Shortest CB Antenna

[Seaking]

Hi guys, what's the shortest CB antenna I can mount on my RSV? I know I may be sacrificing a lot of range by going shorter but I seldom use CB but don't want to give up the capability. I currently have the 36" Firestiks and mods on both sides but soon going to try out the hidden amplified am/fm antenna on the bike.. if it works that well, then I would want to reduce the CB antenna to balance out the look of the bike without losing the CB antenna completely..

 

Part number, where to purchase etc etc.. would be appreciated..

 

Cheers

[flb_78]

Here's a 13" you could put inside the saddlebag.

 

http://www1.dealtime.com/xPO-RoadPro-Roadpro-RP-722-12-8-Magnet-Mount-Cellular-Look-CB-Antenna-Kit-1-Each

[flb_78]

and here's an 8 inch you could easily hide in the trunk or saddlebag.

 

http://www.westcoastmall.net/accessories-unlimited-8-inch-dialamatch-p-3511.html

[Guest tx2sturgis]

and here's an 8 inch you could easily hide in the trunk or saddlebag.

 

http://www.westcoastmall.net/accessories-unlimited-8-inch-dialamatch-p-3511.html

 

Also says 36 inches in the specs chart...kinda hard to hide in the saddlebags!

 

 

Wow...if really IS 8 inches long, its more of a radiating dummy load. Probably limiting range to less than a few hundred feet.

[flb_78]

http://www.wearecb.com/store/accessories-unlimited-au108-8-inch-vmt-adjust-a-match-tune-cb-antennas-p-885.html

 

Here's the same thing at CB world. Specs show 8 inches.

 

I agree that it wont talk very far, but most of the time it's used for short range communications anyways or just for listening. If one only wanted the listen to the CB, a coil of copper wire would be fine. You only need to worry about antenna SWR when transmitting.

[Guest tx2sturgis]

Heres a 15 inch antenna, rubber-duck style it says. Might be a good candidate for listening, and transmitting maybe 1/4 mile or so.

 

 

http://www.wearecb.com/store/procomm-150-15-inch-rubber-antenna-standard-threads-p-3135.html

 

Im afraid that the 8 inch antenna might not even hear very well. When you reduce the antenna this much, then ignition noise from the bike can be as loud as all the signals your trying to hear. On the other hand, only hearing 'bear reports' from a few hundred feet away might be a GOOD thing!

 

 

 

[flb_78]

Super Flexible 24", could be used to follow the contour of the trunk or the saddlebag.

 

http://www.wearecb.com/store/procomm-kf2-b-2-foot-broad-band-super-flexible-antenna-black-p-3148.html

[MiCarl]

One of the guys in our STAR chapter mounted a short (12" or so) antenna inboard of the saddle bag on his RSV. It ended up being highly directional and very short range, enough so that he could only communicate with another motorcycle that was on the correct side and slightly behind.

[Seaking]

Thanks for the info lads.. The short 8 or 12" ones would work for what I'm looking for but gees, is the range cut down to mere hundreds of yards?? The idea would be to remove the antenna and carry it in the bag for those rare moments when it would be needed, as in group rides or catching the local bear reports and such on the highways.. a couple hundred yards might work.. Hmmm I currently do sweeps without the radio, simply can't stand the senseless chatter

 

I'll let you know how it works out..

 

cheers

[utadventure]

My IT guy here was a radio specialist for the military and has educated me a little on antennas.

 

(yes, a little information can be scary)

 

Radio antennas (CB, Ham etc) radiate in the transmission signal outward along the length of the antennas. You need to make sure any antenna mounted is straight up and down. An antenna mounted sideways in the saddlebag or trunk would perform poorly because the signal is being transmitted straight down at the ground or sideways and upward but not forward or back.

 

Another thing I learned is that all antennas are essentially the same length in order to not have excessive signal returned to the CB unit. The difference is that in order to have a shorter antenna, say 2', the wire has to be wound tighter (or in a load). While it works, it does, as was mentioned, have a lower performance.

 

Another idea.... my wife also dislikes and the endless chatter on the CB so, when on group rides, she turns on her IPOD and moves up or down one channel from the group. If I need her, I know where to find her and she can quickly rejoin the group channel if necessary.

 

Good Luck

 

Dave

[Seaking]

Great info Dave.. Yes, I was aware of the directional venue of the CB antenna.. When I mentioned of having it in the 'bag', I meant as taking it off the mount and 'storing' it away for when its not needed. I seldom ever use it, but don't want to completely do away with it, cuz ya never know.. Some says when we're traveling down the highway without comms on, we'd have the CB on at 0 volume. When you wanted the other person's attention about upcoming turns or a warning, a double tap on the mic button would cut out his AM/FM radio,.. a poor man's signaling system lol..

 

So just looking for something that works, short enough not to be intrusive while on the bike and small enough to store in one of the bags when not installed / mounted..

 

I had seen some Harley Bikes with a short CB antenna on them.. I should ask how well those work.. just about the thing I need..

 

Thanks to all for the great info..

[Guest tx2sturgis]

My IT guy here was a radio specialist for the military and has educated me a little on antennas.

 

(yes, a little information can be scary)

 

Radio antennas (CB, Ham etc) radiate in the transmission signal outward along the length of the antennas. You need to make sure any antenna mounted is straight up and down. An antenna mounted sideways in the saddlebag or trunk would perform poorly because the signal is being transmitted straight down at the ground or sideways and upward but not forward or back.

 

 

This is not always true. It IS true when an antenna has 'gain' but a severely shortened antenna for 27 mhz will have negative gain. Radiation effciency will be so low that orientation wont matter. Being close to other metallic objects and the frame of the bike WILL degrade an already poor signal, and will probably result in some directionality, so any shortened CB antenna imbedded in the bike will work VERY poorly, but for other reasons, not the horizontal nature of it.

 

Horizontal antennas are used in many services, including ham radio on the HF band, TV transmitters, broadcast FM transmitters, ( the tower is vertical but the ELEMENTS of the array are horizontally phased), and airplane comm radios on HF and sometimes on VHF...and many others too.

 

Another thing I learned is that all antennas are essentially the same length in order to not have excessive signal returned to the CB unit. The difference is that in order to have a shorter antenna, say 2', the wire has to be wound tighter (or in a load). While it works, it does, as was mentioned, have a lower performance.

 

All antennas are not the same length. For any given wavelength ( a wavelength on 27 mhz is about 36 feet) you can have one that is 1/4 wave, 1/2 wave, 5/8 wave, and many other fractions are possible. Any compact antenna that utilizes loading can have some compromises. The 'load', in other words, the windings, create an electrically correct, tuned antenna, but allow it to be physically smaller. There are exceptions, especially in the VHF-UHF bands, but this does not apply to the CB frequencies.

 

 

I should mention that the SWR will probably be so highly mismatched on an embeded antenna ( or any antenna thats mismatched) that during transmit the final output transistors can overheat and fail. Normally most bike-to-bike transmissions are brief, so the 'finals' have a chance to cool off. But long transmissions or a very poorly matched antenna CAN damage the transmitter of the CB.

Edited July 22, 2010 by tx2sturgis