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Walkie-Textie Wireless Communicator

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Re: Walkie-Textie Wireless Communicator

#91

Post by magnat »

junon wrote: post #86
magnat wrote: post #76

Earlier quoted context omitted.

Hard limit is 3.5kbps with 148dB link budget (Medium Fast preset in Meshtastic [1]). In practice - a packet worth of hundred bytes every half a second or so. [1] https://meshtastic.org/docs/overview/radio-settings/

Is that the cap of the whole system or can multiple users use it with individual caps of 3.5kbps? That's somehow both faster and slower than I expected.

If one node kept transmitting non-stop, it could push data out at 3.5kbps and no one else in that range can transmit at the same time.

However, in EU there is a legal limit of 1% duty cycle on 868MHz band and collision avoidance mechanism, meaning on average you can send a packet (up to 255 bytes) once a minute.

Re: Walkie-Textie Wireless Communicator

#92

Post by throwaway81523 »

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.

Lora data rate is still maybe 100x or 1000x higher than I'd want. I'd like something just fast enough for text chat, let's say 10 bps (maybe 3 chars/sec with some data compression), and a fallback slower rate for messaging, like 1 bps or slower (2 minutes for a 50 char messsage). That would give another 20 or 30 db of coding gain for much better range. There could even be a .01bps mode. Finally, put it on HF for worldwide range ;).

This is all deployed by hams down to around 1 cps, by the way (js8call.com).

Re: Walkie-Textie Wireless Communicator

#94

Post by 0xbadcafebee »

jvm___ wrote: post #53

I'm backwoods camping next week, and we have 25 people spread out over three sites. I was thinking it would be funny to bring some old rotary dial phones and some sort of way of hooking them up, and then just have that as the intercom between sites for when dinner is ready or whatever. It's next week, so unlikely to happen and I'm not sure what technology I would need to make it all work. Something like Lora plus a w…

Less fun but you can also run OpenBTS or Yate to get your own GSM network. Probably illegal but nobody's gonna care in the woods.

Back in the day we would "find" spools of phone cable and string them between houses. If you found that much cable you could definitely wire up a few miles of woods.

Re: Walkie-Textie Wireless Communicator

#95

Post by subscribed »

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?

Amateur, yes, but this is not amateur radio. This is unlicenced.

Re: Walkie-Textie Wireless Communicator

#96

Post by phreeza »

throwaway81523 wrote: post #92
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.

Lora data rate is still maybe 100x or 1000x higher than I'd want. I'd like something just fast enough for text chat, let's say 10 bps (maybe 3 chars/sec with some data compression), and a fallback slower rate for messaging, like 1 bps or slower (2 minutes for a 50 char messsage). That would give another 20 or 30 db of coding gain for much better range. There could even be a .01bps mode. Finally, put it on HF for worl…

I guess this would require a Ham license in most places? Apart from that i would really like a device like you describe (extremely low bps, high range).

Re: Walkie-Textie Wireless Communicator

#97

Post by throwaway81523 »

phreeza wrote: post #96
throwaway81523 wrote: post #92

Earlier quoted context omitted.

Lora data rate is still maybe 100x or 1000x higher than I'd want. I'd like something just fast enough for text chat, let's say 10 bps (maybe 3 chars/sec with some data compression), and a fallback slower rate for messaging, like 1 bps or slower (2 minutes for a 50 char messsage). That would give another 20 or 30 db of coding gain for much better range. There could even be a .01bps mode. Finally, put it on HF for worl…

I guess this would require a Ham license in most places? Apart from that i would really like a device like you describe (extremely low bps, high range).

JS9CALL on the ham bands requires a ham license but in principle you could use it on the unlicensed bands as well.

Re: Walkie-Textie Wireless Communicator

#100

Post by subscribed »

numpad0 wrote: post #31
kingkawn wrote: post #15

Earlier quoted context omitted.

Receipt for LoRa is low power, its transmission that kills the battery

Receiving is just transmitting nothing to see how it's getting disturbed

Wow, that's actually very poetic way to put it. Thank you.
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