I have just purchased USA made (Times Microwave LMR-400) a 50' length of coax with best PL-239 connectors which averages with shipping $75.00. Now the RG-58/U with usually less expensive 239 connectors totals at $25.00. I have had high SWR so I have bought a new antenna and figured I should get new coax not knowing what was causing my SWR problems because I bought only the lowest priced antenna and coax the 1st time. Has anyone experience comparing the 2 coax's RG-58/U Chinese VS. USA LMR-400?
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RG-58/U or the much more$$ LMR 400
- Thread starter hammer0630
- Start date
RG-58U if your running power you will lose a good amount before it goes out the antenna stick with the LMR 400
At HF frequencies, which 11 meters is, with 100 watts or less RG-58 is fine in runs of 50' or less. If you start running over 100 watts then 58 get very lossy. LMR-400 would be much better in runs over 50' or higher power operations.
It's all relative, and depends on how you are using it. LMR-400 has a definite edge over RG-58 at VHF/UHF. Depending on the length of the run, there honestly isn't much difference at HF. Some, sure, but not as much as most people think.
There are characteristics that come into play, power handling ability, losses per 100 feet, and ease of use (don't forget that one). That power handling ability is a real slippery one! If the load on the end of that coax is well tuned, any cable will be able to handle more power than it's rated for. If that load is not well tuned, then any cable will break down at less than it's rated capacity.
All coax cable has losses. When those losses become significant is when you should look for 'better' cable. Those losses are frequency related/dependent, it's not just the cable's length. Cable's behavior changes the higher you go in frequency (bands). What was just fine at HF may be terrible at VHF/UHF.
How about ease of use? The smaller sized cables are more flexible and easier to handle than the bigger stuff. It weighs less. If I had to move it very much I would certainly consider the 'smaller' cables before the bigger stuff. If I've got to remove vehicle body parts to be able to run the bigger/stiffer cable, guess who'z gonna opt for RG-58.
Oh boy! Then you get to consider cost. All things being equal (they never are though), I tend to use the less expensive cables. If one cable that may be marginally 'better' than another is three times the cost, I have to think I would have to do a LOT of thinking about that 'better' cable. If it isn't orders of magnitude better than the cheaper stuff, forget it.
You have to understand about how losses are measured. Usually they are measured in 'dB's. One biggy to keep in mind is that fractions of 1 dB are meaningless as far as you being heard or you hearing things. Until you get to about 3 dB you just aren't going to 'hear' a significant difference.
So... The original question. The LMR-400 cable is usually 'better' than RG-58. If I had to make a long run, more than a 100 feet of so, then I would consider it for HF. If it was for short runs, less than 75 - 100 feet, and if I wasn't running a lot of power (more than 200 - 500 watts) I'd still consider the LMR-400. If the run was less than that and if the power level wasn't a lot then RG-58 would probably be my choice. IF the only choice was between RG-58 and LMR-400 cable! There are a few more choices than that.
So are you gonna bang your head against the wall for going the way you did or not?
- 'Doc
There are characteristics that come into play, power handling ability, losses per 100 feet, and ease of use (don't forget that one). That power handling ability is a real slippery one! If the load on the end of that coax is well tuned, any cable will be able to handle more power than it's rated for. If that load is not well tuned, then any cable will break down at less than it's rated capacity.
All coax cable has losses. When those losses become significant is when you should look for 'better' cable. Those losses are frequency related/dependent, it's not just the cable's length. Cable's behavior changes the higher you go in frequency (bands). What was just fine at HF may be terrible at VHF/UHF.
How about ease of use? The smaller sized cables are more flexible and easier to handle than the bigger stuff. It weighs less. If I had to move it very much I would certainly consider the 'smaller' cables before the bigger stuff. If I've got to remove vehicle body parts to be able to run the bigger/stiffer cable, guess who'z gonna opt for RG-58.
Oh boy! Then you get to consider cost. All things being equal (they never are though), I tend to use the less expensive cables. If one cable that may be marginally 'better' than another is three times the cost, I have to think I would have to do a LOT of thinking about that 'better' cable. If it isn't orders of magnitude better than the cheaper stuff, forget it.
You have to understand about how losses are measured. Usually they are measured in 'dB's. One biggy to keep in mind is that fractions of 1 dB are meaningless as far as you being heard or you hearing things. Until you get to about 3 dB you just aren't going to 'hear' a significant difference.
So... The original question. The LMR-400 cable is usually 'better' than RG-58. If I had to make a long run, more than a 100 feet of so, then I would consider it for HF. If it was for short runs, less than 75 - 100 feet, and if I wasn't running a lot of power (more than 200 - 500 watts) I'd still consider the LMR-400. If the run was less than that and if the power level wasn't a lot then RG-58 would probably be my choice. IF the only choice was between RG-58 and LMR-400 cable! There are a few more choices than that.
So are you gonna bang your head against the wall for going the way you did or not?
- 'Doc
W5LZ very nice article. Well it sounds like the biggest difference in the two is how much the sellers of LMR-400 boast about what they are selling! I guess when you sell something comparative for 3X the money you have to throw a pitch about it. One thing that maybe true is it's possible the LMR-400 UV deterioration quality might be better? The common thing said comparing Chinese and USA made is the purity of the copper that Chinese quality control is not so good and this is true with nearly anything made in china. I am going to do a antenna install soon and don't want to have anything to do with it again "not as young or healthy" I did have a SWR problems and don't know what it was antenna or coax so I figured go with best you can find. This will be for a CB base and sometimes wattages upwards of 380 watts and am running 50' of coax to a new base antenna keeping my fingers crossed for low swr.
"...keeping my fingers crossed for low swr..."
There are always two 'steps' in tuning an antenna. First you make it resonant, then you match impedance with the rest of the antenna system (feed line and transmitter). It's not easy doing those two steps without one of them 'counteracting' the other, which depends on how you do the impedance matching. The length of the antenna determines resonance. If you adjust that length to get a good SWR, then you are also undoing that resonance thingy. Sort of self-defeating, isn't it? There are certainly ways of doing that SWR adjusting that won't destroy/modify the antenna's resonance. What are those ways? That depends on the antenna...
- 'Doc
There are always two 'steps' in tuning an antenna. First you make it resonant, then you match impedance with the rest of the antenna system (feed line and transmitter). It's not easy doing those two steps without one of them 'counteracting' the other, which depends on how you do the impedance matching. The length of the antenna determines resonance. If you adjust that length to get a good SWR, then you are also undoing that resonance thingy. Sort of self-defeating, isn't it? There are certainly ways of doing that SWR adjusting that won't destroy/modify the antenna's resonance. What are those ways? That depends on the antenna...
- 'Doc
There are lots of other cable to consider. And remember that not all RG58 is created equal. Times Microwave has a low loss series of RG58 class cable. The standard is pretty stiff, but they make an ultra flex version as well. There are RG8X cables as well. Standard RG8X only has a 2 db loss per 100' at 30 MHz. It can take a few hundred watts of power too. There is also LMR240 and LMR 240UF that can take a bit more wattage. What kind of install is this for? Is it a base or mobile? How far between your radio and antenna? How much power are you putting through it? These are all questions to consider.
You also don't have to buy the most expensive LMR-400 from Times. Many other companies like Jeffa Tech sell an equivalent of the LMR-400 for a much better price. The only difference is the braid will have slightly less copper in it that provides about 97% shielding. When combined with the 100% foil shield you still have 197% shielding and no issues with signal leakage.
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And just for grins. The last batch of LMR-400 I bought cost about $1.10 per foot including shipping. (100 feet, plus shipping to my door was $120.00 give or take a few cents. The cost of shipping to YOU may cost more, how can I say?) I'm in Oklahoma and the dealer was in Texas. That dealer is not a sponsor here so if you ask I'll tell you. Then you are on your own.
- 'Doc
- 'Doc
Touch Call...
Given only 50 feet and no major power..
The 58 should be Ok..
Myself though...
I prefer the better Stuff...
Have Both ability to handle power better if i wanted to in futrure.
Plus...even though one may be cutting hairs given 50 feet..
I would think..the lower loss cable will help you Hear better as well.
Since it does not seem to be an issue of Cost..
I would Stay with the LMR-400..
I have a run of 140 ft and even though not for high power..
I went with even Better then the LMR-400..
Given only 50 feet and no major power..
The 58 should be Ok..
Myself though...
I prefer the better Stuff...
Have Both ability to handle power better if i wanted to in futrure.
Plus...even though one may be cutting hairs given 50 feet..
I would think..the lower loss cable will help you Hear better as well.
Since it does not seem to be an issue of Cost..
I would Stay with the LMR-400..
I have a run of 140 ft and even though not for high power..
I went with even Better then the LMR-400..
- No one is chatting at the moment.
...runna pile-up on 6m SSB