eHam Forums => Antennas and Towers and more => Topic started by: KF5LQI on October 09, 2012, 06:37:21 PM

Title: Corner lot, high power lines, XYL issues
Post by: KF5LQI on October 09, 2012, 06:37:21 PM
I live on a small corner lot in an urban setting.  Along one side runs 50ft poles with transmission lines for the neighborhood (I'm totally guessing, but 69kV?). Along the back of the property is the typical neighborhood lines at 13kV on shorter poles.  I have a naturally occuring antenna tower (75ft tall pine tree) 20 ft from the 50 ft pole/transmissoin lines.  Probably not the wisest thing, but I had a 11ft UHF/VUF vertical mounted to the top of the pine tree fed with LMR600.  Awesome range with the Icom 910H and antenna height of about 80ft.  I do have concerns about hurricanes in Houston and the tree falling on the 69kV lines, but I guess if it does that would be the least of my worries. 

I also have an Icom AH4 tuner with a 52ft random 14ga wire run up the side of the same pine tree. Literally it is withing inches or touching the tree.  I only have 8 radials that range in length from 25-40ft based on the geography of the yard.  My HF performance is not what I would like it to be.  I'm running an Icom 746Pro with LMR400 to the AH4 at the base of the tree.

Towers and veritcals in the yard are out of the question for reasons that don't need to be hashed and re-hashed here.  I've briefly thought about a beam mounted on the adjacent pine tree, but that many large elements elevated near 69kV power lines makes me nervous.  I can string a horizontal wire from one of the trees to another tree (about 60 ft away) but it would run parallel to the 69kV lines. 

So here are the questions:

1. Does the random vertical wire running right next to the tree affect it's performance?
2. Can one expect significant improvement by increasing the number of radials on the random wire?
3. Should I be worried about mounting a beam or dipole on top of the pine tree in close proximity to the 69kV lines?  (the trees survived hurricane Ike, but I'm sure the wind could have blown the antenna down on to the lines.
4. Does grounding such as PolyPhaser, additional ground rods, etc. protect if the antenna hits the 69kV lines?  I could care less about the equipment, but I don't want the house to burn down.
5. Would a horizontal antenna pick up induction and prohibit good performance ,from the 69kV lines if it was parallel about 30 ft away?

Sorry for the long winded post, but any and all advice would be appreciated.



Title: RE: Corner lot, high power lines, XYL issues
Post by: W1JKA on October 10, 2012, 01:20:25 PM
     FWIW Dept. I have a tree hung vertical also, about 1 ft. away from the trunk and have no problems but I only run low power of 80w or less.With your tall pine tree is it possible to run a sloper dipole,windom or efhw to your house? My lot also has just the regular residential power lines,cable, phone ect. on 2 sides and I do not experience any type of interference even though one end of my windom is only 20 ft. away. Sorry I can't comment on your other questions.  Jim