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coax

Captain Kilowatt said:
Nothing wrong at all with solid core coax cable such as LMR-400. You just have to select the type of coax cable for the specific use for which it will be used. You NEVER use it around a rotator or in any place where it will be subject to continuous flexing. I use Andrews LDF4-50 which is half inch heliax cable which has a copper coated solid aluminum core and it is better that LMR-400as for losses but much stiffer however I do not use it around my rotator or route it through walls up into the shack from the basement. I use something more flexible like Belden 8214 which is an RG8 type cable. LDF4-50 is used in hundreds of thousands of commercial installations without an issue. Once again the key is to select the cable for the use in which you intend to use it.
Click to expand...

Very true and acurate statements..But for the OP's aplication, I think it would
be a mistake to use it. (LMR-400)

Using LDF4 and running jumpers is good for a killer big VHF system with long
runs and all, and I'm sure you use the best connectors available.

I've seen guys run LMR-400 on their towers and jumper @ both ends with
PL259's and I can't help but get a kick out of it...and this was for VHF!!
Why worry about a possible impedance change from a "not perfectly" installed
connector. On modest runs just use a good quality/low loss coax cable that
will make the run in one piece, and last doing it.
 
Why can't a good amphenol pl259 be installed corectly on lmr400?? I have done it many times. They are the easiest connectors to put on lmr400. You can always get n-male or din male connectors as well. I don't run VHF or HF, but I know an n-male connector should work just fine with some good times microwave lmr400, or the lmr400uf as stated. Ldf4 is more for the big boys I guess you could say. Coax and connectors (ldf4) aren't cheap.
 
I am running lmr400 from times microwave, from antenna to radio. I use amphenol connectors (pl259's) and have no issues. I do have about 80ft of ldf4 laying around and all the connectors I will ever need. Get them by the box for work and always end up with extras from previous jobs. I was just joking when I said I was going to use it, I don't need to use the ldf4, but it's nice knowing I can.
 
And I don't have the base setup like most of you guys, my HOA sucks and have already given me a hard time about the dipole I had setup. Had to take that down and now am running an old A99 painted black. I know the a99's suck, but I have used mine to talk around the world on 11 meter ssb. I work out of town a lot so I spend most of my time in my mobile. That is where most of my effort has gone. Not to say I didn't set the antenna system for my base up correctly, as I have. I just don't use my base very often. It's there though just in case shit hits the fan.
 
Duster I use either my pc122XL, or magnum 257hp with the setup listed above. It's no award winner that's for sure, but does what I need it to do. I got the antenna for free and all the coax for free. So I am not bitching one bit. Though I know it's nowhere near what it could be, it works fine for my local and dx'ing.
 
I went with the times microwave lmr-400 because I wanted good shielding.
my lmr-400 has N-male connectors for the lightning arrestor and pl259 for the antenna and radio connections.
good connections everywhere.
 
That's my next plan is to install my poly phaser lightning arrestor. Have the parts, just have to put them together.
 
ahamoperator said:
Very true and acurate statements..But for the OP's aplication, I think it would
be a mistake to use it. (LMR-400)

Using LDF4 and running jumpers is good for a killer big VHF system with long
runs and all, and I'm sure you use the best connectors available.

I've seen guys run LMR-400 on their towers and jumper @ both ends with
PL259's and I can't help but get a kick out of it...and this was for VHF!!
Why worry about a possible impedance change from a "not perfectly" installed
connector. On modest runs just use a good quality/low loss coax cable that
will make the run in one piece, and last doing it.
Click to expand...


It depends on the routing of the cable I guess and less about an impedance bump because any PL-259 on ANY cable will have an impedance bump. You can't use LMR-400 above a rotator without it risking breakage. Some people don't like a stiff cable plugged directly int a radio antenna jack and I understand why. Lots of reasons to install a short piece of more flexible cable on the ends of lower loss cable just like I do with my LDF4.
 
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Captain Kilowatt said:
It depends on the routing of the cable I guess and less about an impedance bump because any PL-259 on ANY cable will have an impedance bump. You can't use LMR-400 above a rotator without it risking breakage. Some people don't like a stiff cable plugged directly int a radio antenna jack and I understand why. Lots of reasons to install a short piece of more flexible cable on the ends of lower loss cable just like I do with my LDF4.
Click to expand...
How much of an impedance bump?

Why can't you rotate LMR400? I've been doing it for 4 years without issue.
 
359 said:
How much of an impedance bump?

Why can't you rotate LMR400? I've been doing it for 4 years without issue.
Click to expand...


Depends on the exact quality of the connector and frequency used I guess. PL-259 connectors are what are classified as a non-constant impedance connector meaning that the impedance will vary over a wide frequency range unlike better connectors like type N or better. As for not rotating LMR-400, no solid core cable should be run past a rotator as the constant flexing as the rotator turns back and forth over time can stress the inner core and cause it to eventually break especially in very cold climates. It also depends on how you make the rotator loop as well. Too tight of a loop and it will flex a lot more whereas a loop consisting of a couple turns will only expand the loop a bit when it turns. It's one of those things that may never happen if you are lucky but why risk it. Finding a bad or intermittent connection like a break in the inner core is a monumental task when it is located at the top of a tower. Stiffer cable like LDF4 is stiff enough to actually place an additional load on the rotator itself while turning unless you are running a LARGE rotator like a Hygain TT2 or Yaesu 2800 etc.
 
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I've got probably 15' between the attachment points on the mast and tower, with a few feet of slack in it. I really don't expect any trouble, but if I have to lop of 15 or so feet, I have ~50' extra gathered in the attic.
 
Like I said in my first post, you run tbe risk of it breaking. I never said it WILL break. When it comes to climbing a tower to look for a cable break I prefer to take that part out of the equation.
 
I wouldn't take chances, especially on a beam setup. When I install antennas, I want everything to last. I'd hate to repair something that could have been prevented.
 
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Exactly my way of thinking. When I do an install I want to have as long a maintenance free period as I can get. I do climb but I hate doing it. The tower gets taller every year I swear.
 
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