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Walkie-Textie Wireless Communicator

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Re: Walkie-Textie Wireless Communicator

#41

Post by codys »

pastorhudson wrote: post #11
etrautmann wrote: post #6

Earlier quoted context omitted.

Can you elaborate on the restrictions? Is it just that the Baofeng allows you to transmit on some frequencies that aren’t legal or at power levels that aren’t allowed or is it not allowed in the US at all?

To use GMRS you need a license to be compliant with fcc. It’s not expensive I think $60 for 10 years and it covers your family. You can then use GMRS. GMRS is all the same FRS channels plus several more. GMRS can also transmit at up to 50mw on some of the non-FRS channels. To be using GMRS in compliance you have to use an FCC Part 95E certified device. These Baofeng / Btech devices are usually not GMRS certified. So…

Btech markets devices that are GMRS type accepted, it's actually one of their main businesses these days to take Chinese developed radios and modify them slightly and get them GMRS approved in the US.

Re: Walkie-Textie Wireless Communicator

#42

Post by IshKebab »

tonyarkles wrote: post #19
clbrmbr wrote: post #8

Earlier quoted context omitted.

LoRa is actually pretty thirsty on receive. You’d need some scheme for synchronization if you want to reduce power consumption.

To elaborate on this a little bit, the conventional use isn't peer-to-peer but rather sleepy IoT nodes that periodically wake up to send to a listening base station. The IoT node transmits and then waits a specified amount of time listening for a response back from the base station. The tradeoff is: - The end nodes can spend the vast majority of the time in deep sleep without the radios turned on. - The base station…

There's no reason you couldn't do this in a peer-to-peer system too, especially if you only have a few nodes. Imagine for 2 nodes:

1. Each node transmits a beacon once per second.

2. While they aren't connected, each node listens for sub subset of time (say 10%).

3. Eventually one node will hear the beacon from the other. They can use this to synchronize clocks (the better your clocks the better this works).

4. Thereafter they just wake up periodically at the same time and one transmits a beacon to the other to synchronize (alternating whose turn it is).

It's the same idea as sleepy edge devices used in IoT, but just both ways. Quite a lot more complicated of course, but you can totally do it.

Re: Walkie-Textie Wireless Communicator

#44

Post by Catbert59 »

magnat wrote: post #34

> LoRa can reach a range of up to 3 miles (4.8 km) in urban areas, and up to 10 miles (16 km) in rural areas In mountainous area LoRa on 868MHz band reaches over 100km. Last month we had a stratospheric balloon with a Meshtastic node attached. It established direct (albeit intermittent) connection between Warsaw and Berlin.

I've tested LoRa from HillHill and Flat LandFlat Land and 30-60km worked with plenty of SNR left.

On 868MHz with standard 5dBi omnis.

Thesis: as long you are using one of the more robust LoRa settings it always will work as long you have LoS or at least only lightly obstructed LoS.

Re: Walkie-Textie Wireless Communicator

#45

Post by junon »

magnat wrote: post #34

> LoRa can reach a range of up to 3 miles (4.8 km) in urban areas, and up to 10 miles (16 km) in rural areas In mountainous area LoRa on 868MHz band reaches over 100km. Last month we had a stratospheric balloon with a Meshtastic node attached. It established direct (albeit intermittent) connection between Warsaw and Berlin.

What's the data transmission rate with the balloon, put of curiosity?

Re: Walkie-Textie Wireless Communicator

#46

Post by junon »

lrvick wrote: post #5

If you want something like this with asymmetric encryption, a qwerty keyboard, mesh range extension, and a GUI, try a T-Deck running Meshtastic.

Isn't there a ban on encrypted amateur signals? Or is this running on a band that allows for it?

Re: Walkie-Textie Wireless Communicator

#47

Post by password4321 »

lxgr wrote: post #33

It's a real shame phones don't have something like this built in. I mean, we literally have satellite communication in every iPhone – or, depending on how you count, every LTE phone, period! Technically, it seems like 90% of what's required is already there anyway, but due to commercial and political pressures, we'll probably never see it happen.

I would settle for push-to-talk over WiFi on my phone interoperable with dedicated devices with no monthly fees.

Re: Walkie-Textie Wireless Communicator

#48

Post by Infernal »

junon wrote: post #46
lrvick wrote: post #5

If you want something like this with asymmetric encryption, a qwerty keyboard, mesh range extension, and a GUI, try a T-Deck running Meshtastic.

Isn't there a ban on encrypted amateur signals? Or is this running on a band that allows for it?

Yes and yes. In the US, 900-930MHz (nominally the 915MHz band) is available for use with no license required so encryption is fine (similar to your 2.4GHz or 5GHz wifi access point).

People interested in LoRa may also be interested in 802.11ah, or Wifi HaLOW

Re: Walkie-Textie Wireless Communicator

#49

Post by shooker435 »

ljf wrote: post #35
kube-system wrote: post #29

Reminds me of what the messenger on the Cybiko was trying to be. Too bad LoRa wasn't a thing back then, it would have been more useful if it had a better range. https://en.wikipedia.org/wiki/Cybiko

I remember seeing these on some tech show here in the UK - and being in love with the idea - seemed so cool and 'archivable' for a young person to own. A few years later they were dirt cheap on ebay - new/boxed, but by then the itch had gone, but I wish now I'd bought one.

Whoa, I wonder if I still have my Cybiko Xtreme somewhere.

Re: Walkie-Textie Wireless Communicator

#50

Post by implements »

retrac wrote: post #38
lxgr wrote: post #33

It's a real shame phones don't have something like this built in. I mean, we literally have satellite communication in every iPhone – or, depending on how you count, every LTE phone, period! Technically, it seems like 90% of what's required is already there anyway, but due to commercial and political pressures, we'll probably never see it happen.

There's a lot of cool radio-related things our smartphones could do but probably never will for regulatory/political/commercial reasons like you note. My pet idea is to make some use of longwave! You know those time signals broadcast around 60 kHz? They cover thousands of kilometres from one transmitter. At 60 kHz the wavelength is 5 kilometres long and the RF tends to diffract around objects like mountains, building…

> My pet idea is to make some use of longwave! […] At 60 kHz the wavelength is 5 kilometres long …

Dim memory from my Ham Radio days that you’d need an antenna length of 1/4 the wavelength, which wouldn’t be very convenient for portable devices, unfortunately.

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