Communication question; what CBs (or other) do people recommend?

[AFBronco235]

Think of it this way. Each antenna is like a light bulb. Instead of radio waves, they send out light. The brighter the light you could see, the better the reception would be. By placing one back and one front, you can see light (get reception) from both directions. If they're only mounted on the front, as I have now, then you won't get much reception to the rear. Mounting one at either end, and towards the corner of the vehicle, provides maximum area coverage.

Now I will say this, truckers mount dual antennae as far apart as possible, usually on their mirror frames. This pushes them out away from the truck enough to reach around the back of the trailer. About the only blind spot from that setup is a few hundred feet directly behind the trailer they may be pulling. However, a semi isn't expected to go places an ambulance would need to go and so doesn't need to worry about snapping antenna off in say a suburban area with low tree clearance, or maybe a parking gargae. So, my point stands about mounting antenna at opposite corners and using springs. This minimizes blind spots on a vehicle like a boxy ambulance, while still avoiding clearance issues mentioned above.

 

[4x4junkie]

Think of it this way. Each antenna is like a light bulb. Instead of radio waves, they send out light. The brighter the light you could see, the better the reception would be. By placing one back and one front, you can see light (get reception) from both directions. If they're only mounted on the front, as I have now, then you won't get much reception to the rear. Mounting one at either end, and towards the corner of the vehicle, provides maximum area coverage.

A lightbulb doesn't emit a specific wavelength of energy so two bulbs are not able to reinforce or cancel out energy in any direction (each bulb's emission is of random wavelengths, and is what constitutes "white" light). Consequently you're just seeing the light of two lightbulbs. There's also the fact the wavelength of light energy is roughly centered around 500-600 nanometers, where your CB's wavelength is 11 full meters, so the emitted energy behaves quite very differently when in the vicinity of your truck's body or another antenna.

Two antennas that are a certain distance apart however are capable of reinforcing radio signals in a broadside direction and canceling out signals from the sides when they are fed a signal "in-phase". It has to do with the timing of when the radio wave's leading edge arrives at (or from) each antenna. It's also possible to change the signal pattern from being broadside to the two antennas to it being an "end-fire" setup, just by changing the timing (phasing) of the wave coming from one antenna by use of a different length of cable on it.

The ARRL Antenna Book explains very well how dual co-phased antennas (a phased vertical array) works. For some reason Google has sucked the big doo-doo as of late and the best thing I could come up with online that sortof explains it in layman's terms was this:
http://www.cbtricks.com/ant_manuals/hygain/model_473/graphics/hygain_phased_engineering_report.pdf
Hopefully it helps.

 

[huskyrunnr]

Line of sight is minimal here.

When a tsunami hits Kauai we will be deep in the valleys. The repeater is 5 valleys away.

Wainiha, I know what you mean, I feel the same way when I'm in a deep hole in the terrain. For that reason, I've become interested in NVIS propagation, but whether there's someone listening in on the other side ...

 

[Catfish37]

If you want to keep it simple get a uniden pro510, external speaker. Spend your money on good coax, mount and antenna. You will easily get 10-15 miles out of it

 

[kojackJKU]

Im running a realistic small form factor cb. No frills basic unit. I am using a Wilson 24" antenna with a big rig mirror mount, mounted on my spare tire carrier. I can get approx. 5 Kms out of that setup. I may step up to a 36" mast on my rig. my antenna just peeks out over my roof on my JK. I think I will get some improved range with one size larger mast. Im trying to keep it low to minimize trail damage.