicle is on

the
front fender or roof. I really wanted to keep the height on this thing

down
while retaining decent transmit range, but that seems to be a

contradiction.

Use a standard 3/8-24 stud-type mount and you can use a wide variety
of antennas both cheap and expensive. You can mount the antenna just
about anywhere, but make sure that the mount has a good connection to
the body/chassis of the truck. Generally, higher is better. The rear
of the bed would be better than mounting it just behind the cab
because you won't have as much reflection/absorbtion from the roof.


I'm definately using a standard mount, and it'd be bolted down near the
tailgate, away from the cab.

So I guess my only question left is tuning. Can I tune a ground-plane
type antenna if there is no ground plane at the back of the truck? If

it's
mounted to the edge of the bed, the ground plane would be a 4" by 6 foot
strip of metal, not counting the floor of the box, of course. I've seen
antenna's mounted there before, but I have no idea if they work. Here's

my
options;
1) a 2' or 3' whip mounted to the left front fender, using the hood as a
ground plane.
2) a 2' whip mounted to the center of the roof, using that as a ground

plane
3) a 4' whip mounted to the edge of the bed at the rear of the truck, with
no effective "ground plane" available.

Which of these will give me the best performance for my money? I will

be
buying a SWR meter since 2 or 3 others at the shop will also be installing
radios. I'm looking at FireStik brand kits, as they've been recommended
everywhere and have an easy-to-adjust tip.

Thanks again, Frank.
-Noltez



Do you have a cap (shell) or a tool box that
goes from bed rail to bed rail?

Landshark


--
Treat people as if they were what
they ought to be and you will help
them become what they are capable
of becoming.


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Old September 26th 04, 07:35 PM
Tim 960
 
Posts: n/a
Default

http://members.tripod.com/~cb_antennas/index.shtml

www.firestik.com

Start at the Firestik site. Read the tech and faq sections. Look at the stake
pocket mount or hood mount. Firestik and Wilson are both high quality and top
performers. 2 - 4 foot tall is best for your needs. The box or the cab are
enough "ground plane" for what you are doing. I have a 3 foot Firestik on the
rear corner of my CJ7, works great.


  #5   Report Post  
Old September 26th 04, 10:25 PM
Noltz
 
Posts: n/a
Default

No, it is an empty box. I'll be having it Rhino sprayed in the spring
after the bodywork is complete. Why do you ask?
-Noltez


Do you have a cap (shell) or a tool box that
goes from bed rail to bed rail?

Landshark


--
Treat people as if they were what
they ought to be and you will help
them become what they are capable
of becoming.






  #6   Report Post  
Old September 26th 04, 10:38 PM
Noltz
 
Posts: n/a
Default

I've read those already, thanks Tim. I'm simply weary of reading how good
something is on the products' own web site. Needed someone to vouch for it.

Any tips on tuning, or just get the meter and do it :-)

Cheers,

"Tim 960" wrote in message
...
http://members.tripod.com/~cb_antennas/index.shtml

www.firestik.com

Start at the Firestik site. Read the tech and faq sections. Look at the

stake
pocket mount or hood mount. Firestik and Wilson are both high quality and

top
performers. 2 - 4 foot tall is best for your needs. The box or the cab

are
enough "ground plane" for what you are doing. I have a 3 foot Firestik on

the
rear corner of my CJ7, works great.




  #7   Report Post  
Old September 27th 04, 01:44 AM
Frank Gilliland
 
Posts: n/a
Default

On Sun, 26 Sep 2004 09:33:47 -0400, "Noltz"
wrote in
:

snip
So I guess my only question left is tuning. Can I tune a ground-plane
type antenna if there is no ground plane at the back of the truck? If it's
mounted to the edge of the bed, the ground plane would be a 4" by 6 foot
strip of metal, not counting the floor of the box, of course. I've seen
antenna's mounted there before, but I have no idea if they work.



They work fine. And the reason they work fine is because of the
confusion between 'ground-plane' and 'RF ground', as I stated before.
The location you have chosen for your antenna should provide a good RF
ground, and that's all you need.

The antennas that are frequently referred to as "ground-plane"
antennas are usually base antennas that have an -artificial- ground
plane. A mobile antenna uses both the vehicle and the ground below the
vehicle as the ground plane, so there is no need for an artificial
ground plane.

IOW, your mobile antenna already has a ground plane regardless of
where it's mounted.


Here's my
options;
1) a 2' or 3' whip mounted to the left front fender, using the hood as a
ground plane.
2) a 2' whip mounted to the center of the roof, using that as a ground plane
3) a 4' whip mounted to the edge of the bed at the rear of the truck, with
no effective "ground plane" available.

Which of these will give me the best performance for my money?



.....uh, the 102" whip on the bumper. I have mine mounted dead center
on the donkey-guard in the front and tied back. Even when tied back it
works better than a 4' fiberglass whip. But if I can't talk you into
the bridge-buster, just remember that longer is better, and anything
shorter than 3' is mostly worthless beyond a few hundred yards.


I will be
buying a SWR meter since 2 or 3 others at the shop will also be installing
radios.



Forget the SWR meter and buy a "field strength meter". Reason: A dummy
load has an SWR of 1:1 but is a very poor antenna; a field strenth
meter measures the field strength directly, which is the point of
tuning the antenna in the first place. And they both cost about the
same (actually, the FSM is even cheaper if you have another radio with
a good signal meter!).


I'm looking at FireStik brand kits, as they've been recommended
everywhere and have an easy-to-adjust tip.



Other antennas are just easy to adjust using a hex wrench -- loosen
the set-screw, slide the whip up or down, then tighten the set-screw.
Either way, both types score pretty low on the even-an-idiot-can-do-it
scale. Just don't limit yourself (and your wallet) to brand-name
products because they claim it's "easy to tune".






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  #8   Report Post  
Old September 27th 04, 02:28 AM
sideband
 
Posts: n/a
Default

Personally, I'd spend the $70, and buy a Wilson 1000 magmount, put it
right in the middle of the hood, tune it up, and be happy with it.

-SSB

Noltz wrote:

I'd like to first say I did browse through the 646 messages my server
currently has stored, and didn't find an answer to my question before I
decided to post this. I hope I'm not repeating a question that was just
answered. There are no 4x4 clubs around to ask, and members from the ones I
managed to contact via email were very unhelpful, with the common response
being "just plug it in man".

I'd like to mount a CB radio into my Dakota for off-road use, to talk with
a few co-workers who are also doing the same. I figured it'd be easy, just
buy a radio & antenna, wire it up and we're off. I've already decided on a
small Cobra unit rated at 4 watts, but the antenna is what worries me. One
of my co-workers bought a magnetic stick on, about 26" long, and it
performed very poorly. Less than ½ mile range with my Radio Shack hand
held. That's when I started researching antennas and found out about ground
plane vs. NGP, wavelengths and the like. Like bellybuttons, everyone has an
opinion on the best setup.

My question is this; I'd LIKE to use a thru-the-glass antenna for
simplicity & cost. I'd be WILLING to use a 3 or 4 foot fiberglass, but I'd
want to mount it to the edge of the bedside, so there's no (or insufficient)
ground plane there. A 102" whip is out of the question, my neighbors would
have a field day. Are thru-glass types REALLY bad? Theoretically speaking,
in the real world environment of buildings and buses, what kind of range
loss would I experience? At twice the cost ($50 vs. $120), a fiberglass
isn't out of the question, but what range increase could I expect with a NGP
4' fiberglass whip mounted at the rear of the bed near the tailgate? And
finally, should I run separate power and ground lines direct to the battery,
or can I use the ignition switched cigar lighter power for supply? Again,
it's a stock Cobra 4 watt transceiver.

Thanks in advance,
-Noltez
(Searching for answers)



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Old September 27th 04, 03:47 AM
Landshark
 
Posts: n/a
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"Noltz" wrote in message
...
No, it is an empty box. I'll be having it Rhino sprayed in the spring
after the bodywork is complete. Why do you ask?
-Noltez


Well, you can use the edges of the truck bed, put an
antenna mount there. If it has stake bed holes, have a
muffler shop make an antenna bar, that mounts in the
stake holes.

Landshark


--
Courage is what it takes to stand up
and speak; courage is also what it
takes to sit down and listen.


  #10   Report Post  
Old September 27th 04, 02:27 PM
Chad Wahls
 
Posts: n/a
Default


"Landshark" wrote in message
m...

"Noltz" wrote in message
...
No, it is an empty box. I'll be having it Rhino sprayed in the spring
after the bodywork is complete. Why do you ask?
-Noltez


Well, you can use the edges of the truck bed, put an
antenna mount there. If it has stake bed holes, have a
muffler shop make an antenna bar, that mounts in the
stake holes.

Landshark


--
Courage is what it takes to stand up
and speak; courage is also what it
takes to sit down and listen.



Firestik makes a stake hole mount that works very well. I had to shim it a
bit on my Dakota to get it plumb but it rocks and looks good. I got it and
a firestik Firefly 4' from Walcott CB www.walcottcb.com They are good folks
and shipped super fast!

Mine looks like this
http://www.walcottcb.com/catalog/pro...5434a92ea79919
but has provisions for using the fire ring connection. I think I paid less
that 40 bucks total for the whole rig (antenna).

If you park under low clearance parking garages you may want to get a swivel
to bring it down, it's a bitch to remove it every time at the last minute as
you will need tools to unscrew it. Remember it's not a mag-mount

Chad


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