Help with Proper Ground for Active Mini Whip Antenna

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ultravista

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I am in Las Vegas, NV, my soil is caliche (soil particles are cemented together by calcium carbonate (CaCO3)). It is nearly impossible to sink a ground rod.

Reading the many articles and blogs for the active mini whip antenna, it is only effective high outdoors with a proper ground. The antenna is RX only ...

My antenna mast ~6 meters high. The first 3 meters is a galvanized steel pipe; the last 3 meters is PVC plastic. The antenna is mounted at the top of the PVC pipe. The base of the mast is similar to the photo links below - powder coated steel legs and springs. It is meant to hold road signs on the highway - but is an excellent vertical stand for the antenna. It rests on concrete in the back yard.

This of course cannot provide an adequate ground.

What do you recommend I do to provide a proper ground for an active mini whip given the facts that my soil is cement-like?

http://www.powerpak.net/sign_stands.png

https://visiflashdotcom.files.wordpress.com/2016/12/dicke-stf-18-rgb.jpg
 

prcguy

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Most short active whip antennas for VLF/HF are considered an E-field probe and benefit from a ground plane right beneath them and not necessarily a distant ground rod. Here is an article from some people who are really up on E-field antennas and near the end of this article they provide suggestions on a ground for this type antenna.
http://www.arrl.org/files/file/Technology/tis/info/pdf/0109031.pdf
prcguy


I am in Las Vegas, NV, my soil is caliche (soil particles are cemented together by calcium carbonate (CaCO3)). It is nearly impossible to sink a ground rod.

Reading the many articles and blogs for the active mini whip antenna, it is only effective high outdoors with a proper ground. The antenna is RX only ...

My antenna mast ~6 meters high. The first 3 meters is a galvanized steel pipe; the last 3 meters is PVC plastic. The antenna is mounted at the top of the PVC pipe. The base of the mast is similar to the photo links below - powder coated steel legs and springs. It is meant to hold road signs on the highway - but is an excellent vertical stand for the antenna. It rests on concrete in the back yard.

This of course cannot provide an adequate ground.

What do you recommend I do to provide a proper ground for an active mini whip given the facts that my soil is cement-like?

http://www.powerpak.net/sign_stands.png

https://visiflashdotcom.files.wordpress.com/2016/12/dicke-stf-18-rgb.jpg
 

cmdrwill

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I have one of the older 'traffic sign' stands that I salvaged. Great antenna stands.

I would think a metal mast and some metallic guy wires from near the base of the antenna would make a good counterpoise. They would have to be long enough to be good at HF frequencies. AKA elevated counterpoise.
 

prcguy

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So Cal - Richardson, TX - Tewksbury, MA
An E-field probe works a little different than a larger HF antenna and an elevated chicken wire ground plane maybe 8ft X 8ft should be fine for the entire HF band plus VLF.
prcguy


I have one of the older 'traffic sign' stands that I salvaged. Great antenna stands.

I would think a metal mast and some metallic guy wires from near the base of the antenna would make a good counterpoise. They would have to be long enough to be good at HF frequencies. AKA elevated counterpoise.
 

ultravista

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An E-field probe works a little different than a larger HF antenna and an elevated chicken wire ground plane maybe 8ft X 8ft should be fine for the entire HF band plus VLF.
prcguy
prcguy - please explain the 8x8 foot ground plane. I can't picture it in my mind. Something, connected to coax ground, connected under the stand or elsewhere?
 

prcguy

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Picture your little antenna mounted to a vent pipe on your roof and low to the roof. Then arrange a couple of strips of overlapping chicken wire on the roof to cover an area about 8ft X 8ft under the antenna and attach that to the ground side of the coax at the antenna. Look at the picture near the end of the article I posted and it shows a similar setup to what I'm trying to describe.

I think a single strip of 4ft wide chicken wire 6 or 8ft long would do ok for your antenna, or lay two 8ft long strips over each other in an X pattern with the antenna in the center.
prcguy


prcguy - please explain the 8x8 foot ground plane. I can't picture it in my mind. Something, connected to coax ground, connected under the stand or elsewhere?
 

jack103

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Hire a qualified electrician they have the proper tools to install ground rods that's what they do on every service they install!
 

RFI-EMI-GUY

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I think a hammer drill might do the trick. I have seen some sort of drill to ground rod adaptor for that purpose.

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ultravista

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I had problems driving 2 FT rebar when building a raised garden bed.

Roelof emailed with the following information.

------
The requirements of this ground are light. A very small capacitance coupled to earth is enough. Using the antenna pedestrian portable, the human body can provide this as well. The antenna works fine without a ground rod or a radial system.

Where a good ground comes in, is to get rid of local interference on the shield of the coax feed line. Using a ground rod, the noise on the shield will flow to earth and not travel over the shield of the
feed line to the antenna.

You can try a square meter of chicken fence at the bottom of the mast. I use a BNC - BNC panel feed through, mounted on a metal plate as a shield break out connection.
------
 

Kb2Jpd

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I am in Las Vegas, NV, my soil is caliche (soil particles are cemented together by calcium carbonate (CaCO3)). It is nearly impossible to sink a ground rod.



Reading the many articles and blogs for the active mini whip antenna, it is only effective high outdoors with a proper ground. The antenna is RX only ...



My antenna mast ~6 meters high. The first 3 meters is a galvanized steel pipe; the last 3 meters is PVC plastic. The antenna is mounted at the top of the PVC pipe. The base of the mast is similar to the photo links below - powder coated steel legs and springs. It is meant to hold road signs on the highway - but is an excellent vertical stand for the antenna. It rests on concrete in the back yard.



This of course cannot provide an adequate ground.



What do you recommend I do to provide a proper ground for an active mini whip given the facts that my soil is cement-like?



http://www.powerpak.net/sign_stands.png



https://visiflashdotcom.files.wordpress.com/2016/12/dicke-stf-18-rgb.jpg


Find a old metal bathtub. Drill holes or weld a decent ground strap to it. If you want to, make a fan of Copper wire surrounding the bathtub out to the rest of the yard.

Make a deep hole into the ground. Drop tub into ground. Bury it.

Connect to your antenna.

Have fun.

Adam Kb2Jpd


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prcguy

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Jun 30, 2006
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So Cal - Richardson, TX - Tewksbury, MA
None of this is appropriate for a short active whip....
prcguy


Find a old metal bathtub. Drill holes or weld a decent ground strap to it. If you want to, make a fan of Copper wire surrounding the bathtub out to the rest of the yard.

Make a deep hole into the ground. Drop tub into ground. Bury it.

Connect to your antenna.

Have fun.

Adam Kb2Jpd


Sent from my iPhone using Tapatalk
 
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