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Showing results for tags 'digital mobile radio'.
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TDMA, specifcally DMR, slot timing errors limiting range?
Lscott posted a question in Technical Discussion
I've read about there being range limitations when using TDMA digital modes, like DMR, due to clock drift in the base and mobile stations. The issue seems to be the slot timing verses distance and length of transmissions. See section 10.2.3.1.3 on page 112 in the following link to one of the ESTI DMR standards. https://www.etsi.org/deliver/etsi_ts/102300_102399/10236101/02.03.01_60/ts_10236101v020301p.pdf Anybody have any experience with this or did the detailed calculations for their installation? I've seen comments where some have gone to FDMA type modes to avoid this issue.- 5 replies
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- digital mobile radio
- dmr
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Hello All, So first off, let's try to keep this on topic. The last thread about "Your favorite digital mode and why" flew off topic rather quickly. From what I've found so far when it comes to digital voice you have 3 choices: 1. System Fusion - Yaesu proprietary, easy to use, internet connected with wires-x, expensive hardware (HT or Mobile), no registration 2. D-Star - JAIA open source project with proprietary CODEC, ICOM's solution, less expensive hardware, a little more difficult to setup but not bad, requires registration to leave local repeater 3. DMR - Completely open source, available from all the CCM folks, requires registration, very involved to setup, cheapest hardware options I know the choice may really come down to availability of repeaters in my area. In a 25-mile radius of my home I see the following: 1. System Fusion - 11 2. D-Star - 4 3, DMR - 3 Each is a mix of 2M and 70CM. I've read where Fusion is falling out of fashion across the US, but winning here, so that would be a logical choice, but the cheapest mobile I've found (used) is around $500. More than I want to spend to try this stuff out. What says the group? JG
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Any other Amateur's on here enjoying DMR if so what talk group do you use most? Just wondering? I enjoy TG 3100 TG 310 TG 91 TG 3106