C B radio install?

I had a full size CB radio on my 75 BMW years ago and would like to put one on my 85 Wing. Anybody have any experience with a good antenna? My radio is a bit modified, it will key 11 watts and swings 42 so antenna is a consideration to make sure I do not damage the radio. I am also not really a fan of multi - use antennas (am/fm and CB combined) or the hideaways. I have been searching online for a while and cannot find any forums or any information on a good antenna for a motorcycle with the problem being not enough metal mass for a good ground plane. My radio does a reliable 13-15 miles on channel 19 with a good antenna mounted on the roof of my Silverado crew cab daily driver and I am hoping for 8 miles or so from the scooter. I had a 4' fiberglass whip on my Beemer back before CB radios were common on bikes and it worked OK but it did damage the radio I had back then over time.

Anyone have any experience with something like this?

Dave / Believer45

Try the truck stops for a mid length whip antennae. Truckers are just about the only ones using cb's anymore. Whip length can be adjusted to set swr if memory serves. Been a long time since I used mine.

I miss the old times of CB radio's.

I had a 200 watt amp at one point and was getting down to San Diego from Mount Wilson.
This was in my VW Dasher wagon.

Ground plane on a bike is a big problem.
Can barely get enough for a non modded rig.

I wonder if Sierra Electronics would have any ideas?

You might give these guys a look: https://www.firestik.com/Tech_Docs/atv-mc.htm

Thank you all for the feedback. My primary issue is trying to get an antenna designed for high performance on a motorcycle. Several years of searching online and talking to folks at CB shops in my travels have resulted in being no closer than when I started.

Firestik is an option I have considered but the lack of ground plane is a problem with these. I understand there are a few no ground plane antennas out there but I have not come across anyone who has actually used them on a motorcycle. We shall see, eh?

Dave / Believer45

A looooong time ago I used to do a lot of CB'ing from my bicycle (pre GW days) here in NYC.... I actually chose a 9 foot stainless steel whip for my antenna... for "optimum" performance from a quarter wave end fed antenna (aka. a 9 foot steel whip) you need an equivalent length of ground plane. This forms the other half of the wavelength to make it the electrical equivalent of a half wave (9 feet of radiator and 9 feet of ground)

Our GL1100's are real close to proper grounding length size for a 9 foot whip, so why not just make a mount from say a trailer hitch and give it a shot??? You will never be able to get any height on the bike to gain a height related increase in talk distance, so try a full sized antenna....

Just follow the usual guidelines for making sure all your stuff on your frame is grounded for transmitting purposes (rather than just electrical purposes which are very different)

Here is a guideline from Diamond Antennas who makes a lot of antennas for the 2 - 30 MHz Ham bands:

HF Mobile Installation Tips
With all the different types of installations possible, there are many unique problems that can occur. We have compiled some additional notes on specified areas.

(1) GROUNDING ANTENNA: Obtaining a good ground is very important to any HF mobile installation. No matter where your antenna is mounted, it is highly recommended your run a heavy copper strap or braid (1” to 3”) between body and frame of your vehicle. (NOTE: Copper wire is not sufficient!) If you have ignition noise problems, it is also recommended to ground the end of your tail pipe to the frame.1

(2) OPTIMUM MOUNTING LOCATION: You should always mount your antenna as high on your vehicle and as far away horizontally from other metal objects as possible. The center of your roof is the best location; however, this is not always practical or possible for most HF antenna installations. The next best location is in the center of the driver's side of the trunk (side mounted on driver side to avoid low hanging curbside branches or objects). The DIAMOND K400C and K600M series mounts work well with the MV3A.
The front or rear bumper is another possible mounting location; however, due to high ground loss, this should be last choice. If you must use a bumper mount, it is recommended to use a base extension to raise bottom of antenna to equal height of top of trunk. Grounding of this extension will become important.

(3) TRUNK LID MOUNTING: Probably the best mounting location for most vehicles. Usually, adding one or two copper straps from the hinge area to car body will improve grounding (and thereby antenna tuning). It is necessary that at least two of the four sockethead screws on mount penetrate paint to metal for proper grounding. (A little clear nail polish or other acrylic paint may be used to seal around mounting screws.)

(4) COAX: If you use an antenna mount other than DIAMOND ANTENNA models K400C or K600M, it is very important to use a quality 52 ohm coax (RG8U, RG58U, RG213, Teflon Coax, etc. with at least 95% shield and stranded center conductor). Do not use foam coax or coaxes with solid center conductors. Foam coax can deform in heat and absorb moisture, solid center conductor coaxes have less flexibility and may become brittle and break in mobile applications.

(5) EMI: Electromagnetic Interference is the single greatest concern for HF mobile applications. Route your cable as far from the vehicles ECM (Engine Control Module) and vehicle's electrical systems as possible. Sometimes a ferrite choke may be required on coax near mount. There are many books on the subject of interference, refer to endnotes for additional information.2


1 J. Seybold, HF Mobile Installation Tips, December 1995 QST, pg. 58-60.
2 ARRL, Radio Frequency Interference Tips: How to find it and fix it., The book is available from your favorite amateur radio dealer or ARRL headquarters.



Good luck and keep us informed,

Rich

n2ppn":2mltj34z said:

A looooong time ago I used to do a lot of CB'ing from my bicycle (pre GW days) here in NYC.... I actually chose a 9 foot stainless steel whip for my antenna... for "optimum" performance from a quarter wave end fed antenna (aka. a 9 foot steel whip) you need an equivalent length of ground plane. This forms the other half of the wavelength to make it the electrical equivalent of a half wave (9 feet of radiator and 9 feet of ground)

Our GL1100's are real close to proper grounding length size for a 9 foot whip, so why not just make a mount from say a trailer hitch and give it a shot??? You will never be able to get any height on the bike to gain a height related increase in talk distance, so try a full sized antenna....

Just follow the usual guidelines for making sure all your stuff on your frame is grounded for transmitting purposes (rather than just electrical purposes which are very different)

Here is a guideline from Diamond Antennas who makes a lot of antennas for the 2 - 30 MHz Ham bands:

HF Mobile Installation Tips
With all the different types of installations possible, there are many unique problems that can occur. We have compiled some additional notes on specified areas.

(1) GROUNDING ANTENNA: Obtaining a good ground is very important to any HF mobile installation. No matter where your antenna is mounted, it is highly recommended your run a heavy copper strap or braid (1” to 3”) between body and frame of your vehicle. (NOTE: Copper wire is not sufficient!) If you have ignition noise problems, it is also recommended to ground the end of your tail pipe to the frame.1

(2) OPTIMUM MOUNTING LOCATION: You should always mount your antenna as high on your vehicle and as far away horizontally from other metal objects as possible. The center of your roof is the best location; however, this is not always practical or possible for most HF antenna installations. The next best location is in the center of the driver's side of the trunk (side mounted on driver side to avoid low hanging curbside branches or objects). The DIAMOND K400C and K600M series mounts work well with the MV3A.
The front or rear bumper is another possible mounting location; however, due to high ground loss, this should be last choice. If you must use a bumper mount, it is recommended to use a base extension to raise bottom of antenna to equal height of top of trunk. Grounding of this extension will become important.

(3) TRUNK LID MOUNTING: Probably the best mounting location for most vehicles. Usually, adding one or two copper straps from the hinge area to car body will improve grounding (and thereby antenna tuning). It is necessary that at least two of the four sockethead screws on mount penetrate paint to metal for proper grounding. (A little clear nail polish or other acrylic paint may be used to seal around mounting screws.)

(4) COAX: If you use an antenna mount other than DIAMOND ANTENNA models K400C or K600M, it is very important to use a quality 52 ohm coax (RG8U, RG58U, RG213, Teflon Coax, etc. with at least 95% shield and stranded center conductor). Do not use foam coax or coaxes with solid center conductors. Foam coax can deform in heat and absorb moisture, solid center conductor coaxes have less flexibility and may become brittle and break in mobile applications.

(5) EMI: Electromagnetic Interference is the single greatest concern for HF mobile applications. Route your cable as far from the vehicles ECM (Engine Control Module) and vehicle's electrical systems as possible. Sometimes a ferrite choke may be required on coax near mount. There are many books on the subject of interference, refer to endnotes for additional information.2


1 J. Seybold, HF Mobile Installation Tips, December 1995 QST, pg. 58-60.
2 ARRL, Radio Frequency Interference Tips: How to find it and fix it., The book is available from your favorite amateur radio dealer or ARRL headquarters.



Good luck and keep us informed,

Rich

Click to expand...

Nice info Rich. Thanks for post. Best '73.

Rich, thank you for a lot of excellent information. I really appreciate the thought and detail you put into your post. It gives me a lot to think about.

What do you think about using a Francis 4' whip (I have successfully used Francis in a number of truck and car applications over the last 40 years) with the rest of the install being the same? I ride with Patriot Guard Riders and am looking to mount parade flags for that so a 9' steel whip could pose some other issues.

Dave / Believer45

Hey Dave,

Happy Easter by the way....

In MY experience anytime you use a "shortened" or less than full sized antenna there will be compromises...

The mere fact that the 4 foot antenna is 4 feet long rather than the 1/4 wave of 9 feet adds challenges to it's effectiveness and ability to get a signal out into the air...

A "dummy load" (a resistor that simulates a perfect antenna) will have a perfect VSWR (ratio of how much signal makes it "out" of the antenna versus the amount "reflected" back to the transmitter..... the closer to 1:1 you get the better the antenna works) , and the transmitter won't get damaged transmitting into it, but it sucks as an actual antenna only giving you a range of about 50 feet.

Anytime an engineer physically shortens an antenna several things have to be done..... the wire or "radiator" contained inside the fiberglass has to be "stuffed" or coiled up to make it shorter.... there still might be 9 feet of wire inside the fiberglass antenna, but it has been coiled up to make the antenna physically shorter..... this affects the signal radiation pattern of the antenna... in order to compensate for the added inductance and capacitance introduced by winding a coil of wire inside the fiberglass antenna other components might have to be added or "tweaks" in the actual way the coil is wound have to be made... Remember, the transmitter wants to see an inductive resistance of 52 ohms in order for it not to overheat from a mis-match and a high VSWR... that is one of the main reasons why coax cable choice is very important.... 50 ohm coax for transmitters, 75 ohm coax for cable TV...etc.....

When you wind a coil for an antenna you create a "concentration" of the RF energy from the transmitter in the horizontal plane all around the antenna.... think a doughnut shape with the antenna through the hole of the doughnut (or bagel)... this "concentration of energy" is sometimes referred to as "gain" when people describe antennas.... now gain is a good thing for a fixed "base station" antenna that doesn't move... but can cause all sorts of things to happen when put on a vehicle and even more when put on a motorcycle...

Go back to the doughnut around the antenna idea... if the antenna is fixed like at a base station, the doughnut stays level and sends most of the signal out to the horizon, where we want it to go (since we aren't trying to talk to a spacecraft or another planet in the sky) and that's good...

On a vehicle, the doughnut will "wiggle" a little off horizontal as the vehicle goes up and down hills and around turns and such (not to even mention getting signal blocked by buildings, trees, etc) causing the transmitted signal to also tilt away from the receiving station and possibly not get heard as it moves around... remember, the doughnut is always at a right angle to the antenna and as the antenna moves around, so does the doughnut....

On cars and trucks this effect is not as noticeable as you would think, until you get into the fringes of radio reception... cars and trucks although moving around, still keep relatively "flat" on the road as they travel and the only things changing the vertical angle of the antenna will be hills and such...

Now take a motorcycle.... I know you see where I am going now.... the motorcycle doesn't spend a great deal of time in a vertical position unless you are going down the superslab at highway speed.... (and then the wind buffeting can make almost ANY antenna dance around) so the transmitted signal will be affected by the motorcycle's speed, attitude and surrounding forces like wind and such....

The best choice for a motorcycle antenna should be one with a minimal "doughnut" shaped pattern and one with a more "ball" shaped pattern so the signal doesn't change as the antenna moves around with the bike...

That is why I preferred a 9 foot whip over a "loaded" (or shortened) antenna, a 1/4 wave full length dipole antenna has this type of radiation pattern... if you want to have a flag on your bike AND a 9 foot whip, then my idea of a modified trailer hitch for your gold wing could be made with a "tee" on it with the antenna on one side and the flagpole mount on the other side... thus giving you "IMHO" the options for an efficient antenna system and a place to fly "old glory"...


Too long winded??? Sorry...

Happy Easter!!!

Rich

Excellent, Rich! And no it's not too long winded.

You've explained well in simple terms a lot of what I never could understand about cb antennas and why it is why it is.

This thread will be added to the forum index for easy find.

I guess an old dinosaur Ham operator like me still can prove useful??? When I did my 9 foot whip on my bicycle as a kid, no one would believe me that I was on my Raleigh 10 speed... I had an old Lafayette DynaCom 12a hooked up to it, and I rode it all over chatting to my "good buddies"...... after that whenever I would do a CB "mobile" install, I used 9 foot whips... my Fiat 128 looked kinda funny with a 9 foot whip on it, but if I could "hear" you, I could get back to you...

Later on as I got my Ham license (N2PPN) I played with lots of different antennas for all sorts of applications.... now I have my 1981 GL1100 all set up with a dual band rig and a nice Bluetooth wireless headset for me to chat to fellow hams as I scoot around.... still get many comments from fellow hams that they can't believe I am "motorcycle mobile" due to both signal quality and no road noise (still use a open face helmet) so I guess the proof is in the pudding??? Now I'm toying around with putting an APRS unit(GPS position reporting transmitter) on the bike so my Ham buddies can "see" where I am.... hope the wife doesn't find out about THAT feature!!! LOL...


Rich

This thread is now linked on the Index page under Electrical, Links to Threads.

I have a question for you, Rich.

As I understand it we're after 9 foot length in the antennae.
Is that why truckers run 2 whips?
Can we get closer to that ideal on our bike by doing the same?

Hey Dan,

When you see a truck (semi) with two 4 foot antennas, one on each mirror, that is called a phased array or in that particular application a co-phased array..

By putting the two antennas in parallel with each other (using a co-phasing harness of coax cable specifically designed for this application) you take that "doughnut shape and "squish it" on the sides to make it more oval with the long sides to the front and rear of the tractor trailer... the sides get thinner and the front and back get thicker... this creates a "directional" pattern to the transmitted signal... more to the front and back of the truck effectively increasing the range in those directions.... making it easier to hear other truckers and less of the local yokels along your sides...

In phased arrays the "lobe" or "squishing" of the "doughnut" radiation pattern from the antenna can be done by placing other resonating antenna sections specific distances from the radiating element, and or electrically changing the "phase" of the transmitted signal to a second antenna using it to "steer" the signal in a particular direction.... (an old CB antenna called a Trick-Stick did this with a control box)

Think of older analog TV antennas.... ever wonder why they had so many "elements" or parallel pieces of metal mounted along the center boom??? Those additional elements "steered" the signals to the one element that was connected to the cable that ran down to the TV in order to get the most signal available to your TV... that's why those antennas always worked better than the "rabbit ears" that came with the TV...

In Radio transmitting these types of antennas are called YAGI type antennas... there are three main component to them no matter how large they are... the driven element (the one actually hooked up the the antenna cable) the director (the one that focuses the signal forward) and the reflector (the one that acts like a mirror and reverses any signal that goes in the wrong direction)

On our motorcycles I wouldn't recommend any type of phased array antenna as it would be even more prone to the "tilting" effect I mentioned earlier, as the "doughnut" shape would be even more compacted and would be more likely to keep the signal from being fully received by the other guys... the increased front to back gain might not be worth it...

The more you "shape" an antenna's radiation pattern, the more it gets like a flattened out doughnut where the two planes of radiation (the E plane and the H plane) can start to become a hindrance rather than a help to your effective range... you have to find a compromise of gain versus practical use...

I once used an extremely high gain antenna on my boat. It was mounted pretty high up off the water on an extension mast... Worked great when we were at anchor in a quiet cove and the boat barely rocked.... but when we were out in the ocean, rolling in the waves, the signal sucked.... reason being that the high gain antenna was so "focused" in it's radiation pattern that the "doughnut" was so flattened out and thin (although quite large if viewed from above) that every time the boat rocked, the signal went either into the water or off into outer space.....

I quickly changed back to a conventional antenna and had much better results when we were offshore..

Same principals apply to motorcycle transmitters...


Rich

One Last note on putting any type of a transmitter on your motorcycle.... RF EXPOSURE!!

I know you might not think of it when putting your CB radio on your bike, but both you AND your passenger (if applicable) are pretty damn close to the antenna... even 10 watts of RF power could be harmful under the right circumstances...Remember, you don't have the metal roof/doors of the car/truck/semi to protect you from the radio waves, and you are sitting real close to the antenna...High gain antennas concentrate the RF (the "doughnut") and increase RF exposure...

Our common kitchen microwave ovens us RF energy to COOK OUR FOOD!! (different frequency and power levels, but same technology)

I won't go into it, but here is a GREAT piece of information on RF exposure and it's effects from the FCC:

https://transition.fcc.gov/oet/rfsafety/rf-faqs.html

Keep this in mind when setting up your bike with a two way radio...

Ride Safe!!


Rich
N2PPN

:thanks: :thanks: :thanks: You have explained it very well. I have installed may an antenna on cas and trucks. Every instillation is different, so antennas all have to be tunned with the use of an SWR meter to minamise. reflected waves. If not the radio dose not last long. Motorcycles are a strange beast and very hard to tune. I have always recomended stopping before transmitting because of the pulling effect on the radlation pattern of a moving M/C, Buildings ,trees, telephone poles, power lines, fences and the such all affect the shape of the signal. Ground plane(or the sedond element of the antenna is most important. you can trim the whip but you can't do to much to trim or lengthen the bike, which is the reflector portion. :Egyptian: :Egyptian: :Egyptian:

well im convinced i dont want a cb on a bike ....sheesh

It's not really naked Joe if it has a CB on it!

Whoa!

I didn't reply to the original post to scare anyone away from putting a CB or other type of two-way radio on their ride.....

You just have to have all the facts when you decide to do something.... having way more information than you need available to you is like having the Snap-on tool truck sittin' in your driveway when you want to fix your bike.... think of all this info as tools in a toolbox... use what you need to get the job done, leave the rest in the toolbox for another day...

Like Sergeant Joe Friday (from Dragnet) used to say "just the facts m'am, just the facts"......


Rich
:hihihi:

Rich I am sure that everyone appreciated your informed response, to CB or not to CB is a personal decision but with your accurate information anyone that does decide to CB now knows how to do it properly :good: :good: