Re: Topband: 160m vertical saltwater grounding

[Grant Saviers]

Rob,

I considered this for my MM SSB.  It doesn't work.  Several published 
tests prove that.  Ok as an AC/DC ground.


Grant

On 1/9/2020 01:18, Herbert Schoenbohm wrote:

A very effective device called *Dynaplate* works very well as a saltwater
grounding system for boats or limited areas to run full-sized radials.  You
can get one for $100 from the link below.
https://www.jamestowndistributors.com/userportal/show_product.do?pid=13331

Herb, KV4FZ

On Wed, Jan 8, 2020 at 6:30 PM Robert Fanfant  wrote:



Am looking to activate a location with very limited space surrounded by
ocean. Think of a small rock surrounded by saltwater/ocean.  The vertical
will be a tall 60???+ fiberglass pole and made to resonate on 160m. I would
like a way to reduce the required space of the 160m antenna radial field
due to the limited physical space available. The vertical will be located
at the waters edge, or even possibly over the oceans surface. At the feed
point, will be a choke designed for 160m. We should also assume maximum
power of 1.5KW being fed into the vertical and the activation will be for a
2 week duration of time.

One idea that came up is to use a floating piece of conductive material as
the verticals counterpoise. Specifically,   a thin conductive plate
designed to float on the oceans surface. From the antenna???s feed point,
will be a short length of  ground wire say about 6??? long,  to this
conductive plate.

Question(s):

   1.  Is it possible to just use the ocean as the ground plane /
counterpoise ? That is, can this idea work?
   2.  If so,
  *   How do I determine the required square footage/size of the plate?
  *   What material should be used as the conductive plate? (Nickel,
copper, aluminum, etc..? )The thought here is to make this plate as light
as possible, yet effective. It  will need to last the duration of the
activation (~2 weeks) in/on saltwater, it needs to handle 1.5KW at the feed
point, and likely exposed to air and saltwater as it floats on the ocean
surface.

-rob N7QT



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Re: Topband: 160m vertical saltwater grounding

[GEORGE WALLNER]

Rob,
This is a good reference. Only one comment: I found recently on C6AGU that 
on 160 m the 2 -3 foot tidal change cause only a small change in the SWR of 
a tuned inverted L with its metal base standing in salt-water. I tuned the 
antenna to resonance with an SWR of 1.2 at mid-tide. Between low and high 
tides the SWR remained below 1.6. (Including losses in 300' of LMR-400 
coax.)

73,
George,
AA7JV/C6AGU


On Thu, 9 Jan 2020 06:40:27 -0600
 Rob Atkinson  wrote:

Interesting information here:

http://www.arrl.org/files/file/Antenna%20Book%20Supplemental%20Files/22nd%20Edition/Seawater%20Grounds%20-%20by%20N6LF.pdf

Rob
K5UJ
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Re: Topband: 160m vertical saltwater grounding

[Ignacy Misztal]

 I operated on a pier over salt water on 160m in 3 locations. Once with
baloon for an inv L. KW with short antenna creates special problems. See my
message yesterday.

Short radials will have extremely high voltage at a KW level. Small metal
plate on salt water may have water sizzling or would introduce losses.

I would try to have 1-4 elevated radials as long as possible. 15 to 50 ft.
Then the transformer needs to be wound with teflon wire to prevent sparcing
and heating due to high voltages.

Ignacy, NO9E
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Re: Topband: 160m vertical saltwater grounding

[GEORGE WALLNER]

Robert,
You only have to "connect" to the salt-water. Don't worry about radials or 
field of radials. From you coax shield, or whatever GND (common) you have, 
run as many wires as you can into the water. They do not have to be long: 
you just want about 6' of wire in the water (even at low tide). (RF does not 
go far in salt water. You need to have the wires in the water to make them 
(capacitively) couple to the water. You need many wires to get a low 
impedance connection.) Of course, if you can tie to a large metal object 
that is in the water, you will need only two or three wires in parallel.
I normally use #14 THHN with rocks (or other weights) tied to the ends. Four 
wires will do OK, but 6 - 8 would be better.

Look at this: http://pt0s.com/index.php?page=photo&shot=antenna_wave

GL and 73,
George
AA7JV


On Wed, 8 Jan 2020 22:30:05 +
 Robert Fanfant  wrote:


Am looking to activate a location with very limited space surrounded by ocean. 
Think of a small rock surrounded by saltwater/ocean.  The vertical will be a 
tall 60’+ fiberglass pole and made to resonate on 160m. I would like a way to 
reduce the required space of the 160m antenna radial field due to the limited 
physical space available. The vertical will be located at the waters edge, or 
even possibly over the oceans surface. At the feed point, will be a choke 
designed for 160m. We should also assume maximum power of 1.5KW being fed into 
the vertical and the activation will be for a 2 week duration of time.

One idea that came up is to use a floating piece of conductive material as the verticals counterpoise. Specifically,   a thin conductive plate designed to float on the oceans surface. From the antenna’s feed point, will be a short length of  ground wire say about 6’ long, 
to this conductive plate.


Question(s):

 1.  Is it possible to just use the ocean as the ground plane / counterpoise ? 
That is, can this idea work?
 2.  If so,
*   How do I determine the required square footage/size of the plate?
*   What material should be used as the conductive plate? (Nickel, copper, 
aluminum, etc..? )The thought here is to make this plate as light as possible, 
yet effective. It  will need to last the duration of the activation (~2 weeks) 
in/on saltwater, it needs to handle 1.5KW at the feed point, and likely exposed 
to air and saltwater as it floats on the ocean surface.

-rob N7QT


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Re: Topband: 160m vertical saltwater grounding

[Rob Atkinson]

Interesting information here:

http://www.arrl.org/files/file/Antenna%20Book%20Supplemental%20Files/22nd%20Edition/Seawater%20Grounds%20-%20by%20N6LF.pdf

Rob
K5UJ
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Re: Topband: 160m vertical saltwater grounding

[Herbert Schoenbohm]

A very effective device called *Dynaplate* works very well as a saltwater
grounding system for boats or limited areas to run full-sized radials.  You
can get one for $100 from the link below.
https://www.jamestowndistributors.com/userportal/show_product.do?pid=13331

Herb, KV4FZ

On Wed, Jan 8, 2020 at 6:30 PM Robert Fanfant  wrote:

>
> Am looking to activate a location with very limited space surrounded by
> ocean. Think of a small rock surrounded by saltwater/ocean.  The vertical
> will be a tall 60’+ fiberglass pole and made to resonate on 160m. I would
> like a way to reduce the required space of the 160m antenna radial field
> due to the limited physical space available. The vertical will be located
> at the waters edge, or even possibly over the oceans surface. At the feed
> point, will be a choke designed for 160m. We should also assume maximum
> power of 1.5KW being fed into the vertical and the activation will be for a
> 2 week duration of time.
>
> One idea that came up is to use a floating piece of conductive material as
> the verticals counterpoise. Specifically,   a thin conductive plate
> designed to float on the oceans surface. From the antenna’s feed point,
> will be a short length of  ground wire say about 6’ long,  to this
> conductive plate.
>
> Question(s):
>
>   1.  Is it possible to just use the ocean as the ground plane /
> counterpoise ? That is, can this idea work?
>   2.  If so,
>  *   How do I determine the required square footage/size of the plate?
>  *   What material should be used as the conductive plate? (Nickel,
> copper, aluminum, etc..? )The thought here is to make this plate as light
> as possible, yet effective. It  will need to last the duration of the
> activation (~2 weeks) in/on saltwater, it needs to handle 1.5KW at the feed
> point, and likely exposed to air and saltwater as it floats on the ocean
> surface.
>
> -rob N7QT
>
>
>
> Sent from Mail for
> Windows 10
>
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Re: Topband: 160m vertical saltwater grounding

[Gary K9GS]

I'm thinking Scarborough Reef?73,Gary K9GS
 Original message From: Stan Stockton  Date: 
1/8/20  6:25 PM  (GMT-06:00) To: Robert Fanfant  Cc: 
topband@contesting.com Subject: Re: Topband: 160m vertical saltwater grounding 
How big is the land area?Stan, ZF9CW> On Jan 8, 2020, at 4:30 PM, Robert 
Fanfant  wrote:> > > Am looking to activate a location 
with very limited space surrounded by ocean. Think of a small rock surrounded 
by saltwater/ocean.  The vertical will be a tall 60’+ fiberglass pole and made 
to resonate on 160m. I would like a way to reduce the required space of the 
160m antenna radial field due to the limited physical space available. The 
vertical will be located at the waters edge, or even possibly over the oceans 
surface. At the feed point, will be a choke designed for 160m. We should also 
assume maximum power of 1.5KW being fed into the vertical and the activation 
will be for a 2 week duration of time.> > One idea that came up is to use a 
floating piece of conductive material as the verticals counterpoise. 
Specifically,   a thin conductive plate designed to float on the oceans 
surface. From the antenna’s feed point, will be a short length of  ground wire 
say about 6’ long,  to this conductive plate.> > Question(s):> >  1.  Is it 
possible to just use the ocean as the ground plane / counterpoise ? That is, 
can this idea work?>  2.  If so,> *   How do I determine the required 
square footage/size of the plate?> *   What material should be used as the 
conductive plate? (Nickel, copper, aluminum, etc..? )The thought here is to 
make this plate as light as possible, yet effective. It  will need to last the 
duration of the activation (~2 weeks) in/on saltwater, it needs to handle 1.5KW 
at the feed point, and likely exposed to air and saltwater as it floats on the 
ocean surface.> > -rob N7QT> > > > Sent from 
Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10> > 
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Re: Topband: 160m vertical saltwater grounding

[Stan Stockton]

How big is the land area?

Stan, ZF9CW

> On Jan 8, 2020, at 4:30 PM, Robert Fanfant  wrote:
> 
> 
> Am looking to activate a location with very limited space surrounded by 
> ocean. Think of a small rock surrounded by saltwater/ocean.  The vertical 
> will be a tall 60’+ fiberglass pole and made to resonate on 160m. I would 
> like a way to reduce the required space of the 160m antenna radial field due 
> to the limited physical space available. The vertical will be located at the 
> waters edge, or even possibly over the oceans surface. At the feed point, 
> will be a choke designed for 160m. We should also assume maximum power of 
> 1.5KW being fed into the vertical and the activation will be for a 2 week 
> duration of time.
> 
> One idea that came up is to use a floating piece of conductive material as 
> the verticals counterpoise. Specifically,   a thin conductive plate designed 
> to float on the oceans surface. From the antenna’s feed point, will be a 
> short length of  ground wire say about 6’ long,  to this conductive plate.
> 
> Question(s):
> 
>  1.  Is it possible to just use the ocean as the ground plane / counterpoise 
> ? That is, can this idea work?
>  2.  If so,
> *   How do I determine the required square footage/size of the plate?
> *   What material should be used as the conductive plate? (Nickel, 
> copper, aluminum, etc..? )The thought here is to make this plate as light as 
> possible, yet effective. It  will need to last the duration of the activation 
> (~2 weeks) in/on saltwater, it needs to handle 1.5KW at the feed point, and 
> likely exposed to air and saltwater as it floats on the ocean surface.
> 
> -rob N7QT
> 
> 
> 
> Sent from Mail for Windows 10
> 
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Re: Topband: 160m vertical saltwater grounding

[jh-...@sbcglobal.net]

 Just bare copper wire with washers or lead fishing weights tied on the ends is 
just fine if you wish to enhance coupling between the vertical and the salt 
water, or 4 raised counterpoise wires in the air will also work extremely well. 
 The main issue is to position the vertical over the near-perfect salt water 
ground vs the terrestrial. 
I used to operate /M 160 from the Monterey (CA) commercial pier, and the salt 
water was amazing for brewster angle and enhanced RX, even with the vehicle 15' 
up over the water.  Your setup as envisioned with "Floating plate" coupling 
will be a maintenance nightmare and will last exactly ONE storm.   Use the KISS 
principle when it comes to salt-water vertical installations!
I laughed when tourists used to pull on the washer-weighted wires hanging off 
the base of my 160 Pro-Am stick thinking I was crab fishing from the pier.  
Come to think of it, I should've attached a turkey leg to that wire and made it 
dual purpose!! 
Best, John H W6UQZ      
On Wednesday, January 8, 2020, 02:30:16 PM PST, Robert Fanfant 
 wrote:  
 
 
Am looking to activate a location with very limited space surrounded by ocean. 
Think of a small rock surrounded by saltwater/ocean.  The vertical will be a 
tall 60’+ fiberglass pole and made to resonate on 160m. I would like a way to 
reduce the required space of the 160m antenna radial field due to the limited 
physical space available. The vertical will be located at the waters edge, or 
even possibly over the oceans surface. At the feed point, will be a choke 
designed for 160m. We should also assume maximum power of 1.5KW being fed into 
the vertical and the activation will be for a 2 week duration of time.

One idea that came up is to use a floating piece of conductive material as the 
verticals counterpoise. Specifically,  a thin conductive plate designed to 
float on the oceans surface. From the antenna’s feed point, will be a short 
length of  ground wire say about 6’ long,  to this conductive plate.

Question(s):

  1.  Is it possible to just use the ocean as the ground plane / counterpoise ? 
That is, can this idea work?
  2.  If so,
    *  How do I determine the required square footage/size of the plate?
    *  What material should be used as the conductive plate? (Nickel, copper, 
aluminum, etc..? )The thought here is to make this plate as light as possible, 
yet effective. It  will need to last the duration of the activation (~2 weeks) 
in/on saltwater, it needs to handle 1.5KW at the feed point, and likely exposed 
to air and saltwater as it floats on the ocean surface.

-rob N7QT



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