I am a user of two generations of goTenna. Range tests have shown that it is less than moto talk for the nextel phones nextel and communication is particularly sensitive to nLOS.
In the city, I do not get more than 0.5 miles for per-to-per. I’m a bit disappointed with the range.
The nextel phones give me a stable 1 mile with a lower transmitter power than in 1-watt gotenna vs 0.8 watts for the phone. Probably the problem is in the antenna or modulation gen2.
Perhaps it’s worth to work out the experience of the company Motorola.
But I like the idea and implementation! I wish good in their project!
You seem to be referring to the old IDEN system. I have not compared the two directly but I do have a couple of those. I suspect you are correct about the antennas making some difference. The real power of the Gotenna mesh is in the Mesh part of the system. Personally I bought an extra unit for the purpose of meshing. Stick one in a high place and you get a giant improvement.
2 Likes
Somewhere in the forum there is information about better electrical efficiency antenna of the 2nd Gen vs 1nd Gen. I have several different models of Motorola phones with direct talk function including i335 with built-in antenna, the range of which is higher.
Perhaps the effect is not so much the antenna as the type modulation for the FHSS in 2 Gen or sensitivity of the radio chip.
This is an interesting exercise in apples and oranges.
I’m not quite sure that would work. I don’t know what the relationship was between the cell transmitter and the direct radio function of the Moto, but I suspect the former came first, with the latter as an addon. I’m not an EE, but I suspect there’s a considerable difference between the Moto and any goTenna in the circuitry, supporting apps to the radio part of the device, etc. So would be a bit hard to put the Moto magic into the goTenna.
More importantly, can you go out and buy a Moto like that right now? I suspect not. Cell mfg’s seem to have abandoned addon radio capability as design goal, at least on the US market (they are available in China, though.) That’s where goTenna is filling an important role in providing a viable option. I suspect the differences between it and other solutions is largely regulatory. Sure, you could build in more sugar, but then you’d have to have a license, which tends to defeat the goal of widespread network access.
1 Like
Hi @Posman, this is JIn, I’m one of the RF engineers at goTenna. This is an interesting observation. Could you provide the model number of the Moto Talk phone you were using? We’d like to dig deeper into this. Could you also let us know how you were using the devices? i.e. goTenna MESH strapped to backpack, Nextel phone held in hand etc.
Thanks!
JC
1 Like
Hmm…could you imagine if cell phones had a built in goTenna, straight out of the box? Given that people carry their phones everywhere, even into areas where there is no coverage (for photos and such), even if they had no clue about the built in gotenna and didn’t use it, the meshing function would still be there. Have the next big releases of iPhones and Samsungs with a built in goTenna…that would be pretty interesting! Haha…even if it limited the range due to size issues, it would be a way to get the product out rapidly, and in city environments, it would drastically increase the mesh network literally overnight.
2 Likes
Hello, Jin_Gutenna! I always keep the phone in front of me like a walkie-talkie. Gotenna also, in a similar polarization. I have several models of Motorola phones: i335, i576, i365 with external antenna.
I noticed that the range of these phones is larger with less transmitter power.
Of course, a great advantage gives the antenna height, but I can remove one phone in the bag, and make a handshake with a range of 1 kilometer in the city building.
I do not understand why the sensitivity of these phones in DT mode is better than Gotenna with 1Watt.
Yes, the modulation is different, but the interference is at the same level, given the FHSS.
The sensitivity of the RFFM6904 chip is at a good level, but I do not know what could be better in moto talk cycle 10 years ago.
What is this they put in their devices?))
I will be glad if you investigate this, and will be able to improve the quality of the radio communication !!
1 Like
I wonder what frequency their radio operates off of? That could account for the better range, given it is a phone, they may have been allowed to use a frequency that works better than 900 MHz…or you may have something in the area that interferes with the 900 MHz band more than whatever band the phone’s radio works off of.
Dear brunota2003,
I like the idea of Gotenna, but I think that from the point of view of physics, transmitter power, etc., the potential of these devices can be higher!
I like the idea of Gotenna, but I think that from the point of view of physics, transmitter power, etc., the potential of these devices can be higher!
MT uses FHSS technology on the 900 MHz ISM band as an unlicensed transmitter.
They transmit with 600mw and in the band ISM of 900 MHz (902-907, 915-928) they use the type of digital modulation 8-level FSK 900 MHz ISM FHSS.
1 Like
Passing data is much harder than passing audio.
The walkies use a tone to cause the receiver to open squelch and then you pass audio noise and all.
With the GoTenna data is being passed in a fraction of a second and noise can have a more dramatic impact as the message is happening in a way that a single pop of noise could take out a significant portion of the data packet.
Take the APRS and refute it.
There is no difference for digital radio communication, whether it’s a voice or a message. There is a bit encoding of certain data in a certain modulation. If the bits are missing because of interference, there is no connection.
1 Like
By the way, phones with moto talk are still sold on Ebay for $ 20 and I collect them)
Not quite . . . .
If I key open a mic and say “Mr. Watson — Come here” and the transmit is 2.5 second of time vs sending that via text and the transmit is in .25 seconds there are some significant factors when range and noise are factors.
A) Audio is a very forgiving signal as far as noise is concerned and a message can be received and understood through a lot of noise and even some breakup since our ears and mind can infer parts of words.
B) Noise or break up for .1 of a second would only impact 4% of 2.5-second audio message and have zero impact on the balance of the message. However, it would wipe out 10% of the digital message and depending on the forward error checking in the digital format it might have damaged the message beyond use.
Obviously, I am guestimating the transmit burst of the GoTenna but I am also using such a small audio example any error favors the audio example since most radio test would be longer than 2.5 seconds.
Given the somewhat one way nature of GoTenna messages (there is a confirmation of receipt but no real digital handshake for real reverse error checking) the messages are somewhat you either got it or you did not get it.
So at the far end of range, an audio signal would outperform the burst digital signal of a GoTenna.
See here for musings on that subject:
2 Likes
Dear Firqby,
I’m an engineer a little in another field (opto-electronic systems), but there is a truth that I’ve always been taught: the receiver and the antenna are the best result.
The main thing that worries me is the question that such a perspective was invented by engineers of motorola, whose range of devices with a lower power is higher than that of a gotenna? You can buy a radio station DTR and see this. There is also a message transfer.
By the way, motorola uses a wonderful schtick - a handshake to check the connection and then sends a message.
This is a very interesting experience that should be taken into account by the engineers of the Gotenna.
1 Like
I also propose to explore the issue of modulation. Why GFSK and not FSK or better MSK!!
The receiver RFFM6904 supports many types. it is worth considering
Yep, would be very cool…but probably something the telecoms would fight tooth and nail. The have a very hierarchical profit model that works by fostering consumer dependence and passiveness. It’s a one way street, presently marching to their orders.
The goTenna Mesh is engineered around the belief that community-based communications systems designed to work together autonomously benefit from a profound change of scale by putting control of the hardware into the hands of the user.
So I won’t say never, just that the stars in DC are currently aligned against policies so beneficial to the consumer. Net neutrality is a parallel policy example of how ideas that clearly benefit the consumer and are overwhelmingly supported by voters get crushed and drowned in a sea of cash from those who benefit from sustaining the existing dominant models of communications. The goTenna Mesh subverts that paradigm by offering what is essentially a net-neutral communications medium, with no cell or internet service required once you have it set up on your phone or text device.
If you look at the various offerings on Chinese websites, there are a variety of FM radio capabilities built into cell phones now. Maybe exploring offering the goTenna in some sort of linked cellular fashion overseas will be what’s needed to apply pressure to update the regulatory regime here to better suit public needs?
3 Likes
Guys, we certainly consider that motorola is a giant. But five years ago no one knew what would appear Lora. Take a couple of engineers of this" wonderful" company and get them a secret))
1 Like