not-so-happy HF antenna deployment/neighborhood CCRs

[mr_hankey]

i live in a new neighborhood where the residents are quick to anger over issues like unkept yards (yeah, n00bs)

anyway, i couldn't just drape my 60 foot HF longwire between my neighbor's house and mine, so i had to come up with a compromise: the attic install.

to further complicate matters, the attic wasn't "long" enough to drape the wire according to it's dipole design - like a "T", so it ended up as a "V".

i've looked at the SWR's and pick-up points and lobes of HF antennas like this and i'm sure i'm compromising something, but i can't tell what exactly.

anyway, i'm getting a strange noise in 11Mhz that sounds like a powerline or something (chukkachukkachukkachukka) and was wondering how much this might be due to the attic install...?

 

[blantonl]

Ahhh.... HF Noise.

There are so many items that can cause significant noise on an HF radio from the house. In order of noisemakers, the items that cause the most noise on my HF rigs are:

1. My 100Mb Ethernet Network, transfering files results in noise all across the spectrum.
2. Old CRT monitors blast noise all across the spectrum.
3. LCD Flat Panels are a little better, but...still very noisy.
4. Each of the 10 or so computers I own.
5. A/C compressors... very noisy
6. Refrig compressors... very noisy.
7. Powerlines outside that are poorly maintained.

In summary, just about everything that plugs into the wall seems to generate lots of noise in the HF Spectrum. The best options are to run coax to a long wire that is as far way from "civilization" as possible.

Lindsay

 

[mr_hankey]

good points.

my biggest concern was that PROXIMITY to the actual antenna (like Romex cable in the attic) might cause more interference than, say, the utility pole down the street...

should have gone with a 2-story house!

 

[Halfpint]

Just out of curiosity would you be able to put up a .WAV file of that noise?

 

[mr_hankey]

mp3 file of noise at 11Mhz

 

[wb5tey]

Lindsay presented a good list of things that can really make your monitoring difficult. I have two other things that will really eat you up.

1. The Ionic Breeze Air Filter - It generates hash well past 30MHz (I have one that has been unplugged for 2 years - and it works almost as well unplugged as it did plugged in)

2. Any lamp with a touch switch or dimmer. The one my wife has produces hash about every 50 KHZ from DC to daylight.

I have a short G5RV im my attic and depending on where the signal is coming from, it works 'almost' as well as the Carolina Windom (40M) I have up at 30 Ft.... Yes, I have CCRs too, but they have a loophole (he smiles) in them!

The point is that both work. Sure, the one in the attic is a bit noisier then the one with the birds sittin on it, but the bottom line is that if you only have one place to put an antenna, put the most wire you can up and enjoy monitoring! Do not let a bit of noise stop you. You can use the circuit breaker method of identifying what circuit in your house the problem is coming from and remedy it. If the problem is not coming from your house, there are some remarkable DSP units available there days.

Good luck in finding the noise source and good monitoring!

Randy - WB5TEY / Carrollton, TX

 

[k5xs]

I doubt the proximity tot he Romex is much of a culprit. As someone else said, there is a broad range of noise sources.

If you can power your receiver with a battery (or borrow a receiver that works on batteries), you could make good progress by flipping off breakers at your breaker box while you or someone else listens to the noise.

Common culprits I have found:

- Lamp dimmers
- Fish tank heaters
- Switching power supplies
- Flourescent light fixtures
- Heater/AC blowers
- Sewing machines
- Television sets
- Computer monitors
- VCR/DVD/Cd player displays (especially flourescent blue displays)

Good luck!

Bernie Skoch, K5XS
Arkansas

 

[mrjon]

Don't forget this culprit:

- Radio Scanners!

If I put my Pro-95 within 4ft of my Grundig, I get hash all over the MW/SW ranges. I've noticed that older scanners (those without alpha tagging and the requisite extra logic) do not create as much interference on HF or MW as my Pro-95, but they still generate some extra noise (and not just from the speakers!)

I'd imagine that the Pro-96 could wreak a little more havoc, but until I have one I won't be able to test that. :roll:

 

[kc4jgc]

After listening to the .wav file I noticed that it was very regular.
10 seconds on, 5 seconds off. Can you think of anything around the house or your neighbors' homes that may cycle like that?

Steve.

 

[mr_hankey]

sorry - i forgot to mention that was "dual watch" between 11Mhz and 8Mhz.

the noise in question is the "chukkachukkachukka" on 11Mhz.

after a week of this, i think it might be a compressor, so i'll be fooling around with the circuit breaker later...

 

[mr_hankey]

well, i've redeployed, with a different antenna, and have 1000% improvement!

also lost my webserver earlier this week, so the files that i've posted in this thread aren't there anymore...

still have a faint "chukka" on the 11Mhz frequencies, but i've done all i can to isolate the noise (circuit breakers off, etc) and it's seemingly not in my house...anyway, i'm back in business!

 

[Alain]

When I was living in an apartment in San Diego, I had "geometrically" fastened a 100' roll of stranded copper wire to the ceiling; first, around the perimeter of the ceiling and gradually winding it towards the center. Connected a short 8' length of Belden 9913 from the ends to the R 71-A.

Just goes to show, you don't need an elaborate or expen$ive antenna to get great reception...

Alain