What does it sound like when you have water in your feedline?

[blindfire]

Starting Tuesday of this week, I was getting ready to check into the MA RI Phone Net at 3978 KHz. About 3 minutes in, my noise level jumped to 30db over S9. Weird thing is, on 20m and 40m, my noise level is normal.

So, I don't know if it really is a feedline problem.

I haven't been able to shut down the house main to see if my noise is local, but just figured I'd throw it out there.

Gotta wonder if the retro encambulator is the problem.

Thanks guys

 

[CaseHardened]

.

(when you have nothing to add)

 

[AHM]

Starting Tuesday of this week, I was getting ready to check into the MA RI Phone Net at 3978 KHz. About 3 minutes in, my noise level jumped to 30db over S9. Weird thing is, on 20m and 40m, my noise level is normal.

So, I don't know if it really is a feedline problem.

Feedline problems usually sound something like this
(click waveform image to hear sample):


73's/AHM

 

[cockpitbob]

I don't think it's water in the feedline. If the connectors are plated with prefamulated amulite, when they corrode they can get noisy only on certain frequencies. Water in the feedline would screw up the SWR pretty good and I assume you aren't seeing that.

I would say it could just be natural QRN, but not if it went from OK to 30dB over all at once. Got an old hand held AM radio you can sniff around the house with?

 

[CaseHardened]

Watson Gear - It's always the Watson Gear.

(don't buy the Chinese ones)

 

[blindfire]

Feedline problems usually sound something like this
(click waveform image to hear sample):


73's/AHM

YOU BASTARD!!!!

Alright...you got me! And no...it doesn't sound like that!

Oh my god...I can't stop laughing. Thank you...I needed that!

I did check the SWR and it is higher than it used to be. I took the antenna down this morning and check the connectors at the balun and it didn't seem wet or anything, but I did shake the cable out just to be safe.

I did this just before I left for work. I'll re-run the SWR test when I get home.

Thanks for the tips and laughs.

 

[AHM]

YOU BASTARD!!!!

Alright...you got me! ...

My job here is done, hi hi.

I did check the SWR and it is higher than it used to be. I took the antenna down this morning and check the connectors at the balun and it didn't seem wet or anything, but I did shake the cable out just to be safe.

I don't recall what your connectors are, but note that PL-259/SO-239 are not intended to be waterproof. If they're not well-wrapped with Coax-Seal, electrical tape, etc., they will leak.

I have no idea how well they drain/outgas if left disconnected.

 

[blindfire]

My job here is done, hi hi.



I don't recall what your connectors are, but note that PL-259/SO-239 are not intended to be waterproof. If they're not well-wrapped with Coax-Seal, electrical tape, etc., they will leak.

I have no idea how well they drain/outgas if left disconnected.

Thanks, man!

I have some coax tape at home and will wrap it this evening. Also, a buddy has some silicon grease that I'll use as well.

 

[drgrant]

Starting Tuesday of this week, I was getting ready to check into the MA RI Phone Net at 3978 KHz. About 3 minutes in, my noise level jumped to 30db over S9. Weird thing is, on 20m and 40m, my noise level is normal.

So, I don't know if it really is a feedline problem.

I haven't been able to shut down the house main to see if my noise is local, but just figured I'd throw it out there.

Gotta wonder if the retro encambulator is the problem.

Thanks guys

Unless you're running air dielectric Heliax or 9913 it'd be tough to get water in there. I used to run 9913 solid core air dielectric (hell I still think I have some on a spool) but eventually I did have a line that got polluted, when I cut the end off it many years later water came dripping out the end....

-Mike

 

[blindfire]

Unless you're running air dielectric Heliax or 9913 it'd be tough to get water in there. I used to run 9913 solid core air dielectric (hell I still think I have some on a spool) but eventually I did have a line that got polluted, when I cut the end off it many years later water came dripping out the end....

-Mike

Yeah...not sure. Dumb question again...but if the feed line had a few twists/kinks in it, could that alter the impedance of the feed enough to alter the SWR? I went out last night thinking some critters went to town on it, and noticed instead that I had 4 or 5 good kinks in it. I straightened the line out. Between that in taking the antenna down and disconnecting/reconnecting, the noise level is back down at S4 or so...as of this morning.

I'll check the SWR when I get home to verify and also see if static is back. If is, then I'm guessing it is something in the neighborhood.

Wish me luck

 

[Matt80]

Yeah...not sure. Dumb question again...but if the feed line had a few twists/kinks in it, could that alter the impedance of the feed enough to alter the SWR?

Depends on how tight the kinks are. IPC spec for cable dress requires a minimum bend radius of 5x the coax cable diameter. Getting too tight of a kink can cause center conductor migration due to dielectric deformation. What size coax are you using?

 

[CaseHardened]

Depends on how tight the kinks are. IPC spec for cable dress requires a minimum bend radius of 5x the coax cable diameter. Getting too tight of a kink can cause center conductor migration due to dielectric deformation. What size coax are you using?

Double-D is my preference.

When paired the performance is amazing.

 

[blindfire]

Depends on how tight the kinks are. IPC spec for cable dress requires a minimum bend radius of 5x the coax cable diameter. Getting too tight of a kink can cause center conductor migration due to dielectric deformation. What size coax are you using?

Using LMR400.

So, I do have some results to report.

1. I was home today and I killed the power to the house. Radio shows S9 noise level at 75m...3978 KHz
2. When power was turned back on, shot up to 30db over...so I know I have noise somewhere in the house....
3. BUT...there is also a shit ton of noise from my neighbors. Neighbor across the street does have solar on his roof. His house is about 250' from the end of the dipole. If it is his inverter causing the noise, shouldn't the static go away after dark?

I'll roam the house tomorrow with a portable AM radio and see if I can find any big sources or noise. This sucks.

 

[cockpitbob]

Did your neighbor just get a new plasma TV or something similar?

 

[blindfire]

Did your neighbor just get a new plasma TV or something similar?

That I don't know. I'll break into his house while he's gone and see. Don't talk to my neighbors all that much. Though, one of them is pretty cool. Electrical Engineer that digs the fact that I've got my antenna up. He works for APC designing network boards for their UPSes.

The other one, I don't really know all that well. He and his wife moved in a few years back.

Odd thing is...today, with the main power on at the house, I'm at S9...so something is not turned on right now. Will keep an eye on it and see when it spikes. I'll then run outside and see if anything is running or anything obvious is going on.

 

[slap shot]

.

(when you have nothing to add)

Idk but this is what it sounds like....


when doves cry

[video=youtube_share;RQAKjkXDHQM]http://youtu.be/RQAKjkXDHQM[/video]

 

[blindfire]

It's gota be a plasma TV.

Will see if my next door neighbor just got one.

Queston is, what do I do if he has a plasma TV? Shoot it?

 

[MisterHappy]

your problem has been diagnosed:

https://xkcd.com/730/

 

[AHM]

Oh, and P.S.

Starting Tuesday of this week, I was getting ready to check into the MA RI Phone Net at 3978 KHz. About 3 minutes in, my noise level jumped to 30db over S9. Weird thing is, on 20m and 40m, my noise level is normal.

​

---

Yeah...not sure. Dumb question again...but if the feed line had a few twists/kinks in it, could that alter the impedance of the feed enough to alter the SWR? I went out last night thinking some critters went to town on it, and noticed instead that I had 4 or 5 good kinks in it. I straightened the line out.

Depends on how tight the kinks are. IPC spec for cable dress requires a minimum bend radius of 5x the coax cable diameter. Getting too tight of a kink can cause center conductor migration due to dielectric deformation. ...

This is an application for feature-laden antenna analyzers with a cable-length measurement mode (or PDP-11 Qbus Ethernet boards w/ onboard time-domain reflectometers (which have other applications)). If the meter measures the cable as shorter than reality, the kinks may be making a significant contribution to lossage.