g5rv mini/rfspace SdrIQ

[SCPD]

Today i finally got the g5rv up on the roof (2 floors up) and i was using a peice of wire before in the same space the g5rv is in. I have it in an inverted v configuration and for some reason i get a ton of noise almost across all the bands. I had the g5rv at ground level and did not get any noise/rfi. Here are some pictures of HDSDR notice the vertical lines every 5khz or so. what am i doing wrong? im not using a balun/unun or anything like that. Just rg6u to the ladder line


Thanks
Mike

View attachment 33351
10khz

View attachment 33352
15khz

View attachment 33353
6khz

 

[KC1UA]

That is almost certainly noise from a router, as radiated by unshielded twisted pair cat 5 cable. If you can, try turning your router off and see if it disappears. It's not the router itself, it's the cabling that's acting like a giant antenna.

If it's not you it's someone very close.

The solution is shielded twisted pair cables. The equidistant spikes that are showing on the FFT are a telltale sign of this type of interference.

 

[SCPD]

Ok thank you. Now the thing is if its not my router than what what can i do to get rid of the rfi?

I will first try my router than see what happens

 

[KC1UA]

I'm guessing you're in an apartment building? If that's the case and your antenna is on the roof two floors up it may well be a neighbor, or a combination thereof. Then it becomes problematic. The onus is on them to fix the problem, but they're no doubt unaware of it entirely if they're not radio hobbyists. It's a tough situation. Hopefully you know them well and can work with them to solve the problem.

Just to be clear, it's NOT a WiFi issue, so if neighbors are purely WiFi you can probably cross them off of the list.

 

[SCPD]

i am in a building with about 7 direct tv dishes up on the roof along with my antenna. Should i just take it down and put it back at ground level in an inverted v config. This really sucks. I was so happy to finally get up on the roof and it was kinda a waste of time now.

 

[KC1UA]

I could be wrong but I doubt it's the dishes. Someone else with experience would have to comment on any interference being radiated from them, but I'd at least try to troubleshoot it a little. If it's you it's an easy and pretty inexpensive fix. If it's not you, then it gets tough. But, experimenting with antennas is fun stuff and this type of thing makes for interesting discussions and solutions. I know for a fact that you're not the only apartment dweller on RR with the problem; hopefully some of them can chip in and offer some suggestions. I know in my case just about all of my interference went away when I switched from UTP to STP cable.

Good luck; you'll win in the end.

 

[SCPD]

Well we have 6 units of 2 family houses here so if its not me then i will need to buy my whole block new stp patch cables this should be fun. The worst part is i bought 2 more monitors and another video card to have a 3 monitor config for my swl

lets see how well this goes and if anyone else can help.

Most likely its my neighbors but what would the range of utp rfi be. i dont mind buying them cables i just dont want to do it for a square block of houses


Thank you again Scott

Mike

 

[ridgescan]

Mike you have chordless phones? If you do, tune the rig to get that noise, put one chordless phone at the speaker-take the other chordless phone up to the roof to monitor with-and move the antenna or reconfigure it in an attempt to kill the noise while listening to the effects on the phone. I did this to determine how effective my ground to the fire escape was (which it turns out is VERY effective for rfi)
You can also try to locate a possible groundpoint at the roof and connect groundage using the phones to indicate results. Sometimes you have to hit the roof and try stuff.

 

[SCPD]

Ridge thanks for the advice. Now here is the weird thing. from 0-16ish i get the vertical lines every 5khz or so then it goes away for about 5 minutes than its back

here is a pic show clean reception
View attachment 33356


5 minutes later i get this
View attachment 33357

 

[brandon]

Is it possible to upload a recording of how the noise sounds in USB and AM mode?

I'm guessing probably some type of switching power supply or perhaps even an old TV/monitor.

Here is a good site with audio clips and screenshots of different noise makers
http://www.arrl.org/household
(other categories on the sidebar)

 

[SCPD]

Here is a new screen shot to match the recording

View attachment 33365

HDSDR_20110730_010331Z_13662kHz_RF.zip

That is the IQ data file
play it in HDSDR

 

[SCPD]

Thank you everyone for all your help and input. All fixed. It was a power line behind my house. I was in 3 rain storms just now moving my antenna and im good to go and happy as a pig in s**t



View attachment 33432

 

[brandon]

Hey Mike glad to hear that you found the culprit. It's always a good relief to find out noise sources.
I know exactly how you feel since going through it last year with that iPod Charger.