CB RANGE MININUM

[shookie]

Hello fellow pog members...any opinions regarding the range of a the cb radio...I have asked liberty (when the coach was in for service) if they have any experience regarding increasing the range of the radio...they said they can check to make sure the system is working well; however, they do not do anything beyond that...i am certain there are "govering" issues regarding range...i can only transmit and receive to a fellow coach if i am following it (or it me) or if it passing the other direction for a very short period of time...i sometimes, hear trucker's conversations for miles...any help?...let me know, please, if it is convenient....best to all, shookie

[merle&louise]

Hi Shookie, good to hear from you again. Most CB radios put out about 25 watts of broadcast power. That is good for short distances like you are experiencing. The truckers that blast you out of your seat have amplifiers that put out over 400 watts! I think that the FCC regulates the output of CB radio and that's why Liberty can't help you. Maybe Truk can weigh in here and help you get a trucker amplifier so you can be illegal too!

[jello_jeep]

As far as transmitting goes, sometimes you have a dial marked "rf gain" on the radio. This adjusts the transmitting power output either up or down. If you are in close quarters, it might be easier for you to turn the gain down, you will sound less distorted to people very close by, but you will not be heard by those far away.
Sometimes you may inadvertently leave the gain down, so check that. Citizens band (11m) is not the greatest for long range transmissions, and I think the maximum legal wattage is still 4.
When comparing yourself to truckers, keep in mind that some of them have amplifiers running anywhere from several hundred to a thousand watts (them doing something illegal, how shocking I know)!
They usually have nice dual antenna setups with quality antennas too, not the norm on an rv. I would guess if you are getting a mile or two from a lower end cb mobile with no great antennas etc, you are doing well.
If you are interested in more range, look into getting a ham radio license, there is a whole new world to explore there!
I was a member of one ham club that had a series of repeaters, to with a radio smaller in size than a normal CB and a small antenna would cover pretty much half of Ca, and out to Vegas. Nice stuff!

[phorner]

Lots of important factors regarding CB range. The antenna needs to be "matched" to the transceiver with an RF meter. You need the best ground plane possible, which means a nice METAL surface to ground the antenna.

Antenna placement is important too, as it impacts the "shape" of the transmitted signal.

And, as has been mentioned, the RF output power (wattage) on many trucker CB transceivers has been modified with linear amplifiers. These are illegal.... but are heavily used by truckers. I doubt the FCC is of concern to them.

Mine is good for about a mile or so. This performance is dismal compared to what it should be under ideal, yet legal, conditions.

[Bill Price]

I will correct a few misconceptions of CB Radio that may help.

1. The FCC limits the 27 Mhz CB Svc to 5 watts input power. This usually figures to approx 2.5 to 3 watts output.

2. Amplifiers of all type are illegal in the CB Svc.

3. The FCC does care and will file charges for amplifier use. These fines can be up to $10,000 per day.

4. The RF gain on CB radios only works on the receive. It has nothng to do with TX power.

5. For ultimate performance you need a 102 inch whip antenna. This is impossible for us due to height restrictions. The little loaded antennas on our Buses just cant do much.

6. If you require range look at Amateur Radio.

Maybe this will help a little. My cb radio is about useless also. I seldom turn it on. We do use our 144/440 Amateur rig in the bus all the time. My wife has her ham license also. I think many of you would enjoy Amateur Radio.

Go to the ARRL website for additional info. or contact me if I can help.



Bill Price
Amateur Extra call WA5NBP

Additional FCC License:

GROL
GMDSS - O
GMDSS - M
Radar Endorsement

[truk4u]

All good advice, but the truckers and amplifiers is way overstated and Smokey and the Bandit days are long gone. Their radios work good because they are set up right. The key is a good ground plane and proper SWR with the radio and antenna's. I have the CB on all the time, usually turned down until I use it and they just plain suck on RV's. Stop at any of the CB shops near the truckstops and they can put the meter on your radio to check it out, but not much will help.

The Ham guys know how to get it done!

[Orren Zook]

Shookie, you might take a look at some of the 10 meter radio offerings by Connex or Galaxy, there are a couple of good CB shops in your area that can get you fixed up on your radio and antenna requirements.

[Jeff Bayley]

I will correct a few misconceptions of CB Radio that may help.

5. For ultimate performance you need a 102 inch whip antenna. This is impossible for us due to height restrictions. The little loaded antennas on our Buses just cant do much.


Bill Price

Radar Endorsement

......to add to; 102" in the proper length to match the wavelength range that CB's operate in. When you see the any shorter antenna (like most of us have and even cars have) they have a stub either at the base or in the middle. This stub (don't know the proper term) or base contains a coil that makes up for the reduced 102" length in an effort to equalize or mimic the proper 102" length.

There is typically an hex/allen screw adjustment allowing you to move the shortened portion of the antenna up or down. If you take the bus to a CB shop, near truck stops as already mentioned, they can put what is called an SWR meter (at Truck says) in line between the antenna and the CB (assuming the back of the radio is accessible) and you can "tune" the antenna for maximum gain by slight adjustments up or down allowed by the hex screw. The SWR meter reads the amount of back feed produced by a properly tuned or un-tuned antenna. The idea is to get all the power OUT of the radio. A CB shop will also have a meter that will show you the actual output in watts of the radio. If you finish tunning the antenna and still have inadequate power, the radio itself may be suspect and the power have eroded over time. A poorly tuned antenna can make the power erode sooner from the power feeding back instead of being released through the antenna. I took my bus recently to have this checked and the shop determined I had a poor microphone. They replaced it with a suitable upgraded used one for $20 or $30 including his time. I somehow dodged the "Prevost Owners" pricing".

Truckers have the same problem we do with height and it's typical to find their antenna's mounted to the mirror(s). This allows them to use less "stub" and more true length to more closely match the 102" target. They typically mount dual antenna's on both mirrors which displaces the wave pattern perpendicular to the antenna's; or parallel with the highway, which is desirable for highway use. However, this installation forfeits the ground plane (the roof of the vehicle in most cases). As already mentioned, when they supplement their radios with extra amplifiers, it walks all over anything no matter other chinks in the installation. The bracket attaching the antenna to the mirror might have a 90 degree bracket with several inches of diameter which provides a small ground plane. Given the fact that our buses have aluminum roofs (correct me if that's wrong), we forfeight a ground plane even with a roof top stub antenna since aluminum is a much less effective ground plane (if it has any effect at all). You could increase your range (transmitting, not receiving) by putting a decent diameter piece of sheet metal between the antenna and the roof of the bus as a baseplate; thereby providing a [better] ground plane. For most of us, I think the mirror installation would look nasty especially with the needed brackets. If your bus is 10 years old, you would probably benefit from a more modern, upgraded / evolved antenna and could take the opportunity to insert a piece of 1/16" sheet metal as a ground plane in the process; primered and painted very well of course to prevent rust stains. You could even have the base plate chrome plated (bling for the birds) or powder coated for longer durability.

If your radio proves to be delinquent on it's power output, a good CB shop could replace the necessary components and possibly give it some hamburger helper to boost it better than new in the event you wanted to keep the same fit and finish instead of replacing the radio. Suggestion: Get the "check up" done on the road at any number of CB shops near truck stops and if you don't want to wait for them to do it, you could get the radio tuned up after uninstalling it yourself and walk into another shop either at your destination or at home to avoid having them give you the "Prevost Owner Rate". If they give you a fair estimate and you feel confident of the tech at the shop and he has the components in stock, we have the luxury of boon docking right at the shop parking lot overnight if needed and just knock it out. The antenna height adjustment above the coil will need to be re-tuned after the radio get's it's tune up for optimum performance.

[Bill Price]

What you are refering to is a base loaded antenna. The device you reference to is know as a loading coil.

Yes you can adjust the 27 mhz loading coil using the proper length whip for a VSWR of 1:1. It will show the perfect match using the swr bridge "meter".

However you still have a poor antenna as a 102 whip will be the most efficent for a mobile antenna at 27Mhz.

The top of any metal bus will work as a groundplane.

If you are interested the American Radio Relay League has many great books on antennas and antenna theory.

[rahangman]

Has anyone ever thought of designating a POG Channel. It could be used to contact a passing Prevost when traveling. As a case in point, my wife was returning from St. Louis to home (via Branson) and mentioned seeing 5 or 6 Prevosts all headed east "Chasing each other" (her words). So I am thinking, if I were to see a Prevost while traveling, just access a quick call on channel ??? to perhaps determine who it could be. Hmmmmm just a thought.