Scored a used very low priced Clarion CB

[NJF6Cowboy]

Purchased a Clarion CB radio for my interstate off of EBay for $110.00. Direct plug in regarding power plug and 5 pin din plug. Yes its true and I feel real lucky. Installed cb radio and  new antenna from wing stuff ( thanks Kingbee for the suggestion ). the cb works perfectly.

Question is I want to stick to one antenna due to low garage door. Only want to fold one antenna twice daily. I know Bagger John and others have talked about a antenna splitter. Having a hard time finding one. any suggestions? and are there any drawbacks to using the splitter?


Thanks in advance, Stan aka NJF6cowboy

[Bigmac2]

Check with  www.sierra-mc.com i think they have what you are looking for

Rich (bigmac2)

[NJF6Cowboy]

Thanks for the reply.

[Bagger John - #3785]

Sierra is where I got mine, and you can also find them on eBay from time to time. They were OEM equipment on the 1100 and 1200 Aspencades.

[humshark]

You asked about drawbacks, and yes there are drawbacks.  I doubt you'll consider them worth not having two antennas however.

CB's operate on a completely different frequency than your FM radio.  They also transmit which is a bit trickier than simply receiving.  Any sort of splitter that allows you to use one antenna for two purposes - especially an antenna designed specifically for one purpose or the other - will have performance trade offs.

If the trade off only effects your ability to be "heard" at a reasonable distance, or receive FM stations at distance, or if your primary use is talking to the guy next to you, then you probably won't care, as I stated earlier. 

If however you are a radio junkie, and like to tease truckers - or call for help, at distance -then you'll want to tune your CB up to your antenna as perfectly as possible - ( hard to do on a motorcycle anyway! )  The real danger with splitters and antennas, is incurring a bad match altogether which not only will keep you from transmitting further than a block, but will eventually kill the output transistors in the CB.  A well made splitter should not damage a CB or FM radio - but will only incur the trade offs in performance of each piece - FM / CB.

[NJF6Cowboy]

Purchased an antenna splitter tonite from the local auto stereo store. Will install tonite. Antenna I purchased from Wing Stuff states it is good for FM and CB use.

Thanks for the help on this it is appreciated as always.

[Bagger John - #3785]

You asked about drawbacks, and yes there are drawbacks.  I doubt you'll consider them worth not having two antennas however.

CB's operate on a completely different frequency than your FM radio.  They also transmit which is a bit trickier than simply receiving.  Any sort of splitter that allows you to use one antenna for two purposes - especially an antenna designed specifically for one purpose or the other - will have performance trade offs.

The key is to use a CB antenna for BOTH AM/FM reception and CB transmission/reception. Honda and a number of other manufacturers have done this for years. In the case of the Clarion splitter, a matching circuit for the AM/FM section is provided - it is adjusted via trimmer capacitors and is usually "set" at the factory.

If however you are a radio junkie, and like to tease truckers - or call for help, at distance -then you'll want to tune your CB up to your antenna as perfectly as possible - ( hard to do on a motorcycle anyway! )  The real danger with splitters and antennas, is incurring a bad match altogether which not only will keep you from transmitting further than a block, but will eventually kill the output transistors in the CB.  A well made splitter should not damage a CB or FM radio - but will only incur the trade offs in performance of each piece - FM / CB.

Blondie's Tourer employs a JMCB2003 which is coupled to a Hondaline I/S CB antenna via an old Hondaline (Clarion) splitter. Maximum SWR from 1-40 is with this arrangement is 1.4:1.

My I/S employs a Hondaline CB and Hondaline AM/FM stereo which are coupled to a Hondaline I/S CB antenna via the Sierra splitter. Maximum SWR from 1-40 is again 1.4:1.

We have been able to talk bike to bike a distance of ~6 miles.

We have been able to talk "bike to base" a distance of almost 15 miles.

Incidentally, the coax cable run on a motorcycle is so short that for all intents and purposes, VSWR is not going to have an effect on reflected power - except in the cases of an open circuit or a dead short.

Get yourself a decent SWR meter and a set of coaxial jumpers and tune your antenna for resonance. A better way to do it is through the use of a field-strength meter. The actual impedance of our Valkyries' CB antenna - in its as-delivered configuration - is on the order of 10-15 ohms. This is going to look like a 3.5:1 - 5:1 mismatch to the transmitter, but the antenna will still be radiating maximally.

A properly constructed splitter ("diplexer" or "triplexer", as they're known commercially) should introduce no more than 0.5dB loss into the feedline circuit. I have in my amateur radio setup a pair of them which are capable of handling more than a kilowatt of power at HF (CB and lower) frequencies. Even when maximum power is applied, neither of mine run warm. This indicates a very low-loss device. Sierra's and Clarion's designs are of similar loss characteristics.

[humshark]

Nice write up Bagger John.  What you are describing IS the way to go and I am somewhat familiar with the setups, but have always been suspicious of great performance.  Sounds like you've got it tuned up perfectly. 

What I'd like to add is not to take away or cast doubt on what you have previously said, just give you an idea of where i came from and my understanding of these things.  ( enough to be dangerous, but not useful?! ) I myself do have a meter and do tune for proper operation.  I'm more of a Junkie than I'd like to admit, having played with electronics and radios and scanners over the years.  I try to stay away from the geek status for my wife's benefit!

While the systems you describe work exceptionally well, due to the laws at work, there are always trade-offs.  In the cases above - the trade off is more on the reception of the FM signals - since these types of setups are tuned obviously for transmission, at whatever frequency range of the transmitting radio.  Tuning the antenna for reception of the FM signal will then not be "optimum" but by most anyone's standards, acceptable.  ( I base this on knowing that a short antenna properly loaded will not receive as strongly, longer waves as a longer antenna would.  And conversely, the same holds true for long antennas and short wavelengths.  Electrically spoofing the circuit through the use of capacitors doesn't make up for the initial property of the radiator / receptor  relationship.  )  Remember when the Optimum FM antenna for a vehicle was a 54" whip?!

Let's be honest here for a moment.....  How many of us still listen to more than a little on the FM radio?  I find with satellite and my trusty Ipod/Zune/whatever file player you have - My time on the FM dial grows ever increasingly less.

Let's be honest here for one more moment.....  How many of us would choose to operate a CB as opposed to the FM bands more available now than ever if our radios had that option?!  Can you imagine the truckers on "family band"? 

Questions, questions - I obviously have too much time, and have written to much for most to read - - Sorry.  I get a bit carried away.

Lets all keep the sunny side up!  I'm outta here.  First sun I've seen in three or four days!
 

[Bagger John - #3785]

In the cases above - the trade off is more on the reception of the FM signals - since these types of setups are tuned obviously for transmission, at whatever frequency range of the transmitting radio.  Tuning the antenna for reception of the FM signal will then not be "optimum" but by most anyone's standards, acceptable.  ( I base this on knowing that a short antenna properly loaded will not receive as strongly, longer waves as a longer antenna would.  And conversely, the same holds true for long antennas and short wavelengths.  Electrically spoofing the circuit through the use of capacitors doesn't make up for the initial property of the radiator / receptor  relationship.  )  Remember when the Optimum FM antenna for a vehicle was a 54" whip?!

Let's examine the use of a matching circuit and look at the relationships of wavelength vs physical length WRT a CB antenna and the FM broadcast band frequencies.

A 1/4w vertical at 100MHz is ~2.5ft in length. The stock "center-loaded" Hondaline CB antenna (or any other 'resonant' 1/4w CB whip) is physically longer than this, and electrically appears around 9ft in length. Such an arrangement also appears to be inductive at 100MHz, the center of the FM broadcast band.

How do we match an inductive load? Simple - with a series capacitor arrangement:   ANT -----------[\(---------- FM RADIO

Those who wish a more thorough explanation of what is going on with an antenna, radio and coupling circuits may wish to peruse the following:

http://en.wikipedia.org/wiki/Impedance_matching

The above being stated, if an antenna is significantly shorter than its intended frequency of operation (and we're talking many wavelengths here, BTW) then capture area and radiator area will be minimized and will affect the overall efficiency of the system. An electrically "longer" antenna - when matched properly to a load or generator impedance - will actually exhibit some free-space gain over an equivalent "resonant" antenna.

This fact is not lost on CB and amateur antenna manufacturers; many of their vertical (ground plane) antenna products are constructed as 5/8w or series-phased, multiple 5/8w radiators. Each of these sections is electrically longer than an 'optimum' 1/2w dipole and is matched to the transmitter through the use of (you guessed it) a series capacitor.

Let's be honest here for a moment.....  How many of us still listen to more than a little on the FM radio?  I find with satellite and my trusty Ipod/Zune/whatever file player you have - My time on the FM dial grows ever increasingly less.

Let's be honest here for one more moment.....  How many of us would choose to operate a CB as opposed to the FM bands more available now than ever if our radios had that option?!  Can you imagine the truckers on "family band"?

Here's another tidbit:

Automotive stereo-equipment manufacturers have long realized that their products would be fed via so-called "compromise" antennas, and as such have designed their receiver front ends with a good amount more gain than the average home-entertainment system has.

They'll work effectively with the figurative "wet noodle" connected to them.

One of my I/Ses has the following antenna installed inside the fairing and mounted to the right-hand stay. In spite of the very limited capture area of the setup, its FM stereo works surprisingly well when fed with the Dakota.

[humshark]

Good info and a lesson for me as i still dream of modifying my I/S into a Super Valk.

Have a good one!