Through-glass antenna power limits
 

(I realize that a through-the-glass antenna is less than ideal.
Nevertheless, that's what I have to use in my situation.) The one I
have is for 2 meters (NOT dual band), and the label says up to 50
watts. I have an Icom IC-2200H, which has a maximum of 65 watts
output.

What bad things may/could/will happen if I put 65 watts through the
antenna?

Thanks!

Tom Mitchell -- KG7U
Port Angeles, Washington. USA
--------------------------------------------------------------------------
Tom Mitchell, Port Angeles, Washington, USA
http://www.olympus.net/personal/kg7u
--------------------------------------------------------------------------

Through-glass antenna power limits
 

"Thomas & Karen Mitchell" kg7uATolympus.net wrote in message
...
(I realize that a through-the-glass antenna is less than ideal.
Nevertheless, that's what I have to use in my situation.) The one I
have is for 2 meters (NOT dual band), and the label says up to 50
watts. I have an Icom IC-2200H, which has a maximum of 65 watts
output.

What bad things may/could/will happen if I put 65 watts through the
antenna?

Thanks!

Tom Mitchell -- KG7U
Port Angeles, Washington. USA
--------------------------------------------------------------------------
Tom Mitchell, Port Angeles, Washington, USA
http://www.olympus.net/personal/kg7u
--------------------------------------------------------------------------

Tom

Through glass antennas work using capacitance. The two plates either side of
the glass form the capacitance with the glass acting as the insulator.
Attempting to put too much power through a capacitor usually results in
overheating or a breakdown of the insulator. This could potentially result
in a broken screen.

Another thing to consider is the mismatch that the through glass capacitor
makes with your transmitter. Some of the power will inevitably be reflected
back to the output stages causing possible overheating at full power.

I would guess that 65 watts would be safe enough for brief transmissions but
for longer chats keep the power down below 50 watts. For mobile use, the
difference in signal strength, a fraction of an S-point, is unlikely to be
noticed by anyone receiving your signal.

Mike G0ULI

Through-glass antenna power limits
 

"Mike Kaliski" wrote in message
...

"Thomas & Karen Mitchell" kg7uATolympus.net wrote in message
...
(I realize that a through-the-glass antenna is less than ideal.
Nevertheless, that's what I have to use in my situation.) The one I
have is for 2 meters (NOT dual band), and the label says up to 50
watts. I have an Icom IC-2200H, which has a maximum of 65 watts
output.

What bad things may/could/will happen if I put 65 watts through the
antenna?

Thanks!

Tom Mitchell -- KG7U
Port Angeles, Washington. USA
--------------------------------------------------------------------------
Tom Mitchell, Port Angeles, Washington, USA
http://www.olympus.net/personal/kg7u
--------------------------------------------------------------------------

Tom

Through glass antennas work using capacitance. The two plates either side
of
the glass form the capacitance with the glass acting as the insulator.
Attempting to put too much power through a capacitor usually results in
overheating or a breakdown of the insulator. This could potentially result
in a broken screen.

Another thing to consider is the mismatch that the through glass capacitor
makes with your transmitter. Some of the power will inevitably be
reflected
back to the output stages causing possible overheating at full power.

I would guess that 65 watts would be safe enough for brief transmissions
but
for longer chats keep the power down below 50 watts. For mobile use, the
difference in signal strength, a fraction of an S-point, is unlikely to be
noticed by anyone receiving your signal.

Mike G0ULI



My friend has a 71 Dodge Charger, He used one because he didnt want to drill
any holes in this classic muscle car. He made the mistake of running about
200 wats to the antenna and it caused the plastic sheet in the saftey glas
to delaminate.. He has a big white spot on the edge of his rear window now.
I have run one without any damage to the window but I got a lot of picket
fencing with it. Didnt keep it for long.

Unless you are talking about a classic car drilling a hole in the roof
doesnt effect resell valure

Jimmie

Through-glass antenna power limits
 

Used a 110 watt MASTR 2 mobile through one in 1980s.

What happens after about 2 minutes of talk time -- box heats up and SWR
rises substantially.
When I removed the tuning box a couple years later -- components toasted.

SO, when it says 50 watts maximum -- they mean it.

gb


"Thomas & Karen Mitchell" kg7uATolympus.net wrote in message
...
(I realize that a through-the-glass antenna is less than ideal.
Nevertheless, that's what I have to use in my situation.) The one I
have is for 2 meters (NOT dual band), and the label says up to 50
watts. I have an Icom IC-2200H, which has a maximum of 65 watts
output.

What bad things may/could/will happen if I put 65 watts through the
antenna?

Thanks!

Tom Mitchell -- KG7U
Port Angeles, Washington. USA
--------------------------------------------------------------------------
Tom Mitchell, Port Angeles, Washington, USA
http://www.olympus.net/personal/kg7u
--------------------------------------------------------------------------

Through-glass antenna power limits
 

Thomas & Karen Mitchell wrote:
(I realize that a through-the-glass antenna is less than ideal.
Nevertheless, that's what I have to use in my situation.) The one I
have is for 2 meters (NOT dual band), and the label says up to 50
watts. I have an Icom IC-2200H, which has a maximum of 65 watts
output.

What bad things may/could/will happen if I put 65 watts through the
antenna?

Thanks!

Tom Mitchell -- KG7U
Port Angeles, Washington. USA
--------------------------------------------------------------------------
Tom Mitchell, Port Angeles, Washington, USA
http://www.olympus.net/personal/kg7u
--------------------------------------------------------------------------


Tom;

The only thing you want to watch out for is to not place the antenna
pads on one of the defrost wires.
I have used one in the past with good success.
Dave WD9BDZ

Through-glass antenna power limits
 

These are not the most effecient, and depending on
the
glass, you may find that there is some metalic
content in the glass, makeing a perfect match
impossible. Think was a pic, in QST couple months
ago of one (struck by lightning), showed the
fractured glass. But, the difference between
50 and 65 watts is very little in the scheme of
things, Maybe 1 Db. Most likely would make little
difference- the METAL CONTENT of the glass, would
make more difference , as the loss would be heat!
Jim NN7K

Thomas & Karen Mitchell wrote:
(I realize that a through-the-glass antenna is less than ideal.
Nevertheless, that's what I have to use in my situation.) The one I
have is for 2 meters (NOT dual band), and the label says up to 50
watts. I have an Icom IC-2200H, which has a maximum of 65 watts
output.

What bad things may/could/will happen if I put 65 watts through the
antenna?

Thanks!

Tom Mitchell -- KG7U
Port Angeles, Washington. USA
--------------------------------------------------------------------------
Tom Mitchell, Port Angeles, Washington, USA
http://www.olympus.net/personal/kg7u
--------------------------------------------------------------------------

Through-glass antenna power limits
 

"Thomas & Karen Mitchell" kg7uATolympus.net wrote in message
...
(I realize that a through-the-glass antenna is less than ideal.
Nevertheless, that's what I have to use in my situation.) The one I
have is for 2 meters (NOT dual band), and the label says up to 50
watts. I have an Icom IC-2200H, which has a maximum of 65 watts
output.

What bad things may/could/will happen if I put 65 watts through the
antenna?

Thanks!

Tom Mitchell -- KG7U
Port Angeles, Washington. USA
--------------------------------------------------------------------------
Tom Mitchell, Port Angeles, Washington, USA
http://www.olympus.net/personal/kg7u
--------------------------------------------------------------------------
Further to my earlier posting and slightly off topic but I have been
browsing through my car manual and note that the manufacturers specifically
forbid the installation of transmitters operating at more than 10 watts
power. Checking up on this reveals that in the event of some of the
electrical earth bonding connections in the car becoming faulty or breaking
two possible disaster scenarios exist. The first is that the computerised
engine management unit might misfunction causing the engine to suddenly stop
or the antilock braking and stability systems to malfunction. The second is
that the pyrotechnic charges in the airbags might be triggered.

Admittedly these two situations are dependent on a chain of faults/failures
occuring and the manufacturers are just trying to cover themselves against
law suits. Vehicles are tested for electromagnetic immunity at far higher
levels than this, but you might want to double check your manual or with the
manufacturer about the maximum permissible transmitter power if the vehicle
is fairly new, fitted with electronic engine management, safety equipment
and airbags.

Take a deep breath before transmitting with all the controls set to 11...

Mike G0ULI

Through-glass antenna power limits
 

On Mon, 4 Jun 2007 02:43:18 +0100, "Mike Kaliski"
wrote:

Take a deep breath before transmitting with all the controls set to 11...

Hi Mike,

Is the warrantee void within 100 yards of a 50KW AM antenna? Or
howabout those half megawatt LF stations that litter the continent?

73's
Richard Clark, KB7QHC

Through-glass antenna power limits
 

Thanks to one and all. The Icom IC-2200H doesn't have a choice of 50
watts output; it goes from 25 to 65.

So: I'll stay at 25 when in the car.

-- KG7U
--------------------------------------------------------------------------
Tom Mitchell, Port Angeles, Washington, USA
http://www.olympus.net/personal/kg7u
--------------------------------------------------------------------------

Through-glass antenna power limits
 

In my search for knowledge I recently went through a big thrash with
antenna tuners... Because of cost I built my own variable caps... To
keep the size down I experimented with various insulators between the
plates, from air up to glass...

Being that the tuners on 40 and 20 were end matching a half wave
antenna element the circulating tank current was considerable... On
20 meters where the capacitor plates are 1.5" square for resonance the
glass would simply shatter at about 800W for 5 seconds... Plexiglass
would boil internally in roughly 20 seconds leaving this interesting
rippled piece with 'steam' bubbles in the center of the plexi...
Ceramic tiles seemed to work OK, but I didn't find any thin ones
locally and the thick pieces resulted in plates being awkwardly
large...

On 80 meters the glass plates are 4" X 6" and the glass runs barely
above ambient at 2KW...

denny / k8do