First Antenna Dilema

[Anonymous]

Hello Elmer’s,

I sat in on yesterday’s boot camp and passed my Tech and General exams last weekend.  The boot camp was very helpful and made me think I should build my shack around what I can do based on the antenna that fits my property, with consideration for my wife and neighbors.

I live in a single story home covered with solar panels  on a small plot of land that is mostly used up by the buildings. I don’t have any suitable trees above 20’ – 25’. I think I can fit a multi band inverted V dipole if I can attach a pole to a rear corner of my house to serve as the high spot for an inverted V dipole.  How close can I put the pole to solar panels?   Fiberglass or metal poles?  How far do the antenna wires need to be from the house or metal fencing?  Do the legs of the dipole have to be perfectly inline across the horizontal axis?  I’m open to any suggestions including going a different route if the dipole won’t work in my situation.

Thank you

Bob

 

 

[Burns FISHER]

Hi Bob,

There is another topic here about solar panels that you might want to review. (https://www.n1fd.org/forums/topic/rooftop-solar-and-rfi/) I also have solar panels and have no problem although I am essentially always on only VHF and UHF for satellites.

My understanding is that the main RF noise-maker is the micro-inverters, string inverter, or optimizer, with the optimizer being the worst.  So whether you need to worry about the panels or your box inside for RFI depends on what sort of inverter is where.

I can’t help with the other parts of your question.

[Anonymous]

Thank you for the solar information link this will help.

[Hamilton]

Hello Bob,

Congrats on the licenses.

The height above the ground of an HF dipole (straight wire, inverted V, Yagi) determines its pattern.

At 1/2 wave high it will have a fairly low elevation angle and a directional figure 8 azimuth pattern making it good for DX but poor for local and regional QSOs.

As the height is reduced to 1/4 wave and below the main beam of a dipole will be nearly straight up and the azimuth pattern will be omnidirectional. Since it is omnidirectional (non-directional) the orientation is not a factor. This is good for local and regional QSOs, but poor for DX.

1/2 wave on 40m is 66′ but on 20m it is only 33′.

Propagation isn’t completely predictable, occasionally you can have a DX QSO with a low antenna or work the next state with a higher antenna. I have a 40m wire antenna at over 1/2 wave high and can rarely hear a local net control or log an adjacent state during 13 Colonies or the NE QSO party but can log CA or Europe most days and VKs and Japan in the mornings when conditions are fair to good…

Step one is to get an antenna up. If 20′ is the limit for now it will be interesting to see how it performs. In the future, you might consider a 50′ fiberglass push-up mast with inverted Vs or lightweight options like a spider beam. The key is to get something up and get on the air.

The legs of an inverted V can be 10 to 20 degrees out of the plane with minimal impact, especially if the antenna is low. It is easy to model using 4NEC2 (it is free) to see the predicted performance. Several of us can help you get started. It is fun to design and model an antenna and then verify it on the air.

I have done a number of Antenna installs within 30’ of solar panels and only one had a noise problem. I would “sniff” the solar panel with a portable AM or AM/SW radio for starters.

73

Hamilton  K1HMS

[Anonymous]

Thanks, Hamilton this puts me on a good path to get started.  Maybe I can strap a fiberglass pole to one of the trees to give me the height until I can do something more permanent?  Now onto finding a rig.

Bob KC1PEZ

[Author]

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