[600MRG] Ground Rods - Connection To -

[Edward R Cole]

Just PS and ditto for what Brian said:

I have two 50-foot, one 70-foot and one 130-foot radial, all lying on 
the ground.  There is one ten foot copper ground rod at the base of 
the Invert-L.  Shorter radials are 2-foot chicken wire fencing lain 
on the ground; the fourth is the shield of my 1-5/8 in hardline (used 
at VHF) and grounded at both ends to ground rods.

With that meager system I measure R=18 ohms with the MFJ 
analyzer.  Ground up here is typical sand-gravel alluvial (remnants 
of glaciers) so not all that conductive.  Water table is about 
50-feet (at nearby fresh water lake).  Soil is fairly moist with the 
frequent rainfall in this maritime climate (salt water 2 miles west).

Idea for using chicken wire came from one of the group and was easy 
to implement.  Since in summer I have grass to mow it is rolled up to 
the base of the antenna.  I hold it down with several half cinder 
blocks.  So far moose have not tripped and drug it (no problem in 
winter under snow).  I do see detuning of the invert-L between frozen 
ground and thawed ground (have taps about two turns apart on the base 
coil (10-dia x 11-inches, 1/4-inch pitch No.12 copper).

been heard in Buffalo on WSPR.

73, Ed - KL7UW

At 11:08 AM 2/1/2015, Brian, WA1ZMS wrote:
>FWIW.....I work in the commercial communications industry as a day 
>job for a large vendor.  The only way we can obtain and maintain 
>good ground connections is to use cad-welds at each joint. Even 
>then, the installers must measure the ground system against a set of 
>reference ground rods used only for testing. The test rods are then 
>cut off and never used again and left to rot.  In other words....if 
>you REALLY want a good ground system, you have to pay $ to play the game.
>
>For ham use: You can silver solder wires to rods, use clamps then 
>seal with Scotch 88T tape and Scotchkote then another layer of 
>tape.  Tin-Lead solder for grounds has a very very short life 
>time.  That's one reason why it's not allowed for AC or Utility 
>grounds. Clamps or cad-weld only meets most Codes.
>
>But to be realistic about it for 600m, the best one can do it what 
>you have budget for. Unless you live in the middle of a farm field 
>with 500ft clear in every direction for an AM broadcast type of 
>ground system the best most of us can do is to sink as many rods as 
>you can and tie them back to a common point of your feed system. 
>Keep in mind the excellent info Rudy posted sometime back about the 
>advantage of more shorter grounds than just a few LONG ground 
>radials.  My ground system is made up of ten 8ft rods all tied back 
>to a single rod and all within a radius of 30ft from the feed 
>point.  A single #6 wire runs over to the base of the VHF tower and 
>its lighting ground. I must have $500 in copper all burried outside 
>and still only get get as low as say 12 or 15 ohms at 
>600m.   Nothing beats trying the best you can, then add a single 
>test rod say 50ft away and measure with a Megger or an impedance 
>bridge or other ground test system. Then add a few more rods and see 
>how much you can improve it. But plan on a 5 year life span unless 
>you cad-weld.
>
>But....don't let a poor ground system keep you off the air! Get on 
>and have fun!  A 35ohm ground connected to an active station is 
>better than working on an ideal ground system while the rig stays off. :- )
>
>-Brian, WA1ZMS & XSH/31 on 477.9 CW beacon in Va.
>iPhone
>
> > On Feb 1, 2015, at 1:54 PM, Frank Lotito <k3dz at live.com> wrote:
> >
> > For the past few days we have seen recommendations to minimize 
> the contact resistance between a ground rod and the 
> earth.  Included were recommendations on minimizing the effects of 
> corrosion.  Maybe I missed it, but I'd like to see recommendations 
> and "how I did it hints" on making a long lasting - low resistance 
> "electrical bond" between the ground rod and the stranded / solid 
> copper wires or woven braid used to join the shack, and if used, 
> the radial field to the ground rod(s).  Once the rod is pounded 
> into the ground you need a little more than a "pencil iron" to join 
> the copper wire / woven brain to the ground rod.  Simple mechanical 
> clamps seem to be accompanied by a lot of wishful thinking when it 
> comes to a long lasting low-resistance connection.
> > Frank Lotito  K3DZ / WH2XHA
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>
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73, Ed - KL7UW
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