[amsat-bb] Re: 2.4GHz broadband router on satellite?

[Lee Maisel]

James French wrote:

What are the possibilities of building a satellite that uses a Linksys
WRT54GL router with a modified DD-wrt or HSMM-Mesh software as a store
and forward BBS, to route a received request from one station to another
station, or even to connect to a on board networked camera to receive
images?

What kind of uplink power would be needed from the home station?

How fast could the speed(s) get theoretically?

How big would the antenna have to be on the craft and for the ground
station to even be able to do this adequately?

Would the doppler be too much to even consider this?

Would the space environment be too harsh for something like this?

This is just something I was thinking about this morning and thought I
would toss it out.

James W8ISS

___
  

THAT is an AWESOME Idea!

I don't see why it wouldn't work, I don't know if doppler is an issue 
though, it may not be if the modulation is FM.

The antenna would not have to be big, it's 2.4Ghz


Why don't you post this on the HSMM-MESH.org web forums and get ideas?

73
Lee
W5LMM


--


ΜΟΛΩΝ ΛΑΒΕ

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[amsat-bb] Re: 2.4GHz broadband router on satellite?

[Andrew Glasbrenner]

One of the recent 3u DOD sponsored cubes has a S dish for tracking wifi type 
tags on containers. I'm not sure how much lick they had with that.

73, Drew KO4MA

Sent from my iPhone

On Feb 21, 2013, at 7:58 PM, Lee Maisel  wrote:

> James French wrote:
>> What are the possibilities of building a satellite that uses a Linksys
>> WRT54GL router with a modified DD-wrt or HSMM-Mesh software as a store
>> and forward BBS, to route a received request from one station to another
>> station, or even to connect to a on board networked camera to receive
>> images?
>> 
>> What kind of uplink power would be needed from the home station?
>> 
>> How fast could the speed(s) get theoretically?
>> 
>> How big would the antenna have to be on the craft and for the ground
>> station to even be able to do this adequately?
>> 
>> Would the doppler be too much to even consider this?
>> 
>> Would the space environment be too harsh for something like this?
>> 
>> This is just something I was thinking about this morning and thought I
>> would toss it out.
>> 
>> James W8ISS
>> 
>> ___
> THAT is an AWESOME Idea!
> 
> I don't see why it wouldn't work, I don't know if doppler is an issue though, 
> it may not be if the modulation is FM.
> The antenna would not have to be big, it's 2.4Ghz
> 
> 
> Why don't you post this on the HSMM-MESH.org web forums and get ideas?
> 
> 73
> Lee
> W5LMM
> 
> 
> -- 
> 
> 
> ΜΟΛΩΝ ΛΑΒΕ
> 
> ___
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[amsat-bb] Re: 2.4GHz broadband router on satellite?

[Greg D]

Lee Maisel wrote:

James French wrote:

What are the possibilities of building a satellite that uses a Linksys
WRT54GL router with a modified DD-wrt or HSMM-Mesh software as a store
and forward BBS, to route a received request from one station to another
station, or even to connect to a on board networked camera to receive
images?

What kind of uplink power would be needed from the home station?

How fast could the speed(s) get theoretically?

How big would the antenna have to be on the craft and for the ground
station to even be able to do this adequately?

Would the doppler be too much to even consider this?

Would the space environment be too harsh for something like this?

This is just something I was thinking about this morning and thought I
would toss it out.

James W8ISS

___

THAT is an AWESOME Idea!

I don't see why it wouldn't work, I don't know if doppler is an issue 
though, it may not be if the modulation is FM.

The antenna would not have to be big, it's 2.4Ghz


Why don't you post this on the HSMM-MESH.org web forums and get ideas?

73
Lee
W5LMM



Hi James, Lee,

If you are thinking of using standard Wi-Fi as the link protocol, be 
aware that the timers that drive the protocol don't well work over long 
distances (few miles).  Something about the speed of light not being 
fast enough.  Real bummer.  These would need to be adjusted, though I 
think the implications for a point-point connection may not be too severe.


Besides doppler shift, which could be a problem depending on how agile 
the ground station is, the modulation scheme (it's NOT simply FM) uses 
about 20 mhz of bandwidth, so you will need significant power to get the 
20db S/N needed to decode anything halfway reliably.  Remember, a 
typical AP runs 100mw on 2.4 ghz, and gets reliable communication over 
distances of 100's of FEET with omni antennas.  Add some gain on both 
ends (so now you need attitude control on the satellite!), and you can 
go a few miles.  But 100's of miles to orbit?  I need someone to "do the 
numbers", but I bet it's not too good.


Greg  KO6TH


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[amsat-bb] Re: 2.4GHz broadband router on satellite?

[Simone]

Hi all,

wifi over long distance is a reality on earth-based point-to-point links,
with distances up to 200miles. The long distance means long latencies, thus
the standard wifi protocol needs to be modified. It exists today
implementations of the modified protocols for the WRT54G router.

To cope with the link budget you need higher power (i.e power amplifier)
and high gain antennas, and this should not be a big deal even on a
spacecraft, although I am a bit concerned on the possibility of fitting a
high gain antenna on top of a cubesat. Maybe it would be feasible at 5GHz,
but in any case you would need 3 axes stabilization of the spacecraft.

What looks more difficult to me is the Doppler shift compensation, as the
wifi transceivers do not have (at least to my knowledge) the possibility to
fine tune the channel frequency.

I know that long range wifi has been investigated on south america to help
connecting isolated villages in the jungle, and by a group of Italian
researchers (http://www.ixem.polito.it/index_e.htm), and a high datarate
link has been established with a stratospheric balloon.

It is an interesting discussion topic, and I hope somebody with more
experience on the topic will jump into the discussion.

Simone IW1FYV


2013/2/22 Greg D 

> Lee Maisel wrote:
>
>> James French wrote:
>>
>>> What are the possibilities of building a satellite that uses a Linksys
>>> WRT54GL router with a modified DD-wrt or HSMM-Mesh software as a store
>>> and forward BBS, to route a received request from one station to another
>>> station, or even to connect to a on board networked camera to receive
>>> images?
>>>
>>> What kind of uplink power would be needed from the home station?
>>>
>>> How fast could the speed(s) get theoretically?
>>>
>>> How big would the antenna have to be on the craft and for the ground
>>> station to even be able to do this adequately?
>>>
>>> Would the doppler be too much to even consider this?
>>>
>>> Would the space environment be too harsh for something like this?
>>>
>>> This is just something I was thinking about this morning and thought I
>>> would toss it out.
>>>
>>> James W8ISS
>>>
>>> __**_
>>>
>> THAT is an AWESOME Idea!
>>
>> I don't see why it wouldn't work, I don't know if doppler is an issue
>> though, it may not be if the modulation is FM.
>> The antenna would not have to be big, it's 2.4Ghz
>>
>>
>> Why don't you post this on the HSMM-MESH.org web forums and get ideas?
>>
>> 73
>> Lee
>> W5LMM
>>
>>
>>  Hi James, Lee,
>
> If you are thinking of using standard Wi-Fi as the link protocol, be aware
> that the timers that drive the protocol don't well work over long distances
> (few miles).  Something about the speed of light not being fast enough.
>  Real bummer.  These would need to be adjusted, though I think the
> implications for a point-point connection may not be too severe.
>
> Besides doppler shift, which could be a problem depending on how agile the
> ground station is, the modulation scheme (it's NOT simply FM) uses about 20
> mhz of bandwidth, so you will need significant power to get the 20db S/N
> needed to decode anything halfway reliably.  Remember, a typical AP runs
> 100mw on 2.4 ghz, and gets reliable communication over distances of 100's
> of FEET with omni antennas.  Add some gain on both ends (so now you need
> attitude control on the satellite!), and you can go a few miles.  But 100's
> of miles to orbit?  I need someone to "do the numbers", but I bet it's not
> too good.
>
> Greg  KO6TH
>
>
>
> __**_
> Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: 
> http://amsat.org/mailman/**listinfo/amsat-bb
>
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[amsat-bb] Re: 2.4GHz broadband router on satellite?

[Trevor .]

Apart from power budget issues and Doppler the real killer will be the very 
high noise level on 2.4 GHz. 

In urban areas you can expected to receive strong WiFi signals across all of 
2402-2450 almost regardless of where you beam. 

Any signals from a satellite would need to be strong enough to overcome this 
interference. 5 GHz is likely to suffer a similar problem in a few years as 
more use is made of that band for WiFi etc.

73 Trevor M5AKA


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[amsat-bb] Re: 2.4GHz broadband router on satellite?

[Mark L. Hammond]

Maybe Drew KO4MA will reply--but I thought he did some "global
listening" on 2.4GHz with AO-51 (frequency agile receiver).  Seems
like he published some plots in The Journal?

Take home from what I recall--it was very noisy!

Mark N8MH

On Fri, Feb 22, 2013 at 10:49 AM, Trevor .  wrote:
> Apart from power budget issues and Doppler the real killer will be the very 
> high noise level on 2.4 GHz.
>
> In urban areas you can expected to receive strong WiFi signals across all of 
> 2402-2450 almost regardless of where you beam.
>
> Any signals from a satellite would need to be strong enough to overcome this 
> interference. 5 GHz is likely to suffer a similar problem in a few years as 
> more use is made of that band for WiFi etc.
>
> 73 Trevor M5AKA
>
>
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-- 
Mark L. Hammond [N8MH]
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[amsat-bb] Re: 2.4GHz broadband router on satellite?

[Andrew Glasbrenner]

Close, but not on 2.4Ghz. We did that on 2m, 70cm, and 33cm.

Aeneas was the satellite I was thinking of that had a WiFi-like payload.

http://viterbi.usc.edu/news/news/2012/usc-viterbi-s36.htm

73, Drew KO4MA


-Original Message-
>From: "Mark L. Hammond" 
>Sent: Feb 22, 2013 11:20 AM
>To: "Trevor ." 
>Cc: amsat-bb 
>Subject: [amsat-bb] Re: 2.4GHz broadband router on satellite?
>
>Maybe Drew KO4MA will reply--but I thought he did some "global
>listening" on 2.4GHz with AO-51 (frequency agile receiver).  Seems
>like he published some plots in The Journal?
>
>Take home from what I recall--it was very noisy!
>
>Mark N8MH
>
>On Fri, Feb 22, 2013 at 10:49 AM, Trevor .  wrote:
>> Apart from power budget issues and Doppler the real killer will be the very 
>> high noise level on 2.4 GHz.
>>
>> In urban areas you can expected to receive strong WiFi signals across all of 
>> 2402-2450 almost regardless of where you beam.
>>
>> Any signals from a satellite would need to be strong enough to overcome this 
>> interference. 5 GHz is likely to suffer a similar problem in a few years as 
>> more use is made of that band for WiFi etc.
>>
>> 73 Trevor M5AKA
>>
>>
>> ___
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>> Not an AMSAT-NA member? Join now to support the amateur satellite program!
>> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>
>
>
>-- 
>Mark L. Hammond [N8MH]
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[amsat-bb] Re: 2.4GHz broadband router on satellite?

[James French]

Lee and those who have responded so far,

Those are the questions that would need to be answered before even
considering this 'novel' idea.

I use the WRT54GL as a reference since that is what I am familiar with.
The WRT54GL would need to be almost redesigned because of space
radiation conditions plus it may just not have enough output power to
even be considered especially with trying to fit it into a microsat or
smaller frame and then finding a suitable launch. Could the satellite
utilize a modified 'backfire' antenna (referencing AO-40 2.4GHz
antennas) that utilizes dipoles offset from the surface on every side
and then use the surface of the satellite itself for gain?

As for HSMM-Mesh, this maybe the software to consider for something like
this as its robust enough for what I have played with three WRT54G
around my area (EN82jg), both mobile and stationary. My laptop (a
Fujitsu Lifebook T4020) is sensitive enough to pick up one 54g half a
mile away using just the supplied antennas and if I add a BBQ style dish
(from my AO-40 reception days) to replace the supplied antenna, I can
almost quadruple that range. Granted the laptop and 54g are both at
ground level and have a lot of obstructions. Still have to take it out
to one of the local parks to see what I can actually get for range with
no buildings. With the laptop being so sensitive, I can connect to the
local McD's free wi-fi almost half a mile away better than I can my
d-link router in the basement.

As for frequency usage, going by the 'slide-band' chart (available at
http://www.hsmm-mesh.org), there are 6 available 'channels' that fall in
the satellite sub-band the way I am interpreting FCC rules. If the
'slide-band ' crystal modification is done, that gives 4 'channels' for
use. Something to consider there about 'channel' hopping in the
software.

Greg, KO6TH, brings up about the timing protocols. Maybe the HSMM group
or TAPR would consider looking at the protocols and maybe modify them
much like AX.25 was done for packet back in the 1980's.


Mark and Drew bring up about noise levels being unacceptable on a few of
the lower bands. This might be mitigated with the use of the
'slide-band' modification by changing out the 20MHz crystal for a more
appropriate frequency. As I noted earlier, more about the 'slide-band'
mod for the 54GL is at the hsmm-mesh pages.

So if some of these obstacles can be 'overcome', would this be a
'viable' consideration? Could something like this be utilized to gain
the faster input speeds that are wanted for uploading/ downloading
images, files, and maybe store and forward systems that could tie into
the regional packet networks utilizing JNOS 2.0, WinLink, and FBB.
 
I just miss having something that is more than just APRS-related on the
satellites. This in no way is a knock on the present 1k2 sats, its just
that my KPC-9612 has been VERY under-utilized since the mid-1990's and I
miss having that fun :(

I am not a rocket scientist, electrical engineer, or a sat designer.
These are just personal thoughts to see if this 'idea' is even feasible.
My thoughts could be seriously flawed and skewed and totally 'out of
this world' to say. For all I know, this might be one of those bright
ideas that would work better with a placement on the lunar surface as
long as it doesn't interfere with EME work and can survive the harsh
environment there. That would be a TOTALLY separate discussion in itself
alone.

James W8ISS 
=
On Tue, 2013-02-19 at 10:12 -0500, James French wrote:
> What are the possibilities of building a satellite that uses a Linksys
> WRT54GL router with a modified DD-wrt or HSMM-Mesh software as a store
> and forward BBS, to route a received request from one station to another
> station, or even to connect to a on board networked camera to receive
> images?
> 
> What kind of uplink power would be needed from the home station?
> 
> How fast could the speed(s) get theoretically?
> 
> How big would the antenna have to be on the craft and for the ground
> station to even be able to do this adequately?
> 
> Would the doppler be too much to even consider this?
> 
> Would the space environment be too harsh for something like this?
> 
> This is just something I was thinking about this morning and thought I
> would toss it out.
> 
> James W8ISS


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[amsat-bb] Re: 2.4GHz broadband router on satellite?

[Joshua Abraham]

Hello James, I just wanted to throw my two cents in on the protocols. I'm
not sure about the need for AX.25 implementation. The 802.11(Wi-Fi)
standard should server the purpose needed. AX.25 is a considerably limited
protocol. Low speeds, limited error correction, and frankly, it defeats the
purpose of putting a wifi router in orbit to begin with. One key feature of
802.11 is its ability to operate in less than ideal conditions. The
protocol natively supports error correction, multiple simultaneous users,
and can avoid data collision with "carrier-sense" technology.
Also, long distance shouldn't be too large a concern. I seem to remember
reading about a successful experiment involving high altitude balloons.
I may too not be entirely accurate on the above, I'm still in college for a
networking degree. I'm just going on what I've learned so far.

Joshua KJ4VYR

On Fri, Feb 22, 2013 at 3:06 PM, James French  wrote:

> Lee and those who have responded so far,
>
> Those are the questions that would need to be answered before even
> considering this 'novel' idea.
>
> I use the WRT54GL as a reference since that is what I am familiar with.
> The WRT54GL would need to be almost redesigned because of space
> radiation conditions plus it may just not have enough output power to
> even be considered especially with trying to fit it into a microsat or
> smaller frame and then finding a suitable launch. Could the satellite
> utilize a modified 'backfire' antenna (referencing AO-40 2.4GHz
> antennas) that utilizes dipoles offset from the surface on every side
> and then use the surface of the satellite itself for gain?
>
> As for HSMM-Mesh, this maybe the software to consider for something like
> this as its robust enough for what I have played with three WRT54G
> around my area (EN82jg), both mobile and stationary. My laptop (a
> Fujitsu Lifebook T4020) is sensitive enough to pick up one 54g half a
> mile away using just the supplied antennas and if I add a BBQ style dish
> (from my AO-40 reception days) to replace the supplied antenna, I can
> almost quadruple that range. Granted the laptop and 54g are both at
> ground level and have a lot of obstructions. Still have to take it out
> to one of the local parks to see what I can actually get for range with
> no buildings. With the laptop being so sensitive, I can connect to the
> local McD's free wi-fi almost half a mile away better than I can my
> d-link router in the basement.
>
> As for frequency usage, going by the 'slide-band' chart (available at
> http://www.hsmm-mesh.org), there are 6 available 'channels' that fall in
> the satellite sub-band the way I am interpreting FCC rules. If the
> 'slide-band ' crystal modification is done, that gives 4 'channels' for
> use. Something to consider there about 'channel' hopping in the
> software.
>
> Greg, KO6TH, brings up about the timing protocols. Maybe the HSMM group
> or TAPR would consider looking at the protocols and maybe modify them
> much like AX.25 was done for packet back in the 1980's.
>
>
> Mark and Drew bring up about noise levels being unacceptable on a few of
> the lower bands. This might be mitigated with the use of the
> 'slide-band' modification by changing out the 20MHz crystal for a more
> appropriate frequency. As I noted earlier, more about the 'slide-band'
> mod for the 54GL is at the hsmm-mesh pages.
>
> So if some of these obstacles can be 'overcome', would this be a
> 'viable' consideration? Could something like this be utilized to gain
> the faster input speeds that are wanted for uploading/ downloading
> images, files, and maybe store and forward systems that could tie into
> the regional packet networks utilizing JNOS 2.0, WinLink, and FBB.
>
> I just miss having something that is more than just APRS-related on the
> satellites. This in no way is a knock on the present 1k2 sats, its just
> that my KPC-9612 has been VERY under-utilized since the mid-1990's and I
> miss having that fun :(
>
> I am not a rocket scientist, electrical engineer, or a sat designer.
> These are just personal thoughts to see if this 'idea' is even feasible.
> My thoughts could be seriously flawed and skewed and totally 'out of
> this world' to say. For all I know, this might be one of those bright
> ideas that would work better with a placement on the lunar surface as
> long as it doesn't interfere with EME work and can survive the harsh
> environment there. That would be a TOTALLY separate discussion in itself
> alone.
>
> James W8ISS
> =
> On Tue, 2013-02-19 at 10:12 -0500, James French wrote:
> > What are the possibilities of building a satellite that uses a Linksys
> > WRT54GL router with a modified DD-wrt or HSMM-Mesh software as a store
> > and forward BBS, to route a received request from one station to another
> > station, or even to connect to a on board networked camera to receive
> > images?
> >
> > What kind of uplink power would be needed from the home station?
> >
> > How fast could the speed(s) get th

[amsat-bb] Re: 2.4GHz broadband router on satellite?

[Roger]

Could a gain antenna be incorporated into a gradient boom for aiming?

Roger
WA1KAT

On 2/22/2013 3:06 PM, James French wrote:

Lee and those who have responded so far,

Those are the questions that would need to be answered before even
considering this 'novel' idea.
Could the satellite
utilize a modified 'backfire' antenna (referencing AO-40 2.4GHz
antennas) that utilizes dipoles offset from the surface on every side
and then use the surface of the satellite itself for gain?




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[amsat-bb] Re: 2.4GHz broadband router on satellite?

[Trevor .]

--- On Fri, 22/2/13, Joshua Abraham  wrote:
> I seem to remember reading about a successful experiment involving high
> altitude balloons.

See http://www.nrl.navy.mil/content_images/07Information_Rupar.pdf

73 Trevor M5AKA


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[amsat-bb] Re: 2.4GHz broadband router on satellite?

[R Oler]

There has been some work done with wireless routers and amplifiers in several 
balloon flights in association with the Wx bureau.  A group which I am a part 
of got the equivalent of an SBIR from a federal agency to do this work (plus 
they helped us get on the balloons.  There is no secret here really, the 
various formulas associated with link margins etc "work" (grin) and the links 
were quite solid AND city RF made little difference.  Directional arrays on the 
ground are ones friend and even near "WiFI" hotspots the systems worked well 
(that was part of the test).

The main issue for a satellite particularly one in LEO is going to be doppler 
shift.  Farther out of course the shift is less but link margin is more 
difficult.

The frequencies are different but we are now using TACSAT 4 for some test.  
Robert WB5MZO

> Date: Fri, 22 Feb 2013 21:36:01 +
> From: m5...@yahoo.co.uk
> To: amsat-bb@amsat.org
> Subject: [amsat-bb] Re: 2.4GHz broadband router on satellite?
> 
> --- On Fri, 22/2/13, Joshua Abraham  wrote:
> > I seem to remember reading about a successful experiment involving high
> > altitude balloons.
> 
> See http://www.nrl.navy.mil/content_images/07Information_Rupar.pdf
> 
> 73 Trevor M5AKA
> 
> 
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[amsat-bb] Re: 2.4GHz broadband router on satellite?

[John Stephensen]

Yes, 2.4 GHz was very noisy. AMSAT Eagle was to use a 3.4 GHz high-speed 
(0.5-1 Mbps) BPSK downlink. BPSK was chosen for maximum efficiency in the 
PA. WiFi and WiMAX use complex modulation schemes that are optimized for 
terrestrial applications where the signal is diffused and scattered by 
nearby objects. This results in a PA DC to RF conversion efficiency of less 
than 20%.


73,

John
KD6OZH

- Original Message - 
From: "Mark L. Hammond" 

To: "Trevor ." 
Cc: "amsat-bb" 
Sent: Friday, February 22, 2013 16:20 UTC
Subject: [amsat-bb] Re: 2.4GHz broadband router on satellite?



Maybe Drew KO4MA will reply--but I thought he did some "global
listening" on 2.4GHz with AO-51 (frequency agile receiver).  Seems
like he published some plots in The Journal?

Take home from what I recall--it was very noisy!

Mark N8MH

On Fri, Feb 22, 2013 at 10:49 AM, Trevor .  wrote:
Apart from power budget issues and Doppler the real killer will be the 
very high noise level on 2.4 GHz.


In urban areas you can expected to receive strong WiFi signals across all 
of 2402-2450 almost regardless of where you beam.


Any signals from a satellite would need to be strong enough to overcome 
this interference. 5 GHz is likely to suffer a similar problem in a few 
years as more use is made of that band for WiFi etc.


73 Trevor M5AKA


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Mark L. Hammond [N8MH]
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[amsat-bb] Re: 2.4GHz broadband router on satellite?

[Trevor .]

--- On Wed, 27/2/13, John Stephensen  wrote:
> Yes, 2.4 GHz was very noisy. AMSAT Eagle was to use a 3.4 GHz 
> high-speed (0.5-1 Mbps) BPSK downlink. 

In terms of noise a 3400-3410 MHz satellite band would have a lot going for it, 
unfortunately it isn't a Global Amateur-satellite allocation - it's not 
available in 1/3 of the World (Region 1).

73 Trevor M5AKA


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