What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Tuning my Cobra 29 LTD *need help*

CherryK5

CherryK5

1/2 ton status
Joined
Jul 3, 2010
Posts
1,340
Reaction score
2
Location
Austin Texas
The communication section seems dead so here go's...


Are these settings okay? I have no idea what im doing sooooo yea.
I dont know if my antenna needs to be lengthened and what that changes.

I set the CAL but thats it, im not sure how to do the swr and s/rf

CIMG0180.jpg
CIMG0181.jpg
CIMG0182.jpg
 
few big things. you want low swr. and you need to check it on ch#1 & ch#40 . need to match if possible if i recall.

and the length of your ant wire is a big key to the system. i thing its around 18ft total helps. even if you have to hide some of the extra.

and a big no no but a lot of us do it the ant cant be blocked by steal body panels. but limited mounting spots limits the locations to mount.

its been a long time since i did a adjustment. so my info might be a bit off.
 
Been years since I used my CB's and tried adjusting the SWR on them,but if I remember correctly,you turn to channel 1 and switch the meter to the "FWD" (forward) position and adjust the knobs on it till the needle pegs to the end of the scale,then switch the meter to the "REF" (reflected) wavw position and the needle will usually drop and indicate the amount of mismatch between the antenna and radio, (like 2:1,etc)--anything over 3:1 is excessive and can damage the output transistors in the transmitter--the lower you can get the SWR by adjusting antenna length and as close to the same on the highest and lowest channels ( ! and 40) ,the better the radio will perform and youll get the most output and reception with it..
 
Ok, this is simple.
Put the channel selector to 20
Switch to Cal.
Key the mic and adjust the calibration knob until the needle lines up with the little arrow.
Unkey, switch to Swr, rekey.

The needle should not go past 2.

If it pegs STOP. Either your cable is shorted or not connected and you are about to damage the radio.

If it does not peg, then switch to channel 1, and redo the Entire procedure.
You must recalibrate it before checking the swr.

Then go to 40 and redo it again.
Odds are there will be a difference.
Some antenna systems will show up as flat swr across the whole band, but most won't.
As long as you are not going over 2 at any channel, then I would not worry about it. If there is a large difference, you might want to do some adjusting, or if you have a favorite channel you might want to adjust for lowest swr on that channel.

To adjust, here is the secret. The higher the number, the shorter the antenna.

If your numbers are good on 1 and bad on 40, the antenna needs to be shorter. If you have an adjustable tip, just screw it down slightly.

As for the length of cable, it does not make any difference for a single antenna.
If the swr changes with the length of cable, then you have other problems. The swr is not actually changing, just your reading of it is.
Believe me, I could probably explain it, but it is a large can of worms and I am not in the mood.

Be sure to recal every time you make a change, and all should be well.
Don't be confused by Diesel4me. He is correct, but what he is calling forward, is cal on your radio.

As for S/RF, short answer, ignore them.

If something seems flaky, try a pic of your antenna, where the wires hook on, and a shot of how its mounted.
 
Fordum said:
Ok, this is simple.
Put the channel selector to 20
Switch to Cal.
Key the mic and adjust the calibration knob until the needle lines up with the little arrow.
Unkey, switch to Swr, rekey.

The needle should not go past 2.
Click to expand...

:waytogo:

this is the way i always check and set mine, never had any problems with it.

The other thing to consider is antenna placement. I used to have mine on the left rear bumper, on the side of the truck, mainly for heithe clearence, as i used to pull the truck in a carport all the time. problem was i had a VERY directional send and receive signal, and kept ripping it off on the rocks & mountain sides :doah: Was really only good for closer range stuff, which i lived with, cause it was really only used on the trails.

BUT, i acquired a K40 magnet mount whip antenna, and have it in the center of the roof between the rear passenger doors, and it gets out a TON better.

Of course i also hit every awning and overhang on drive throughs and banks, but oh well :D
 
The other thing to consider is antenna placement.
Click to expand...

Yep, thats why I suggested pics. I put a lot of the old steel whips on back bumpers. Nowhere close to an ideal placement, but it was quick and dirty and it worked.

And if you pointed the opposite front fender in the direction you were wanting to talk, you could actually tell a difference.

Had a friend who wanted to mount his higher on his old Nova for better range.
I begged him not to, but he made a mount and put her on.

Did pretty good until he drove under a service station and took out every fluorescent bulb he had.

Of course he called me to come loan him enough money to pay off.......
 
Fordum said:
Ok, this is simple.
Put the channel selector to 20
Switch to Cal.
Key the mic and adjust the calibration knob until the needle lines up with the little arrow.
Unkey, switch to Swr, rekey.

The needle should not go past 2.

If it pegs STOP. Either your cable is shorted or not connected and you are about to damage the radio.

If it does not peg, then switch to channel 1, and redo the Entire procedure.
You must recalibrate it before checking the swr.

Then go to 40 and redo it again.
Odds are there will be a difference.
Some antenna systems will show up as flat swr across the whole band, but most won't.
As long as you are not going over 2 at any channel, then I would not worry about it. If there is a large difference, you might want to do some adjusting, or if you have a favorite channel you might want to adjust for lowest swr on that channel.

To adjust, here is the secret. The higher the number, the shorter the antenna.

If your numbers are good on 1 and bad on 40, the antenna needs to be shorter. If you have an adjustable tip, just screw it down slightly.

As for the length of cable, it does not make any difference for a single antenna.
If the swr changes with the length of cable, then you have other problems. The swr is not actually changing, just your reading of it is.
Believe me, I could probably explain it, but it is a large can of worms and I am not in the mood.

Be sure to recal every time you make a change, and all should be well.
Don't be confused by Diesel4me. He is correct, but what he is calling forward, is cal on your radio.

As for S/RF, short answer, ignore them.

If something seems flaky, try a pic of your antenna, where the wires hook on, and a shot of how its mounted.
Click to expand...

So i want the CAL all the way in the red??
 
You must log in or register to reply here.

Latest Posts

Top Bottom