What is the highest radio frequency used for astronomy? Is it 3,438
GHz?

According to the link below, it is 3,438 GHz:

http://books.nap.edu/openbook.php?re...=11719&page=11

Is 3,438 GHz the highest radio frequency used for astronomy?

That's very much a matter of convention. It all depends what you
choose to call "radio frequency" and what you choose to call something
else.

As the article you cite points out, the measurements at 3438 GHz
(3.438 THz) blur the lines between microwave measurements (which many
would call "radio") and far-infrared measurements (which may would not
call "radio frequency").

One source I see gives a frequency of 3.0 THz as the boundary between
"microwave" and "infrared". That boundary point is, I believe,
entirely one of human convention - there's no magical change in the
behavior of the signals as you cross from one side of this frequency
to the other.

If you choose to treat the conventional boundary point of 3.0 THz as
being significant for the purpose of your question, then one would
have to say that the 3,438 GHz measurements you refer to are *not*
"radio frequency" measurements, but rather "far-infrared"
measurements.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

"Dave Platt" wrote in message
...
What is the highest radio frequency used for astronomy? Is it 3,438
GHz?

According to the link below, it is 3,438 GHz:

http://books.nap.edu/openbook.php?re...=11719&page=11

Is 3,438 GHz the highest radio frequency used for astronomy?

That's very much a matter of convention. It all depends what you
choose to call "radio frequency" and what you choose to call something
else.

As the article you cite points out, the measurements at 3438 GHz
(3.438 THz) blur the lines between microwave measurements (which many
would call "radio") and far-infrared measurements (which may would not
call "radio frequency").

One source I see gives a frequency of 3.0 THz as the boundary between
"microwave" and "infrared". That boundary point is, I believe,
entirely one of human convention - there's no magical change in the
behavior of the signals as you cross from one side of this frequency
to the other.

If you choose to treat the conventional boundary point of 3.0 THz as
being significant for the purpose of your question, then one would
have to say that the 3,438 GHz measurements you refer to are *not*
"radio frequency" measurements, but rather "far-infrared"
measurements.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

I am curious here. At some point you have to switch from metallic conductors
and antennas to lenses and other optics. Any idea what the highest frequency
RF amplifier works at?

Tam

On 8/30/07 4:31 PM, in article ,
"Tam/WB2TT" wrote:


"Dave Platt" wrote in message
...
What is the highest radio frequency used for astronomy? Is it 3,438
GHz?

According to the link below, it is 3,438 GHz:

http://books.nap.edu/openbook.php?re...=11719&page=11

Is 3,438 GHz the highest radio frequency used for astronomy?

That's very much a matter of convention. It all depends what you
choose to call "radio frequency" and what you choose to call something
else.

As the article you cite points out, the measurements at 3438 GHz
(3.438 THz) blur the lines between microwave measurements (which many
would call "radio") and far-infrared measurements (which may would not
call "radio frequency").

One source I see gives a frequency of 3.0 THz as the boundary between
"microwave" and "infrared". That boundary point is, I believe,
entirely one of human convention - there's no magical change in the
behavior of the signals as you cross from one side of this frequency
to the other.

If you choose to treat the conventional boundary point of 3.0 THz as
being significant for the purpose of your question, then one would
have to say that the 3,438 GHz measurements you refer to are *not*
"radio frequency" measurements, but rather "far-infrared"
measurements.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

I am curious here. At some point you have to switch from metallic conductors
and antennas to lenses and other optics. Any idea what the highest frequency
RF amplifier works at?

Tam



It's all subject to state-of-the-art. 50 years ago 300 MHz. was complex to
work with and 10 GHz. was considered way out there. Today 300 MHz is about
as simple as DC and 10 GHz. is fairly straightforward to work with.

I imagine that in another 50 years or less, Integrated hybrid circuits for 3
THz. will be on the shelf items for experimenters to play with.

On Thu, 30 Aug 2007 17:02:02 -0700, Don Bowey wrote:
"Tam/WB2TT" wrote:
...
I am curious here. At some point you have to switch from metallic conductors
and antennas to lenses and other optics. Any idea what the highest frequency
RF amplifier works at?

It's all subject to state-of-the-art. 50 years ago 300 MHz. was complex to
work with and 10 GHz. was considered way out there. Today 300 MHz is about
as simple as DC and 10 GHz. is fairly straightforward to work with.

I imagine that in another 50 years or less, Integrated hybrid circuits for 3
THz. will be on the shelf items for experimenters to play with.

Whenever they discover neutronium, they can make ångstrom-sized
klystrons. ;-)

Cheers!
Rich

Tam/WB2TT wrote:
"Dave Platt" wrote in message
...
What is the highest radio frequency used for astronomy? Is it 3,438
GHz?

According to the link below, it is 3,438 GHz:

http://books.nap.edu/openbook.php?re...=11719&page=11

Is 3,438 GHz the highest radio frequency used for astronomy?
That's very much a matter of convention. It all depends what you
choose to call "radio frequency" and what you choose to call something
else.

As the article you cite points out, the measurements at 3438 GHz
(3.438 THz) blur the lines between microwave measurements (which many
would call "radio") and far-infrared measurements (which may would not
call "radio frequency").

One source I see gives a frequency of 3.0 THz as the boundary between
"microwave" and "infrared". That boundary point is, I believe,
entirely one of human convention - there's no magical change in the
behavior of the signals as you cross from one side of this frequency
to the other.

If you choose to treat the conventional boundary point of 3.0 THz as
being significant for the purpose of your question, then one would
have to say that the 3,438 GHz measurements you refer to are *not*
"radio frequency" measurements, but rather "far-infrared"
measurements.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

I am curious here. At some point you have to switch from metallic conductors
and antennas to lenses and other optics. Any idea what the highest frequency
RF amplifier works at?

Tam


I have even seen optics and electronics combined in an experimental
Road radar for car control from Philips, radar output was a very small
horn antenna connected to a wave guide, and in front of that they used a
plexyglass condensor lens to make a narrow beam, like you do with light.
Apparently those mm waves liked that plastic lens just fine.

On Aug 30, 5:25 pm, Sjouke Burry
wrote:
Tam/WB2TT wrote:
"Dave Platt" wrote in message
...
What is the highest radio frequency used for astronomy? Is it 3,438
GHz?

According to the link below, it is 3,438 GHz:

http://books.nap.edu/openbook.php?re...=11719&page=11

Is 3,438 GHz the highest radio frequency used for astronomy?
That's very much a matter of convention. It all depends what you
choose to call "radio frequency" and what you choose to call something
else.

As the article you cite points out, the measurements at 3438 GHz
(3.438 THz) blur the lines between microwave measurements (which many
would call "radio") and far-infrared measurements (which may would not
call "radio frequency").

One source I see gives a frequency of 3.0 THz as the boundary between
"microwave" and "infrared". That boundary point is, I believe,
entirely one of human convention - there's no magical change in the
behavior of the signals as you cross from one side of this frequency
to the other.

If you choose to treat the conventional boundary point of 3.0 THz as
being significant for the purpose of your question, then one would
have to say that the 3,438 GHz measurements you refer to are *not*
"radio frequency" measurements, but rather "far-infrared"
measurements.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

I am curious here. At some point you have to switch from metallic conductors
and antennas to lenses and other optics. Any idea what the highest frequency
RF amplifier works at?

Tam

I have even seen optics and electronics combined in an experimental
Road radar for car control from Philips, radar output was a very small
horn antenna connected to a wave guide, and in front of that they used a
plexyglass condensor lens to make a narrow beam, like you do with light.
Apparently those mm waves liked that plastic lens just fine.

In fact, that would work fine at 10GHz, at 1GHz, and even at 1MHz,
though the amount of material you'd have to use for the lens gets
prohibitive at lower frequencies. It's all engineering tradeoffs. I
know that "geodesic" lenses are used in some radar systems; the idea
is that you have the signal travel a longer path (through a curved
waveguide structure) in the center of the antenna/feed than it does
toward the edges, just as in a convex lens the light in the center of
the beam is slowed for a greater distance (and therefore retarded
more) than the light at the outer edges.

I expect the boundary between "optics" and "electronics" will blur
even more than it is already as both electronics and optical
technologies continue to advance.

Cheers,
Tom

Apparently those mm waves liked that plastic lens just fine.

In fact, that would work fine at 10GHz, at 1GHz, and even at 1MHz,
though the amount of material you'd have to use for the lens gets
prohibitive at lower frequencies. It's all engineering tradeoffs. I
know that "geodesic" lenses are used in some radar systems; the idea
is that you have the signal travel a longer path (through a curved
waveguide structure) in the center of the antenna/feed than it does
toward the edges, just as in a convex lens the light in the center of
the beam is slowed for a greater distance (and therefore retarded
more) than the light at the outer edges.

I expect the boundary between "optics" and "electronics" will blur
even more than it is already as both electronics and optical
technologies continue to advance.

Cheers,
Tom

Hi Tom, we've used plastic lensing since at least the late 60's for focusing
mundane 4-12 GHz radio waves. Dielectric refraction was used back then to
extract additional gain from dish antennas by allowing more even
illumination of the dish without illuminating the area around the dish.
Harris radio had a patent on it.

W4ZCB

On Aug 30, 7:26 pm, "Harold E. Johnson" wrote:
Apparently those mm waves liked that plastic lens just fine.

In fact, that would work fine at 10GHz, at 1GHz, and even at 1MHz,
though the amount of material you'd have to use for the lens gets
prohibitive at lower frequencies. It's all engineering tradeoffs. I
know that "geodesic" lenses are used in some radar systems; the idea
is that you have the signal travel a longer path (through a curved
waveguide structure) in the center of the antenna/feed than it does
toward the edges, just as in a convex lens the light in the center of
the beam is slowed for a greater distance (and therefore retarded
more) than the light at the outer edges.

I expect the boundary between "optics" and "electronics" will blur
even more than it is already as both electronics and optical
technologies continue to advance.

Cheers,
Tom

Hi Tom, we've used plastic lensing since at least the late 60's for focusing
mundane 4-12 GHz radio waves. Dielectric refraction was used back then to
extract additional gain from dish antennas by allowing more even
illumination of the dish without illuminating the area around the dish.
Harris radio had a patent on it.

W4ZCB



Hi Harold,

Yep. The radar stuff I wrote about is from that era. I wouldn't be
at all surprised to see mention of it from well before that; certainly
we knew about the effect that makes dielectric lens action possible
for RF (which is after all just a continuation of the spectrum that
includes visible light) since before we knew how to generate
appreciable energy at microwave frequencies.

Cheers,
Tom

Harold E. Johnson wrote:



Hi Tom, we've used plastic lensing since at least the late 60's for focusing
mundane 4-12 GHz radio waves. Dielectric refraction was used back then to
extract additional gain from dish antennas by allowing more even
illumination of the dish without illuminating the area around the dish.
Harris radio had a patent on it.


J.C. Bose used dielectric lenses at 90 GHz back at the end of 19th
century (that is, in the late 1800s) when doing his experiments in Calcutta.

Optical techniques have been used in radio for a very, very long time.

In article ,
Sjouke Burry wrote:

I have even seen optics and electronics combined in an experimental
Road radar for car control from Philips, radar output was a very small
horn antenna connected to a wave guide, and in front of that they used a
plexyglass condensor lens to make a narrow beam, like you do with light.
Apparently those mm waves liked that plastic lens just fine.

It's also possible to use photonic crystals and quasicrystals to
refract and band-process electromagnetic energy across a very wide
range of frequencies... all the way from radio, through microwave,
through far infrared, and into the optical spectrum.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!