What happens if you exceed the wattage of a transmitter antenna...

[Unlisted]

I have a FM OMNI antenna hooked to a 30 watt fm transmitter. The antenna
is rated at 50 watts max. What would happen if i ran a 60 watt
transmitter thru it? Or 100 watts? Will the antenna melt or what?

 

[Mike Coon]

In article <s3lkls$pml$1@dont-email.me>, fizzbintuesday@that-google-
mail-domain.com says...

Mike Coon wrote:

But then pigeon shit on the antenna might lead to discovering Cosmic
microwave background radiation
https://en.wikipedia.org/wiki/Cosmic_microwave_background ...

That doesn\'t mention pigeons or birds. I vaguely remember there was a
connection to the need to clean out the horns, but it would seem to be
irrelevant since they would have detected the radiation anyway.

Ah, maybe the pigeon shit angle is a physics equivalent of an urban
myth. I believe it was the temperature spectrum of the radiation that
had to be determined, but I may actually read that article...

 

[Phil Hobbs]

Mike Coon wrote:

In article <s3lkls$pml$1@dont-email.me>, fizzbintuesday@that-google-
mail-domain.com says...

Mike Coon wrote:

But then pigeon shit on the antenna might lead to discovering Cosmic
microwave background radiation
https://en.wikipedia.org/wiki/Cosmic_microwave_background ...

That doesn\'t mention pigeons or birds. I vaguely remember there was a
connection to the need to clean out the horns, but it would seem to be
irrelevant since they would have detected the radiation anyway.

Ah, maybe the pigeon shit angle is a physics equivalent of an urban
myth. I believe it was the temperature spectrum of the radiation that
had to be determined, but I may actually read that article...

The excess noise measurement came first. Then Penzias and Wilson
started looking for any possible terrestrial noise sources. Bird
droppings are a lossy dielectric among their other less pleasant
properties, so P&W cleaned their horn antenna carefully, calibrated the
receiver, and so on, but the noise was still there.

There\'s still science today that\'s done that carefully, but I fear it
has gotten a lot less common. (Certainly the quality of papers I get
sent to review has tanked in the last 25 years or so--and yes, it\'s the
same journals.)

Cheers

Phil Hobbs

 

[Phil Hobbs]

Mike Coon wrote:

In article <s3lkls$pml$1@dont-email.me>, fizzbintuesday@that-google-
mail-domain.com says...

Mike Coon wrote:

But then pigeon shit on the antenna might lead to discovering Cosmic
microwave background radiation
https://en.wikipedia.org/wiki/Cosmic_microwave_background ...

That doesn\'t mention pigeons or birds. I vaguely remember there was a
connection to the need to clean out the horns, but it would seem to be
irrelevant since they would have detected the radiation anyway.

Ah, maybe the pigeon shit angle is a physics equivalent of an urban
myth. I believe it was the temperature spectrum of the radiation that
had to be determined, but I may actually read that article...

The excess noise measurement came first. Then Penzias and Wilson
started looking for any possible terrestrial noise sources. Bird
droppings are a lossy dielectric among their other less pleasant
properties, so P&W cleaned their horn antenna carefully, calibrated the
receiver, and so on, but the noise was still there.

There\'s still science today that\'s done that carefully, but I fear it
has gotten a lot less common. (Certainly the quality of papers I get
sent to review has tanked in the last 25 years or so--and yes, it\'s the
same journals.)

Cheers

Phil Hobbs

 

[Fox\'s Mercantile]

On 3/23/21 6:22 PM, Unlisted wrote:

I have a FM OMNI antenna hooked to a 30 watt fm transmitter. The antenna
is rated at 50 watts max. What would happen if i ran a 60 watt
transmitter thru it? Or 100 watts? Will the antenna melt or what?

Two things limit the power handling capability of an antenna.
The RF current abilities of any coils of wire, and the RF voltage
breakdown rating of any insulation.

As to whether or not it would put up with 60 or 100 watts, that\'s
entirely dependent on how well (over designed) that antenna was
made.



--
\"I am a river to my people.\"
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[Phil Allison]

Fox\'s Mercantile wrote:

---------------------------------------

:
I have a FM OMNI antenna hooked to a 30 watt fm transmitter. The antenna
is rated at 50 watts max. What would happen if i ran a 60 watt
transmitter thru it? Or 100 watts? Will the antenna melt or what?

Two things limit the power handling capability of an antenna.
The RF current abilities of any coils of wire, and the RF voltage
breakdown rating of any insulation.

** Ain\'t it more likely to be a user safety issue ?

50 watts at 50 ohms = 50V rms .



...... Phil

 

[John Robertson]

On 2021/03/23 9:31 p.m., Phil Allison wrote:

Fox\'s Mercantile wrote:

---------------------------------------
:
I have a FM OMNI antenna hooked to a 30 watt fm transmitter. The antenna
is rated at 50 watts max. What would happen if i ran a 60 watt
transmitter thru it? Or 100 watts? Will the antenna melt or what?

Two things limit the power handling capability of an antenna.
The RF current abilities of any coils of wire, and the RF voltage
breakdown rating of any insulation.


** Ain\'t it more likely to be a user safety issue ?

50 watts at 50 ohms = 50V rms .



..... Phil

Might be hard on the pigeons...

John ;-#)#

 

[John Robertson]

On 2021/03/23 9:31 p.m., Phil Allison wrote:

Fox\'s Mercantile wrote:

---------------------------------------
:
I have a FM OMNI antenna hooked to a 30 watt fm transmitter. The antenna
is rated at 50 watts max. What would happen if i ran a 60 watt
transmitter thru it? Or 100 watts? Will the antenna melt or what?

Two things limit the power handling capability of an antenna.
The RF current abilities of any coils of wire, and the RF voltage
breakdown rating of any insulation.


** Ain\'t it more likely to be a user safety issue ?

50 watts at 50 ohms = 50V rms .



..... Phil

Might be hard on the pigeons...

John ;-#)#

 

[Mike Coon]

In article <e9ydnepOVOCJTMf9nZ2dnUU7-SmdnZ2d@giganews.com>,
spam@flippers.com says...

On 2021/03/23 9:31 p.m., Phil Allison wrote:
Fox\'s Mercantile wrote:

---------------------------------------
:
I have a FM OMNI antenna hooked to a 30 watt fm transmitter. The antenna
is rated at 50 watts max. What would happen if i ran a 60 watt
transmitter thru it? Or 100 watts? Will the antenna melt or what?

Two things limit the power handling capability of an antenna.
The RF current abilities of any coils of wire, and the RF voltage
breakdown rating of any insulation.


** Ain\'t it more likely to be a user safety issue ?

50 watts at 50 ohms = 50V rms .

..... Phil


Might be hard on the pigeons...

John ;-#)#

But then pigeon shit on the antenna might lead to discovering Cosmic
microwave background radiation
https://en.wikipedia.org/wiki/Cosmic_microwave_background ...

 

[Mike Coon]

In article <e9ydnepOVOCJTMf9nZ2dnUU7-SmdnZ2d@giganews.com>,
spam@flippers.com says...

On 2021/03/23 9:31 p.m., Phil Allison wrote:
Fox\'s Mercantile wrote:

---------------------------------------
:
I have a FM OMNI antenna hooked to a 30 watt fm transmitter. The antenna
is rated at 50 watts max. What would happen if i ran a 60 watt
transmitter thru it? Or 100 watts? Will the antenna melt or what?

Two things limit the power handling capability of an antenna.
The RF current abilities of any coils of wire, and the RF voltage
breakdown rating of any insulation.


** Ain\'t it more likely to be a user safety issue ?

50 watts at 50 ohms = 50V rms .

..... Phil


Might be hard on the pigeons...

John ;-#)#

But then pigeon shit on the antenna might lead to discovering Cosmic
microwave background radiation
https://en.wikipedia.org/wiki/Cosmic_microwave_background ...

 

[Ralph Mowery]

In article <494d4ddc-4d84-4291-ba6b-6a2049fa4dc4n@googlegroups.com>,
pallison49@gmail.com says...

:
I have a FM OMNI antenna hooked to a 30 watt fm transmitter. The antenna
is rated at 50 watts max. What would happen if i ran a 60 watt
transmitter thru it? Or 100 watts? Will the antenna melt or what?

Two things limit the power handling capability of an antenna.
The RF current abilities of any coils of wire, and the RF voltage
breakdown rating of any insulation.


** Ain\'t it more likely to be a user safety issue ?

50 watts at 50 ohms = 50V rms .

Just thought of one more issue. Some antennas have capacitors in them
and they will have a limit of voltage and current .

Some antennas can heat up enough (usually the coils) to melt out the
plastic parts seperating the elements.

Anyway it is usually the components that make up the antenna that
determin how much power they will withstand.

Too much power and you either get a voltage breakdown of the components
or a heat melt down of the components, or a combination of both.

 

[Ralph Mowery]

In article <494d4ddc-4d84-4291-ba6b-6a2049fa4dc4n@googlegroups.com>,
pallison49@gmail.com says...

:
I have a FM OMNI antenna hooked to a 30 watt fm transmitter. The antenna
is rated at 50 watts max. What would happen if i ran a 60 watt
transmitter thru it? Or 100 watts? Will the antenna melt or what?

Two things limit the power handling capability of an antenna.
The RF current abilities of any coils of wire, and the RF voltage
breakdown rating of any insulation.


** Ain\'t it more likely to be a user safety issue ?

50 watts at 50 ohms = 50V rms .

Just thought of one more issue. Some antennas have capacitors in them
and they will have a limit of voltage and current .

Some antennas can heat up enough (usually the coils) to melt out the
plastic parts seperating the elements.

Anyway it is usually the components that make up the antenna that
determin how much power they will withstand.

Too much power and you either get a voltage breakdown of the components
or a heat melt down of the components, or a combination of both.

 

[Phil Allison]

Ralph Mowery wrote:
==================

Two things limit the power handling capability of an antenna.
The RF current abilities of any coils of wire, and the RF voltage
breakdown rating of any insulation.

** Ain\'t it more likely to be a user safety issue ?

50 watts at 50 ohms = 50V rms .


Just thought of one more issue. Some antennas have capacitors in them
and they will have a limit of voltage and current .

Some antennas can heat up enough (usually the coils) to melt out the
plastic parts seperating the elements.

** The makers have experience with such failures and set a safe limit to prevent complaints.


..... Phil

 

[Phil Allison]

Ralph Mowery wrote:
==================

Two things limit the power handling capability of an antenna.
The RF current abilities of any coils of wire, and the RF voltage
breakdown rating of any insulation.

** Ain\'t it more likely to be a user safety issue ?

50 watts at 50 ohms = 50V rms .


Just thought of one more issue. Some antennas have capacitors in them
and they will have a limit of voltage and current .

Some antennas can heat up enough (usually the coils) to melt out the
plastic parts seperating the elements.

** The makers have experience with such failures and set a safe limit to prevent complaints.


..... Phil

 

[Phil Allison]

Ralph Mowery wrote:
==================

Two things limit the power handling capability of an antenna.
The RF current abilities of any coils of wire, and the RF voltage
breakdown rating of any insulation.

** Ain\'t it more likely to be a user safety issue ?

50 watts at 50 ohms = 50V rms .


Just thought of one more issue. Some antennas have capacitors in them
and they will have a limit of voltage and current .

Some antennas can heat up enough (usually the coils) to melt out the
plastic parts seperating the elements.

** The makers have experience with such failures and set a safe limit to prevent complaints.


..... Phil

 

[Ralph Mowery]

In article <599bdc13-5c2c-4ae3-8451-5f575e1ea6abn@googlegroups.com>,
pallison49@gmail.com says...

** The makers have experience with such failures and set a safe limit to prevent complaints.

Sometimes they do, some times they don\'t.

Around 1980 some hams were sending radio teletype using around 500 watts
into trap beams and melting out the traps. The antennas were rated for
the full power limit of over 1000 watts. However as it turned out the
1000 wats was for peak power of sideband and not continious power that
was being sent to the antenna. The antenna companies had to revise
their specifications.

 

[Ralph Mowery]

In article <599bdc13-5c2c-4ae3-8451-5f575e1ea6abn@googlegroups.com>,
pallison49@gmail.com says...

** The makers have experience with such failures and set a safe limit to prevent complaints.

Sometimes they do, some times they don\'t.

Around 1980 some hams were sending radio teletype using around 500 watts
into trap beams and melting out the traps. The antennas were rated for
the full power limit of over 1000 watts. However as it turned out the
1000 wats was for peak power of sideband and not continious power that
was being sent to the antenna. The antenna companies had to revise
their specifications.

 

[Ralph Mowery]

In article <599bdc13-5c2c-4ae3-8451-5f575e1ea6abn@googlegroups.com>,
pallison49@gmail.com says...

** The makers have experience with such failures and set a safe limit to prevent complaints.

Sometimes they do, some times they don\'t.

Around 1980 some hams were sending radio teletype using around 500 watts
into trap beams and melting out the traps. The antennas were rated for
the full power limit of over 1000 watts. However as it turned out the
1000 wats was for peak power of sideband and not continious power that
was being sent to the antenna. The antenna companies had to revise
their specifications.

 

[Phil Allison]

Ralph Mowery wrote:
=================

** The makers have experience with such failures and set a safe limit to prevent complaints.

Sometimes they do, some times they don\'t.

Around 1980 some hams were sending radio teletype using around 500 watts
into trap beams and melting out the traps. The antennas were rated for
the full power limit of over 1000 watts. However as it turned out the
1000 wats was for peak power of sideband and not continious power that
was being sent to the antenna. The antenna companies had to revise
their specifications.

** Just shows that experience comes first.

** Once upon a time loudspeaker makers rated their products power handling based on normal home usage - even if used with a guitar amplifier. Then \" hard rock \" was invented and blew that method out of the water.



...... Phil

 

[Phil Allison]

Ralph Mowery wrote:
=================

** The makers have experience with such failures and set a safe limit to prevent complaints.

Sometimes they do, some times they don\'t.

Around 1980 some hams were sending radio teletype using around 500 watts
into trap beams and melting out the traps. The antennas were rated for
the full power limit of over 1000 watts. However as it turned out the
1000 wats was for peak power of sideband and not continious power that
was being sent to the antenna. The antenna companies had to revise
their specifications.

** Just shows that experience comes first.

** Once upon a time loudspeaker makers rated their products power handling based on normal home usage - even if used with a guitar amplifier. Then \" hard rock \" was invented and blew that method out of the water.



...... Phil