| Author |
Message |
    
Charliebrown
Member
Username: Charliebrown
Post Number: 98
Registered: 10-2002
| | Posted on Thursday, September 02, 2010 - 3:06 pm: | 
|
Tech833 or another Tech, I had seen somewhere on here a posting that a person could run 3 copper wires 36 feet long with ground rods inserted at the end of each wire and the wires burried a few inches in the ground connected to the ground rod that the antenna mast is connected to and that was suppose to help the antennas performance. Now, my question is if that was done would that help the i max 2000 with a gpk already on it or would it null the effect of the gpk. I hope this does not seem to be too silly a question however with you being the best radio myth buster I assume you would enjoy this one and perhaps other people might also. MYTH OR FACT. Just something I read here that made me wonder. |
Sitm
Intermediate Member
Username: Sitm
Post Number: 337
Registered: 1-2004
| | Posted on Thursday, September 02, 2010 - 4:49 pm: |
|
A symmetrical rradial patter around the base is important for collecting RF current away from earth soil. The purpose of the radials is to reduce loss, teh elements radiate in all directions in the near field, intercept current and return it to the base. You can find many examples of technic on how to effectively install ground radials but remember, the more effective your system is the better your performance overall. There are alot of factors in this, ground conductivity, moisture, terrain, etc. There is always debate as to using ground radials over sky radials and you can read varing opinions on the internet. The best way to approach this is to just do both and insall them correctly by utilizing proper instructions from an educated elmer. In the end you eliminate each and every source of loss in your entire system, ground, ground radials, sky radials, quality coax, standing wave combined with a clean signal source. This is what makes this hobby a good one, you can constantly improve your system through education and hard work...... Good luck |
Sitm
Intermediate Member
Username: Sitm
Post Number: 338
Registered: 1-2004
| | Posted on Thursday, September 02, 2010 - 4:52 pm: |
|
And my above post is the reason you use spell check and don't post things while you are working.....sorry guys....honestly I paid for an education......apparently not enough. |
Mikefromms
Senior Member
Username: Mikefromms
Post Number: 1074
Registered: 6-2003
| | Posted on Thursday, September 02, 2010 - 5:40 pm: |
|
I'm going to take a stab at this one and do eagerly await the tech's response. I doubt it would help it enough to justify all the extra cost and expense. Probably make it operate quieter. What I think would help it more would be to install a high quality 1:1 current balun at the feedpoint to prevent current nodes. |
Tech833
Moderator
Username: Tech833
Post Number: 1867
Registered: 8-2002
| | Posted on Thursday, September 02, 2010 - 7:21 pm: |
|
So far, nobody here quite got it right.
There IS an advantage to burying bare copper wires a few inches below the surface around the base of your CB antenna. The advantage is that ground conductivity is increased, and it can lower the takeoff angle of your transmissions and improve the S/N ratio for your receiver. Wire radials over 1/4 wave in length are no more effective than radials 1/4 wave in length. So, if you bury 36 foot long radials and you only intend to use CB, each wire length over 9 feet is wasted wire and effort.
Having ground planes at the feedpoint of your Imax 2000 goes a long way to lowering the takeoff angle (see the GPK review). Having radials buried around the base of the support structure has nothing to do with ground planes on the antenna and vice-verse.
Ground radials are an RF ground. Ground rods are a lightning ground. They are not exactly one in the same. Putting ground rods at the end of your ground radials is OK, it won't hurt anything. However, unless the ground radials are made of a large cross section wire or strap (at least as large or larger than the diameter of the ground rod), then they will sever if you take a lightning strike, and be ineffective.
Best bet- Drive a ground rod into the ground at the base of your mast and use that to connect all of your ground radials to. Then, bond the rod to the mast. Make sure the antenna and mast are well bonded. If not, run a copper wire from the base of the antenna to the ground rod also.
You can also bond your coax shield at the ground rod for safety.
Do an internet search for "single point ground" and follow those suggestions.
Your radio 'Mythbuster' since 1998
|
Charliebrown
Member
Username: Charliebrown
Post Number: 99
Registered: 10-2002
| | Posted on Thursday, September 02, 2010 - 8:22 pm: |
|
Tech 833, that is exactly what I was talking about. At the base of the antenna I do have a ground rod connected to the base of the mast and I was talking about the ground radials being connected to that ground rod. Thanks for the correction on the length of the ground radials and the diameter. This is a very interesting subject and with the help of others on this forum I always am learning. Thanks to Sitm and Mikefromms for the fast response. Special thanks to Tech 833 the radio myth buster for being patient with some of my questions. I just want to learn and grow in knowledge of this hobby. |
Larryf
New member
Username: Larryf
Post Number: 1
Registered: 9-2012
| | Posted on Saturday, September 29, 2012 - 9:12 pm: |
|
I am trying to find info from someone who has a chimney mounted Imax 2000 over a metal roof. On this type of installation would radials be of any benefit. If so, how should they be installed. I'd like to do something which would cut down background noise. Thanks |
Tech237
Moderator
Username: Tech237
Post Number: 1622
Registered: 4-2004
| | Posted on Sunday, September 30, 2012 - 8:55 am: |
|
Larryf - why add radilas, when you already have a great ground system. Bond the ground point to the metal roof.
The problem with noise is that most man-made noise is vertically polarized, and adding ground radials may not help at all. The best way of reducing the majority of noise is to switch to a horizontal antenna,
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
|
Snowfire
Intermediate Member
Username: Snowfire
Post Number: 177
Registered: 2-2004
| | Posted on Sunday, September 30, 2012 - 11:33 am: |
|
I am useing a t.v. antinna for a ground plane on my I-Max 2000. Seems to be working good.
Kent Kerr
Cef 294
Snowfire
Union Valley, Oklahoma
MID-SOUTH CEF NET CONTROL
|
Larryf
New member
Username: Larryf
Post Number: 2
Registered: 9-2012
| | Posted on Monday, October 01, 2012 - 8:50 am: |
|
I have been getting pretty good receptipon as is but at my age , with some hearing deficet, background noise is a problem and every little bit helps. Much appreciate your advuce . I will connect the roof to a deeply driven stake which I currently use go ground the 8 ft. antenna mast. Many thanks again. Larryf |
