6 ms·

We want to do that, but FCC regulations don't enable meshing (currently) on the bands we're using (151-154 MHz, aka the MURS band). We considered releasing a 90

by daniper 12y ago

We want to do that, but FCC regulations don't enable meshing (currently) on the bands we're using (151-154 MHz, aka the MURS band). We considered releasing a 900 MHz device that the FCC allows to mesh but then you only get, if you're lucky, up to 0.5 km range and it has to be line-of-sight. So we went with MURS because you can get greater range and don't have to be line-of-sight; the propagation characteristics are better down at MURS. Also, when we asked 1000 people (including testers) what they preferred -- a long-range MURS device or a short-range meshing device -- about 8 of 10 picked the former. So that's why the goTenna device you see today is our first release!

jrockway 12y ago
How often are you getting non-line-of-sight propagation with MURS?
- daniper 12y ago
  Most of the time. We live in NYC and have gotten anywhere from 0.5 mile to 3.5 miles range here, depending what part of the city you're in. There's nearly no such thing as LOS in a city unless, say, you're in a skyscraper ;)
  - jrockway 12y ago
    Ah, I'm just surprised that buildings ended up mattering when you were deciding between 150MHz or 900MHz. While people like to complain about the frequency getting higher and propagation dropping off (especially related to 2.4GHz and 5GHz wifi), I haven't found a good paper that guarantees that's the case. Anecdotally, I can receive a 5GHz signal in my office in Manhattan from a radar in Floyd Bennett Field, 12 miles away, with buildings in the way. Similarly, inside my apartment, I have much better luck with 440MHz radio communication than 144MHz communication. (Ground floor, so not that great either way.) Being limited to 4W EIRP in the 900MHz ISM band probably played more of a role? Anyway, you might want to find these guys: https://news.ycombinator.com/item?id=7981431 https://news.ycombinator.com/item?id=7981431 The combination of your product with their technology could be quite interesting. Also, follow up question: does your protocol attempt to recover signals from below the noise floor?
    - daniper 12y ago
      No on the noise floor question ;)
bengotow 12y ago
Would it be possible to build a software-level mesh on top of these devices even though they don't officially support meshing? In other words, could someone build an iPhone app that implements some sort of decentralized DNS and routes messages, even though the hardware can't do that on it's own?
- sbierwagen 12y ago
  CFR 2009 § 95.1311 MURS stations are prohibited from operating as a repeater station or as a signal booster. This prohibition in- cludes store-and-forward packet oper- ation. http://www.gpo.gov/fdsys/pkg/CFR-2009-title47-vol5/pdf/CFR-2009-title47-vol5-part95.pdf http://www.gpo.gov/fdsys/pkg/CFR-2009-title47-vol5/pdf/CFR-2... Pretty clear cut. No packet routing, at all, for any reason, using any method. Doesn't matter if the radio firmware is doing it or if the client is doing it. (There is a general exemption to all licensing rules, at least in ham radio, in the case of "to provide essential communication needs in connection with the immediate safety of human life and immediate protection of property when normal communication systems are not available." (§97.403 Safety of life and protection of property.) Not terribly applicable in this situation, but a general "the Constitution is not a suicide pact" kinda thing.)
  - FindersKeep 12y ago
    Then don't use packets, use a streams of hashes or something mathematically similar that doesn't fit the characteristics of a packet, but still retains the security, and integrity of the information.
  - meatmanek 12y ago
    I wonder whether the FCC is going to consider Bluetooth <-> MURS interconnection to be in violation of this rule.
    - konstruktor 12y ago
      You're right, that seems to be a very real regulatory risk for this product. Basically, this product is a cross band repeater between the ISM band and the MURS band. Just because the encoding is different doesn't not make it a repeater.
glomek 12y ago
Do you intend to release the specifications for the protocol you are using? For example, would I be able to hook a computer with gnuradio up to a MURS radio and write software that could communicate with a goTenna?
- TD-Linux 12y ago
  This. I am super excited about the GoTenna because it is basically Ham Radio for the masses. But I'd also like to talk to GoTenna users with SDR or similar - in the spririt of non-encrypted ham communication.
- daniper 12y ago
  We have an open SDK coming out soon -- you can sign up for developer updates at our website
  - glomek 12y ago
    That sounds like a way to write programs that use a bluetooth attached gotenna. Is that correct? What I am asking is, could I talk to a gotenna using another radio setup of my own creation. Are you publishing enough information about gotenna for me to do that?
Nrsolis 12y ago
I ordered mine when the page went live. I hope to get them soon and start enjoying them. I'm actually headed out to Colorado to climb the Collegiate Peaks so I'm hoping they get here before mid-August. Don't worry. I've got a ham license and I'm bringing my 2m/70cm HT with me and a SatCom set too. Would be nice to give it a go in real-world conditions.
malandrew 12y ago
What about for users of GoTenna in other countries that don't have the MURS band mesh restriction? Will they be allowed to enable mesh delivery through a third party on their device?

by daniper 12y ago

jrockway 12y ago

How often are you getting non-line-of-sight propagation with MURS?

daniper 12y ago
Most of the time. We live in NYC and have gotten anywhere from 0.5 mile to 3.5 miles range here, depending what part of the city you're in. There's nearly no such thing as LOS in a city unless, say, you're in a skyscraper ;)
- jrockway 12y ago
  Ah, I'm just surprised that buildings ended up mattering when you were deciding between 150MHz or 900MHz. While people like to complain about the frequency getting higher and propagation dropping off (especially related to 2.4GHz and 5GHz wifi), I haven't found a good paper that guarantees that's the case. Anecdotally, I can receive a 5GHz signal in my office in Manhattan from a radar in Floyd Bennett Field, 12 miles away, with buildings in the way. Similarly, inside my apartment, I have much better luck with 440MHz radio communication than 144MHz communication. (Ground floor, so not that great either way.) Being limited to 4W EIRP in the 900MHz ISM band probably played more of a role? Anyway, you might want to find these guys: https://news.ycombinator.com/item?id=7981431 https://news.ycombinator.com/item?id=7981431 The combination of your product with their technology could be quite interesting. Also, follow up question: does your protocol attempt to recover signals from below the noise floor?
  - daniper 12y ago
    No on the noise floor question ;)

bengotow 12y ago

Would it be possible to build a software-level mesh on top of these devices even though they don't officially support meshing? In other words, could someone build an iPhone app that implements some sort of decentralized DNS and routes messages, even though the hardware can't do that on it's own?

sbierwagen 12y ago
CFR 2009 § 95.1311 MURS stations are prohibited from operating as a repeater station or as a signal booster. This prohibition in- cludes store-and-forward packet oper- ation. http://www.gpo.gov/fdsys/pkg/CFR-2009-title47-vol5/pdf/CFR-2009-title47-vol5-part95.pdf http://www.gpo.gov/fdsys/pkg/CFR-2009-title47-vol5/pdf/CFR-2... Pretty clear cut. No packet routing, at all, for any reason, using any method. Doesn't matter if the radio firmware is doing it or if the client is doing it. (There is a general exemption to all licensing rules, at least in ham radio, in the case of "to provide essential communication needs in connection with the immediate safety of human life and immediate protection of property when normal communication systems are not available." (§97.403 Safety of life and protection of property.) Not terribly applicable in this situation, but a general "the Constitution is not a suicide pact" kinda thing.)
- FindersKeep 12y ago
  Then don't use packets, use a streams of hashes or something mathematically similar that doesn't fit the characteristics of a packet, but still retains the security, and integrity of the information.
- meatmanek 12y ago
  I wonder whether the FCC is going to consider Bluetooth <-> MURS interconnection to be in violation of this rule.
  - konstruktor 12y ago
    You're right, that seems to be a very real regulatory risk for this product. Basically, this product is a cross band repeater between the ISM band and the MURS band. Just because the encoding is different doesn't not make it a repeater.

glomek 12y ago

Do you intend to release the specifications for the protocol you are using? For example, would I be able to hook a computer with gnuradio up to a MURS radio and write software that could communicate with a goTenna?

TD-Linux 12y ago
This. I am super excited about the GoTenna because it is basically Ham Radio for the masses. But I'd also like to talk to GoTenna users with SDR or similar - in the spririt of non-encrypted ham communication.
daniper 12y ago
We have an open SDK coming out soon -- you can sign up for developer updates at our website
- glomek 12y ago
  That sounds like a way to write programs that use a bluetooth attached gotenna. Is that correct? What I am asking is, could I talk to a gotenna using another radio setup of my own creation. Are you publishing enough information about gotenna for me to do that?

Nrsolis 12y ago

I ordered mine when the page went live. I hope to get them soon and start enjoying them. I'm actually headed out to Colorado to climb the Collegiate Peaks so I'm hoping they get here before mid-August. Don't worry. I've got a ham license and I'm bringing my 2m/70cm HT with me and a SatCom set too. Would be nice to give it a go in real-world conditions.

malandrew 12y ago

What about for users of GoTenna in other countries that don't have the MURS band mesh restriction? Will they be allowed to enable mesh delivery through a third party on their device?