| Author |
Message |
    
BW
| | Posted on Sunday, June 23, 2002 - 09:05 pm: | 
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I am getting ready to run my CB cable through the little grommet on the D2 back door. Of course the connector is too large so I must splice.
1. Can you connect the cut CB cable with a soldering iron like one would with "radio" copper wires?
2. If one did . . . would that degrade the quality of reception/transmission?
Thanks,
BW |
Al Oliveira (Offroaddisco)
| | Posted on Sunday, June 23, 2002 - 11:05 pm: |
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If you're going to do it just cut off the UHF connector at the end and pick up a new one at the rat shack. You should be okay. Just don't cut the cable in the middle.
What grommet on the back door are you talking about? I'm currently running my cable for my GMRS radio into the back door but I've been using the weather striping. |
BW
| | Posted on Monday, June 24, 2002 - 12:28 am: |
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Al,
A grommet exist behind the wheel carrier for the rear window washer. This is on a D2 not a D1.
Thanks,
BW |
Al Oliveira (Offroaddisco)
| | Posted on Monday, June 24, 2002 - 09:02 am: |
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Ah... I haven't looked behind my rear wheel. My antenna is mounted on the roofrack.
Al
'99 Disco II |
Paul D. Morgan (V22guy)
| | Posted on Monday, June 24, 2002 - 09:50 am: |
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BW,
To maintain water tight integrity of the outside connector; using a pair of dikes, I cut the connector on the CB side of the RG-59 cable.
I then routed the entire length through the vasoline lubed washer grommet; through the flex conduit between the back door and frame, behind the storage box, under the carpet all the way to the drivers seat.
After re-soldering in a new connector at the CB location, a SWR meter tune was performed to match my antenna to the CB.
Hope that helps....
I am off to Maryland now, I'll keep an eye out for Dwebber's.
Paul
'00 DII |
Paul T. Schram (Paulschram)
| | Posted on Monday, June 24, 2002 - 10:37 am: |
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Paul:
RG-59 has a characteristic impedance of approximately 75 ohms, and as a result, will not exactly match the 52 ohm output of your rig. RG-59 might be indicated if one were installing an inverted V, but not necessarily in a mobile vertical configuration.
Are you sure you didn't mean RG-58?
BW, you will need to buy a new RF connector, commonly, this is a PL-259, and you will need a reducer for the cable you are using. I believe that for RG-58 you will need a UG-174 reducer, but I could be far off on that one. Given all of the issues that can negatively impact the performance of your CB, make sure that you use a solder style, rather than some of the non-soldered connectors. A good discussion on how to install these connectors is available in the Amateur Radio Handbook that your library most likely has.
Paul |
p m
| | Posted on Monday, June 24, 2002 - 12:32 pm: |
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Al,
it is okay to cut and solder the coax cable for the 27MHz application. It will have as much effect on SWR as, say, two or three BNC connectors.
peter |
Paul T. Schram (Paulschram)
| | Posted on Monday, June 24, 2002 - 01:02 pm: |
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Peter, Peter, Peter...
I know this is your area of expertise (and education), but don't you think that given the circumstances we should take every step possible to maintain the integrity of this cable?
If one were to cut the cable in the middle, rather than replacing the connector, there are many questionable splicing devices that could be employed. Again, given the environmental conditions (little to no protection from moisture, flexing, etc.), and the likely non-existent maintenance of the cabling, don't you think it would be better to cut the connector and replace? Or perhaps cut the cable, put PL-259s on both ends and use an SO-238 barrel connector?
Also, I don't think that SWR is particularly of importance here as I am more concerned about efficiency of the puny 5 watts input of CB. Wouldn't the BNC connectors result in loss, rather than a mismatched antenna? You're probably right that at the low frequencies, the losses would be miniscule, compared to higher frequencies where RG-58 is practically useless for anything more than very short jumpers.
Paul |
p m
| | Posted on Monday, June 24, 2002 - 01:51 pm: |
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LOL Paul,
i could come up with quite a few questionnable splicing devices 
what i had in mind is a more or less neat splice, with soldered joint for both shield and core, and reasonably neat shrink wrap around the core joint and the entire splice.
but, at this frequency, the ugliest electrician-type twist splice will do the job as well. No, BNC connectors will not result in any loss; as any other RF connector, they will introduce a very short in length disruption in impedance, and therefore a little change in SWR.
BTW, SWR is exactly as important as power input/output of a CB transceiver. That is, with SWR more than about 2 the transceiver won't be able to produce 5 watts at all.
speaking of RG58, it works really fine up to 2.4GHz. There are different varieties of it, limited by choice of dielectric, quality of inner conductor and shield, and O.D. of the cable. There's an excellent table with all RG coax cables listed at Belden's website -
http://bwcecom.belden.com/college/Cable101/coaxrefc.pdf .
peter |
BW
| | Posted on Tuesday, June 25, 2002 - 08:13 pm: |
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Well,
I went to the rat shack and was "schooled" on how to do the job. I bought a Non-Soldering connector from the shack(did this before I saw your advice Paul) and installed it right away.
Now my radio sounds like crap. I can barely transmit and can not receive.
I did solder the Non-Soldering connector hoping that would solve the problem, but it didn't.
This pisses me off. The radio sounded as clear a a cell phone prior to the cut.
I'll try it one more time, then back to the shack if no success.
BW |
p m
| | Posted on Tuesday, June 25, 2002 - 08:39 pm: |
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BW,
when you chop the coax cable, sometimes the strands from the shield sneak up into the core connection and short it out.
non-soldering connectors are junk, don't bother with these. they may work, but they will crap out, sooner or later.
peter |
Al Oliveira (Offroaddisco)
| | Posted on Tuesday, June 25, 2002 - 09:20 pm: |
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BW, Did you check the SWR after the splice?
Peter, on anything higher than 400MHz RG58 is junk unless you're talking short runs. Even then RG58 gives you too much loss at anything over 800MHz. But at 27MHz it's fine. At 100' runs RG58 gives you over 2db loss in the CB range but at 900MHz you get 16db loss! That's like swapping your discos engine for a 4cyl VW Rabbit engine and saying it's just fine. |
BW
| | Posted on Tuesday, June 25, 2002 - 09:56 pm: |
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I don't have a SWR meter to test it with. The CB was SO clear before I cut it, I didn't see the need. I really didn't want to buy something just to confirm the reception was near perfect.
Now, I might have too. How much is too much for an SWR meter.
BW |
BW
| | Posted on Tuesday, June 25, 2002 - 11:28 pm: |
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I gave it another try. This time I noticed that the male end of the new connector probably wasn't going up far enough. I had only hand tightened the previous time. So, I got it on there REAL snug this time. It's working really nice now.
My only complaint is the feed back I'm getting when operating the windows or even sometimes the turn signal. I used the sunroof wires overhead for power.
I've read on a thread before that the recommended technique is to wire the cb radio directly to the battery.
Is this the best option to eliminate the feedback?
BW |
Al Oliveira (Offroaddisco)
| | Posted on Tuesday, June 25, 2002 - 11:30 pm: |
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Like anything else the more you pay the more you get but you can pick one up for about $10 bucks if you want to ball park it. You might even be able to borrow one if you ask someone at a radio shop. Be sure to pick up a very short cable to go between the SWR meter and the radio too.
Also check the connection you made like Peter said to rule out a short. Even if the reception is clear without a SWR meter you have no way to tune your transmission. So you could have a situation where you can hear but no one else can hear you. I was on a trip with a few vehicles and one of the vehicles could hear everyone but other than the truck right in front of him no one could hear his rig. His transmission range was about 100 feet because his SWR was so bad. |
Paul T. Schram (Paulschram)
| | Posted on Wednesday, June 26, 2002 - 09:59 am: |
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Thank you Al. The attenuation was what I was referring to as far as RG-58 not being suitable for much over HF frequencies. Another problem with RG-58 is its inability to handle much more than a few hundred watts without melting the dielectric.
Peace,
Paul |
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