Why do truckers tilt their antennas forward about 20 degrees?
 

Seen this a lot lately on the road..




--
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet?

It cuts them some slack when they back up to something that
hits it/them.

"Dave VanHorn" wrote:
Seen this a lot lately on the road..

--
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet?

Also when they drive down the road going real fast, The antennas move up a
little
and keep a good groundplane instead of folding back and loosing it.

"Steveo" wrote in message
...
It cuts them some slack when they back up to something that
hits it/them.

"Dave VanHorn" wrote:
Seen this a lot lately on the road..

--
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet?

In , "Dave VanHorn"
wrote:

Seen this a lot lately on the road..


Beats me why they do that, but it's possible the reason is founded somewhere
deep in CB mythology.


--
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet?


I think it's a Carnac thing.....

A: Shish-Poom-Pah
Q: What does it sound like when a sheep explodes?






-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

On Tue, 23 Mar 2004 23:11:43 -0500, "Dave VanHorn"
wrote:

Seen this a lot lately on the road..

I have heard 2 reasons, some of them have got the idea that it
"points" their signal down the road, and that they want to keep them
away from their trailer.

"Juafi" wrote in message
link.net...
Also when they drive down the road going real fast, The antennas move up a
little and keep a good groundplane instead of folding back and loosing it.


??? "keep a good groundplane" ???

This technique must be geared twoard running at about 300 MPH then, at 70+
they are still tilted way forward.

"Frank Gilliland" wrote in message
...
In , "Dave VanHorn"

wrote:

Seen this a lot lately on the road..

Beats me why they do that, but it's possible the reason is founded
somewhere
deep in CB mythology.

That's a subject that almost deserves a book.

The "ground plane" gadgets that extend about 3" from the base of the antenna
are pretty good, along with the "5kW" antenna I saw packaged with a mount
that had non-removeable RG-58 coax.

the so-called ground plane that attaches to the base of the antenna IS NOT a
ground-plane because it's mounted above the insulator.
inexperienced truckers who buy them know absolutely nothing about Rf.
they are simply wasting their money on doo-dads that they think are going to
make their radio get out farther.
anything that is added to the the antenna above the fiber washer simply
increases the electrical length of the antenna.
Capacitance hats do not add length but they must be mounted above the
loading coil.
as far as tilting the antennas forward are concerned,
there are sevewral possible scenarios involved.
(1) the antenna is taller than 13'6" when mounted veertical
and hits the low bridge when passing under therefore a forward tilt is
mandatory.
(2)they no absolutely nothing about RF radiation or
take-off angle and tilt them forward 45 degrees to look cool.
(3)tilting the the antenna forward about 15-20 degrees can increase the
forward range of the signal by angling the signal closer to the horizon
because antennas that are mounted closer to earth ground than 1 wavelength
have a higher take-off angle than those that are mounted at or above 1
wavelength.

A truckers CB is his/her pride and joy and the ultimate
tool we use to communicate with each other over long distances.
money is not a object when it comes to building a nice
rig for talking on because we spend hours and hours
communicating with each other on long trips cross-country
--
Mad Dog
aka 714 Sandpile
aka KG4LBD
2002 KW T2000



"Dave VanHorn" wrote in message
...

"Frank Gilliland" wrote in message
...
In , "Dave VanHorn"

wrote:

Seen this a lot lately on the road..

Beats me why they do that, but it's possible the reason is founded
somewhere
deep in CB mythology.

That's a subject that almost deserves a book.

The "ground plane" gadgets that extend about 3" from the base of the
antenna
are pretty good, along with the "5kW" antenna I saw packaged with a mount
that had non-removeable RG-58 coax.

The reality is this - if a vertical is tilted 45 degrees, then you
experience a 3 dB signal loss off to the sides to a vertical that is truely
vertical. A horizontal antenna can loose over 20 dB when communicating to a
vertical antenna via direct line of site. With skip, it doesn't much matter
as the signals will get twisted around a bit, but for local communication,
figure the cosine of the angle difference. Cosine of 45 degrees is .707.
The cosine of 90 degrees is zero (but there will be some reflected signals
and you will usually get a 20 dB attenuation - a 100 times loss of signal
*both* on transmit and receive). 3 dB isn't huge, but why have a loss both
ways on a circuit?

73 from Rochester, NY
Jim



---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.639 / Virus Database: 408 - Release Date: 3/22/04

On Wed, 24 Mar 2004 04:37:08 -0800, Frank Gilliland
wrote:

In , "Dave VanHorn"
wrote:

Seen this a lot lately on the road..



There could be a logical reason for this. Since an antenna is bent
back when moving forward, by tilting it forward, it will compensate
for the "bend", and end up straight when moving.

Of course, some people exaggerate the effect for reasons which, as of
yet, are not known.

Dave
"Sandbagger"
http://home.ptd.net/~n3cvj