WA Radio Scanner Users' Group

meg wrote:
Yep, the station earth isn't a problem - there's a lug on the back of my rig and I have some copper pipe - just a matter of drilling a hole in the floor to feed the wire through and digging some kind of hole in this gravel!

When I used a length of copper tube for an RF earth, I stuck a hose in the end and turned it on. The water dug a hole rather quickly. Does the trick. To be of any use the earth stake has to be down probably further than you would want to dig a hole and being copper tube its a bit soft to hit.

meg wrote:
Yep, the station earth isn't a problem - there's a lug on the back of my rig and I have some copper pipe - just a matter of drilling a hole in the floor to feed the wire through and digging some kind of hole in this gravel!

G'day Meg,

Your dipole antenna doesn't need earthing, although some do earth their tower structures.

For my station earth I have used a 1.8m star picket driven into the ground as I also have some gravel to get through.

FoxtrotZu;u wrote:AS/NZS3000:2008 states that all copper water pipe (amongst others) in an installation is required to be bonded to the protective earthing system of the installation at the main earth stake. This joint is known as the equipotential bond.

First of all, that sounds like you're talking about the same earth which the electrical system is connected to.

While this is fine for electrical earthing, connecting your amateur station's RF earth to here also is generally considered to be a bad idea.

Quoting the ARRL Handbook 2008:

The second job the ground system must perform is to provide a low impedance path to ground for any stray RF current inside the station. Stray RF can cause equipment to malfunction and contributes to RFI problems.

Noise in ground systems can affect our sensitive radio equipment. It is usually related to one of three problems:

1) Insufficient ground conductor size
2) Loose ground connections
3) Ground loops

The ground conductor should be at least as large as the largest conductor in the primary circuit.

A loose grouned connection is a tremendous source of noise, particularly in a sensitive receiving system.

Ground loops should be avoided at all cost. A ground loop is formed when more than one ground current is flowing in a single conductor.

Ground noise can affect transmitted and received signals. With the low sudio levels required to drive amateur transmitters, and the ever-increasing sensitivity of our receivers, correct grounding is critical.

The Ham College Advanced Theory Manual says on pg 215:

If you are operating a transceiver that is powered by the mains it will usually be earthed through the earth wire in the mains power cable. However due to the length of the mains wiring ina typical house it is not effective for Radio Frequency energy.

A proper RF earth can be obtained by driving a length of copper rod into the ground and securing a thick multi-strand wire to it with a cable clamp. The other end of the wire is connected to your transceiver or antenna tunder. Without a station earth, your equipment and everything connected to it may carry RF energy when you transmit. This energy can get back into your own equipment causing RF feedback and interference to household appliances.

Other sources on the Internet also talk about keeping electrical earth and RF earth separate:

... electrical service ground is NOT a substitute for a good RF Earth ground, which is required for a good antenna system. In fact, your service ground will probably be a very bad RF ground and a good source of (household / neighborhood) noise ...

Ref: http://www.bobsamerica.com/9-1balun.html

While grounding is a subject of a separate tutorial, one of the key points is that your ... device may be electrically grounded but not earth grounded. That is, your device may have a ground connector to an electrical ground but if the electrical ground is not properly grounded, the equipment could still have significant damage.

One more time: Electrical ground is not earth ground. According to various sources, broad copper conductors such as #6 AWG [Average Wire Gauge] or braided strap or wide copper strap must be used. The earth ground must have a large surface area in contact with dirt/soil typically buried down to six feet below the surface. It is critical that the earth ground be placed outside of the structure and properly maintained. Ideally, the ground point should be directly beneath the entry point for the antenna line.

Ref: http://www.lockergnome.com/it/2006/09/1 ... -antennas/

Your station must have an RF earth. All modern equipment has an earthing terminal on the back panel and this should be connected to a good earth. Drive a length of water pipe into the ground - a couple of metres long. A thick copper cable should be connected from the back of the radio to the earth pipe.

Ref: http://www.nzart.org.nz/nzart/exam/AMAT ... SAFETY.htm

FoxtrotZu;u wrote:Clear enough?

Please take care when responding that your words don't have the potential to convey a "snippy tone" as your comment above did. It's not a good way for new forum members to make a first impression!

vk6jrc wrote:For my station earth I have used a 1.8m star picket driven into the ground as I also have some gravel to get through.

That sounds ideal, Meg was only saying yesterday how much fun it is to hammer stuff into the ground at her QTH

vk6jrc wrote: G'day Meg,

Your dipole antenna doesn't need earthing, although some do earth their tower structures.

For my station earth I have used a 1.8m star picket driven into the ground as I also have some gravel to get through.

The "towers" are going to be a couple of trees - I'm going to assume they're earthed adequately

Fantastic idea with the star picket though, and we have a few around the place.

Thanks everyone for the thoughts - it's fantastic that all the VK6 people are so friendly and helpful

Cheers,
Meg

meg wrote:Thanks Robbage - yep, it's got a balun already. So, this means I might be able to get this rig fired up by the end of the long weekend, which would be fantastic!

Thanks again, and particularly for not laughing at the dumb question! I'm sure I'll have more...

I'll laugh at 'dumb' questions when I stop asking them There probably isn't any reason why you need to panic about the earth if you're just going to be receiving for the next couple of weeks until you're licenced.

Blinky wrote:When I used a length of copper tube for an RF earth, I stuck a hose in the end and turned it on. The water dug a hole rather quickly. Does the trick.

Brilliant! Should work in most areas of Perth.

I'll back up Zebedee's comments on separate earth from mains earth. I've come across this recommendation on many antenna sites. Now... how about lightning protection.

Zebedee wrote:

FoxtrotZu;u wrote:AS/NZS3000:2008 states that all copper water pipe (amongst others) in an installation is required to be bonded to the protective earthing system of the installation at the main earth stake. This joint is known as the equipotential bond.

First of all, that sounds like you're talking about the same earth which the electrical system is connected to.

While this is fine for electrical earthing, connecting your amateur station's RF earth to here also is generally considered to be a bad idea.

Quoting the ARRL Handbook 2008:

The second job the ground system must perform is to provide a low impedance path to ground for any stray RF current inside the station. Stray RF can cause equipment to malfunction and contributes to RFI problems.

Noise in ground systems can affect our sensitive radio equipment. It is usually related to one of three problems:

1) Insufficient ground conductor size
2) Loose ground connections
3) Ground loops

The ground conductor should be at least as large as the largest conductor in the primary circuit.

A loose grouned connection is a tremendous source of noise, particularly in a sensitive receiving system.

Ground loops should be avoided at all cost. A ground loop is formed when more than one ground current is flowing in a single conductor.

Ground noise can affect transmitted and received signals. With the low sudio levels required to drive amateur transmitters, and the ever-increasing sensitivity of our receivers, correct grounding is critical.

The Ham College Advanced Theory Manual says on pg 215:

If you are operating a transceiver that is powered by the mains it will usually be earthed through the earth wire in the mains power cable. However due to the length of the mains wiring ina typical house it is not effective for Radio Frequency energy.

A proper RF earth can be obtained by driving a length of copper rod into the ground and securing a thick multi-strand wire to it with a cable clamp. The other end of the wire is connected to your transceiver or antenna tunder. Without a station earth, your equipment and everything connected to it may carry RF energy when you transmit. This energy can get back into your own equipment causing RF feedback and interference to household appliances.

Other sources on the Internet also talk about keeping electrical earth and RF earth separate:

... electrical service ground is NOT a substitute for a good RF Earth ground, which is required for a good antenna system. In fact, your service ground will probably be a very bad RF ground and a good source of (household / neighborhood) noise ...

Ref: http://www.bobsamerica.com/9-1balun.html

While grounding is a subject of a separate tutorial, one of the key points is that your ... device may be electrically grounded but not earth grounded. That is, your device may have a ground connector to an electrical ground but if the electrical ground is not properly grounded, the equipment could still have significant damage.

One more time: Electrical ground is not earth ground. According to various sources, broad copper conductors such as #6 AWG [Average Wire Gauge] or braided strap or wide copper strap must be used. The earth ground must have a large surface area in contact with dirt/soil typically buried down to six feet below the surface. It is critical that the earth ground be placed outside of the structure and properly maintained. Ideally, the ground point should be directly beneath the entry point for the antenna line.

Ref: http://www.lockergnome.com/it/2006/09/1 ... -antennas/

Your station must have an RF earth. All modern equipment has an earthing terminal on the back panel and this should be connected to a good earth. Drive a length of water pipe into the ground - a couple of metres long. A thick copper cable should be connected from the back of the radio to the earth pipe.

Ref: http://www.nzart.org.nz/nzart/exam/AMAT ... SAFETY.htm

FoxtrotZu;u wrote:Clear enough?

Please take care when responding that your words don't have the potential to convey a "snippy tone" as your comment above did. It's not a good way for new forum members to make a first impression!

You forgot to include the idea in your original post where you stated that:

Zebedee wrote:the book mentions a water pipe

A well earthed copper patch panel where the coax comes into the house and coax fuses inline (they shunt HV to ground and go open circuit to isolate the radio). Properly grounding the mast and choosing the right antenna also helps if you are in a prone area. We found changing to folded dipoles (are at ground potential already) instead of colinear antennae dramtically reduce maintenance. After a strike we usually only had to change the fuse assembly not everything else.

FoxtrotZu;u wrote:You forgot to include the idea in your original post where you stated that:

Zebedee wrote:the book mentions a water pipe

Again, I'm not understanding what you are trying to say from your one-line response.

The Foundation manual mentions that you can ground to a water pipe. My post said that I'd prefer to ground to a separate RF earth stake.

Your post, if I'm understanding it, was claiming that a water pipe was OK because it should be connected through to the electrical earth. However sharing electrical earth as an RF earth also is not generally recommended for amateur radio use.

I hope that clears any confusion.

Zebedee wrote:

FoxtrotZu;u wrote:You forgot to include the idea in your original post where you stated that:

Zebedee wrote:the book mentions a water pipe

Again, I'm not understanding what you are trying to say from your one-line response.

The Foundation manual mentions that you can ground to a water pipe. My post said that I'd prefer to ground to a separate RF earth stake.

Your post, if I'm understanding it, was claiming that a water pipe was OK because it should be connected through to the electrical earth. However sharing electrical earth as an RF earth also is not generally recommended for amateur radio use.

I hope that clears any confusion.

I was stating, as you had pointed out in your post where you referenced 'the book', that using a water pipe was adequate to use as a signal earth.

Originally I was pointing out that in fact the water pipe was bonded to the main earth and connecting to either should have the same result. If it doesn't, as robbage pointed out, there is a fault with your electrical system - this would lead to you getting shocks from showers, taps etc and is potentially fatal and people have died in Western Australia from this situation. In any case, aside from signal interference, connecting to water pipes provides a much larger earthing mass than an individual earth stake or galvanised star picket.

Hope my position is more clear now.

FoxtrotZu;u wrote:Originally I was pointing out that in fact the water pipe was bonded to the main earth and connecting to either should have the same result. If it doesn't, as robbage pointed out, there is a fault with your electrical system - this would lead to you getting shocks from showers, taps etc and is potentially fatal and people have died in Western Australia from this situation. In any case, aside from signal interference, connecting to water pipes provides a much larger earthing mass than an individual earth stake or galvanised star picket.

However it's generally recommended in amateur radio circles that a separate RF earth is more desirable than using an electrical earth (including a water pipe that is connected to the electrical earth).

FoxtrotZu;u wrote:Hope my position is more clear now.

It is yes, thankyou. However I'm still not convinced that using an electrical earth as an RF earth is a good idea The stuff I'm reading seems to suggest it's less than ideal ...

Zebedee wrote: It is yes, thankyou. However I'm still not convinced that using an electrical earth as an RF earth is a good idea The stuff I'm reading seems to suggest it's less than ideal ...

=D>

Hi Meg
What band(s) will your dipole cover?
Cheers

It says it covers 2-30Mhz - it's one of these
http://www.prestigecom.net.au/index.php ... ts_id=1506
so I'm taking it that means all bar 160 meters.

And I meant to post an update today - have slung the antenna across a couple of trees. It probably needs to be higher, about 15 feet off the ground at the ends at the moment and the middle sags downward. We'll need someone with proper tree climbing gear to put it up higher though.

Got a star picket (thanks VK6JRC) about 2-3 feet into the ground and the earth wire attached.

Sadly I didn't have a long enough coax cable to hook it up though Going to remedy this during the week and hopefully get the unit running

That looks like a good starting antenna, try and get it as high as possible.
In the evening you will hear a few WA stations around 3.615MHz and a lots of overseas stations between 7 to 7.1MHz.
During the day up to half a dozen WA people listen to 7.093Mhz.

Let me know if you want a local contact to test out your radio. I am in Yokine.

BTW
Make sure you take the paint off the star picket.