Radio "tuning"

[BuffaloJustice]

So I bought a cobra 29 about 8 years ago for off roading. One of our drivers told me to take it to a shop and have it tuned. So I took it in, gave the guy 20 bucks and he went to work spacing some coils and adjusting this and that and boom the thing was hot hot hot. Between that and the wilson 2000 I was regularly getting out 30 plus miles in the SW Missouri hills, and getting great audio reports to boot.

So the question, what exactly is a tune job? Is it just adjusting the components to proper parameters inside the radio, like fixing the inconsistencies from the mass production line? Or are they jacking the output power up internally? Just something I wander about from time to time and this forum brought that back up.

As a side note that radio was a great little rig, even before the tune job. It had great clear audio and I got great audio reports back. With a noise canceling mic I was able to use it on the highway with the top off the Jeep. When a group of us would hit the trail I became the "relay station" many a time since the others were using X-Mart crap. I went to hook the thing up last summer after a few years of it sitting around and now it won't hold SWR for anything, I was kinda sad actually.

 

[mancow]

SWR mismatch is a result of a problem in the antenna or feedline.

 

[BuffaloJustice]

I used a new antenna and feedline, I guess I should have checked the cable. It has the SWR calibration knob so I guess I thought something with that was bad. I did contemplate a BFH job but thought I might have it looked at before I went to jarring it around to much.

 

[mancow]

I suppose something could be wrong with the built in SWR metering but I would definitely check the antenna and feed first.
Does it still seem to work ok even though the SWR is reading high?

 

[BuffaloJustice]

It picks up ok, not like it used to but then again I wasn't using it much since I didn't have an external speaker on it, Wranglers aren't known for their super quite highway travel. I went and grabbed an SWR meter from Rat Shack to make sure it wasn't just the radio meter messing up. I didn't transmit since it was all over the board. I may throw it back in but I've got the 2 meter rig as soon as my call sign posts. Although as I typed that my more bull headed side chimed in so I may do it just to do it.

 

[freqs]

So I bought a cobra 29 about 8 years ago for off roading. One of our drivers told me to take it to a shop and have it tuned. So I took it in, gave the guy 20 bucks and he went to work spacing some coils and adjusting this and that and boom the thing was hot hot hot. Between that and the wilson 2000 I was regularly getting out 30 plus miles in the SW Missouri hills, and getting great audio reports to boot.

So the question, what exactly is a tune job? Is it just adjusting the components to proper parameters inside the radio, like fixing the inconsistencies from the mass production line? Or are they jacking the output power up internally? Just something I wander about from time to time and this forum brought that back up.

As a side note that radio was a great little rig, even before the tune job. It had great clear audio and I got great audio reports back. With a noise canceling mic I was able to use it on the highway with the top off the Jeep. When a group of us would hit the trail I became the "relay station" many a time since the others were using X-Mart crap. I went to hook the thing up last summer after a few years of it sitting around and now it won't hold SWR for anything, I was kinda sad actually.

Try this check that the antenna is getting the proper ground if its not that will make the swr to go nuts. rust on the mount or the bolts will kill the ground or you off road you could have bad coax from water or something came up and cut the coax ( i dont know how you have it run maybe under the jeep)just take the mount off clean the bolts and mount and the holes the bolts go in from rust try that first .and like was said that swr in the radio maybe bad as well

 

[James04TJ]

Where and how do you have the antenna mounted on the TJ? A TJ is not the easiest vehicle to get a good ground plane on. When my TJ was in one piece I had a 4' firestick mounted to my swingaway tire carrier/bumber. I ended up grounding the coax braid out to the frame and SWR was greatly improved (1.3:1 from 3:1). Placing it on top the tire carrier also got it up and away from the tub.

 

[BuffaloJustice]

Well for the new 2M rig I bought a tail light bracket from Quadratec and reamed the hole to 3/4". If I put the CB back in I will get one for the other side. I had half a mirror mount attached to the back of the 3d brake light bracket but after a few years the bottom of the light bracket cracked presumably from the stress of the antenna whacking trees off road. Now I don't trust it to hold up. I had the mount grounded to the frame to be sure it was grounded. Mine's a '94 YJ with AC, which is an aftermarket unit even if equipped from the factory. That unit takes up a lot of real estate in an already cramped interior. It's commin out eventually and I will do the compressor mod when it does. This will get me on board air as well as free up a great deal of space under the console. I have thought about the Tuffy overhead console for the radios but I'm still not to sure.

BTW, beautiful TJ. Mine needs some serious TLC, both functional and cosmetic. It's been places a stock Jeep should never have been, and she always loves it.

 

[BuffaloJustice]

Oh yea I forgot about the tuffy center console. I may put the 2M in that but then I have to relocate the stereo back to it's original spot, which took me a couple of hours to move to the console in the first place. I put the CB on the back of that last summer, but 1. It's a horrible spot if you need to adjust anything and 2. the kids hit it with their feet making frequent adjustments necessary. When I get a remote head radio I will put it inside the center console.

 

[James04TJ]

I had a Tuffy center stereo console as well. I tried the Tuffy overhead console but didn't care for it. I would hit my head on it when off camber. I had my stereo in the Tuffy console and had my dual band rig installed flat under the stereo with the remote head mounted to the front after market roll cage (Toys by Troy). I just took a 1/8" piece of steel to run between the front spreader bars of the cage and mounted the CB to that. I had a cheap Radio Shack CB so I considered this as disposable.

You can mount a lot to an aftermarket front cage if you install one and I would highly recommend one anyway if you wheel. It is well worth the investment.

 

[BuffaloJustice]

My baby is in no shape for anything serious at the moment. Unfortunately this is my daily driver so I can't get to crazy with the repairs right now. I've got some motor troubles and the springs are done, on the plus side when I get enough time for the springs she'll get a little taller as well. Downside, motor first.

 

[motorola_otaku]

To answer your original question, "peaking" or "peak and tune" usually entails two things:
-Removing the modulation limiter
-Cranking the TX power up to whatever the final amplifier is capable of

Both of those will void the radio's FCC certification and make it illegal to operate, but as you noticed they do make a big improvement in how well people can hear you. However, most of the improvement is perceived; meaning that since everyone else uses similarly-modified radios, someone who doesn't is going to sound weak or distant.

 

[125]

I was going to ask who has a CB that hasn't been "tuned up" I only know of one and he is "10-9" everyone knows this guy!!!! "He don't git out" His radio aint got no condition" (Oh man I have stop!).

 

[BuffaloJustice]

I was going to ask who has a CB that hasn't been "tuned up"

Most of the CB'rs I know don't have their radios tuned, of course most of them are using the little black boxes from x-mart.

Thanks, I was wondering what he was doing in there. The perception thing makes sense. Funny that it's illegal yet 99% of all over the road rigs are done up.

 

[zzdiesel]

Did any of the real hardcore CBers care about what the FCC CB rules said?

 

[kb2vxa]

"-Removing the modulation limiter
-Cranking the TX power up to whatever the final amplifier is capable of
"...but as you noticed they do make a big improvement in how well people can hear you."

Please explain how over modulation and driving the final closer to class C operation and out of the linear portion of it's operating curve further increasing distortion may improve communications effectiveness?

 

[zzdiesel]

Back in the day; most CBers wanted to squeeze evey ounce of power they could. I was like that for a long time till I realized that it was splatter and all that other nasty noise.

 

[wesct]

"-Removing the modulation limiter
-Cranking the TX power up to whatever the final amplifier is capable of
"...but as you noticed they do make a big improvement in how well people can hear you."

Please explain how over modulation and driving the final closer to class C operation and out of the linear portion of it's operating curve further increasing distortion may improve communications effectiveness?

Well, it goes like this:

I have a new car. The maximum rpm for the engine is 6,000 rpm.
Maximum torque occurs at 4,800 rpm.
If I drive that engine to lets say 7,000 rpm, it will go faster, but I might leave pieces of the motor all over the ground. And it will cost me alot of money.

Same thing for your cb radio.

The radio is DESIGNED for a 4 watt carrier and 95% modulation. If you "peak it out" , the radio might get out a little further, but everyone will hear you on all 40 channels. This is great for the radio repair man because you want the MAXIMUM- be prepared to pay.

Just to let you know, you have to go 4 times the power for 1 s-unit of signal increase, so the radio will have to do a 16 watt carrier and FULLY modulate it as well.

Best thing to do- make the antenna do the work for you.

wesct

 

[W6KRU]

Just to let you know, you have to go 4 times the power for 1 s-unit of signal increase, so the radio will have to do a 16 watt carrier and FULLY modulate it as well.

Best thing to do- make the antenna do the work for you.

wesct

Heh heh. I can run my 857 @ 100 watts but I don't. I have it set at 80 because I know it will never make a difference. It's all about antenna and propagation.

 

[kb2vxa]

Heh, you guys sure have a knack for stating the obvious. (;->) Another way of stating the obvious is 90% of the shack is on the roof or in other words a better antenna also improves reception. Trouble is, try explaining "if you can't hear 'em ya can't work 'em" to certain thick heads we called alligators, all mouth and no ears. Heh, nothing like having a QSO interrupted by a dummy yelling "Breaker breaker, is anybody out there?" and thinking to yourself "Yeah, you're out there now go away!"

That reminds me of a tale of years gone by when High Pockets was the king of Ocean County until Thunder Base came along. Never mind what WA2V and myself were using besides drugs, it's a trade secret but I will tell you it had something to do with a home brew 3el Yagi and a low noise VFET front end receiver. We were talking to Bus Driver in Atlantic City when HP came on wondering if we were "ghost talking" and it all went downhill from there, for him. He had stacked 3s on a 50' tower and couldn't hear him so he cranked up his 100W leenyar and shouted his head off. Bus Driver came back to him only to get stepped on time and time again until he gave us a message for High Pockets, I won't repeat the words here. I relayed a toned down version leaving the horse he rode in on out of it, you can imagine the magnitude of the shock waves when an alligator head explodes. (;->)

The moral of the story is Bus Driver heard him before he upped the power but we let him pull his hair out anyway so if you should hear an LDE from the Jersey Shore beware, you're about to get goofed on.