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 Subject :BBHN on 70cm?.. 2014-12-17- 15:27:11 
N1OBU
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Joined: 2013-04-14- 18:36:48
Posts: 13
Location: Preston, CT

Hello,

  Is it possible to run BBHN on 70cm using the Doodle Labs DL435-30 WiFi card?  The Mbps looks to be about 12 with a 5Mhz bandwidth.


--73 de Doug (N1OBU)

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 Subject :Re:BBHN on 70cm?.. 2014-12-17- 20:43:16 
KG6JEI
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Joined: 2013-12-02- 19:52:05
Posts: 516
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I'm not going to say its possible or not as I have not ever had one of these cards in my hands.  The online quick datasheet is a little iffy on if it supports Adhoc mode, but assuming it does, it is an ath5k device which means Linux supports it and that you can build up a computer to run the BBHN protocol across it (Adhoc, OLSRD, etc)  but no build exists for it at this time (and it would be hard to make a dedicated build for it as it is a PCI card that can slip into any computer)

But assuming adhoc mode one should be able to do it I don't see why not.


The next question that crosses my mind is Part 97 licensing on the subject, I'm not going to render an opinion, I'm just going to say I'm not sure if its permitted or not as I've read conflicting information, enough to make me feel to say it needs to be researched more.


I will say i would LIKE it to be permitted as that can clear up some of the NLOS issues possibly better than the 900mhz band does and may open more options.


The parts I believe to be the relevent text from Part 97 is as follows for authorized transmissions on 70cm

97.307(6) A RTTY, data or multiplexed emission using a specified digital code listed in § 97.309(a) of this part may be transmitted. The symbol rate must not exceed 56 kilobauds. A RTTY, data or multiplexed emission using an unspecified digital code under the limitations listed in § 97.309(b) of this part also may be transmitted. The authorized band-width is 100 kHz

(8) A RTTY or data emission having designators with A, B, C, D, E, F, G, H, J or R as the first symbol; 1, 2, 7 or 9 as the second symbol; and D or W as the third symbol is also authorized.

OFDM (802.11g) from what I can find is designator: 16M8GXW


Ive read one article but I haven't found a reputable reference for its claims other than an opinion  that the 'bandwith" rule applies to each carrier (and I'm not even sure how  big each subcarrier of an 802.11 signal is)

I've seen some argument brought on by the Google WIFI case to argue that each subcarrier is unique and independent (and that the receiving of all of them at once was special equipment)   to possibly give this some merit, but not enough that I would personally say if its permitted or not. I also saw another document try and argue it was "image" not "data" because you could put video across it, not sure I would suggest that as a valid interpretation either considering how the mesh normally functions.

Of course if you could some how  lock them to the  low 1mb speed (not sure if it can be done off hand or not)  one could claim they are Spread Spectrum (which I'm not sure is or is not subject to the data restriction or not)

I would suggest researching those items .  I can say If i managed to stumble upon some of those boards at an affordable price I could see them being useful and would love to press them into service if its permissible.

So there you have my thoughts on it, I don't know enough to give an opinion one way or the other on the licensing side, only enough to say I have questions. 

Otherwise from a technical standpoint, if they support adhoc mode they would be likely physically capable of being put into service.

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 Subject :Re:BBHN on 70cm?.. 2014-12-18- 09:22:17 
N1OBU
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Joined: 2013-04-14- 18:36:48
Posts: 13
Location: Preston, CT
Hello.. Hmm.. Well.. I got my info about "High Speed Networking" from YouTube's HamRadioNow Episodes 176 and 41. It looks like David Bern W2LNX has done some High Speed point-to-point tests on 70cm using the Doodle Labs DL435-30 card. Just wondering it was possible to integrate OSLR meshing. It's just adding another band where BBHN could function. --73 de Doug
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 Subject :Re:BBHN on 70cm?.. 2014-12-18- 10:51:56 
KG6JEI
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Joined: 2013-12-02- 19:52:05
Posts: 516
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As noted, I don't see why it wouldn't run olsr (it would be a wifi card inside Linux same as any other), and even if it didn't support AdHoc it could be used in a AP style deployment for more cord instead nodes.


Big unknown to me is the licensing part.  Perhaps David will jump in as I've seen him talk about them in the past and provide some more information about the licensing for us, as noted it's an area I'm not sure on and have questions about,

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 Subject :Re:BBHN on 70cm?.. 2014-12-18- 18:52:40 
AE6XE
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Joined: 2013-11-05- 00:09:51
Posts: 116
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There is a section 97.311 Spread Spectrum (or bandwidth-expansion modulation emissions) which is designated for many bands including 70cm. This does give some precedence for 5MHz+ channels and other 802.11 protocols.

While bbhn may not have any direct control over the 802.11 low levels protocols used, SS is one of them. It seems unlikely that the 97.37(f)(6) intent would apply to 802.11 protocols, because all this language is around symbols at 1200/300 baud.

The ATV channels on 70cm are 6Mhz wide and also sets a precedence on bandwidth usage. Many of these folks are no doubt looking at bbhn and locally have already put a mesh node on the ATV tower.

My opinion is that experimenting with bbhn on 70cm is fully in the spirit of ham radio, BUT as long as the ATV and bbhn folks are talking, getting alone, and sharing the band, there would be opportunity. Let's not go throw up a node and trash a well established ATV used space (well, it's more like ATV will completely trash the low power bbhn).

Locally, Don KE6BXT is working to integrate a VOIP-video device with analog video feeds to bridge the traditional ATV repeater with the local mesh. ATV folks are drawn to video over bbhn...

Joe AE6XE

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Last Edited On: 2014-12-18- 18:59:07 By AE6XE for the Reason
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