Hi all,
Some friends from south of France submitted the idea of a 5 GHz link between France and Corsica. The distance is 200-250 km, mostly over the sea. It's far longer than what I could see on HamNetDB, for example. But it's shorter than WiFi world records (some of them attempted more than 10 years ago between Italy and Sardinia). I never attempted links longer than 40km, so I don't have any experience. And we don't have any SHF expert locally...
1/ Do you think a permanent and stable 250 km link over the Mediterranean sea is doable ? Are some of you using such long links in 5 GHz ? If so, could you share your technical experience here ?
2/ Are there any people from Italy on this list ? Are there any volunteers between Genova and Roma to attempt a link with the East coast of Corsica ? If it works, would there be an interest in establishing a permanent link ?
Thank you for your comments,
73 de TK1BI
You might check with the https://hamwan.org folks, they have experience with long haul links over the Salish sea.
On Thu, Sep 9, 2021, 05:43 Toussaint OTTAVI via 44Net < 44net@mailman.ampr.org> wrote:
Hi all,
Some friends from south of France submitted the idea of a 5 GHz link between France and Corsica. The distance is 200-250 km, mostly over the sea. It's far longer than what I could see on HamNetDB, for example. But it's shorter than WiFi world records (some of them attempted more than 10 years ago between Italy and Sardinia). I never attempted links longer than 40km, so I don't have any experience. And we don't have any SHF expert locally...
1/ Do you think a permanent and stable 250 km link over the Mediterranean sea is doable ? Are some of you using such long links in 5 GHz ? If so, could you share your technical experience here ?
2/ Are there any people from Italy on this list ? Are there any volunteers between Genova and Roma to attempt a link with the East coast of Corsica ? If it works, would there be an interest in establishing a permanent link ?
Thank you for your comments,
73 de TK1BI _________________________________________ 44Net mailing list 44Net@mailman.ampr.org https://mailman.ampr.org/mailman/listinfo/44net
Hi, there is one Hamnet link in Germany: https://hamnetdb.net/map.cgi#zoom=9&lat=48.42&lon=12.469&layer=M...
216km
rssi data can be found here: https://grafana.hamnetdb.net/d/s3tmR0hWk/rssi-values?orgId=1&refresh=2m&...
Due to changing in refraction there is no infinite stability and a lot of fading.
73 Lucas
On 2021-09-09 16:46, K7VE - John via 44Net wrote:
You might check with the https://hamwan.org folks, they have experience with long haul links over the Salish sea.
On Thu, Sep 9, 2021, 05:43 Toussaint OTTAVI via 44Net < 44net@mailman.ampr.org> wrote:
Hi all,
Some friends from south of France submitted the idea of a 5 GHz link between France and Corsica. The distance is 200-250 km, mostly over the sea. It's far longer than what I could see on HamNetDB, for example. But it's shorter than WiFi world records (some of them attempted more than 10 years ago between Italy and Sardinia). I never attempted links longer than 40km, so I don't have any experience. And we don't have any SHF expert locally...
1/ Do you think a permanent and stable 250 km link over the Mediterranean sea is doable ? Are some of you using such long links in 5 GHz ? If so, could you share your technical experience here ?
2/ Are there any people from Italy on this list ? Are there any volunteers between Genova and Roma to attempt a link with the East coast of Corsica ? If it works, would there be an interest in establishing a permanent link ?
Thank you for your comments,
73 de TK1BI _________________________________________ 44Net mailing list 44Net@mailman.ampr.org https://mailman.ampr.org/mailman/listinfo/44net
44Net mailing list 44Net@mailman.ampr.org https://mailman.ampr.org/mailman/listinfo/44net
The problem, as I see it, would not only be signal strength, but also overcoming the curvature of the earth with suitably high antennae on both ends
-- Chaplain Dave Sparks - Callsign: AF6AS
[image: Mailtrack] https://mailtrack.io?utm_source=gmail&utm_medium=signature&utm_campaign=signaturevirality5& Sender notified by Mailtrack https://mailtrack.io?utm_source=gmail&utm_medium=signature&utm_campaign=signaturevirality5& 09/09/21, 08:50:16 AM
On Thu, Sep 9, 2021 at 5:42 AM Toussaint OTTAVI via 44Net < 44net@mailman.ampr.org> wrote:
Hi all,
Some friends from south of France submitted the idea of a 5 GHz link between France and Corsica. The distance is 200-250 km, mostly over the sea. It's far longer than what I could see on HamNetDB, for example. But it's shorter than WiFi world records (some of them attempted more than 10 years ago between Italy and Sardinia). I never attempted links longer than 40km, so I don't have any experience. And we don't have any SHF expert locally...
1/ Do you think a permanent and stable 250 km link over the Mediterranean sea is doable ? Are some of you using such long links in 5 GHz ? If so, could you share your technical experience here ?
2/ Are there any people from Italy on this list ? Are there any volunteers between Genova and Roma to attempt a link with the East coast of Corsica ? If it works, would there be an interest in establishing a permanent link ?
Thank you for your comments,
73 de TK1BI _________________________________________ 44Net mailing list 44Net@mailman.ampr.org https://mailman.ampr.org/mailman/listinfo/44net
The issue with such long SHF links (especially over water) is "tropospheric ducting". You need to calculate the antenna height based on line-of-sight and have antennas at that height, but you also need extra link antennas at much lower height because tropospheric ducting may curve the signals along the water surface and they can be received in the inversion layer close to the ground, but not at the height you need for a line-of-sight path. SHF DX-ers are very familiar with this phenomenon, where it is possible to make a QSO from the beach or from a coast house at 30m elevation, but not from a mountain 400m high. With two different link setups you may be able to get coverage for a larger percentage of time.
Rob
On 9/9/21 5:52 PM, Chaplain Dave Sparks via 44Net wrote:
The problem, as I see it, would not only be signal strength, but also overcoming the curvature of the earth with suitably high antennae on both ends
Le 09/09/2021 à 17:58, Rob PE1CHL via 44Net a écrit :
SHF DX-ers are very familiar with this phenomenon, where it is possible to make a QSO from the beach or from a coast house at 30m elevation, but not from a mountain 400m high. With two different link setups you may be able to get coverage for a larger percentage of time.
Having two links with monitoring and metrics may be an interesting tool for propagation checking :-) We must also set up routing priorities in relation with link quality. But that's another topic :-)
Anyway, that's what I was fearing : we are in the SHF domain, we cant' just put some UBNT stuff on the highest point and see if it works, but we need real SHF experts in the team.
73 de TK1BI
Toussaint OTTAVI via 44Net 44net@mailman.ampr.org writes:
Having two links with monitoring and metrics may be an interesting tool for propagation checking :-) We must also set up routing priorities in relation with link quality. But that's another topic :-)
A proposal to set up such a system and publish measured results is the kind of potential improvement in our collective understanding of atmospheric effects and impact on SHF digital links could be an interesting grant request.
Anyway, that's what I was fearing : we are in the SHF domain, we cant' just put some UBNT stuff on the highest point and see if it works, but we need real SHF experts in the team.
Yes. I learned this the hard way myself when I was young and naive, and thought I could change the world setting up some "easy" mountaintop 10 GHz data links...
73 - Bdale, KB0G
To request a grant see https://www.ampr.org/apply (yes, we can do international grants to non-profits that are equivalent to a US IRS 501(c)(3) -- just some extra paperwork before dispersing the funds)
thanks Bdale, I was going to mention this, but you beat me to it.
On Fri, Sep 10, 2021 at 9:24 AM Bdale Garbee via 44Net < 44net@mailman.ampr.org> wrote:
Toussaint OTTAVI via 44Net 44net@mailman.ampr.org writes:
Having two links with monitoring and metrics may be an interesting tool for propagation checking :-) We must also set up routing priorities in relation with link quality. But that's another topic :-)
A proposal to set up such a system and publish measured results is the kind of potential improvement in our collective understanding of atmospheric effects and impact on SHF digital links could be an interesting grant request.
Anyway, that's what I was fearing : we are in the SHF domain, we cant' just put some UBNT stuff on the highest point and see if it works, but we need real SHF experts in the team.
Yes. I learned this the hard way myself when I was young and naive, and thought I could change the world setting up some "easy" mountaintop 10 GHz data links...
73 - Bdale, KB0G _________________________________________ 44Net mailing list 44Net@mailman.ampr.org https://mailman.ampr.org/mailman/listinfo/44net
If anyone wants to work on such project. Can I give a pointer into the Pluto sdr platform for the receiving ends? Don't need to redo the week as the whole device run linux, have in fact 2 tx and 2 rx ports and it can support USB ethernet d'ongle for inter connection locally. They go up to 6ghz.
Might be a nice radio to play with and you can set a high powe amplifier at the tx port and have a separate antenna for rx and put a preamp in line for higher performance on the ham bands part of 5 ghz.
Pierre Ve2pf
Sent from my Samsung Galaxy Tab®4
-------- Original message -------- From: Bdale Garbee via 44Net 44net@mailman.ampr.org Date: 09-10-2021 12:23 PM (GMT-05:00) To: Toussaint OTTAVI via 44Net 44net@mailman.ampr.org, 44Net general discussion 44net@mailman.ampr.org Cc: Bdale Garbee bdale@gag.com Subject: Re: [44net] 5 GHz link over 250 km of sea between Corsica and France / Italy ?
Toussaint OTTAVI via 44Net 44net@mailman.ampr.org writes:
Having two links with monitoring and metrics may be an interesting tool for propagation checking :-) We must also set up routing priorities in relation with link quality. But that's another topic :-)
A proposal to set up such a system and publish measured results is the kind of potential improvement in our collective understanding of atmospheric effects and impact on SHF digital links could be an interesting grant request.
Anyway, that's what I was fearing : we are in the SHF domain, we cant' just put some UBNT stuff on the highest point and see if it works, but we need real SHF experts in the team.
Yes. I learned this the hard way myself when I was young and naive, and thought I could change the world setting up some "easy" mountaintop 10 GHz data links...
73 - Bdale, KB0G
On Thu, 9 Sep 2021, Chaplain Dave Sparks via 44Net wrote:
The problem, as I see it, would not only be signal strength, but also overcoming the curvature of the earth with suitably high antennae on both ends
This is a factor. The 125 mile / 200 km shot across America took a 6,000 ft (1,829m) peak at each end over a 125 mile long valley.
Most of AT&T's USA microwave network used 300 ft (90m) towers over 25-35 mile (40 - 56 km) hops or equivalents with terrain assistance.
-- Kris Kirby, KE4AHR Disinformation Architect, Systems Mangler, & Network Mismanager
I ran a 150km link between Southern Vancouver Island and Northwest Washington State for a few years. About 50% of the distance was over sea. We used 5GHz with 3 ft dishes on both ends.
The link worked reasonably well, there were huge deviations in signal strength though, we needed to account for 20 dB of fade on any given day, sometimes we would loose 10dB of signal in a matter of minutes. Overall the link was reliable; 15mbps was our average speed on a 'bad' day, and we could push as much as 40 on a 'good' day.
Chris VE7ALB
On 09/09/2021 05:41, Toussaint OTTAVI via 44Net wrote:
Hi all,
Some friends from south of France submitted the idea of a 5 GHz link between France and Corsica. The distance is 200-250 km, mostly over the sea. It's far longer than what I could see on HamNetDB, for example. But it's shorter than WiFi world records (some of them attempted more than 10 years ago between Italy and Sardinia). I never attempted links longer than 40km, so I don't have any experience. And we don't have any SHF expert locally...
1/ Do you think a permanent and stable 250 km link over the Mediterranean sea is doable ? Are some of you using such long links in 5 GHz ? If so, could you share your technical experience here ?
2/ Are there any people from Italy on this list ? Are there any volunteers between Genova and Roma to attempt a link with the East coast of Corsica ? If it works, would there be an interest in establishing a permanent link ?
Thank you for your comments,
73 de TK1BI _________________________________________ 44Net mailing list 44Net@mailman.ampr.org https://mailman.ampr.org/mailman/listinfo/44net
Hi Toussaint,
1/ Do you think a permanent and stable 250 km link over the Mediterranean sea is doable ?
There used to be a few (PTT&military) links between Corsica & continental France, some as early as 1947[0,1], although way down around 100MHz[1].
Those areas have a huge advantage of having somewhat high mountains not that far from the sea. Quickly looking at radiomobile, there seems to be around 154dB of free space loss between Grasse (Le Haut Montet, alt 1330m) and Calenzana (Monte Grosso, alt 1900m) for a distance of 210km, with no obstruction from the curvature of earth.
Using commercial ubiquiti 34dB dishes and 30dBm of power, this seems to fit within the receiver sensitivity on airfibers 5x (-90dBm), so depending on fading and tropo ducting conditions, this could work at times.
Bonne chance !
[0] https://www.persee.fr/doc/reso_0984-5372_1996_hos_14_1_3673 (p.190) [1] https://www.hertzien.fr/evolutions_46-60.htm
73 de f4inu
Hi all, and thank you for your answers. I think we have some good experiments on the go...
Le 09/09/2021 à 22:38, Pierre Emeriaud a écrit :
There used to be a few (PTT&military) links between Corsica & continental France, some as early as 1947[0,1], although way down around 100MHz[1].
Yes, but their dishes had more than decent diameters, HI :-) We often used their 50 meters tower as a support for our low band dipoles during HF contests :-) This tower has been dismantled 10 years ago, but it was already offline when I got my ham license in the 1990s. A similar tower with two parabolic antennas can still be seen on a hill in the middle of the city of Bastia. That's the first thing you see from the harbor, HI :-) It was used to forward communications to the military Solenzara Air Base (also called the "Mediterranean aircraft carrier"), on the south east coast of the island. Now, they are using submarine fiber optics :-) And we are using VPNs, over two "civilian" fiber pairs on the same fiber. A funny detail : due to its primary military function, this fiber does not appear on any public submarine fiber map. The main advantage for us is that in case of problems, it's repaired quickly :-)
Those areas have a huge advantage of having somewhat high mountains not that far from the sea. Quickly looking at radiomobile, there seems to be around 154dB of free space loss between Grasse (Le Haut Montet, alt 1330m) and Calenzana (Monte Grosso, alt 1900m) for a distance of 210km, with no obstruction from the curvature of earth.
Monte Grossu may not be the best location for a radio high point, unless you want to build a one-shot blitzortung.org receiver, HI :-) Our "usable" high points, over Bastia and Ajaccio, are 800-900m ASL, just over sea. Anyway, as Rob said in a previous message about "tropospheric ducting", higher locations may not be the better.
This may be an interesting project...
73 de TK1BI
Ciao Toussaint, first of all, sorry for being late in my answer. I was involved in the working group who established the record of 304 km during the first experiments in the first months of 2007 (https://www.cisar.it/index.php?option=com_content&view=article&id=38...) and then improved the bandwidth of the original link with the collaboration of a notorious brand in the 2016 (https://en.wikipedia.org/wiki/Long-range_Wi-Fi#Italy) If you like, please consider both myself as first point of contact for old memories and Gian Leonardo Solazzi IW2NKE as coordinator of nowadays WiFi working group of Italian CISAR association if you have any specific question about our unforgettable and wonderful experience about the WiFi longest ham radio world record.
Ciao from Italy.
IW0SAB Renzo Rossi
Il 09/09/2021 14:41 Toussaint OTTAVI via 44Net 44net@mailman.ampr.org ha scritto:
Hi all,
Some friends from south of France submitted the idea of a 5 GHz link between France and Corsica. The distance is 200-250 km, mostly over the sea. It's far longer than what I could see on HamNetDB, for example. But it's shorter than WiFi world records (some of them attempted more than 10 years ago between Italy and Sardinia). I never attempted links longer than 40km, so I don't have any experience. And we don't have any SHF expert locally...
1/ Do you think a permanent and stable 250 km link over the Mediterranean sea is doable ? Are some of you using such long links in 5 GHz ? If so, could you share your technical experience here ?
2/ Are there any people from Italy on this list ? Are there any volunteers between Genova and Roma to attempt a link with the East coast of Corsica ? If it works, would there be an interest in establishing a permanent link ?
Thank you for your comments,
73 de TK1BI _________________________________________ 44Net mailing list 44Net@mailman.ampr.org https://mailman.ampr.org/mailman/listinfo/44net
Ciao Renzo,
Thank you very much for your answer. We were aware of your world record of 304 km in 2007, that's why we wanted to evaluate permanent links of 200-250km. We moved the talk to "44net-fr" mailing-list, and we may attempt a first 200km link between Bastia and south-east of France soon.
During the last century, Corsica was a bridgehead in the Mediterranean sea, with 9k6 packet-radio links to France, Italy (San Remo) and Sardinia. Do you think there could be volunteers in Italy and Sardinia to establish permanent links with Corsica with modern 44net / upcoming "NGN" technologies ?
As said a few posts ago, having such links with precise monitoring and measurements could improve our collective understanding of atmospheric effects and impact on SHF digital links, and could benefit from ARDC grants. I think it would be a nice technical and scientific challenge...
73 de TK1BI
Le 19/09/2021 à 13:10, renzorossi@libero.it a écrit :
Ciao Toussaint, first of all, sorry for being late in my answer. I was involved in the working group who established the record of 304 km during the first experiments in the first months of 2007 (https://www.cisar.it/index.php?option=com_content&view=article&id=38...) and then improved the bandwidth of the original link with the collaboration of a notorious brand in the 2016 (https://en.wikipedia.org/wiki/Long-range_Wi-Fi#Italy) If you like, please consider both myself as first point of contact for old memories and Gian Leonardo Solazzi IW2NKE as coordinator of nowadays WiFi working group of Italian CISAR association if you have any specific question about our unforgettable and wonderful experience about the WiFi longest ham radio world record.
Ciao from Italy.
IW0SAB Renzo Rossi
Il 09/09/2021 14:41 Toussaint OTTAVI via 44Net 44net@mailman.ampr.org ha scritto:
Hi all,
Some friends from south of France submitted the idea of a 5 GHz link between France and Corsica. The distance is 200-250 km, mostly over the sea. It's far longer than what I could see on HamNetDB, for example. But it's shorter than WiFi world records (some of them attempted more than 10 years ago between Italy and Sardinia). I never attempted links longer than 40km, so I don't have any experience. And we don't have any SHF expert locally...
1/ Do you think a permanent and stable 250 km link over the Mediterranean sea is doable ? Are some of you using such long links in 5 GHz ? If so, could you share your technical experience here ?
2/ Are there any people from Italy on this list ? Are there any volunteers between Genova and Roma to attempt a link with the East coast of Corsica ? If it works, would there be an interest in establishing a permanent link ?
Thank you for your comments,
73 de TK1BI _________________________________________ 44Net mailing list 44Net@mailman.ampr.org https://mailman.ampr.org/mailman/listinfo/44net
Ciao Toussaint, first of all, sorry for being late in my answer. I was involved in the working group who established the record of 304 km during the first experiments in the first months of 2007 (https://www.cisar.it/index.php?option=com_content&view=article&id=38...) and then improved the bandwidth of the original link with the collaboration of a notorious brand in the 2016 (https://en.wikipedia.org/wiki/Long-range_Wi-Fi#Italy) If you like, please consider both myself as first point of contact for old memories and Gian Leonardo Solazzi IW2NKE as coordinator of nowadays WiFi working group of Italian CISAR association if you have any specific question about our unforgettable and wonderful experience about the WiFi longest ham radio world record.
Ciao from Italy.
IW0SAB Renzo Rossi
Il 09/09/2021 14:41 Toussaint OTTAVI via 44Net 44net@mailman.ampr.org ha scritto:
Hi all,
Some friends from south of France submitted the idea of a 5 GHz link between France and Corsica. The distance is 200-250 km, mostly over the sea. It's far longer than what I could see on HamNetDB, for example. But it's shorter than WiFi world records (some of them attempted more than 10 years ago between Italy and Sardinia). I never attempted links longer than 40km, so I don't have any experience. And we don't have any SHF expert locally...
1/ Do you think a permanent and stable 250 km link over the Mediterranean sea is doable ? Are some of you using such long links in 5 GHz ? If so, could you share your technical experience here ?
2/ Are there any people from Italy on this list ? Are there any volunteers between Genova and Roma to attempt a link with the East coast of Corsica ? If it works, would there be an interest in establishing a permanent link ?
Thank you for your comments,
73 de TK1BI _________________________________________ 44Net mailing list 44Net@mailman.ampr.org https://mailman.ampr.org/mailman/listinfo/44net
Le 19/09/2021 à 13:16, renzorossi@libero.it a écrit :
I was involved in the working group who established the record of 304 km during the first experiments in the first months of 2007 (https://www.cisar.it/index.php?option=com_content&view=article&id=38...)
"... in particolare la grande inventiva e creativita’ dei radioamatori ha permesso di costruire efficientissimi illuminatori partendo da bronzine dei pistoni di motori per autobus"
Wow ! Here's why hamradio spirit is really amazing :-)
73 de TK1BI
-
Bdale Garbee -
Chaplain Dave Sparks -
Christopher Munz-Michielin -
K7VE - John -
Kris Kirby -
Lucas Speckbacher OE2LSP -
pete M -
Pierre Emeriaud -
renzorossi＠libero.it -
Rob PE1CHL -
Toussaint OTTAVI