Relay Nodes/Base Stations

#1

Hello everyone, my name is Austin and I am new to the Mesh community.
I think the GoTenna Mesh idea is very cool, and I love a decentralized network. It is even more amazing that other GTMs act as repeaters, making these a step above PTT radios. GoTenna combines a universal way to communicate, as opposed to buying a radio, and then knowing what frequencies to be on in your area.
With that being said… I have been thinking of ways, and locations to set up relay nodes around my area to build the network, but after a while I started to think, isn’t it silly that we are using GoTenna mesh units as relays. Retro-fitting them with batteries, solar panels and making sure they’re waterproof. Why though? It’s as we are making due with what we have because the company sells its products and provides 0 support afterwards and doesn’t aim to satisfy customer needs.
But… that’s not the case. GoTenna is very active with their customers, talking with them, helping them and getting feedback on their products. The company seems very forward thinking, and I see the co-founder and CEO very active on the forums, helping anyone she can. She believes in the product and wants to help her customers.
So I guess my question is, if we have such a helpful and supportive company by our side, why are we trying to build a network with jury-rigged devices to act as relays (repeaters) that also act as base stations for some, and portable units for others?
Here is my real question. Are there any plans in the future to develop and release systems that are exclusively relays, or base stations? Because while the GTM is great for portable communications, they’re not good for relays. And they’re also not good indoors because your house will absorb the some of the 1 watt it transmits with. In my opinion, it would be much more efficient to throw an antenna high on my roof, or on an antenna mast, then run a RF cable down to another GoTenna device that can be plugged into a power source, just like most other radios on the market. It would essentially be like attaching an antenna to the current GTM, but with the antenna placed somewhere were it can reach more GTM users.
I know if GoTenna were to make a box that you could plug in RF cable into, the mesh community would go crazy! I don’t think GoTenna would be able to produce them fast enough. It would make the ambassador program 10x easier. With these Base station/relay boxes, you could plug it in on the top of a building, put a 20ft mast on that building, an antenna on that mast, and if it was in the center of town, it would provide coverage for everyone in that town. This way everyone could buy one, buy 20 ft of RF cables and a base station antenna and put it on your house and bam, you have 10x more coverage than your small GTM unit that’s in your pocket. And it’s waterproof and doesn’t have to be hooked up to a solar panel/retrieved to be charged.
Let me know what you think? Maybe I’m crazy and have no idea what I’m talking about.
One more question, why are the GTM only 1W? Is it due to FCC regulations?

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#2

We’ll start with the easy one. Yes, that’s because that’s how it is licensed for mass market use. There is mesh in another form in the goTenna Pro, which operates with 5W, but this requires the sort of specific licensing that comes only in conjunction with being a government agency or other specific-ally licensed uses for industry and research.

But that is also the answer to most of your longer question about goTennas being produced in form factors different than the current form. In fact, the biggest catch is that the FCC requires that the antenna NOT be able to be changed out.

Coax is part of that issue, since it implies a separate antenna. But there’s also some technical issues here, too. In the 900 mHz band, you need high quality coax to carry that tiny signal up higher - and it’s not cheap. In the end, it’s easier to simply put the GTM up high than to send its signal to a high antenna.

This doesn’t mean you can’t do it. That’s why there is a proliferation of DIY projects, which you mention. The diversity of these efforts is also a matter of trying to find the best cost/benefit ratio when building mesh infrastructure. It can’t be too intrusive or visually annoying or node hosts get harder to find.

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#3

@MikeL
I guess I figured the GTM would’ve been at the 300-450 range. I didn’t know it was in the 900 MHz band.
But… you do not need very high quality coax to send a signal through a cable. What about tv antennas and cctv, they are around the 900mhz band and I have bought cable for both of those.
And I guess this may be for another time, but why did goTenna use the 900 band? Seems like the worst freq to use. Higher freqs are absorbed and dissipate much faster than lower bands. That’s why ham operates use it to bounce it off the ionosphere. Not to mention, in the lower bands, you can go buy an 80 watt radio, which means GoTenna can manufacture an 80 watt radio.

#4

I don’t know the entire history, but goTenna Uses the 900 mHz band because that is where this type of emission is allowed by the FCC.

There was the earlier Gen 1 goTenna that used what are known as MURS frequencies in the 150 mHz VHF band. These had to share the air with voice operators, but it worked. They just weren’t allowed to use mesh technology, they were simply radio-to-radio links. To be able to use mesh, goTenna has to use the 900 mHz band.

While higher powered radios are allowed in lower frequency bands, these are always LICENSED radios where the user has to qualify to be able to use it. The GTM is designed for unlicensed use, i.e. you can pick it up and start using it without doing anything more than buying and unboxing it. The highest power I know of for unlicensed use is 5 W in Citizen band radios (although SSB mode does allow a somewhat higher output on CB.}.

#5

Hi Austin I agree with you. A good example is the 20,000 volunteer ADS-B receiving base stations inn the Flightaware group.

I happily paid $200 for the equipment to build out my station and would do the same if I could buy a more convenient to charge GoTenna relay mesh node.

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#6

The problem isn’t receiving the signal, it’s transmitting the signal. You need very high quality, low loss coax to be able to have enough usable signal coming out the end of an external antenna when you’re transmitting with only 1W. I would think most wireless CCTV systems would use 2.4 GHz or 5.8 GHz so there’d be significant bandwidth, but you’re transmitting over very short distances. TV antennas a receive-only, and the TV station is pumping out thousands to hundreds of thousands of watts.

The lower the frequency, the less bandwidth available for a signal, and the less data you’re able to transmit. Because space in the lower frequency bands is highly limited, there are many, many more restrictions on what you’re able to do with it, and you often need a license (such as an amateur radio license) to operate. The majority of the unlicensed bands that would allow mesh networking at are at 900 MHz and up. So goTenna chose to use the band that would let them accomplish their goal with the greatest possible distance. Just because you can buy a radio that transmits 80 watts doesn’t mean you can use that transceiver on all bands or without a license.

#7

What do you mean? It takes next to nothing to charge a GTM unit.

#8

I mean that like Austin suggested : If GoTenna produced a dedicated relay station with ability to run Coax out to an antenna so that more of the 1 W was outside my house I would buy several to help build out the network.

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#9

I think a dedicated relay version of the goTenna would be successful.

Barring a change in the FCC’s position on this restriction, though, the factory option of a separable/replaceable antenna is unlikely to happen. Antenna choice makes a great difference in the effective radiated power of a device. The FCC clearly intended to limit max ERP by making this a requirement. That’s what has happened with the GMRS and MURS band radios, for instance.

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#10

They can’t, though. Per the FCC regulations for unlicensed operation of digital devices in the 33-centimeter (900 MHz) band, they can’t have a removable antenna. Unlicensed devices have to be evaluated and receive their authorization with specific antennas. While they can be tested with multiple antenna configurations, the certification would apply to only those antennas, and that can’t be guaranteed if everything is removable.

Many people have devised different ways to getting GTMs up higher. There are several projects in the DIY section of these forums. Essentially, a waterproof case and a long USB cable to connect it to power is enough to keep everything operational outside and protect the unit from the weather. There are several people who have put GTMs on towers, on mountains, on their roofs, etc., using similar methods.

#11

Exactly. I actually came back to amplify my earlier comment and alliekbean is right on; this is the easy road. Assuming a future designated relay version of the goTenna Mesh had about the same form-factor, putting the device up high, which is what a coax-fed antenna is intended to do, is effectively the same result. Perhaps even better, because there’s no coax line loss this way.

Maybe some better way than a USB cord could be developed to allow a higher mounting than is permitted by available USB cords. I’ve managed to source some 15’ ones lately, which could make things easier at some future installs. Allowing this mounting the device up higher could be even more powerful if the two wires that aren’t used for power in the standard USB cord (generally the white and green wires) were configured to allow a user to reboot the GTM over the wire, saving some climbing.

And I just had another idea for how to help leverage these network infrastructure-oriented devices. Instead of pairing with your phone, it might be possible to pair one goTenna permanently with one acting to control the other acting as a relay. This amalgamation of existing goTenna technology would allow far greater than Bluetooth distance connections to monitor and reconfigure relay nodes. Essentially it would allow management of the network devices from anywhere in the network within hop-reach of network operators.

There would need to be some type of software/firmware interface developed to allow the two units involved to interact via a hardwired connection. But the rest is pretty much already working in the units we already have. Making them rebootable “over the power wire” in combination with pairing them together with a networked relay would solve most such issues. The wired connection down to more solid ground than up on the mast would also allow injection of power with battery packs when the lack of sun plus snow takes things down like they have recently here.

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