Range vs moto talk

#41

Not sure what’s at that link…It says “You are not authorized to access this page.”

I did use the wrong link for that citation. Instead, it should have been https://fccid.io/IHDT56HG2/Operational-Description/BLUETOOTH-CHARACTERISTICS-831886 and go to page 6d.1-3.

"The measurement shows 79 non-overlapping channels over a span of 79 MHz. "

Perhaps theat’s the available channels and the Moto uses only 50 of them, but I read 79 channels measured so assumed this is the output of the Motos being measured. YMMV

I’m not all that sure the channel numbers used is of much relevance here. I simply wanted to use it to point out that the testing criteria in 2007 (Moto) were different than in 2016 (goTenna Mesh) and thus not as comparable as you seem to believe. Unless you have a time machine available to take the goTenna engineering team back to 2007, what Moto managed to get past the FCC then is not very useful in 2018.

Well, if it’s unobtanium, then I guess it’s not very useful to discuss marketing that. But what I’m really after here is regulatory compliance. Once again, 2016 or 2018 is not 2007. If the engineering guidelines that made it possible then are not available now, then why bother beating goTenna up over something that doesn’t exist as an option?

And if it is simply a marketing issue, then why doesn’t down on their luck Motorola go ahead and license this, as well as produce newer models for itself with the supposedly superior technology? Most likely because it doesn’t meet current regulatory requirements.

#42

The measurement shows 79 non-overlapping channels over a span of 79 MHz

Please, do not write something you do not know about

I’m not all that sure the channel numbers used is of much relevance here

answer yourself to the question: what is the chance to encounter interference on 50 channels and what is at 20 or 10…

Once again, 2016 or 2018 is not 2007

Once again: In this discussion, I only compare physics RF!

#43

Ummm, that’s not me writing, that’s a quote from the test document. Problem is it’s the test document for the Bluetooth section. That does happen in an argument where one party has to bear the burden of discovering all the citations, figuring out what exactly the other party is even referring to because it’s apparently beneath them to bother pointing to their evidence. So instead of trying to read your mind here, I just went back and re-read it from end to end. There are useful bits and pieces, so I’ll use them since you consider actual citations to be beneath your dignity.

Finally found the reference to the Moto’s ISM antenna. It’s got 1.81 dBd gain. See page 1 here:
https://fccid.io/IHDT56HG2/RF-Exposure-Info/RF-EXPOSURE-2-OF-2-831890

In contrast, the GTM is apparently limited by its antenna, which is cited as having 1.0 dBi gain. See page 9 here:
https://fccid.io/2ABVK80085/Test-Report/Test-report-3233950

I don’t know how significant the difference between the dBd and dBi is in units. If they are roughly equivalent, then that is probably where what you seem to say is a problem with the GTM. Yet that antenna is exactly how the FCC limits ERP in Part 15 devices.

If you read through the bulk of the document (covering RF testing), sorting out what is 900 mHz vs what is 2.4 G, it does look more and more like there is just one antenna being tested for both freq ranges. It never states so and the circuit documents apparently remain confidential. Even assuming that goTenna could use a better gain antenna, they would never have the excuse of needing to provide a cell antenna on the same circuit. I suspect even Motorola couldn’t get away with it now, since things have changed since 2006 with the testing procedure and allowable circuitry.

Also, keep in mind that part of this is just technical obsolescence. The Mototalk technology was superseded in cell use is my understanding. The feature can still be found, but not the RF circuitry that originally supported MotoTalk, although old phones will still work. Doesn’t matter if the FCC no longer will approve its use as originally configured in the current Part 15 environment.

Part of the problem with the MotoTalk was that it was a technology that had some significant limits on the number of users it could accommodate within a 8-10 mile radius, something like (x15 channelsx) 10 channels (corrected, see below), so the number of conversations was a problem in many situations, especially emergencies. From
Wikipedia on MotoTalk

The off network walkie talkie feature has a total of 10 channels on newer phones and within those 10 channels, the phones can handle 15 separate group codes. This means there can be 15 conversations operating on each of the 10 channels within any single 6 miles radius. As with FRS and GMRS radios, the 15 group codes work to block calls that are not on the same code. The group codes do not secure your conversation. Only one person can talk on a code at a time. The phone can listen to all activity on a channel, but cannot transmit when in this “receive-all” mode. It uses FHSS technology on the 900 MHz ISM band as an unlicensed transmitter.

The goTenna has it’s limits, too, but generally holds up much better because of the nature of mesh systems overcoming those sorts of limits when the need for surge traffic arises. The enhanced privacy and security features of the GTM are also worthwhile considering vs Mototalk.

Apparently, Motorola was able to use the higher gain antenna in 2006. I’m pretty darn certain that goTenna used every bit of gain they could in the GTM before submitting it for testing in 2016.

There are threads here where people are hacking at DIY solutions by installing their own connectors to allow attachment of higher gains antennas. As a FCC-compliant manufacturer, goTenna can’t do that or they already would have. If that’s what you feel it needs, then you would more productively go ahead and DIY such a connection yourself. Chastising goTenna for not changing this when its required to observe a limit that is necessary for the device’s FCC certification seems utterly pointless.

Thus, it seems you’re complaining about goTenna giving the consumer everything they’re legally entitled to because you believe since it’s technically possible for goTenna to violate FCC regulations by installing either an illicit antenna or a clearly prohibited connection that would allow the illicit installation of such an antenna later, goTenna should do that.

Or what is your so far vaguely laid out point getting at in terms of an identifiable solution to what you claim is a problem - the range isn’t suitable to your tastes?

I will say, if you want to do some testing, go ahead and extract the antenna from the Moto and install it on the GTM then see what you get. As I noted before, since the Moto is using voice, the goTenna should outperform it on text-only – ALL THINGS BEING EQUAL.

If you think it’s a problem with the goTenna, then your issue isn’t there, it’s with the FCC. Because I’m absolutely certain that the radio designers at goTenna would love to work with more power. They even have a product like that, if you have a license for it. I’m actually pretty amazed with what the GTM is and the performance it gives. So I’d love to have more power, but I suspect its the increasing power of the mesh as it is improved that range will grow sharply. Building a small mesh network taught me that very quickly. Thinking that the radio needs to be more powerful is starting to be rather old school. Sometimes we don’t see the future when it’s already right there in front of us because our nostalgia impedes our view.

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#44

I am very glad that you have carefully read the reports FCC.

But you are mistaken about the possibilities of MT.

The technology works on the basis of the TDMA principle. The number of channels and codes 10 and 15 allows for group access, but there is also a personal call with 10-character coding, which greatly increases the number of subscribers and the confidentiality of the technology. Also, there is a FHSS and an audio codec of the VSELP, which in total makes it unrealistic to listen to the conversation without knowing the subscriber’s number.

I draw your attention to the fact that I’m not trying to advertise the technology and do not argue.

I disassemble the physics of operation in the 900-MHz range in relatively equal conditions, namely transmitter power and antenna.

There are questions to the effective use of spectrum and the ability to work in point-to-point mode.

These questions are not for you but for the GT

#45

Yeah, I kind of wish you were as conscientious. If you want to make a point, you need to be a little more specific than you have been - or are here.

Please be more specific. What exactly do you find mistaken? The dual use of significantly higher gain antenna for both cell and ISM service? That was established already, but more is here on the first page where they refer to only a single antenna for the three services the Moto uses.

_Antenna(s):
8571054M01 (806-825MHz internal ¼ wave antenna, -1.76Bd, 896-902MHz; -1.76dBd, 902-928MHz; -1.81dBd) _

Yes, cellphone technology. Are you saying that goTenna should have just been a cellphone? Because that’s what you’re asking. I was also able to establish that even though the claim is made that in ISM service mode there is no connection to the cell network, in fact the cell network’s signal is used to improve the accuracy of frequencies used in the 900 mHz range. See pages 7a-6 and 7a-7 here: https://fccid.io/IHDT56HG2/Test-Report/MEASUREMENT-PROCEDURES-831888

As has been established already, what worked for Motorola in 2006 wasn’t permissible for goTenna to use in 2016 in the ISM band. I mentioned you taking the initiative and swapping the Moto antenna onto your GTM and seeing what the results are. I’d also suggest applying the GTM’s fractal antenna to your Moto and then seeing how it performs with significantly less gain. But I suspect I’m expecting too much…

As for the user limits on MotoTalk, 10 channels is ten channels. The codes help you stand in line to wait for a channel, but they don’t provide additional airtime. Yes, multiple users can be on the air if they all share the same code for access. But that’s still only one conversation. As for hacking into MotoTalk, got no experience but if it’s not encrypted, it’s not secure even if it’s digital and there’s a codec. And if someone wants to listen to your private conversations, there’s a good chance they may just happen to know your number. It only seems secure. But if you need it and that illusion of security works for you, go for it. Otherwise, the differences between voice and text encryption are substantial enough it is, once again, an apples vs oranges comparison - especially when the Moto doesn’t have encryption.

I’ll agree it’s not much of an argument when you don’t bother much with citing specific evidence. But don’t fear, constructing a substantive argument isn’t “advertising” – it’s just what you do when you expect people to take your point of view seriously.

Well, you have dissembled a lot. Disassembly? I’m not s sure of, unless you’re working on swapping those antennas around so you can give us a report on what the range of the GTM is with the Moto’s antenna. Then you might at least prove the point that if goTenna could use 2006 technology it would have greater range. Then right after that you can start lobbying the FCC to allow goTenna to apply that finding to production. Good luck.

The transmitter powers are roughly equivalent or at least not enough different to account for what you’re perceiving as the Moto’s superiority. If you want to argue that, then please cite the specific figures and documents you are deriving them from. IIRC, they’re within a few hundredths of a watt of each other at around 0.8 W and all were measured as slightly less than the 1 W advertised output.

The antenna is a different matter. 1.8 dB is a big difference from 1.0 dB. Unless you want to specifically point to another factor - and CITE it - then that is more than enough to account for the range difference you find troublesome.

Please define “effective use of spectrum” as based on the evidence already presented in this thread it’s clear that goTenna makes more efficient use of the spectrum. Certainly, simply adding the additional ERP through a higher gain antenna as the Moto does is not the way to go about finding spectrum efficiency. And on the face of it, it appears that the easiest way to make the Moto more efficient would be to remove the voice feature and limit it to text, where right now there is no text in its ISM mode, only voice. I’d bet a hacked and hopped-up unit like that would really get out. It would also not be FCC type-accepted for sale in 2018.

As for what goTenna thinks about this, if you were paying attention, you would already know. The goTenna Mesh is designed to provide communication in the absence of cell service. It makes no sense to try to turn it into a cellphone. If you want a cellphone, buy one, they’re cheap enough. I don’t want a cellphone, I want what the goTenna has to offer in a very efficient and effective package. I tolerate my (former cell) device as a terminal for the goTenna. I am a lot less tolerant of a monthly cell bill and even less enamored of the privacy compromises required of using a cell phone.

#46

Currently Moto Talk does support encryption although I don’t know if the original standard supported it. I guess they just didn’t consider encryption necessary with the old devices.

Moto Talk as implemented in the old cell phones is relatively private but without encryption it’s not really secure… Obscurity is not security! It’s privacy is much better then GMRS , FRS, MURS, CB, HAM bands, ect… GTM is secure compared to Moto Talk. In particular the GTM SDK will even let you use your own encryption if you don’t like theirs. That’s pretty darn sweet although the default GTM encryption IMHO is plenty secure for 99.9% of us. Security is a moving target.

If I were going to hack a Moto call it’s unlikely I could do it in real time but likely I could record the data and do it in a reasonable time. Once I determined the parameters I could likely listen in real time. Someone else could probably do it better and faster. In fact with what is available now I could actually crack a regular cell phone call made on those old phones. Once again security is a moving target.

dBi is the gain over a theoretically perfect isotropic antenna. dBd is gain compared to a dipole antenna. You could use this calculation dBi = dBd + 2.15

Moto 1.81 dBd
GTM 3.15 dBd

GTM has a 1.34 db advantage over old Motos. It take 3db to double effective power so that isn’t a huge advantage.

TDMA would not benefit GTM but I’m confused by the rest of your statement. Motorola is still using “Moto talk” in it’s commercial radio division. Amateur radio operators also use “Moto Talk” although almost no one uses that term anymore. It’s generically referred to as Time Division Multiple Access or TDMA (not to be confused with CDMA Code division Multiple Access). What part isn’t permitted? I can’t think of any rule TDMA would violate. I use TDMA devices in the HAM bands.

“Moto talk” which uses TDMA can allow multiple simultaneous conversations on 1 channel effectively doubling (or more) the number of channels. However it can only do that when a third controller device is being used. It does this by compressing the sound and sending it in short data bursts. 1 second of audio can be compressed into around 0.3 seconds of data. The transceivers then take turns transmitting. The end users device puts the bursts back together the conversation is output as a single long audio stream. In the middle extra time other data is transmitted as overhead and additional information. Motorola is being very efficient in this respect but GTM is much more efficient.

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#47

Here I’m referring not to the cell side of things, but the overlap of that and the ISM mode. I think you sorted out the antenna as being not as significant a factor as I thought. I bailed from electronics to history about the time dB anything started coming up, probably a good decision. But I’m pretty sure that the way part 15 is interpreted now the antennas wouldn’t be permitted to be piggybacked together. While the measurements as you’ve reinterpreted so they’re all on the same page and comparable seem to speak against it, because if the Moto is actually working with less power, then what else explains the claimed advantage?

Possibly the use of the enhancement of frequency stability through the cell side’s polling of time from the towers for greater accuracy for the ISM, too. I’m somewhat skeptical of how much that improves range, but I could be persuaded. But again, I don’t think that would pass muster with such a connection now for a Part 15 device.

Now that after almost half a hundred posts we find out that the supposed trick to fixing the goTenna’s supposed range deficiencies is to make it into a cell phone, just as dependent as any other on a centralized network, I remain unimpressed about there being much substance here.

Now, as for MotoTalk still being around, that why I referred to the feature still being around, but not that particular implementation of it. I read various dates for the original version being dropped starting around 2012, but this included the non-Moto-branded versions and I read so much n this topic that I frankly don’t recall. How the did it in 2006 isn’t how they do it now, thus my later reference to its fading away being part of a larger obsolescence cycle where the phones that used it were discontinued and replaced by the later versions.

Yep, exactly my point. Couldn’t agree more, as well as what you want to pay attention to now if this is a factor in choosing your comm methods. Anything is breakable. If the concern is state actors, then you are well-advised to use the latest and greatest as many surveillance decisions are about allocating resources. Easy pickings tends to attract the sort of secret police who are aiming to fill their quotas, while a locked door tends to send that sort down the hall to the next door they find ajar. If they have the resources they may return to probe your place further or they may just continue on their rounds. Private actors tend to be less capable of sophisticated techniques, but may be more persistent for motives of vengeance, etc.

Yeah, once again, dependence on a centralized system does lead to certain benefits. But it’s clear that goTenna isn’t moving in that direction. It’s a strong, capable system that doesn’t do some things exactly as in the past, which can mostly be done without, while reliably doing other things that add impressive feature and capabilities.

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#48

To the best of my knowledge a piggybacked antenna should be fine as long as it doesn’t create any spurious emissions. Using one antenna for multiple services is pretty common. It doesn’t really help performance but rather it often decreases performance. They get used primarily to reduce space and cost. Honestly that adds nothing to the debate going on here.

What we need it some independent testing from other users. It just so happens I already own GTM and a couple Moto talk enabled phones. I was waiting for warmer weather which by the way just arrived. We’ll see if my results line up with @Posman tests. I don’t know about his devices but my Moto’s have the original antennas. @Posman can you confirm yours have original antennas?

#49

That was my concern, as I’ve seen lots of antennas do things they shouldn’t, because that’s not what they were designed for, but they will yield surprisingly robust results in action that seem inexplicable if one looks over the test results. If the Moto actually does have less power and a more inefficient antenna, then how is it possible that it gets out farther on voice than a GTM does with text? Extraordinary claims require extraordinary proof.

So far, we’ve had one person make this claim of such a decided advantage, but not too many folks are nursing along obsolete 10+ year old Motos to verify the claim or refute it. So I’d be very interested if you or anyone else in a position to do so could reproduce those results or not.

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#50

Yes, the antennas are original.
The model 335 has a built-in antenna.

#51

Are there cases of interception of FHSS and decryption of the VSELP? I do not know about such.
10 digit number for private mode (not 15 codes) is a billion combinations and you will need serious equipment for calculating the hopping algorithm.

#52

Read another comment by the engineer RF (Jin_Gotenna)
So by the above data, goTenna MESH and Motorola i335 should have the same range performance, but it does not appear so, and we have a hypothesis - it has to do with the network protocol and the choice between optimizing a point to point system or a scalable mesh network.

#53

Based on copious other evidence present here, I think that reads as goTenna having made the wise choice to pursue a scalable mesh network.

As my mother used to say, doing something just because everyone else is doing it is not a good excuse for you to do it. Since there are plenty of choices if you want a cellphone, I fail to see the need for turning goTenna Mesh into one more cellphone choice. Not all, but many people choose to use goTenna specifically because it’s not a cellphone.

Given your marked disinclination to move this conversation away from opinion to a discussion of specific facts, I think there little point in my continuing to attempt to engage with the facts.

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#54

I only ask because antennas can be switched easily on many of the old Motos and it’s a common mod that only requires a screwdriver.

#55

Edit: I thought it was already established that the old Motos weren’t using encryption for Moto talk so we aren’t decrypting Moto talk we are just decoding it.

The 15 codes can be outright ignored since the receiver can just be set to ignore them. They could however be used to identify the conversation later for decoding.

The frequency hopping is pseudo random and therefore crackable. To get the initial data you would record the whole spectrum which sounds like a lot but it isn’t so bad when you realize it’s channelized. I also have a theory that I could force Moto to stay off certain channels by making sure they are “busy”. After identify a few pieces of header information the conversation could be pieced together. From there it’s just time. I wouldn’t call the whole thing a cake walk but it’s nothing like encryption.

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#56

The main facts I have already cited. range Motorola, yes - 10i! year old in the condition of dense urban development is a stable 1 kilometer!

#57

A simpler explanation of the reduced range of the gotenna vs the moto talk “which I own many of” is that the antennas on the Moto talk flip phones typically have an extendable vertical antenna compared to the compromise internal antenna on the gotenna which will reduce its performance.

The GoTenna’s effective range is further reduced due to it typically being used while still in your backpack or pocket. Antenna performance always suffers when against your body or miscellaneous items in a backpack, especially at these frequencies. The moto talk devices on the other hand are typically used handheld away from your body. Which would explain the difference in performance between the two.

#58

As for a multipurpose antenna, the iPhone 6 uses a single antenna ribbon for Wi-Fi, Bluetooth, and GPS. The only difference there is that cellular technically requires a license to operate, which is one of the fees included in cellular plans, whereas everything else is license-free.

I, for one, definitely purchased the goTennas because they are their own infrastructure.

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#59

I’m not sure the Iphone 6 uses one “antenna ribbon” for all of that. I had my Iphone 6+ Bluetooth antenna stop working while Wi-Fi and cell still worked.

#61

“I don’t know how significant the difference between the dBd and dBi is in units…”

I’m not an EE, and I’ve never played one on TV. But I’ve been a licensed HAM radio op for about fourty years, and spent a lot of time designing and building antennas.

As I understand it, there is a major significant difference between dBd and dBi. dBd is relative to a dipole, and is the equivalent of a 3.1 dBi antenna.

The GM’s 1 dBi is essentially “unity” gain - providing no increase in effective radiated power. 3.1 dBd, in theory, should roughly double your effective radiated power, giving a substantial advantage to the Moto. If goTenna could legally incorporate a 3.1 dBd antenna into their unit, they would. It would be a huge improvement. Unfortunately, the FCC has made that impossible.

I have a collection of old electronics, all built in an era when just about anything was legal. It is all fun to play with, and someday some of it will be valuable as collectors’ items. Perhaps the Motos will soon fall into that category.

Those who find goTenna’s range too limited should do some web searches (and poke around on this forum) and look into building a MOAN to boost the effective range of your goTenna. Many others have built these using goTennas and have gotten VERY impressive range.

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