Help with Cobra 148 GTL ST

[jonah]

So, I picked up this CB today off craig's list. It didn't come with the power cord, so I went to radio shack to get one. The CB has three pins, the plug has three holes, but only two wires, is this correct?

The plug had the 148 GTL listed as compatible, I don't know if the ST is any different in the plug area.

Thanks!

[EricMCJ5]

Here's some info on the radio:

http://www.cbtricks.com/radios/cobra/148gtl/index.htm

The schematic diagram shows only 2 pins are used:

http://www.cbtricks.com/radios/cobra/148gtl/graphics/cobra_148gtl_sch_b_size.pdf

[jonah]

OK, I see it now. Thanks!!

[chris142]

The plug should only go in one way.

[jonah]

Yes, it is the standard plug with the one end that is pointed. I actually just fired it up a few minutes ago and it looks like it is working fine. I did a quick SWR check with the magnetic base whip antenna it came with and was about 1.3 or so (just sitting on the shelf in my shop. Hopefully tomorrow I will get it mounted in my jeep and see what is what...

My first CB, any advice is welcome.

Thanks!

[chris142]

My first CB, any advice is welcome.

That radio has SSB which you probly will never use. Most 4x4 runs use AM channel 4. Channel 35 through 40 is used by the SSB guys and theres a non written agreement that the AM guys won't talk on those 5 channels and the SSB guys wont go below channel 35.

Where are you mounting that monster of a radio?:D

[jonah]

Man I don't know, because it is huge. My thought is to mount it to the back of the center console (after I build it). My only concern then is being able to hear it. I could put it on the "b" pillar hoop but it might be a head knocker there.

I was about to get a little unidens, but when this came up on Craig's list I couldn't resist - lights, dials, meter, shiny chrome face....:drool:

Thanks for the channel info, I had no idea.

[chris142]

I built an overhead mount for my CB. This pic is a Galaxy 99 and it's the same size as your 148. This is the only place I could find for it.

I really like it up there. The speaker is pointing down so hearing it is not a problem.

http://i60.photobucket.com/albums/h3/spoink142/0906001718.jpg

http://i60.photobucket.com/albums/h3/spoink142/0906001717.jpg

[chris142]

My thought is to mount it to the back of the center console (after I build it). My only concern then is being able to hear it. I like looking at mine. But if you mount it somewhere out of the way You can buy an external speaker that will plug into the back of it.

Any truckstop will have the speaker as well as online places.

http://www.copper.com/cart/product_info.php?products_id=528

[jonah]

Yeah, I like the idea of being able to see it. I could fab something up to make it go into that area. Probably a couple of tabs off the "A" pillar hoop would do. I need to take a look at it. One issue is that I don't have a top, so having a way to keep it out of the weather would be good, not to mention security issues.

[Matt2001TJ]

That radio has SSB which you probly will never use. Most 4x4 runs use AM channel 4. Channel 35 through 40 is used by the SSB guys and theres a non written agreement that the AM guys won't talk on those 5 channels and the SSB guys wont go below channel 35.

Where are you mounting that monster of a radio?:Dif you can find anyone left on ssb on those channels is more like it. 38 lower was most common and in the 23 ch. days it was 17 on sideband. Lots of mods can be done to that radio to should we say enhance it's performance and then some. Either way, As for mounting I used a ratchet strap to mount my DX radio or my 148 based radio to the passenger side of the factory speaker/rollbar assembly in a TJ as noted in the pic for the purpose of simplicity.

http://i47.photobucket.com/albums/f159/jeeptjrockcrawler/Galaxy88.jpg

[chris142]

Fire in the wire! I've got a 250HD under my rear seat.;)

[Matt2001TJ]

Fire in the wire! I've got a 250HD under my rear seat.;)Ya,... I used to run a Texas Star HD 250 also. It was my driver amp for my Texas Star "Sweet Sixteen".....ah,... the old days of hell....the stories I could tell...

[jonah]

On going saga....

It seems that my radio only wants to transmit in LSB. When I go to AM others can hear the mic key and a very faint transmission. When I tuned the antenna with the built in meter I got 1.5. Now it is a little over 2, but the meter is acting funny (won't go down to zero ever, even messing with the calibration knob, or when turned off). Is it time to take it to a shop? Throw it out? Smash it with a hammer?

[chris142]

Is the mic gain turned up?

[jonah]

Yes, tried the the entire range. When turned up all of the way, others could pick up a faint transmission.

[chris142]

Did it ever work on AM?

[jonah]

Nope, not since I have had it.

[chris142]

Well we have a decient CB guy in Hesperia at the Pilot truckstop.

I wonder if you lost a ground on the antenna end?

[jonah]

I am using a magnetic base antenna that came with the radio. When I first hooked it up and tested the SRW it all looked good, but then it just didn't work. I guess I have to take it in.

I was just thinking. People with AM CBs shouldn't have been able to hear me on the LSB should they? I am not sure how that works, but it was coming through loud when I transmitted on LSB.

[chris142]

If you talk on SSB and somebody is on AM all they should hear is garble.

Back when CB was new the radios could be damaged by having too high of an SWR. Later on the manufacturers(sp?)added a circut that dropped the output power if the SWR is too high.

I'm wondering if your SWR is off and it's cutting the output power. But that does not explain why they heard you when you were on SSB.

[jonah]

Hmm, it did sound a little garbled, but you could understand it. Maybe I should get my hands on a real SWR meter and check. Perhaps the built in meter is way off.

Or take it in...

Thanks for the trouble shooting!

[chris142]

Did the guy that you bought it from say anything about it being modified in any way?

[jonah]

No, he said like he knew nothing about the radio. I wish I would have checked it earlier, but when I powered it up it all acted normal so I thought I was good.

[chris142]

Well keep us posted. I'm curious to find out what the fix was.

[jonah]

Will do. I think I might take it to the only shop within 50 miles (Torrance) tomorrow and have it looked at. It drives me crazy when things aren't working right.

[Matt2001TJ]

Is the mic gain turned up?Like he said,...And, do not trust the factory swr meter. Check it with a swr bridge inline. What kind of antenna are you using ?

[jonah]

Thanks for the input. I ended up taking it to the shop in Torrance. The mic was bad, the capsule was damaged which he said was unusual and that the mic must have been hit very hard.

While it was there, he tuned it up. He said it was running at about 80% of what the stock reading should be and he took it to 110%. So I just hooked it up, my SWR readings (with the built in meter) are still just over 2, I guess I need to get my hands on an inline swr bridge, to see what is really going on. But I need another CB to see if it is really working at all now.

[Nipple Twister]

Jonah, I will be home all day tomorrow if ya wanna do a radio test or I have a 148 that you can have for comparison purposes....they are great radios.

Lemme know, I'll check back here in the AM..



John

PS, I'm at Warner/Bolsa Chica

[Nipple Twister]

....was it Albert the radio guy you saw in Torrance?

[jonah]

That would be great to stop by tomorrow. I am surfing with my brother in law in the morning but should be finished by 11 or so. I will pm you my number.

Yes, it was Albert.

Thanks!
Jonah

[red baron 13]

So Jonah, did Ñip Twist help prove ur CB is good to go?

[jonah]

Well, he gave me some tips and another radio to test. But I haven't got around to actually testing it. I have been trying to get the magnetic mount to work and give me a decent SWR reading. It is ok on the hood, but I don't like having the antenna there, so I think I am going to get a regular hard mount antenna.

How is your jeep holding up, did you get everything sorted?

[red baron 13]

Workin on it. Got one leaf repaired; noticed other leaf has @ a 3/4 inch gap between axle and connector plate!! Trying to get that leaf off; the bolt connecting it to frame mount won't come out. Also, I had heard a sof thump when limping off trail--thought it was driveshaft rollin @ on floor. Uh no, I realized this week that the lower mounting bolt for front pass side shock is gone - the thumping was my shock swinging in the breeze! That's why me new saying above my avatar is "one bolt at a time" -- figure that's how I will do my re-build!!

[jonah]

Wow, that gap explains why you were getting the axle wrap. I kept thinking, how is that axle wrapping with spring under, 4 cylinder motor and 31 inch tires? It should never happen, now we know! Glad to hear you are getting everything tightened up.

Hope to see you out on the trail again soon.

[red baron 13]

Thanks, hope to be out soon. Neil (NeilByrd) is gonna help me Sunday - installing that Aussie Locker and tidying up a few other things. I'm excited to see how she handles after installing the re-furbed leafs. Amazed I made it thru Cleg and JV with that axle like it was. And, its a D35!!