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Grex Radio Item 57: Help with CB Transmissions.
Entered by manthac on Thu Feb 2 20:19:06 UTC 2006:

Is there anyway to legally make my cb transmissions get out better? Some
places I can transmit 30+ miles and other times I only get out about .5 miles.
I am a SWR meter hookup and the SWR reading is always low 1.5 or less on
channel 17. I can talk 30 - 45 miles away from my house and sometimes just
.5 mile away on the road. The power output and input into the cb is always
the same. I have been looking at some preamps, and was wondering if one of
those may help?

9 responses total.

#1 of 9 by gull on Thu Feb 2 21:05:00 2006:

The only legal way is to improve your antenna.  This can be difficult 
in a mobile installation because short antennas are very inefficient on 
the CB band.  What are you using now?

#2 of 9 by eprom on Fri Feb 3 18:19:00 2006:

is using a CB yagi legal? 

I'm not exactly sure, but I thought you are limited to an elevation of 60 ft
above the surface it's mounted on....so an antenna on a 1000 ft building can
have a total height of 1060 ft(?). correct me if i'm wrong.

#3 of 9 by gull on Fri Feb 3 19:33:11 2006:

As far as I know directional antennas are legal.  A Yagi might be 
impractical in a mobile installation, though. ;)

#4 of 9 by rcurl on Fri Feb 3 19:36:31 2006:

A *rotateable* Yagi - with a compass for automatic orientation. Hams do think
of such things....

(Come to think of it, you might was a bus for carrying a CB Yagi...)

#5 of 9 by gull on Fri Feb 3 19:55:06 2006:

I've seen mobile 2m and 70cm Yagis, but they were used for "fox hunts." 
 
The best mobile antenna for CB that's at all practical is a 1/4-wave 
whip.  It has no gain, but that still makes it better than the 
shortened antennas with loading coils most people use -- there are 
significant losses in those coils.  Unfortunately, at a little over 8 
feet long, it's still impractical on most vehicles, especially if you 
drive in town.  But basically, the longer the antenna, the better off 
you are. 
 
There's a good introduction to CB antennas here: 
http://www.signalengineering.com/ultimate/mobile_antennas.html 
It'll help you cut through the hype.  Most CBers don't understand 
antenna theory, and the antenna manufacturers know it!

#6 of 9 by springne on Fri Feb 3 20:14:58 2006:

Get a copy of the "Big Dummies Guide to CB Radio"; it's excellent.
Has quite a bit on antennas including a home brew one made out of just coax
that you can throw up in a tree.

#7 of 9 by krokus on Sun Feb 19 04:38:21 2006:

Yes, directional antennas are legal on Class D radios.  But while
that will help greatly, I'd also suggest operating SSB for covering
the distance.  (Most SSB work is done on Channels 36 through 40.)

What is the application you're trying to use this in?

#8 of 9 by gull on Thu Feb 23 03:08:56 2006:

I thought about suggesting that, but I wasn't sure if there were many
people using SSB on CB.

#9 of 9 by krokus on Sun Feb 26 18:07:36 2006:

Yes, SSB is used often on CB.  There are even ways to get callsigns
for doing that, and exchanging QSL cards.  (Many people chase DX on
CB, despite it being illegal to do so in the US.)

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