On Sun, 12 Oct 1997 07:38:42 +0000 w8jitom@postoffice.worldnet.att.net
writes:
>> From: km1h@juno.com (km1h @ juno.com)
To: <topband@contesting.com>
>> Date: Fri, 10 Oct 97 14:20:38 +0000
>
>Hi Carl,
>
>> Another question.... I have 4 Beverages coming to one tree. I run
>a
>> short length of coax from each transformer to the RCS-4 remote
>switch.
>> Each Beverage has its own ground rod and they are not directly
>connected
>> to each other in the ground. Spacing of the rods is about 4' from
>each
>> other.
>> How would you guys suggest re-configuring this? Since the RCS-4 is
>a
>> common point for all cables, doesnt this contribute to all sort of
>ground
>> loop problems?
>
>I'm sure others will have good suggestions, but here's what I'd do.
>
>The switch can be a problem point. Just how much of a problem
>depends on what the ground impedance is, and how your antennas are
>configured. If the ground impedance is really low and the antenna's
>impedance high, the antennas won't cross-talk much through ground
>loops. That isn't the case here, because I have rocky clay and
>ground rods don't do the trick like they did in Ohio.
>
>What I do here is use a separate grounds at each Beverage (keeping
>them ten or twenty feet away from each other) and run coax back to
>the switch. I use beads between the switch and the antennas, and
>ground the switch box to its own ground. Of course isolated primarys
>in the matching transformers helps a lot, and maybe you won't need
>any feedline chokes at all.
>
>No point in going through all kinds of grief to terminate the
>antennas properly, just to lose F/B in a ground loop. My neighbor
>has a touch-light that gives me a test signal to the south-west.
>
>
>
>73, Tom W8JI
>
Many tnx for the reply Tom;
If I read the above correct :
Each xfmr secondary goes to a seperate rod with 20' or so spacing. I have
about 6-8" of black earth in the woods and the final 0-20" is bony sand
before I hit solid rock....not a good ground I surmise. I have to run the
8' rods in at a very shallow angle.
The xfmr primarys are connected to the shield only of the coax jumpers
and beads are placed over the coax.
The switch box has its own ground rod so that is the only common point
for all four antenna lines plus the main feed back to the house.
Place beads over the main feed also.
Now the questions...... accumulated from other responses also.
Except for a short RG-6 jumper to the switch the main feed is jacketed
hardline.....should I strip the jacket 20-30' down and install another
ground rod?
Does the control voltages for the RCS-4 on the main feed cause any
problems with BC band pickup, etc.?....Ie: do I need more decoupling ?
I might as well do it all correct and at one time before the snow
arrives. I dont mind overkill; beads and rods are cheap enough.
Tnx Carl KM1H
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