Help with Proper Ground for Active Mini Whip Antenna

Status
Not open for further replies.

ultravista

Member
Joined
Sep 19, 2012
Messages
99
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

Member
Joined
Jun 30, 2006
Messages
15,226
Location
So Cal - Richardson, TX - Tewksbury, MA
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

Member
Joined
Mar 30, 2005
Messages
3,984
Location
So Cali
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

Member
Joined
Jun 30, 2006
Messages
15,226
Location
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

Member
Joined
Sep 19, 2012
Messages
99
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

Member
Joined
Jun 30, 2006
Messages
15,226
Location
So Cal - Richardson, TX - Tewksbury, MA
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

Member
Premium Subscriber
Joined
Nov 17, 2002
Messages
470
Location
Tewksbury MA
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

Member
Joined
Dec 22, 2013
Messages
6,859
I think a hammer drill might do the trick. I have seen some sort of drill to ground rod adaptor for that purpose.

Sent from my SM-T350 using Tapatalk
 

ultravista

Member
Joined
Sep 19, 2012
Messages
99
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

Member
Joined
May 6, 2016
Messages
207
Location
New York City, NY
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


Sent from my iPhone using Tapatalk
 

prcguy

Member
Joined
Jun 30, 2006
Messages
15,226
Location
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
 
Status
Not open for further replies.
Top