Matching a New Antenna

[MasterGuns]

I've searched but to no avail to find a thread on how to set the cb radio on the first edition. Due to a small mishap ruining mine, I picked up a replacement from Buckeye Performance. I even went out and picked up a SWR meter. But exactly how does not go about matching a new antenna on the first edition, or for that matter any stock m/c cb radio. I am lost. I'm sure there is lots of expertise out there so please help. It won't be long before heading out on about a 1400 miles ride to Big Bend, Texas so I'd really like to be able communicate well. Thanks all.

 

[GeorgeS]

SWR Meter usage, is basicly as follows.

Hook meter In Series with cable, going to antenna.

Problem here is you need an extra cable ( RG-58 U type cable ) with a connector that will fit the Output side of the Meter, and go to the Antenna coax plug. ( You should be able to buy at Radio shack )

 

OK, with meter in the line. Put meter to the " Forward position" and hit the Key. You will see a " High " Reading on the meter. ( if it has a " SET " control, then set to the Reference mark, it may not.

 

Now, Switch to the " Reflected Power " switch position.

 

One more comment, Its kind of like sighting in your rifle, as a Marine, I know you understand how that works,

 

Hit the key again, You should see a Much Lower reading. This is the amount of " Reflected Power " (((( THIS WILL BE OUR REFFERENCE READING )))

 

Want you want here is the LOWER, the Better.

 

Now your New Antenna if probably Physically tuned to about the Physical, Center, of its Adjustment Range.

 

IF---- The second reading is, 3 to 1 or higher, you will want to make an adjustment.

 

Take the cap off end of antenna. give it about 1/4 inch of extension,

( ie. make the antenna physically longer ) and then Repeat takeing the Reflected reading.

 

IF--- It went Lower, Thats Better.

 

IF--- It went Higher, go back the same 1/4 inch, and then make it 1/4 inch shorter.

 

Take another reading. It should now be Lower, ( less reflected power) then ' YOUR INITIAL READING " ( that you made a record of )

 

((( keep in mind, that you may have went past the lowest reading, and gone back up ))

((( so make small adjustments, this is trial and error procedure )))

 

 

OK, what your are trying to accomplish, is to get the " Reflected " power reading down to 1 on the scale. As a rule of thumb, 1 is about as good as it gets.

 

Now, one more consideration. If you intend to use all 40 chanels, then do the adjustment around channel 20, In other words, you will have the lowest SWR in the Middle of the Frequency Range.

 

I would reccomend useing channel 19 .

 

Now read thru this several times, untill you have it fixed in your mind

exactly what the proceedure is.

 

Did you get the Antenna with the Plastic cap that goes on the TIP.??????? IF so, Replace the Plastic Tip, Cause the reading will change if its not installed.

 

Hope this helps.

 

IF not send me the Type of Meter You bought, I can probably look it up on the internet, And maby more specific.

 

GeorgeS, ( N7UY Ham radio operator )

 

One more comment, If the initial reading is 2 to 1 or less, on

channel 20, Don't mess with it. Thats Good Enough, Go have a BEER !!! Your time will be better spent.

 

People go overboard , worring about this.

[Guest tx2sturgis]

I'm not familiar with the setup on that bike, but generally speaking, its a matter of checking the SWR by putting the meter inline with the coax, then keying the mic, calibrating the meter to the 'set' mark on the dial, then flipping the switch and reading the indicated SWR.

 

Calibrate each time, and check the readings on your highest channel, (23 or 40), then check the reading on channel 1. If the SWR reading is higher on the high channel, your antenna should be shortened, either by sliding the 'stinger', or physically grinding off the whip at the bottom.

 

If the SWR is highest on channel 1, then you need to lenghten the whip.

 

If the reading is 'off the scale', or in other words, infinite, you may have a short or open in the coax or connectors, bad ground, or a bad antenna.

 

If the meter will not move when you transmit, you probably have a failed output transistor in the CB.

 

Normally the adjustments to the whip are made in small increments, around 1/4 inch or so, until it is balanced, meaning, the SWR reading is about the same on channel 1 as it is on ch 40..(or 23)

 

At this point it should have the lowest reading probably on channel 12 for a 23 channel radio, or channel 19 for a 40 channel radio.

 

If you dont end up with a reading that is somewhere around 1.5 or less, then you either have to be happy with reduced range, OR, put a better (meaning longer) whip on the bike and start over. Its not uncommon to find these whips wont tune to much better than a 2 or 2.5 SWR reading....this is still usable, but if its reading a 3 or more, you can end up damaging the finals in the radio when you transmit.

 

If you have any friends who are ham operators, they may own an antenna analyzer, and this makes matching an antenna a much quicker and easier operation.

 

 

 

 

[lonestarmedic]

Hi Gunny,

I am coming your wat for the Dallas swap meet the weekend of the 14th. If you dont have it fixed by then I will give you a hand. Do you still have a single antenna? By then you should have those mufflers ready to show off. I am going to be looking for a new riding jacket.

 

JB