Red Wave Radio

by **Herb Rosenbe** » Wed, 07 Sep 1994 11:50:22

I am trying to set up a ham shack in the second story (upstairs) of my
house. Based upon where the shack is located, I can't easily get to a
cold water pipe, and the run to an earth ground is going to be 40feet or
so. I wanted to use the copper foil that is 3-4 inches wide to run to
the earth ground, but beacuse of the length of this run, I don't know if
I will be creating more problems than I will solve.

Does anyone have any suggestions on providing the best ground possible
for HF when the shack is located on teh second floor?

Any thoughts or suggestions would eb appreciated.

Thanks.

HERB - KG6OK

--

by **W. E. Van Hor** » Wed, 07 Sep 1994 18:48:28

: Does anyone have any suggestions on providing the best ground possible
: for HF when the shack is located on teh second floor?

: Any thoughts or suggestions would eb appreciated.

Herb -

I can't comment on your idea of using wide foil for your ground lead as I
have no relevant experience. But I can give a word of advice regarding
resonance in the ground lead itself.

Any ground lead you run will be of a length that will be near to an odd
number of quarter-wavelengths on one or more bands. On those bands its
r.f. impedance will be VERY high, nearly an open circuit, so you will
have no grounding at all on those bands. The solution is to run at least
two ground leads, of different lengths, in parallel.

Good luck and 73,

Van - W8UOF

* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* It ain't wot ya don't know 't gets ya into trouble. *
* It's wot ya know 't ain't true. - "Mr. Dooley" *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *

by **Gregory Chare** » Thu, 08 Sep 1994 09:22:35

Quote:
>Does anyone have any suggestions on providing the best ground possible
>for HF when the shack is located on teh second floor?

>I've had pretty good luck with 2 separate ground runs of #10 copper wire.

One goes out a window to a couple of ground rods and the other drops through
inside partitions to the cold water service pipe. They are differnt lengths
to (hopefully) provide a reasonably low impedance rf ground at most
frequencies.

Greg - KA1KTW

by **clay torst** » Thu, 08 Sep 1994 23:14:17

Quote:
>>Does anyone have any suggestions on providing the best ground possible
>>for HF when the shack is located on teh second floor?

You can do just fine without a ground connection in this case. My station is
on the 3rd floor with no ground connection, and I have no problems with 'RF
in the shack' (running up to 700w on 160-10m). Do make sure that all of your
equipment is grounded together, and don't use end-fed or indoor antennas. If
you do have RF problems, a few 1/4 wave radials can help.
I do use an external ground to ground the antennas when not in use for
lightning protection, but this is never connected to the equipment.

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by **Andy Domonk** » Fri, 09 Sep 1994 04:05:42

>>Does anyone have any suggestions on providing the best ground possible
>>for HF when the shack is located on teh second floor?

I use a counter-poise cut for the lowest frequency connected to the shield
of the cable at the feedpoint of the antenna. Also wind some of the coax on
Radio Shack type snap together RF chokes. This will help reduce feedline
radiation tremendously.

Andy N3LCW

by **Robert D. Calkin** » Fri, 09 Sep 1994 10:55:06

Hi-

The best way I found was to use flat wire braid with as many strands as
possible. I had to go to a specialty electric store to get it but it was
sure worth the trip.

It's essentially the braided outer conductor from some RG-8 cable,
stomped flat.

Remember skin effect, where RF travels along the skin of a conductor? You
want to present a low resistance to the RF current so it will bleed off
to ground....and the individual strands in the braid have LOTSA skin.

It works much better than one single cable, regardless of that cable's
diameter.

73

by **Doyle Soude** » Sun, 11 Sep 1994 05:05:10

Horne) writes:
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> Newsgroups: rec.radio.amateur.equipment
> Subject: Re: How to ground a second story shack?
> Date: 6 Sep 1994 09:48:28 GMT
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> : Does anyone have any suggestions on providing the best ground
> possible : for HF when the shack is located on teh second floor?

> : Any thoughts or suggestions would eb appreciated.

> Herb -

> I can't comment on your idea of using wide foil for your ground lead as
> I have no relevant experience. But I can give a word of advice
> regarding resonance in the ground lead itself.

> Any ground lead you run will be of a length that will be near to an odd
> number of quarter-wavelengths on one or more bands. On those bands its
> r.f. impedance will be VERY high, nearly an open circuit, so you will
> have no grounding at all on those bands. The solution is to run at
> least two ground leads, of different lengths, in parallel.

> Good luck and 73,

> Van - W8UOF

> * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
> * It ain't wot ya don't know 't gets ya into trouble. *
> * It's wot ya know 't ain't true. - "Mr. Dooley" *
> * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

The problem of grounding you describe is also common to many Field Day
operations. The solution is in providing an RF ground for your equipment.
To do this you need to run a quarter wave wire for each band you want to
operate on. Each wire should have one end connected to the ground point on
your rig. Not providing an RF ground will often cause your SWR readings to
be high and many auto antenna tuners will have difficulty achieving a proper
match. You also can have RF getting into mike cords and notice small shocks
when touching metal portions of your rig or equipment. The DC or power
ground is a different subject and is safety oriented. That should be
provided through your 3 terminal line plug. If you have to make a separate
"DC" ground then you may want to decouple the RF from that line with Large
Ferrites or an inductor that prevents RF from flowing in that path. The 80M
quarter wave line will be a problem for most rooms as it is difficult to run
that around the room. This one if you need it may have to exit the shack and
run on an outside wall. Keep in mind that while these quarter wave lines
will create an RF ground at your rig, the other end of these lines is 90
degrees out of phase and will be a voltage maximum. (you can get a good
shock if you are running high power) Make sure the wire is insulated and that
you do not have an exposed end. You will likely get a number of inputs and
I offer these suggestions as they worked for my 2nd story shack and every
year on field day we face exactly the same problem. Quarter wave radials
always fixes the problem! Hope these suggestions help.

Doyle ... KG6MY