Wednesday, July 23, 2014

Random Antenna Musings and Power Line Noise

As I have shared in the past I have a 66' dipole in the attic fed with ladder line.  I live in a HOA controlled neighborhood so my antenna options are pretty limited.

Last night I set WSPR up running 2 watts on 20 meters.  Started about 2200 UTC.  Wow it really seemed open.  My 2 watts was spotted multiple times into Europe, Alaska and all over the USA.  This antenna does not have a problem getting out.

The problem with my antenna setup is on receive.  I have minimum S5 noise on 40 and 30 meters.  Typically S7 on 20 meters.  Interestingly enough 15 is quieter and 10 meters is typically S2 or so.  The noise is static with some noticeable "crackling".

Last night on WSPR was a great example.  I was getting heard ALL over, but I was only decoding about 2 or 3 stations - all in the USA.  Also on PSK31 or JT-65 I see guys working DX that I can't even here or see on the waterfall - my noise level is just too high.

Sometime soon I am going to cut all the power to my QTH and see what the noise level is.  If significantly reduced, I will see what I identify as noise sources in my QTH.

Beyond that, less than a 1/4 mile as the crow flies I have identified some very noisy power lines.  They are so noisy that it they will completely blank the AM radio in your car when you drive past them.

Here is a picture of where my house sits in relation to the power lines (my dipole runs parallel to the power lines):

Blue marker is my QTH - Red line is power line (X's are noisy poles)
I will be contacting the utility company at some point, but first I want to see how much of the noise is coming from my own QTH.

I think the other problem with my poor receive performance is that fact that the antenna is in the attic.  I have been thinking about some solutions to get some wire outside the house to see if that can help.

I have to be very stealth, for both the happiness of the XYL and the HOA :)

I was thinking about setting up a long wire using the 9:1 UNUN that I use for my Portable QRP Antenna - only using trees and setting it up as an inverted L.

You can see in the picture below, I have 2 trees that are taller than my house.  The tree on the left, which is the front of the house will hold the vertical portion of the wire, and then it will run horizontal to the tree on the right, which is in the back of the house.  

Red markers are trees - red line would be horizontal leg of inverted L
I am thinking if I use like a 22 or 24 gauge grey wire it should be almost invisible.  The horizontal leg will be about 25' fee in the air.  All told I should be able to get about 70-80 feet of wire for the inverted L.

I will probably wait until the leaves drop this fall to make it easier to fish the wires through the trees.  I just wonder how much of a difference getting wire in the clear will make to my receive quality and noise issues.

I guess that's enough rambling for today.  If you have any thoughts I would be happy to hear them!


  1. Hi Burke,
    I have recently erected an inverted-L using some red 32 SWG wire that I was given many years ago. It is virtually invisible. I'm not sure it will last the winter but I reckon that it is not going to be a big deal if I have to replace it if it breaks. On rx the inverted-L had a very much lower noise figure than my G5RV. See
    73 Simon

  2. Thanks Simon - I am going to give it a try!

  3. Okay you got the trees to make that 4 band vertical. And try to keep the coax as short as possible. And put out as many radials as possible (33 ft if possible)
    The other problem with the dipole is height above ground. It's more of a cloud burner. High angle radiation. The dipole is seeing the ceiling as the ground. The vertical will give you higher angle of radiation.

    So keep me posted on how you make out with it.
    73 Shawn, N3TEE