Expanding the mesh via Ham Radio network


#1

I’m a licensed amature (ham) radio operator. My home rig is set up to allow simultaneous reception on one channel and re-transmission on a separate channel, we call this a repeater. In theory if the Rx and Tx frequencies and any codes of the goTenna mesh system are known then the rig I have should be able to operate as a “super node” in the mesh network. This should eliminate the need to “hack” a physical mesh device to connect an external antenna to expand the mesh network. Has anyone tried this? Does anyone have specs on the goTenna mesh devices that lists the frequencies and codes they use for Tx and Rx?


#2

The data from gotenna is encrypted. Using your amature license, you cannot transmit encrypted messages.


#3

In addition, Mesh works on different frequencies


#4

As others have said the goTenna is encrypted. These units will do just fine if you can get them up high.

I’d be more interested in setting up a long distance link between two goTenna Mesh networks using the Winlink email system. There are new modes (Vara and ardop). The transfer between Winlink stations would be just the message from one user to another. Just like a normal ICS-213 message. Basically you would need a program to collect the goTenna message and que it up in Winlink. A Ham operator still needs to be at the station to send the message


#5

This would be pretty hard to do. You need an interface into winlink. I don’t think the winlink development team has any plans for that. There is a Linux version to interface with winlink. That might be your best bet. We need the SDK to interface with the gotenna and a pc.

You could do relay today with the shout mode or one to one. Read the message and type it in winlink.
You might be sitting in front of your radio for a long time.


#6

That would not be problem, as we do “cross band” all the time. As Luigi & Wvs have stated, there are rules to be followed, as the GoTenna group well knows.


#7

Could this problem be overcome by sending out a message as a shout?


#8

Shout should be fine, as that is a public, non-encrypted message.


#9

Does anyone know the frequencies and codes?


#10

Which frequencies & codes ? GoTenna is in the 900MHz ISM band.


#11

Good to have more Ham folks here.

Depending on how the repeater is set up, it doesn’t need to decrypt messages. It just “repeats” or echos the message. So encryption on it’s own shouldn’t be a problem (see below for one case where it might be a problem)

A bigger problem, I think is that goTennas are simplex, i.e. the Rx and Tx frequencies are the same. I haven’t looked at the goTenna radio specs but there might be tricks with sub-channels which can be only figured out by decrypting the message.

And of course, a repeater is most useful if it repeat messages with more power. I don’t know the precise FCC rules but I would be careful at transmitting too much power in the goTenna bands.


#12

It’s been posted before, but here is the poop sheet on the transceiver.


And I still think that re-transmitting encrypted data is the same as an original transmission as far as the FCC is concerned.
The ISM band is pretty restricted as to power. I think its under Part 18.


#13

Yup, ISM power limit for “Transmitter output” is 1 watt. So that’s not much of a repeater.


#14

I am a ham operator. I have gotenna and if you use it as node, it becomes a simplex repeater. I also have 2X Motorola DLR that are on 900mhz spread spectrum digital, the same as gotenna, they are great.


#15

If I understand correctly, the GoTenna data is encrypted over-the-air, but what you see coming out of the app (or via USB?) is the decrypted plaintext version. This would imply that a data-level serial gateway between GoTenna and WinLink or AX.25 or whatnot should be OK regarding the no-encryption aspect. What would not be allowed is repeating/crossbanding of the “raw RF” transmission (which would be much more difficult than a serial bridge anyway, IMO).
Still need to restrict use to licensed amateur traffic and the rest of the rules.


#16

A few days ago I put together an APRS IGate and digipeater with Xastir on a TNC+RaspBerry Pi 3 (see my node for an example). An interesting aspect of the digipeater is it is restricted to only communicating with nodes it has heard before thus not flooding the airwaves over 2m (and within a certain time frame I think).

So, using the digipeater as a basis one could write some software that does roughly the same thing with the gotenna attached over USB. Though I’m wondering how useful this would be since I’m assuming in relay mode the decrypted text is not available (doesn’t have the key to decrypt the msg). And if it is my paired gotenna is likely not talking to a lot of other gotennas normally (just friends and family). And unlike APRS the gotenna is silent unless it receives something to relay so I don’t know how we would know when the destination gotenna is in the vicinity of the digipeater. Lots of challenges…