Antenna link

A

AssTelescope

Guest
Hi,

A while ago i posted a question about what I can do with that dish i found.
Something useful i though others might like

http://www.wwc.edu/~frohro/Airport/Primestar/Primestar.html
 
"AssTelescope" <jasd@aaaa> wrote in message
news:41cf446c$1@duster.adelaide.on.net...
Hi,

A while ago i posted a question about what I can do with that dish i
found.
Something useful i though others might like

http://www.wwc.edu/~frohro/Airport/Primestar/Primestar.html
Click to expand...
I think that this size dish is too small for the 2.4 GHz that the can
antenna is putting out. Probably a lot of the signal just goes out the
back and is wasted.
 
"Clarence_A" <no@No.com> wrote in message news:DA4Ad.3229$wZ2.1179@newssvr13.news.prodigy.com...
"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote in
message news:10t1gf95av8ca85@corp.supernews.com...
....
I think that this size dish is too small for the 2.4 GHz that the can
antenna is putting out. Probably a lot of the signal just goes out the
back and is wasted.


???
At 2.4GHz a full wave is .00041 inches. The reflector will work just fine!
getting it at the focus is more of a problem.
Click to expand...
In my universe, the wavelength in free space is more
like 4.9 inches at 2.4 GHz. I'm willing to believe c
is different in your neighborhood, but please tell me
how you post here from over there.

--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.
 
"Tom MacIntyre" <tom__macintyre@hotmail.com> wrote in message
news:kbi3t05ldli3fvr20fejg0pvu4i2o4nk9h@4ax.com...
On Tue, 28 Dec 2004 13:39:30 -0330, "Terry" <tsanford@nf.sympatico.ca
wrote:

12.5 mm is 0.4921259 inches on this planet ...... snipped .........
Nope: Ignoring the banter. It's 4.9 inches!
No it isn't...12.5 cm is 4.9-whatever inches.
Tom
Click to expand...

Perhaps you mean 4.9212598?
 
"Terry" <tsanford@nf.sympatico.ca> wrote in message
news:8tgAd.22312$Tn1.769112@news20.bellglobal.com...
12.5 mm is 0.4921259 inches on this planet ...... snipped .........

Nope: Ignoring the banter. It's 4.9 inches!
Click to expand...
Wrong again.

Whatever you think, 12.5 mm is really 0.4921259 inches.

Yes the wavelength at 2.4 gigahertz is 4.92 inches or 12.5 CENTIMETRES
but I was replying to the conversion in the previous post which was
MILLImetres to inches
--
John G

Wot's Your Real Problem?
..
 
"Tom MacIntyre" <tom__macintyre@hotmail.com> wrote in message
news:kbi3t05ldli3fvr20fejg0pvu4i2o4nk9h@4ax.com...
On Tue, 28 Dec 2004 13:39:30 -0330, "Terry" <tsanford@nf.sympatico.ca
wrote:


12.5 mm is 0.4921259 inches on this planet ...... snipped .........

Nope: Ignoring the banter. It's 4.9 inches!

No it isn't...12.5 cm is 4.9-whatever inches.

Tom
Click to expand...
Well, the way I figured it is 3x10^8 / 2.45x10^9 = .12245 meters =
12.245 CM

..12245 * 39.37 = 4.82 inches.

Of course, that xdoesn't take into account that the speed of light is a
bit less in the antenna, so it's maybe 5% too long.
 
"John G" <Greentest@ozemail.com.au> wrote in message
news:kMaAd.112$564.6209@nnrp1.ozemail.com.au...
"Clarence_A" <no@No.com> wrote in message
news:IZ8Ad.4054$yV1.3737@newssvr14.news.prodigy.com...

"Larry Brasfield" <donotspam_larry_brasfield@hotmail.com> wrote in
message
news:qt6Ad.1297$Is5.3323@news.uswest.net...
"Clarence_A" <no@No.com> wrote in message
news:DA4Ad.3229$wZ2.1179@newssvr13.news.prodigy.com...

"Watson A.Name - "Watt Sun, the Dark Remover""
NOSPAM@dslextreme.com
wrote in
message news:10t1gf95av8ca85@corp.supernews.com...
...
I think that this size dish is too small for the 2.4 GHz that
the
can
antenna is putting out. Probably a lot of the signal just goes
out the
back and is wasted.

Gee, I guess I shouldn't try to convert from meters to inches in my
head...
12.5 mm IS closer to 4.9 inches.

12.5 mm is 0.4921259 inches on this planet and has been since the
French
invented the metre.

But then the metre is an unknown standard in the USA isn't it?
Click to expand...
No, it is not. Rulers and tape measures come with both scales.
So the ultimate question is, "Wot's Your Real Problem?"

--
John G

Wot's Your Real Problem?
Click to expand...
 
"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote in
message news:10t1gf95av8ca85@corp.supernews.com...
"AssTelescope" <jasd@aaaa> wrote in message
news:41cf446c$1@duster.adelaide.on.net...
Hi,

A while ago i posted a question about what I can do with that dish i
found.
Something useful i though others might like

http://www.wwc.edu/~frohro/Airport/Primestar/Primestar.html

I think that this size dish is too small for the 2.4 GHz that the can
antenna is putting out. Probably a lot of the signal just goes out the
back and is wasted.


???
Click to expand...
At 2.4GHz a full wave is .00041 inches. The reflector will work just fine!
getting it at the focus is more of a problem.
 
"Clarence_A" <no@No.com> wrote in message
news:DA4Ad.3229$wZ2.1179@newssvr13.news.prodigy.com...
"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote in
message news:10t1gf95av8ca85@corp.supernews.com...

"AssTelescope" <jasd@aaaa> wrote in message
news:41cf446c$1@duster.adelaide.on.net...
Hi,

A while ago i posted a question about what I can do with that dish
i
found.
Something useful i though others might like

http://www.wwc.edu/~frohro/Airport/Primestar/Primestar.html

I think that this size dish is too small for the 2.4 GHz that the
can
antenna is putting out. Probably a lot of the signal just goes out
the
back and is wasted.


???
At 2.4GHz a full wave is .00041 inches. The reflector will work just
fine!
getting it at the focus is more of a problem.
Click to expand...
You'd better recalculate that wavelength. More like it's a bit less
than 5 inches. And that antenna dish was made for frequencies much
higher than 2.45 GHz with wavelengths much shorter.
 
"Larry Brasfield" <donotspam_larry_brasfield@hotmail.com> wrote in message
news:qt6Ad.1297$Is5.3323@news.uswest.net...
"Clarence_A" <no@No.com> wrote in message
news:DA4Ad.3229$wZ2.1179@newssvr13.news.prodigy.com...

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote in
message news:10t1gf95av8ca85@corp.supernews.com...
...
I think that this size dish is too small for the 2.4 GHz that the can
antenna is putting out. Probably a lot of the signal just goes out the
back and is wasted.


???
At 2.4GHz a full wave is .00041 inches. The reflector will work just fine!
Click to expand...
SB 4.1 inches....... !

getting it at the focus is more of a problem.

In my universe, the wavelength in free space is more
like 4.9 inches at 2.4 GHz. I'm willing to believe c
is different in your neighborhood, but please tell me
how you post here from over there.

Yes, bad copy.... The point was that the reflector is made for 8 to 10GHz, so
Click to expand...
it will work. IF the feed is at the focalpoint.
 
"Larry Brasfield" <donotspam_larry_brasfield@hotmail.com> wrote in message
news:qt6Ad.1297$Is5.3323@news.uswest.net...
"Clarence_A" <no@No.com> wrote in message
news:DA4Ad.3229$wZ2.1179@newssvr13.news.prodigy.com...

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote in
message news:10t1gf95av8ca85@corp.supernews.com...
...
I think that this size dish is too small for the 2.4 GHz that the can
antenna is putting out. Probably a lot of the signal just goes out the
back and is wasted.
Click to expand...
Gee, I guess I shouldn't try to convert from meters to inches in my head...
12.5 mm IS closer to 4.9 inches.
 
"Clarence_A" <no@No.com> wrote in message
news:IZ8Ad.4054$yV1.3737@newssvr14.news.prodigy.com...
"Larry Brasfield" <donotspam_larry_brasfield@hotmail.com> wrote in
message
news:qt6Ad.1297$Is5.3323@news.uswest.net...
"Clarence_A" <no@No.com> wrote in message
news:DA4Ad.3229$wZ2.1179@newssvr13.news.prodigy.com...

"Watson A.Name - "Watt Sun, the Dark Remover""
NOSPAM@dslextreme.com
wrote in
message news:10t1gf95av8ca85@corp.supernews.com...
...
I think that this size dish is too small for the 2.4 GHz that the
can
antenna is putting out. Probably a lot of the signal just goes
out the
back and is wasted.

Gee, I guess I shouldn't try to convert from meters to inches in my
head...
12.5 mm IS closer to 4.9 inches.

12.5 mm is 0.4921259 inches on this planet and has been since the French
Click to expand...
invented the metre.

But then the metre is an unknown standard in the USA isn't it?
--
John G

Wot's Your Real Problem?
 
12.5 mm is 0.4921259 inches on this planet ...... snipped .........

Nope: Ignoring the banter. It's 4.9 inches!
Click to expand...

At 2.4 gHz One Wavelength = 300/2400 = 0.125 metres = 12.5 centimetres

Centimetres!
(A typical 6" 8" doorway is roughly two metres or two hundred centimetres
high).
And one hundred centimetres is roughly 39.3 inches.
So 12.5/100 x 39.3 = 4.9 inches.

But the 'probe' that launches and receives the signal would presumably be
one quarter wavelength? To match the 50 ohm feed line?
So probe length (inside the can and hopefully at the dish focal point?)
would be 4.9/4 = 1.23 inches approx?????????

The dish being 'too small', having been designed for 10 gigahertz would have
only a portion of the capture area . It would therefore exhibit a 'loss' or
'lower gain' at 2.4 gHz? Possibly expressed in decibels?

f w
m.hertz centimetres
300 100 (One metre)
600 50
1200 25
2400 12.5
4800 6.25
9600 ` 3.125

Here in Canada we are becoming pretty well bilingual in regard to metric or
non-metric.
We measure building materials both ways. Gasoline in litres and distances in
kilometres. Car engines in may countries have been measured in litres/ccs
for years! Radio wavelength which is inversely related to frequency has been
measured in metres almost from the word go.
I've never heard of radio station frequency or wavelength measured in feet
or miles?

Terry.
 
"Terry" <tsanford@nf.sympatico.ca> wrote in message
news:8tgAd.22312$Tn1.769112@news20.bellglobal.com...
12.5 mm is 0.4921259 inches on this planet ...... snipped .........

Nope: Ignoring the banter. It's 4.9 inches!

At 2.4 gHz One Wavelength = 300/2400 = 0.125 metres = 12.5 centimetres

Centimetres!
(A typical 6" 8" doorway is roughly two metres or two hundred centimetres
high).
And one hundred centimetres is roughly 39.3 inches.
So 12.5/100 x 39.3 = 4.9 inches.

But the 'probe' that launches and receives the signal would presumably be
one quarter wavelength? To match the 50 ohm feed line?
So probe length (inside the can and hopefully at the dish focal point?)
would be 4.9/4 = 1.23 inches approx?????????

The dish being 'too small', having been designed for 10 gigahertz would have
only a portion of the capture area . It would therefore exhibit a 'loss' or
'lower gain' at 2.4 gHz? Possibly expressed in decibels?
Click to expand...
One quarter the size would reduce the gain by about 6db. Still substantial!

f w
m.hertz centimetres
300 100 (One metre)
600 50
1200 25
2400 12.5
4800 6.25
9600 ` 3.125

Here in Canada we are becoming pretty well bilingual in regard to metric or
non-metric.
We measure building materials both ways. Gasoline in litres and distances in
kilometres. Car engines in may countries have been measured in litres/ccs
for years! Radio wavelength which is inversely related to frequency has been
measured in metres almost from the word go.
I've never heard of radio station frequency or wavelength measured in feet
or miles?

Terry.
Click to expand...
Can't spell it, but it MUST be the way to go?
BTW, you buy 'petrol' in liters, distance is approximated in Kilometers, and
all are convertible to usable numbers with care if the person doing it isn't
too tired!

Seems pretty easy to tweak you guys. :)>)
However 'metric meters' are a rather recent invention. Feet and inches were
used since the invention of radio. Before that "Cubits" "fathoms" and
'leagues' were the standard!
 
On Tue, 28 Dec 2004 13:39:30 -0330, "Terry" <tsanford@nf.sympatico.ca>
wrote:

12.5 mm is 0.4921259 inches on this planet ...... snipped .........

Nope: Ignoring the banter. It's 4.9 inches!
Click to expand...
No it isn't...12.5 cm is 4.9-whatever inches.

Tom
 
"Clarence_A" <no@No.com> wrote in message
news:IZ8Ad.4054$yV1.3737@newssvr14.news.prodigy.com...
"Larry Brasfield" <donotspam_larry_brasfield@hotmail.com> wrote in
message
news:qt6Ad.1297$Is5.3323@news.uswest.net...
"Clarence_A" <no@No.com> wrote in message
news:DA4Ad.3229$wZ2.1179@newssvr13.news.prodigy.com...

"Watson A.Name - "Watt Sun, the Dark Remover""
NOSPAM@dslextreme.com
wrote in
message news:10t1gf95av8ca85@corp.supernews.com...
...
I think that this size dish is too small for the 2.4 GHz that the
can
antenna is putting out. Probably a lot of the signal just goes
out the
back and is wasted.

Gee, I guess I shouldn't try to convert from meters to inches in my
head...
12.5 mm IS closer to 4.9 inches.
Click to expand...
I think you had better try again - practice makes perfect. 4.9 inches
is right, but 12.5 mm is about a half inch. Try 12.5 CM.
 
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