Do we have to lease out 24GHz?

[Winfield Hill]

NOAA's Advanced Technology Microwave Sounder (ATMS),
passively-measures water-vapor levels, using weak
signals at 23.8 GHz. NOAA uses this data for their
critical hurricane forecasting.

FCC Chairman Ajit Pai wants to lease the 24 GHz band
for 5G networks. NOAA and many scientists, have said
this will ruin the measurements, severely degrading
the storm forecasts we now rely on. Ajit Pai says,
fuck off, the State Dept (!) says it's OK. With that,
he's not going to attend the next scheduled meeting.


--
Thanks,
- Win

 

[Steve Wilson]

Winfield Hill <hill@rowland.harvard.edu> wrote:

NOAA's Advanced Technology Microwave Sounder (ATMS),
passively-measures water-vapor levels, using weak
signals at 23.8 GHz. NOAA uses this data for their
critical hurricane forecasting.

FCC Chairman Ajit Pai wants to lease the 24 GHz band
for 5G networks. NOAA and many scientists, have said
this will ruin the measurements, severely degrading
the storm forecasts we now rely on. Ajit Pai says,
fuck off, the State Dept (!) says it's OK. With that,
he's not going to attend the next scheduled meeting.

I'm not sure Ajit Pai has the authority to make such a decision alone. It
might require rulings by Congress to implement.

A similar situation occurred recently with GPS. A company called
LightSquared wanted to use frequencies adjacent to the GPS frequencies for
broadband cellular transmissions. Here is some background information:

https://insidegnss.com/?s=lightsquared

This appeared to end the threat:

"Lobbying and new spectrum: One last shot for LightSquared"

http://arstechnica.com/business/2013/08/lobbying-and-new-spectrum-one-last-
shot-for-lightsquared/

It appears there may be other factors involved other than the decision of
one man.

 

[boB]

On Fri, 24 May 2019 04:06:53 GMT, Steve Wilson <no@spam.com> wrote:

Winfield Hill <hill@rowland.harvard.edu> wrote:

NOAA's Advanced Technology Microwave Sounder (ATMS),
passively-measures water-vapor levels, using weak
signals at 23.8 GHz. NOAA uses this data for their
critical hurricane forecasting.

FCC Chairman Ajit Pai wants to lease the 24 GHz band
for 5G networks. NOAA and many scientists, have said
this will ruin the measurements, severely degrading
the storm forecasts we now rely on. Ajit Pai says,
fuck off, the State Dept (!) says it's OK. With that,
he's not going to attend the next scheduled meeting.

I'm not sure Ajit Pai has the authority to make such a decision alone. It
might require rulings by Congress to implement.

A similar situation occurred recently with GPS. A company called
LightSquared wanted to use frequencies adjacent to the GPS frequencies for
broadband cellular transmissions. Here is some background information:

https://insidegnss.com/?s=lightsquared

This appeared to end the threat:

"Lobbying and new spectrum: One last shot for LightSquared"

http://arstechnica.com/business/2013/08/lobbying-and-new-spectrum-one-last-
shot-for-lightsquared/

It appears there may be other factors involved other than the decision of
one man.

The FCC needs to be run less by crooked lawyers and more by people
that understand what is needed and how this stuff (RF) works and the
science of why what frequencies need to be used for what.

 

[Jan Panteltje]

On a sunny day (Fri, 24 May 2019 00:17:02 -0700) it happened boB
<boB@K7IQ.com> wrote in <9e6feedbc4v3vd6o0genv7gmkrtq2odtfo@4ax.com>:

On Fri, 24 May 2019 04:06:53 GMT, Steve Wilson <no@spam.com> wrote:

Winfield Hill <hill@rowland.harvard.edu> wrote:

NOAA's Advanced Technology Microwave Sounder (ATMS),
passively-measures water-vapor levels, using weak
signals at 23.8 GHz. NOAA uses this data for their
critical hurricane forecasting.

FCC Chairman Ajit Pai wants to lease the 24 GHz band
for 5G networks. NOAA and many scientists, have said
this will ruin the measurements, severely degrading
the storm forecasts we now rely on. Ajit Pai says,
fuck off, the State Dept (!) says it's OK. With that,
he's not going to attend the next scheduled meeting.

I'm not sure Ajit Pai has the authority to make such a decision alone. It
might require rulings by Congress to implement.

A similar situation occurred recently with GPS. A company called
LightSquared wanted to use frequencies adjacent to the GPS frequencies for
broadband cellular transmissions. Here is some background information:

https://insidegnss.com/?s=lightsquared

This appeared to end the threat:

"Lobbying and new spectrum: One last shot for LightSquared"

http://arstechnica.com/business/2013/08/lobbying-and-new-spectrum-one-last-
shot-for-lightsquared/

It appears there may be other factors involved other than the decision of
one man.

The FCC needs to be run less by crooked lawyers and more by people
that understand what is needed and how this stuff (RF) works and the
science of why what frequencies need to be used for what.

Spectrum is big money,
here in Europe governments are auctioning spectrum for 5G now,
and asking a LOT, driving the price up, as if the spectrum is theirs.
Big mony may win. It is a capitalist system after all.

They are also trying to get the ham bands,
I pay more every year for my license,
and they make it more difficult to pay each time.
Tactics

One day perhaps alien empire will auction solar system spectrum to them humans and then you work for them.

 

[Martin Brown]

On 24/05/2019 03:00, Winfield Hill wrote:

NOAA's Advanced Technology Microwave Sounder (ATMS),
passively-measures water-vapor levels, using weak
signals at 23.8 GHz. NOAA uses this data for their
critical hurricane forecasting.

FCC Chairman Ajit Pai wants to lease the 24 GHz band
for 5G networks. NOAA and many scientists, have said
this will ruin the measurements, severely degrading
the storm forecasts we now rely on. Ajit Pai says,
fuck off, the State Dept (!) says it's OK. With that,
he's not going to attend the next scheduled meeting.

It will probably end up with NOAA and their weather forecasters being
blamed for failing to forecast a hurricane after all their instruments
are blinded by the sidebands of the 5G cellular transmissions.

TBH I am surprised that we have managed to preserve enough clear radio
spectrum to still be able to do radio astronomy and passive water vapour
detection in this era of spread spectrum mass mobile phone use.

--
Regards,
Martin Brown

 

Winfield Hill <hill@rowland.harvard.edu> wrote in
news:qc7j7j01s9q@drn.newsguy.com:

NOAA's Advanced Technology Microwave Sounder (ATMS),
passively-measures water-vapor levels, using weak
signals at 23.8 GHz. NOAA uses this data for their
critical hurricane forecasting.

FCC Chairman Ajit Pai wants to lease the 24 GHz band
for 5G networks. NOAA and many scientists, have said
this will ruin the measurements, severely degrading
the storm forecasts we now rely on. Ajit Pai says,
fuck off, the State Dept (!) says it's OK. With that,
he's not going to attend the next scheduled meeting.

Another proof that Donald J. Trump AND virtually ALL of his
"appointments" are as stupid and lame as it gets.

Some idiot examines the spectral chart looking for a block of
space to SELL to the people, and the science community gets
screwed... again. How quaint.

 

boB <boB@K7IQ.com> wrote in
news:9e6feedbc4v3vd6o0genv7gmkrtq2odtfo@4ax.com:

snip

The FCC needs to be run less by crooked lawyers and more by people
that understand what is needed and how this stuff (RF) works and
the science of why what frequencies need to be used for what.

Sadly, there was a time when it was that way, but that was decades
ago.

 

[Johann Klammer]

On 05/24/2019 10:12 AM, Jan Panteltje wrote:

Spectrum is big money,
here in Europe governments are auctioning spectrum for 5G now,
and asking a LOT, driving the price up, as if the spectrum is theirs.
Big mony may win. It is a capitalist system after all.

They are also trying to get the ham bands,
I pay more every year for my license,
and they make it more difficult to pay each time.
Tactics

One day perhaps alien empire will auction solar system spectrum to them humans and then you work for them.

And the ham bands are mostly shoddy narrowband ones anyways. What do they even want those for?

 

[Jan Panteltje]

On a sunny day (Fri, 24 May 2019 15:20:01 +0200) it happened Johann Klammer
<klammerj@NOSPAM.a1.net> wrote in <qc8r28$2qj$1@gioia.aioe.org>:

On 05/24/2019 10:12 AM, Jan Panteltje wrote:

Spectrum is big money,
here in Europe governments are auctioning spectrum for 5G now,
and asking a LOT, driving the price up, as if the spectrum is theirs.
Big mony may win. It is a capitalist system after all.

They are also trying to get the ham bands,
I pay more every year for my license,
and they make it more difficult to pay each time.
Tactics

One day perhaps alien empire will auction solar system spectrum to them humans and then you work for them.

And the ham bands are mostly shoddy narrowband ones anyways. What do they even want those for?

Well, ehh
this is from my list:
http://panteltje.com/pub/higher_frequency_ham_bands_IMG_6931.JPG
the left column is how many watts I am allowed to output,
the most right column is 'S' for shared with other services,
and 'P' for hams only.

As we move into the 24 GHz we have 50 MHz wide there,
and an other 200 MHz wide shared.
The higher up you go the more bandwidth.

The 24 GHz part could be very attractive for 5G and other future systems.

The 70 cm / 430 MHz band could be in danger too.

 

[John Larkin]

On Fri, 24 May 2019 09:49:45 +0100, Martin Brown
<'''newspam'''@nezumi.demon.co.uk> wrote:

On 24/05/2019 03:00, Winfield Hill wrote:
NOAA's Advanced Technology Microwave Sounder (ATMS),
passively-measures water-vapor levels, using weak
signals at 23.8 GHz. NOAA uses this data for their
critical hurricane forecasting.

FCC Chairman Ajit Pai wants to lease the 24 GHz band
for 5G networks. NOAA and many scientists, have said
this will ruin the measurements, severely degrading
the storm forecasts we now rely on. Ajit Pai says,
fuck off, the State Dept (!) says it's OK. With that,
he's not going to attend the next scheduled meeting.

It will probably end up with NOAA and their weather forecasters being
blamed for failing to forecast a hurricane after all their instruments
are blinded by the sidebands of the 5G cellular transmissions.

TBH I am surprised that we have managed to preserve enough clear radio
spectrum to still be able to do radio astronomy and passive water vapour
detection in this era of spread spectrum mass mobile phone use.

Hurricanes won't sneak up on anybody. They are pretty obvious at
visual and thermal wavelengths.

Before satellites, ships did a pretty good job reporting things.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

On 23 May 2019 19:00:19 -0700, Winfield Hill
<hill@rowland.harvard.edu> wrote:

NOAA's Advanced Technology Microwave Sounder (ATMS),
passively-measures water-vapor levels, using weak
signals at 23.8 GHz. NOAA uses this data for their
critical hurricane forecasting.

Around 22 GHz there is a quite wide notch due to water vapor, making
ground based long distance communication practically useless. Thus,
very few services would like to use the 22 GHz band.

As long as the spectral purity for 24+ GHz systems are very good, this
should not interfere with 22 or even 23.8 GHz sensors. Of course, if
the satellite sensor front end is as wide as 20 to 30 GHz, all bets
are off.

FCC Chairman Ajit Pai wants to lease the 24 GHz band
for 5G networks. NOAA and many scientists, have said
this will ruin the measurements, severely degrading
the storm forecasts we now rely on. Ajit Pai says,
fuck off, the State Dept (!) says it's OK. With that,
he's not going to attend the next scheduled meeting.

 

On Fri, 24 May 2019 15:33:19 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Fri, 24 May 2019 15:20:01 +0200) it happened Johann Klammer
klammerj@NOSPAM.a1.net> wrote in <qc8r28$2qj$1@gioia.aioe.org>:

On 05/24/2019 10:12 AM, Jan Panteltje wrote:

Spectrum is big money,
here in Europe governments are auctioning spectrum for 5G now,
and asking a LOT, driving the price up, as if the spectrum is theirs.
Big mony may win. It is a capitalist system after all.

They are also trying to get the ham bands,

Some historical background information about the amateur microwave
radio frequency allocations.

Previously huge microwave segments were allocated for "radiolocation"
i.e. radar with bad frequency stability. Of course, any serious user
would not like to be colocated with radar, so these bands were also
given to hams on a secondary basis.

With improved radar technology, these radar bands were reduces, which
also reduced the amateur secondary allocations, giving large chunks of
spectrum to other uses.

I pay more every year for my license,
and they make it more difficult to pay each time.
Tactics

One day perhaps alien empire will auction solar system spectrum to them humans and then you work for them.

And the ham bands are mostly shoddy narrowband ones anyways. What do they even want those for?

This is a good question.

Previously several hundred MHz wide microwave allocations were handy
e.g. for running unstable 10 GHz or 24 GHz 10 mW Gunplexer frequency
modulated by analog ATV.

These days generating reasonable good stability carriers with a few
MHz wide digital TV signals is not a problem, so quite high SNR can be
achieved with reasonable bandwidths.

Apart for some UWB (Ultra Wide Band) experiments, I do not understand,
why hams would need frequency segments larger than about 10 MHz. For
UWB experiment some large segment shared with other UWB services would
suffice.

Well, ehh
this is from my list:
http://panteltje.com/pub/higher_frequency_ham_bands_IMG_6931.JPG
the left column is how many watts I am allowed to output,
the most right column is 'S' for shared with other services,
and 'P' for hams only.

As we move into the 24 GHz we have 50 MHz wide there,
and an other 200 MHz wide shared.
The higher up you go the more bandwidth.

Realistically, what data could you put into that range at least a few
hours each week. ?

The 24 GHz part could be very attractive for 5G and other future systems.

At least in Europe, the 5G mm-wave allocation starts at 26 GHz.


>The 70 cm / 430 MHz band could be in danger too.

That low range is of interest only for very rural systems.

 

[Jan Panteltje]

On a sunny day (Fri, 24 May 2019 22:47:02 +0300) it happened
upsidedown@downunder.com wrote in
<h2ggee9bc8m471r2ldsld7skmcbj9344g8@4ax.com>:

On Fri, 24 May 2019 15:33:19 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Fri, 24 May 2019 15:20:01 +0200) it happened Johann Klammer
klammerj@NOSPAM.a1.net> wrote in <qc8r28$2qj$1@gioia.aioe.org>:

On 05/24/2019 10:12 AM, Jan Panteltje wrote:

Spectrum is big money,
here in Europe governments are auctioning spectrum for 5G now,
and asking a LOT, driving the price up, as if the spectrum is theirs.
Big mony may win. It is a capitalist system after all.

They are also trying to get the ham bands,

Some historical background information about the amateur microwave
radio frequency allocations.

Previously huge microwave segments were allocated for "radiolocation"
i.e. radar with bad frequency stability. Of course, any serious user
would not like to be colocated with radar, so these bands were also
given to hams on a secondary basis.

With improved radar technology, these radar bands were reduces, which
also reduced the amateur secondary allocations, giving large chunks of
spectrum to other uses.

I pay more every year for my license,
and they make it more difficult to pay each time.
Tactics

One day perhaps alien empire will auction solar system spectrum to them humans and then you work for them.

And the ham bands are mostly shoddy narrowband ones anyways. What do they even want those for?

This is a good question.

Previously several hundred MHz wide microwave allocations were handy
e.g. for running unstable 10 GHz or 24 GHz 10 mW Gunplexer frequency
modulated by analog ATV.

These days generating reasonable good stability carriers with a few
MHz wide digital TV signals is not a problem, so quite high SNR can be
achieved with reasonable bandwidths.

Apart for some UWB (Ultra Wide Band) experiments, I do not understand,
why hams would need frequency segments larger than about 10 MHz. For
UWB experiment some large segment shared with other UWB services would
suffice.

Well, ehh
this is from my list:
http://panteltje.com/pub/higher_frequency_ham_bands_IMG_6931.JPG
the left column is how many watts I am allowed to output,
the most right column is 'S' for shared with other services,
and 'P' for hams only.

As we move into the 24 GHz we have 50 MHz wide there,
and an other 200 MHz wide shared.
The higher up you go the more bandwidth.

Realistically, what data could you put into that range at least a few
hours each week. ?

Good question, in some city areas with many hams with DVB channels perhaps?

The 24 GHz part could be very attractive for 5G and other future systems.

At least in Europe, the 5G mm-wave allocation starts at 26 GHz.


The 70 cm / 430 MHz band could be in danger too.

That low range is of interest only for very rural systems.

The range is big, compared to that 24 GHz stuff...

We will see where it goes.
At least some HF band stuff was allocated to hams, nobody else seems to use it
until the sats are shot down..

About sats:
That Space-X thing did a show here in the Netherlands last night:
https://www.youtube.com/watch?v=ytUygPqjXEc

He will have to spread those out I think?
How does that work, do those sats have their own propulsion?
I want that internet !

 

[Tom Gardner]

On 25/05/19 08:29, Jan Panteltje wrote:

About sats:
That Space-X thing did a show here in the Netherlands last night:
https://www.youtube.com/watch?v=ytUygPqjXEc

He will have to spread those out I think?
How does that work, do those sats have their own propulsion?
I want that internet !

Has he published any figures about the aggregate
bandwidth available? He touts a headline figure
of 50Mb/s, but that's boring.

 

[Jan Panteltje]

On a sunny day (Sat, 25 May 2019 09:35:05 +0100) it happened Tom Gardner
<spamjunk@blueyonder.co.uk> wrote in <Z67GE.1679598$%SF.1174557@fx15.am4>:

On 25/05/19 08:29, Jan Panteltje wrote:
About sats:
That Space-X thing did a show here in the Netherlands last night:
https://www.youtube.com/watch?v=ytUygPqjXEc

He will have to spread those out I think?
How does that work, do those sats have their own propulsion?
I want that internet !


Has he published any figures about the aggregate
bandwidth available? He touts a headline figure
of 50Mb/s, but that's boring.

If you are at sea on a boat that would be great,
if it is a lot cheaper than iridium etc..
I mean places out of reach of 4G and 5G towers.
Competition will get the pices down.

 

Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> wrote in
news:qcb1rb$ati$1@dont-email.me:

On a sunny day (Sat, 25 May 2019 09:35:05 +0100) it happened Tom
Gardner <spamjunk@blueyonder.co.uk> wrote in
Z67GE.1679598$%SF.1174557@fx15.am4>:

On 25/05/19 08:29, Jan Panteltje wrote:
About sats:
That Space-X thing did a show here in the Netherlands last
night:
https://www.youtube.com/watch?v=ytUygPqjXEc

He will have to spread those out I think?
How does that work, do those sats have their own propulsion?
I want that internet !


Has he published any figures about the aggregate
bandwidth available? He touts a headline figure
of 50Mb/s, but that's boring.

If you are at sea on a boat that would be great,
if it is a lot cheaper than iridium etc..
I mean places out of reach of 4G and 5G towers.
Competition will get the pices down.

ViaSat1 covers North America and part of Canada. I do not know what
areas ViaSat2 or any newer placements service.

But ViaSat1 is like $79 a month and I think it is like 15Mb/s.
That is on what was the fastest satellite up there until they
launched more. The first was over 140Gb/s.

I have serious doubts that Musk's devices will be delivering
50Mb/s ever.

And what is he going to do for ground stations?

Every satellite would need access to an Earth based/Internet
hooked Satellite Gateway with dishes and feeds onto the main
backbone.

ViaSat has Earth Gateway stations in 15 US cities from anchorage
to Honolulu. Each one has two 8 meter dishes and a set of ten racks
of gear for the hooks. It is Ka-band.

 

On Sat, 25 May 2019 07:29:08 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Fri, 24 May 2019 22:47:02 +0300) it happened
upsidedown@downunder.com wrote in
h2ggee9bc8m471r2ldsld7skmcbj9344g8@4ax.com>:

On Fri, 24 May 2019 15:33:19 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Fri, 24 May 2019 15:20:01 +0200) it happened Johann Klammer
klammerj@NOSPAM.a1.net> wrote in <qc8r28$2qj$1@gioia.aioe.org>:

On 05/24/2019 10:12 AM, Jan Panteltje wrote:

Spectrum is big money,
here in Europe governments are auctioning spectrum for 5G now,
and asking a LOT, driving the price up, as if the spectrum is theirs.
Big mony may win. It is a capitalist system after all.

They are also trying to get the ham bands,

Some historical background information about the amateur microwave
radio frequency allocations.

Previously huge microwave segments were allocated for "radiolocation"
i.e. radar with bad frequency stability. Of course, any serious user
would not like to be colocated with radar, so these bands were also
given to hams on a secondary basis.

With improved radar technology, these radar bands were reduces, which
also reduced the amateur secondary allocations, giving large chunks of
spectrum to other uses.

I pay more every year for my license,
and they make it more difficult to pay each time.
Tactics

One day perhaps alien empire will auction solar system spectrum to them humans and then you work for them.

And the ham bands are mostly shoddy narrowband ones anyways. What do they even want those for?

This is a good question.

Previously several hundred MHz wide microwave allocations were handy
e.g. for running unstable 10 GHz or 24 GHz 10 mW Gunplexer frequency
modulated by analog ATV.

These days generating reasonable good stability carriers with a few
MHz wide digital TV signals is not a problem, so quite high SNR can be
achieved with reasonable bandwidths.

Apart for some UWB (Ultra Wide Band) experiments, I do not understand,
why hams would need frequency segments larger than about 10 MHz. For
UWB experiment some large segment shared with other UWB services would
suffice.

Well, ehh
this is from my list:
http://panteltje.com/pub/higher_frequency_ham_bands_IMG_6931.JPG
the left column is how many watts I am allowed to output,
the most right column is 'S' for shared with other services,
and 'P' for hams only.

As we move into the 24 GHz we have 50 MHz wide there,
and an other 200 MHz wide shared.
The higher up you go the more bandwidth.

Realistically, what data could you put into that range at least a few
hours each week. ?

Good question, in some city areas with many hams with DVB channels perhaps?

You might get sufficient usage with a digital amateur TV (DATV)
repeater in a large city.

I haven't recently heard much of DATV experimentation. About a decade
ago, there were some experimentation using DVB-S. The DVB-S was
initially designed for satellite reception and thus is not very good
in handling multipath, preferably line-of-sight paths would be
preferable.

OTOH, DVB-T (or other multitone OFDM) is designed for terrestrial
multipath environment and would be better suited for DATV.

A single program stream could be put into a 2 MHz bandwidth or
multiple program stream in a 8 MHz multiplex, so not much frequency
demand on higher frequency bands.

The 24 GHz part could be very attractive for 5G and other future systems.

At least in Europe, the 5G mm-wave allocation starts at 26 GHz.


The 70 cm / 430 MHz band could be in danger too.

That low range is of interest only for very rural systems.

The range is big, compared to that 24 GHz stuff...

That is partially a myth. While it is true that vegetation will absorb
higher frequencies quite effectively In urban areas the higher
frequencies are reflected very well from hard surfaces and the signal
level drop is not much worse than on lower frequencies.

While the gain is a good quality measurement for transmitting
antennas, for receiving antennas, the antenna capture area is the
critical thing. Of course gain can be converted to capture area and
visa versa for a specific wavelength.

The antenna capture area is proportional to the square of wavelength,
thus for a constant field strength the received power will drop
rapidly. The capture area for a half-wave dipole is little more than
0.1 square wavelengths. On HF, the capture area is as big as hangar
doors, while up in the microwave bands about the size of a coin, thus
much less power is delivered to the receiver.

To increase the received power, an array of dipoles can be used. This
may also increase directivity (and gain) which might be desirable or
undesirable feature depending of the situation. Too much directivity
is a bad thing, if multipath reflected signals come from different
directions. One way o handle this problems to use antennas with
steerable radiation patterns, such as MIMO antennas.

We will see where it goes.
At least some HF band stuff was allocated to hams, nobody else seems to use it
until the sats are shot down..

About sats:
That Space-X thing did a show here in the Netherlands last night:
https://www.youtube.com/watch?v=ytUygPqjXEc

He will have to spread those out I think?
How does that work, do those sats have their own propulsion?
I want that internet !

Every time someone announces some new satellite based internet system,
I have wondered, where do you get sufficient spectrum to handle the
large number of simultaneous customers. The whole idea of any cellular
system is the frequency reuse, so you want to keep the cell size small
and avoid spilling over signals into neighbor cells. With satellites,
one would need very good steerable antennas which is hard, if the
satellites are small.

OK, so don't even try to serve urban customers, since the local cell
towers will handle them with lower cost. What is left, customers on
high seas, in the tundra and in the desert. But are these customers
capable of paying for the satellite constellation ?

Since the oceans occupy a huge part of the earth, thus LEO satellites
will fly over the water for quite a long time each orbit, Does the
island and cruise ship users generate enough revenue ?

 

[amdx]

On 5/23/2019 9:00 PM, Winfield Hill wrote:

NOAA's Advanced Technology Microwave Sounder (ATMS),
passively-measures water-vapor levels, using weak
signals at 23.8 GHz. NOAA uses this data for their
critical hurricane forecasting.

FCC Chairman Ajit Pai wants to lease the 24 GHz band
for 5G networks. NOAA and many scientists, have said
this will ruin the measurements, severely degrading
the storm forecasts we now rely on. Ajit Pai says,
fuck off, the State Dept (!) says it's OK. With that,
he's not going to attend the next scheduled meeting.

I suspect if it isn't worked out politically, it will be worked out
technically.
I saw my first 5G antenna about 3 weeks ago here, in Panama City Fl,
about 1500ft from my house. Then saw the second one about 10 days later,
about 1 mile from my home
I don't know what it means to me, I'm frugal, paying $40 a month for
my phone and $24 a month for my wife's phone and $45 a month for
Internet service. Not sure I want to pay more for something I don't have
a need or desire for, I already spend to much time in front of a screen.
But maybe I'll have a better deal with cable and phone bundle?
They are putting in 5G because the 4G system was so damaged by the
hurricane, that they decided to rebuild with 5G. They have the 4G
working well enough, you can stream Youtube videos without buffering.
Service was very poor for 3 months, which they gave us without charge.
Anyway, I'm fine with 4G, but I was fine with my flip phone too!

Mikek


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[Jan Panteltje]

On a sunny day (Sat, 25 May 2019 20:51:34 +0300) it happened
upsidedown@downunder.com wrote in
<lmviee1tt1bsna24ohfp7lelt2dqoo7emi@4ax.com>:

On a sunny day (Fri, 24 May 2019 15:20:01 +0200) it happened Johann Klammer
klammerj@NOSPAM.a1.net> wrote in <qc8r28$2qj$1@gioia.aioe.org>:

On 05/24/2019 10:12 AM, Jan Panteltje wrote:
Good question, in some city areas with many hams with DVB channels perhaps?

You might get sufficient usage with a digital amateur TV (DATV)
repeater in a large city.

I haven't recently heard much of DATV experimentation. About a decade
ago, there were some experimentation using DVB-S. The DVB-S was
initially designed for satellite reception and thus is not very good
in handling multipath, preferably line-of-sight paths would be
preferable.

Yes, I did (and do) the DVB-S stuff:
http://panteltje.com/panteltje/raspberry_pi_dvb-s_transmitter/

Modified version now for QO100 satellite.

OTOH, DVB-T (or other multitone OFDM) is designed for terrestrial
multipath environment and would be better suited for DATV.

True, but I know little about DVB-T, did read up on it. but have not desihned or build anything for it,
I do have plenty DVB-T USB sticks ;-)

A single program stream could be put into a 2 MHz bandwidth or
multiple program stream in a 8 MHz multiplex, so not much frequency
demand on higher frequency bands.

This may interest you for spectrum usage, lots of experiments going on with DVB-S2 and some DVB-S
https://eshail.batc.org.uk/wb/

Anyways a few MHz is enough, lower symbolratea are possible.

The 24 GHz part could be very attractive for 5G and other future systems.

At least in Europe, the 5G mm-wave allocation starts at 26 GHz.


The 70 cm / 430 MHz band could be in danger too.

That low range is of interest only for very rural systems.

The range is big, compared to that 24 GHz stuff...

That is partially a myth. While it is true that vegetation will absorb
higher frequencies quite effectively In urban areas the higher
frequencies are reflected very well from hard surfaces and the signal
level drop is not much worse than on lower frequencies.

Antenna height rules of course.
There is a 70 cm repeater network here that covers much of the NE part of the country
http://www.pi2non.nl/systeem17.html
and an other one that does the west.
Not much here on 24 GHz that I know about?
QO100 satellite is a geostationary sat and can be accessed with a small commercial TV dish
and just a few watts for SSB. from almost anywhere.
2.4 GHz uplink. Even S Africa and Brasil is easy from here, but local chatting via that
sat happens too, all of Europe, Russia, Middle East.
So much for the large antennas....

While the gain is a good quality measurement for transmitting
antennas, for receiving antennas, the antenna capture area is the
critical thing. Of course gain can be converted to capture area and
visa versa for a specific wavelength.

The antenna capture area is proportional to the square of wavelength,
thus for a constant field strength the received power will drop
rapidly. The capture area for a half-wave dipole is little more than
0.1 square wavelengths. On HF, the capture area is as big as hangar
doors, while up in the microwave bands about the size of a coin, thus
much less power is delivered to the receiver.

To increase the received power, an array of dipoles can be used. This
may also increase directivity (and gain) which might be desirable or
undesirable feature depending of the situation. Too much directivity
is a bad thing, if multipath reflected signals come from different
directions. One way o handle this problems to use antennas with
steerable radiation patterns, such as MIMO antennas.


We will see where it goes.
At least some HF band stuff was allocated to hams, nobody else seems to use it
until the sats are shot down..

About sats:
That Space-X thing did a show here in the Netherlands last night:
https://www.youtube.com/watch?v=ytUygPqjXEc

He will have to spread those out I think?
How does that work, do those sats have their own propulsion?
I want that internet !

Every time someone announces some new satellite based internet system,
I have wondered, where do you get sufficient spectrum to handle the
large number of simultaneous customers. The whole idea of any cellular
system is the frequency reuse, so you want to keep the cell size small
and avoid spilling over signals into neighbor cells. With satellites,
one would need very good steerable antennas which is hard, if the
satellites are small.

OK, so don't even try to serve urban customers, since the local cell
towers will handle them with lower cost. What is left, customers on
high seas, in the tundra and in the desert. But are these customers
capable of paying for the satellite constellation ?

Since the oceans occupy a huge part of the earth, thus LEO satellites
will fly over the water for quite a long time each orbit, Does the
island and cruise ship users generate enough revenue ?

Yes good question, Elon Musk making profit ? SpaceX does.
Geostationary sats would be an other approach, dish pointing at sea is
possible, for 1000$ you have a stabilized pointing system to a geo sat,
no problem for a cruiseship, gives them TV too.
I am sure somebody at SpaceX did the math...
We will see where it goes.

 

[Tom Gardner]

On 25/05/19 10:28, Jan Panteltje wrote:

On a sunny day (Sat, 25 May 2019 09:35:05 +0100) it happened Tom Gardner
spamjunk@blueyonder.co.uk> wrote in <Z67GE.1679598$%SF.1174557@fx15.am4>:

On 25/05/19 08:29, Jan Panteltje wrote:
About sats:
That Space-X thing did a show here in the Netherlands last night:
https://www.youtube.com/watch?v=ytUygPqjXEc

He will have to spread those out I think?
How does that work, do those sats have their own propulsion?
I want that internet !


Has he published any figures about the aggregate
bandwidth available? He touts a headline figure
of 50Mb/s, but that's boring.

If you are at sea on a boat that would be great,
if it is a lot cheaper than iridium etc..
I mean places out of reach of 4G and 5G towers.
Competition will get the pices down.

Or in many locations on land where the infrastructure
is inadequate.

While I doubt investment could be recouped from maritime
use alone, I expect the land-based demand to be *much*
more than necessary - hence the question.

For cellular systems, a prime figure of merit is
bits/s / MHz / km^2, i.e. how closely the Shannon
limit is approached plus how densely the frequencies
can be reused by adjacent cells. I would expect
something similar for this system.