1/4 Wave on 28.500MHz
 

I have a stainless steal 1/4 wave length mobile whip.

Can I mount this on top of a 20ft aluminium scaffold pole and use the pole
as the ground radial?
I also have a mobile AM-80 for 80 meters. Can I mount this in the same way
and will it work ok?

Thanks

1/4 Wave on 28.500MHz
 

On Thu, 17 Apr 2008 16:09:10 +0100, "Barrett"
wrote:

I have a stainless steal 1/4 wave length mobile whip.

Can I mount this on top of a 20ft aluminium scaffold pole and use the pole
as the ground radial?
I also have a mobile AM-80 for 80 meters. Can I mount this in the same way
and will it work ok?

Hi Barrett,

The combination will give you an offcenter, vertical dipole (for
either band you are investigating).

This is not a bad thing, just something that may not tune up the way
you think it "should."

The 10M application will have three sections:
1. The quarterwave whip;
2. a 5/8ths wave lower section (the pole);
3. an undefined length of transmission line (unless you choke it).

73's
Richard Clark, KB7QHC

1/4 Wave on 28.500MHz
 

Thanks Richard


"Richard Clark" wrote in message
...
On Thu, 17 Apr 2008 16:09:10 +0100, "Barrett"
wrote:

I have a stainless steal 1/4 wave length mobile whip.

Can I mount this on top of a 20ft aluminium scaffold pole and use the pole
as the ground radial?
I also have a mobile AM-80 for 80 meters. Can I mount this in the same way
and will it work ok?

Hi Barrett,

The combination will give you an offcenter, vertical dipole (for
either band you are investigating).

This is not a bad thing, just something that may not tune up the way
you think it "should."

The 10M application will have three sections:
1. The quarterwave whip;
2. a 5/8ths wave lower section (the pole);
3. an undefined length of transmission line (unless you choke it).

73's
Richard Clark, KB7QHC

1/4 Wave on 28.500MHz
 

Just went out to get things ready to try the Ariel's out tomorrow and it
occurred to me that the 20ft pole is resting on the patio. To make this
work, would I need to lift the pole off the floor and would 1ft be enough?

Thanks


"Barrett" wrote in message
...
Thanks Richard


"Richard Clark" wrote in message
...
On Thu, 17 Apr 2008 16:09:10 +0100, "Barrett"
wrote:

I have a stainless steal 1/4 wave length mobile whip.

Can I mount this on top of a 20ft aluminium scaffold pole and use the
pole
as the ground radial?
I also have a mobile AM-80 for 80 meters. Can I mount this in the same
way
and will it work ok?

Hi Barrett,

The combination will give you an offcenter, vertical dipole (for
either band you are investigating).

This is not a bad thing, just something that may not tune up the way
you think it "should."

The 10M application will have three sections:
1. The quarterwave whip;
2. a 5/8ths wave lower section (the pole);
3. an undefined length of transmission line (unless you choke it).

73's
Richard Clark, KB7QHC

1/4 Wave on 28.500MHz
 

Barrett wrote:
Just went out to get things ready to try the Ariel's out tomorrow and it
occurred to me that the 20ft pole is resting on the patio. To make this
work, would I need to lift the pole off the floor and would 1ft be enough?

Depends on whether the patio is conductive or not.
Probably best to rest the base on an insulator.
Also be aware that, at 100 watts, there will be
hundreds, if not thousands of volts present at
the base of the pole. I once keyed down while
a cat was standing on one of my radials. Not
sure where it went, but it might have gone
into orbit. Have you considered sleeving the
pole inside PVC pipe for safety reasons?
--
73, Cecil http://www.w5dxp.com

1/4 Wave on 28.500MHz
 

On Thu, 17 Apr 2008 19:17:23 +0100, "Barrett"
wrote:

Just went out to get things ready to try the Ariel's out tomorrow and it
occurred to me that the 20ft pole is resting on the patio. To make this
work, would I need to lift the pole off the floor and would 1ft be enough?

Hi Barrett,

Not something I would worry about. Others may, and they will
certainly chime in if they do. I had a 10M vertical off-center dipole
mounted about 1 foot above ground and it seemed to work fine; but not
as well as my buddies with higher antennas. My guess is that an 80M
version may suffer more. I fed the transmission line up through the
bottom section.

73's
Richard Clark, KB7QHC

1/4 Wave on 28.500MHz
 

In message , Cecil Moore
writes
Barrett wrote:
Just went out to get things ready to try the Ariel's out tomorrow and
it occurred to me that the 20ft pole is resting on the patio. To make
this work, would I need to lift the pole off the floor and would 1ft
be enough?

Depends on whether the patio is conductive or not.
Probably best to rest the base on an insulator.
Also be aware that, at 100 watts, there will be
hundreds, if not thousands of volts present at
the base of the pole. I once keyed down while
a cat was standing on one of my radials. Not
sure where it went, but it might have gone
into orbit. Have you considered sleeving the
pole inside PVC pipe for safety reasons?

A glass jar (eg a jam jar) makes an effective insulator for the base of
a pole. Or a polythene bucket!
--
Ian

1/4 Wave on 28.500MHz
 

Ian Jackson wrote:
A glass jar (eg a jam jar) makes an effective insulator for the base of
a pole. Or a polythene bucket!

Remember when we used to use those one quart
Coca-Cola bottles that down-spouts fit over
perfectly?
--
73, Cecil http://www.w5dxp.com

1/4 Wave on 28.500MHz
 

Cecil, got a question for you.
I have another 20ft pole mounted on the back of my house and it is rested on
the patio floor. I plane to put up a Cushcraft MA5B on this pole and a 2/70
collinear on top. Does this mean that there will be high voltage on the pole
beneath the beam from the beam or from the collinear?

The children will be out in the garden when the weather gets better.

Thanks


"Cecil Moore" wrote in message
...
Barrett wrote:
Just went out to get things ready to try the Ariel's out tomorrow and it
occurred to me that the 20ft pole is resting on the patio. To make this
work, would I need to lift the pole off the floor and would 1ft be
enough?

Depends on whether the patio is conductive or not.
Probably best to rest the base on an insulator.
Also be aware that, at 100 watts, there will be
hundreds, if not thousands of volts present at
the base of the pole. I once keyed down while
a cat was standing on one of my radials. Not
sure where it went, but it might have gone
into orbit. Have you considered sleeving the
pole inside PVC pipe for safety reasons?
--
73, Cecil http://www.w5dxp.com

1/4 Wave on 28.500MHz
 

Barrett wrote:
Cecil, got a question for you.
I have another 20ft pole mounted on the back of my house and it is rested on
the patio floor. I plan to put up a Cushcraft MA5B on this pole and a 2/70
collinear on top. Does this mean that there will be high voltage on the pole
beneath the beam from the beam or from the collinear?

Are the beam and collinear isolated from the pole?
If so, there's probably no real problem.

If a mobile antenna is being used with the pole as
the counterpoise, then about half of the RF energy
flows in the pole. RF burns can be the result.
--
73, Cecil http://www.w5dxp.com