anyone having new LMR400 problems?

[speedway_navigator]

I got a 60' cut from Talley, my standard test is to put on a connector and do a DTF to make sure I got all I paid for.
For some reason I put a connector on both ends and ran a test, there is a fault at 15' or 45' depending on which end I test from.
This return loss looks crappy too, not the smooth sine wave I expect to see.

I was talking to a service manager a few minutes ago, he said his guys ran into the same issue on a PD station roof. The installed 4 antennas and the last
run of LMR400 had a fault in the middle.

 

[WB5UOM]

Lovely, I have just received a 125 ft run and a 100 ft run for a couple of projects. The 100ft is installed on top but not till Wednesday on bottom.
hope Im not jinxed...

 

[ramal121]

OK, I'll be paying attention now that you mentioned this.

On the other hand, is it me or are the Times EZ connectors a real bear to get pushed on now?

 

[Ubbe]

I have always told myself than anything below -20dB are acceptable. It's 100 times lower so in SWR it will be 1:1.01
Isn't those -30dB peaks what you get when you use a too narrow tiewrap around a coax?

/Ubbe

 

[merlin]

I would think the coax ha been kinked or bent smaller than the minimum bend radius.
My fix would be chop out the bad section and splice together with N connectors. there will be a little ripple at the splice, but no change in loss.

 

[jeepsandradios]

Gee now you have me wondering. Just had 1500' dropped off in my garage. Guess I need to do some sweeps. Mine are all spools of 500' so hoping its fine.

 

[AM909]

I got a 60' cut from Talley, my standard test is to put on a connector and do a DTF to make sure I got all I paid for.
For some reason I put a connector on both ends and ran a test, there is a fault at 15' or 45' depending on which end I test from. ...

Is there any apparent physical damage at that point?

 

[TampaTyron]

Not good................... we have been moving away from 400 and 600 due to PIM concerns.

TT

 

[Ubbe]

Not good................... we have been moving away from 400 and 600 due to PIM concerns.

TT

LMR400 are never used at comercial sites, I've never seen that in any of the maybe 50 sites I've been to, but for a hobbyist that never use two transmitters at the same time PIM isn't an issue.

/Ubbe

 

[speedway_navigator]

This is replacing RG-213 on a VHF single channel base. I hit the downtown site with a portable on this existing system which I
suspect has water intrusion.
I have not uncoiled the roll yet, going to email the Times folks to see if they want to inspect it or let Talley handle it. I want to keep it
as a training aid. Too bad this did not come 2nd day like I asked for and probably paid for, Talley sent an email wanting my resale tax ID number, I think that held up shipping.

This was waiting for me when I got home from teaching line sweeping at the EDMSSA training session.

 

[mmckenna]

This was waiting for me when I got home from teaching line sweeping at the EDMSSA training session.

Sounds like someones idea of a joke, or maybe it's a trap….

 

[TampaTyron]

LMR400 are never used at comercial sites, I've never seen that in any of the maybe 50 sites I've been to, but for a hobbyist that never use two transmitters at the same time PIM isn't an issue.

/Ubbe

Sorry man........ Here is the US, there is a significant lack of training and expertise in the subject. Everyone just uses whatever they think is correct. I am not even that good and people treat me like I am some kind of wizard.

However, it took me a lot of pushing before our org moved away from braided cable for repeaters. This is for a shop that maintains more than 700-800 repeater installs (some customers are more than 80 sites on their own). AND... I came from Motorola, where the Engineering standards are very strict. But, here in the business world, there is such resistance to change. TT

 

[AM909]

So what do people use for pigtails on both ends? I recently saw what would have been a 20' run of hardline with jumpers and service loops at both ends, use straight-through LMR400DB instead. Seems like a lot less opportunity for water intrusion to cause that oxidation and mixing. Or is it a noise/mixer when new (compared to what)?