4 ms·

It's too bad srsRAN doesn't support TDMA (yet). LTE band 42 and the 9 cm amateur radio band overlap, so it would be legal for hams to run LTE/5G nodes. Having

by drmpeg 5y ago

It's too bad srsRAN doesn't support TDMA (yet). LTE band 42 and the 9 cm amateur radio band overlap, so it would be legal for hams to run LTE/5G nodes. Having your phone being your first ham radio might be a great way to get younger folks into the hobby.

g_p 5y ago
Yeah, once TDD is implemented, things will get interesting for sure - also the CBRS band will open up opportunities for much lower cost radio devices that can have some "serious" range (i.e. small neighbourhood scale WiFi AP) - maybe we'll see that new generation get into ham, and also learning more about networking and launch their own metro-net ISPs? One minor thing - hams would need to be careful they can run LTE/5G "out the box", given most setups use an encrypted layer to the base station. You can turn that down to zero confidentiality (EEA0) but still using integrity checking (EIA>0), but I am not sure if that's a particularly well-supported mode of operation.
- cschmittiey 5y ago
  I believe you can also satisfy the encryption requirement by publishing the keys, fwiw
RF_Savage 5y ago
There's also the 13cm band (2300-2450MHz) that overlaps in part or fully TDD-LTE Band40 and FDD-LTE Band30. North americans also have 902-928MHz 33cm band, but that lacks the paired spectrum above it, so FDD-LTE or GSM are not possible. And I don't think there's a widely supported TDD-LTE spec for it.
- drmpeg 5y ago
  Thanks for pointing out band 40. Apparently it's just used in China, but it is supported on the iPhone 13. Band 30 is a no-go because the downlink is at 2350 to 2360 MHz, which is not a ham band. The ham band is split because of satellite radio. It's 2300 to 2310 and 2390 to 2450 MHz.
  - RF_Savage 5y ago
    The 13cm band is a bit of a mess globally. Here in Finland it's still full 2300-2450MHz. But in 2300-2320MHz it is shared with lightly licenced "provate LTE". Hop over to Sweden and it's 2400-2450MHz only with a powerlimit under a watt. And im USA it's that pumctured mess, isn't there also AT&T running Band30 FDD-LTE? Years back when I was searching for LTE phones with Band30 for hamLTE use I only found AT&T carrier locked stuff from USA.
  - namibj 5y ago
    Band38 is the one most 2.4 GHz WiFi-covering half-duplex SDR can handle, at least if modified/adjusted with a local oscillator quartz suitable for LTE. It's an ugly fraction to synthesize with a fractional PLL to LTE-specs of local-oscillator-quality. Yeah, it's not ham, but low power levels and RF-shielding-cages should suffice to keep radiated emissions far below interfering levels. It's also surprisingly well supported, at least on non-US handsets, from when I researched it a bit a few months before the first wave hit and blocked collaborative hardware hacking.

by drmpeg 5y ago

g_p 5y ago

Yeah, once TDD is implemented, things will get interesting for sure - also the CBRS band will open up opportunities for much lower cost radio devices that can have some "serious" range (i.e. small neighbourhood scale WiFi AP) - maybe we'll see that new generation get into ham, and also learning more about networking and launch their own metro-net ISPs? One minor thing - hams would need to be careful they can run LTE/5G "out the box", given most setups use an encrypted layer to the base station. You can turn that down to zero confidentiality (EEA0) but still using integrity checking (EIA>0), but I am not sure if that's a particularly well-supported mode of operation.

cschmittiey 5y ago
I believe you can also satisfy the encryption requirement by publishing the keys, fwiw

RF_Savage 5y ago

There's also the 13cm band (2300-2450MHz) that overlaps in part or fully TDD-LTE Band40 and FDD-LTE Band30. North americans also have 902-928MHz 33cm band, but that lacks the paired spectrum above it, so FDD-LTE or GSM are not possible. And I don't think there's a widely supported TDD-LTE spec for it.

drmpeg 5y ago
Thanks for pointing out band 40. Apparently it's just used in China, but it is supported on the iPhone 13. Band 30 is a no-go because the downlink is at 2350 to 2360 MHz, which is not a ham band. The ham band is split because of satellite radio. It's 2300 to 2310 and 2390 to 2450 MHz.
- RF_Savage 5y ago
  The 13cm band is a bit of a mess globally. Here in Finland it's still full 2300-2450MHz. But in 2300-2320MHz it is shared with lightly licenced "provate LTE". Hop over to Sweden and it's 2400-2450MHz only with a powerlimit under a watt. And im USA it's that pumctured mess, isn't there also AT&T running Band30 FDD-LTE? Years back when I was searching for LTE phones with Band30 for hamLTE use I only found AT&T carrier locked stuff from USA.
- namibj 5y ago
  Band38 is the one most 2.4 GHz WiFi-covering half-duplex SDR can handle, at least if modified/adjusted with a local oscillator quartz suitable for LTE. It's an ugly fraction to synthesize with a fractional PLL to LTE-specs of local-oscillator-quality. Yeah, it's not ham, but low power levels and RF-shielding-cages should suffice to keep radiated emissions far below interfering levels. It's also surprisingly well supported, at least on non-US handsets, from when I researched it a bit a few months before the first wave hit and blocked collaborative hardware hacking.