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by birdiesanders 421 days ago
Trunked is essentially useless to HAMs, and we never really use it much. We have essentially everything that trunking was meant to solve for a company; large pre-authorized spectrum space, self-coordination in that space without having to get fcc involved. Use of 25khz FM where part 90 is now only 12.5 also is enabled by being a ham.
5 comments
wolrah 421 days ago
> Trunked is essentially useless to HAMs, and we never really use it much.

I wouldn't say it's useless, but the utility is reduced because we typically don't have the density of users where two timeslots on a single channel becomes a real limiting factor. A repeater that's set up for local talkgroups on one timeslot and then open access on the second is generally more than enough unless you have a lot of people trying to use it at once, especially in a world where anyone who wants to can have their own personal hotspot for less than the cost of a HT.

Also the usual "ham not HAM" thing.

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ac29 420 days ago
> part 90 is now only 12.5

This is wrong. 25kHz part 90 licenses are still available so long as the system meets the minimum efficiency standard (19.2kbps or better for 25kHz).

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wkat4242 420 days ago
I don't think it's useless at all. It would be amazing, roaming the country and never having to worry about frequency settings. And in that case you do need more time slots. Tetra would be nice with 4 slots. I know in Holland and Germany they're experimenting with it.
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mschuster91 421 days ago
> Use of 25khz FM where part 90 is now only 12.5 also is enabled by being a ham.

Y'all can use 25 kHz for repeaters? Here in Germany repeaters are 12.5 kHz only, allegedly due to a lack of free frequencies...

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colanderman 420 days ago
In the US frequency allocation within each band (including repeaters) is left up to regional spectrum management organizations (which have no legal authority). So it varies by region.

Here is the allocation for eastern New England for example: https://nesmc.org/docs/nesmc_bandplans_2023.pdf On the crowded 2m band we have 20 kHz for major repeaters and 9 kHz for smaller ones.

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kotaKat 420 days ago
Not really.

Leveraging dvmproject, dvmhost, and the FNE bits, hams can operate their own APCO Project 25 trunking systems with commodity MMDVM hardware and link them across the Internet. You can use various MMDVM boards, use a v.24 serial link to a Quantar repeater, etc...

https://github.com/DVMProject/dvmhost

Ain't nothing wrong in running a single voice-on-control channel simplex hotspot to experiment with P25, or link to bigger systems ;)

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