Alright, I finally got my new CB & finished installing it today.

I got a Uniden PC78XL CB. It looks like, and has the same features as a Cobra 29. I read somewhere they are the same radio.

I installed new Firestick antenna wire, antenna base, HD spring & 4' Firestick II antenna. I installed the antenna on my tire rack. I did not ground the antenna pigtail to the tire rack. Instead, I added extra wire to the pigtail & ran it to the frame. Right or wrong?

My questions are about SWR tuning, I've read that a SWR over 2 can damage the CB transmitter. The manual is not well written and I want to make sure I understand what I'm doing & don't screw up my new radio.

The steps I followed are:
Set switch to "CAL"
Press & hold hand set key (transmit)
Use "SWR CAL" knob to set needle to "^" mark on far right end of meter
Press & hold hand set key & switch from "CAL" to "SWR"

That is all in the manual, but there is no further explanation of adjusting SWR.

After doing this, I keyed the hand set & the meter pegged (VERY HIGH SWR). Then, I keyed the hand set & moved the "SWR CAL" knob so that when the hand set is keyed the SWR meter reads between 1 & 2.

Have I done this right? Am I correct that the CB adjusts the SWR, so there is no need to use the adjustment on the antenna? How much time with a high SWR will ruin a CB?

There is an "ANT" light that the manual says is a "high SWR indicator". This light lights every time I key the handset, even after I made the adjustments above. The antenna system is brand new & I don't think there are any problems. We have another CB at work I was transmitting & receiving fine.

Thanks
Chad

I was just out messing with things. I figured out one of my issues. Seems my antenna wire ground wasn't good. I don't know what was wrong, but I put a new terminal on the ground & the "ANT" light doesn't come on anymore.

Still don't know if I'm tuning right.

Chad

We don't kid about aliens 'round these parts. Didn't you see "Alien vs Predator II", it took place in "Gunnison, CO". I put it in quotes because it looked a whole lot more like the Pacific Northwest than Gunnison. It was hilarious to watch if you actually live here. I never knew it, but apparently, there is a nuclear power plant in Almont, it was central to the film.

I've been reading and anytime the "ANT" light is on is a bad thing, if your antenna isn't grounded the SWR pegs and you can smoke your CB. Hope I didn't shorten the life of mine too much. The manual for this thing sucks.

Chad

Chad,

It sounds like the steps you are doing are correct. The best you can tune a radio to is 1:1. You would be alright though with 1.5:1. You also correct that 2:1 is too far out of range to safely operate the radio.
Your antenna should be tuned and checked on various channels to ensure you are tuned to an average of all the channels e.g. begin checking on channel 1 then progress up the channels checking randomly to channel 40 and then check channel 1 again.
You should also consider fine tuning your radio to the channel you are going to use the most. This would give you the best performance for that channel. Just make sure you are not out of range for the rest of the channels.
Hope this helps,
Mike

Here is the best description I found of how to tune the SWR on a Cobra 29 (or Uniden 78) with a built in SWR meter:

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 manual says to keep the mic keyed & switch to SWR)

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.

I found this here, post #5:
http://coloradok5.com/forums/showthread.php?t=280058

If the SWR is greater on channel 40 than channel 1, the antenna is too long and needs shortened

If the SWR is less on channel 40 than channel 1, the atenna is too short and needs lengthened.

another good explanation is here, post #4
http://www.thetruckersreport.com/trucki ... ng-my.html

I only hope I haven't damaged the CB. That would suck. Its been keyed maybe 10 or 15 times screwing around with things before figuring out the bad ground. The Uniden has a 2 yr warranty, vs Cobra's 1 yr warranty. Maybe I'll have to test out their warranty service. I bet the damage caused by a bad SWR is pretty easy to spot & deny warranty repair.

Interesting info on the antenna ground. After I put a new end on the wire the "ANT" light hasn't come back on. I haven't tried tuning anything yet, I'll do that tomorrow. The tire rack is not grounded to the frame, but its a significant amount of metal. Tomorrow, I'll move the ground to the tire rack, and compare the SWR to the ground at the frame. Maybe I'll even check with the wire grounded to the rack & jumped to the frame. I don't want to put the antenna on the roof, I'd like to keep the antenna if I pull the top.

Chad

Chad,

I would strongly recommend buying an external SWR meter to tune the antenna. Also to make this easy, buy a tunable antenna (if you haven't already). Rox Crusher and I went to a CB shop yesterday and he actually bought a pre-tuned antenna. If you can get it close, I'll bring my SWR meter with me next week.

Mike

Thanks guys. Very excited about next weekend. My antenna is tunable. I'm sure I'll get it close with the built in meter. I did read that the external ones are better. Mike if you want to bring it up, great, if you don't think we'll have time to mess with it, I'm not worried. If everything goes south, I've always got my backup ready now, thanks Mike. I don't really plan on moding this radio, I'll read up on it sometime.

I bought my antenna & wire from the only place in town offering SWR tuning. They had one CB available, it was about $50 overpriced, so I ended up buying online. I didn't want to walk back in with someone else's radio & ask for it to be tuned. Plus I'd like to learn how to do it myself, I'm a glutton for punishment.

I'm not stoked with where the CB is mounted, but it is for the short term, hopefully by next summer I'll have a new dashboard & the truck completely rewired.

Thanks
Chad

Rox is right about having your CB tuned. I am currently having a cobra 29 tuned and will get it next week.

Your steps to tune it are not entirely correct.
1- turn to ch 20
2- set the meter to cal.
3- when holding the mic button set the cal knob so the needle is right on the little heart shaped icon toward the right of the meter.
4- while holding the mic, flip the meter to swr.
That is your reeding.
5- adjust the tip of the antenna up or down about 1/4"
6- start over at step 2 and see if the swr is better.
Keep adjusting and going thru the EXACT STEPS EVErY TIME until you have reached the lowest SWR you can.

A couple things about your system.
1- your "ground" wire can't be more than 8" and should be 12 ga.
2- your setting the swr on the CB is not the tuning process. And yes even though CBs are "tuned" they still need a tuned antenna to work well at all. Its like having a tuned motor and an auto tranny that can't shift gears properly. You need them BOTH to work RIGHT.
Here is a test for you.... Go to the cb end of the antenna wire. Disconnect it from the cb. Take an ohm meter and check the outside metal housing to the inner pin. If you get any reading at all (this includes all 0000s) you have an issue. You need to make sure that there is a plastic isolator around the stud that goes thru the mounting bracket. The isolator goes on the top of the mounting bracket and the base mounts on top of the isolator. This keeps the center pin from touching ANY metal at all. The bottom side of the base will touch the underside of te mounting bracket. This is how it's "grounded". If your antenna is on a swing arm, run a small ground wire from the swing arm to the bumper to make sure the swing arm is grounded.

Maybe post a pic of your mount?

Thanks for all the info.

I took some time today & rechecked & attempted to tune the antenna (SWR). I understand that CBs can be "tweeked", and that is not what I'm after right now. I just want my CB to work & not blow itself up.

I followed the instructions I found on line last night (same as rtread's). After reading last night, I realized that I was "tuning" the CB/antenna wrong. I understand how the SWR meter & antenna tuning works now. The antenna wire is brand new, I don't have a multimeter at home, but I'll go to work tomorrow & check it. Here is a pic of my antenna mount. I have a plastic spacer above & below the mounting bracket. I know I assembled it per the instructions on the packaging. Sorry the pics are bad, it was dark already.



So here is what I found today:

With the antenna wire grounded to the tire carrier very close to the antenna mount, with no extra wire added, got rid of the "ANT" warning light. But the best SWR readings I could achieve on Ch 40 were just over 3. My reading on Ch 1 was better, around 1.5. Ch 20 was around 2. When I adjusted the tip of the antenna (made it longer), the SWR readings just got higher. I tried adding a jumper wire to the frame from the tire carrier, and removing the HD spring from under the antenna, both made little or no difference.

Like the info Zilla posted, I don't think there is anything wrong with my antenna or wire, just a bad mounting point. I had read that the best place to mount the antenna was the center of the roof. That gives the best ground plane. I think tomorrow I'll try a mount on the back corner of the truck body, see if the larger metal panel of the truck's quarter gives a better SWR.

Chad

I don't know what the hell Photobucket is doing to my pics, but I can't seem to rotate one.

It doesn't really matter now. I did some more reading & found info at Firestik.com, go figure.

My SWR was higher on Ch 40 than it was on Ch 1. So the antenna was too long, but the screw was all the way in on the antenna. The only adjustment I seemed to have was to make the antenna longer, making my SWR readings worse.

There is a page at Firestik.com that describes what to do if your antenna needs to be shorter:
http://www.firestik.com/Tech_Docs/long-tt.htm

The short story: you can remove the adjustment screw, vinyl cover, lock nut, even cut down the adjustment screw or vinyl cover, to make the antenna shorter. In the end, I reinstalled my spring, removed the adjustment screw & lock nut, & reinstalled the red vinyl tip cover. I've got an SWR just below 1.5 on Ch 1 and just above 1.5 on Ch 40. And never gets much above 1.5 across the whole dial. I think I'm going to leave it be.

Chad

1.5 is pretty good. That's only 4% loss.

With a swing out tire carrier mounted antenna, 1.5 is great!

Hey also check the swr reading on ch20. It should be slightly better than ch1 and ch40.

I checked across about every channel. The lowest is Ch1, just under 1.5 & the highest is Ch 40, just over 1.5, Ch 20 is right about 1.5. There is almost no fluctuation, the lowest channels have the lowest SWR, and only channels 35-40 go much over 1.5.

I had to take my Hi-Lift jack off my tire carrier to get an almost flat SWR. Both can sit next to each other but don't play well together. SWR with the old FireStik I have wouldn't budge the needle, can't get any better than that, but with the Hi-Lift in place it pegs the needle (I expected it to affect it). Even using my antenna analyzer shows almost perfect 1:1.

My 2 meter ham radio antenna is mounted in the middle top of the windshield. Now I just have to figure out how to get my IC-706MKIIG mounted in the Bronco as well. Luckily I can move the remote display wherever it fits to be mounted. Wish I could use it on 11 meters (CB frequencies) then would only need one radio., well that and GMRS/FRS freqs as well.

Hey booger, call summit radio. He will set you up to use your radio on an 11 meter set up!

I knew I was not making the best choice for location, I read some about antenna location & it all agreed with what you posted. I wanted a location I could leave on, even if I pull the hard top in the summer. I bought a 4' antenna and its 2' above the roof, so hopefully that will help. I'm guessing my set up will be ok for wheeling in small groups. But I'm always considering emergency situations, and getting the most range would be important at that point. I wouldn't mind bolting a shorter antenna through the front of my roof. It would be easy enough to pull the wire & remount the antenna to a tab on the roll cage if you removed the top. Good info for future upgrades.

Just so you guys know I have an off the shelf radio, antenna from radio shack, I cut rg-58 to the length I needed, mounted it low on the fuel rack on my rear bumper so it would clear the garage door, I've never tuned it and it works pretty well. I'm sure I won't get the same range as some but it does the job.

So one of the things I read at Firestik.com was that if your antenna is not vertical, it will affect the SWR tuning. Mine was at a bit on an angle, so I bent the mount straighter & now all my SWR readings are under 1.0.

Chad

Is there a lunar mission your guys are planning to command with these juiced up CBs ?

Zilla, you might want to get a NICE noise canceling mic. I am sure you are aware, that if you amplify a poor quality transmission, you get a worse quality transmission. With my new cobra 29 with a peak and tune from summit radio, it's still clear on the receiving end. Though he did show me some $60 orange noise canceling mic. It was a HUGE difference on the receiving end. It was like the difference between being 20 ft apart and 20 miles apart! I am going to mount this new cb and mess with my locations some, but I think one of those are in my future.

...the difference is HUGE huh! I can't wait to get mine mounted and see how bad it is with a loud exhaust, no top, and 37" mud tires. But I am guessing that I will be in for one of those too!

I once used my old 10 meter (CB frequencies are classified as 11 meter wavelength) ham radio to make a contact with someone in Brazil. 10 meter is a little higher frequency than the CB. Of course I was barefoot (at 25 watts). Antenna was a vertical antenna that I still have in the garage. Antenna was mounted on spare tire carrier and if I remember correctly I had the hardtop on the 83 Bronco at the time. It's remarkable what you can do with a clean setup even with low power. Oh and SSB too, AM not so good.

SSB has more efficient use of the transmitters power. AM broadcasts the carrier and both sidebands so the power is spread out over that entire frequency range. SSB eliminates the carrier (no intelligence in the carrier so it's useless to broadcast) and one of the sidebands (identical intelligence in both sidebands so why waste power transmitting both).