Passive cellular "repeaters" in rural Australia - Page 1
Forum section: electronics / general

author: Halcyon
author_rank: Unknown
timestamp: August 25, 2022, 04:03:23 am
content: The video is aimed at non-technical users, however I had no idea these things existed. What a neat idea.

author: e100
author_rank: Frequent Contributor
timestamp: August 25, 2022, 08:31:03 am
content: Does that mean I can walk around anywhere in Australia with a mobile phone (or radio of some kind) with my own reflector dish and not violate EIRP limits?

author: Miyuki
author_rank: Frequent Contributor
timestamp: August 25, 2022, 08:39:13 am
content: Quote from: e100 on August 25, 2022, 08:31:03 amProbably not, you'll have to be in a far far away area with no signal, people, and other devices

author: Halcyon
author_rank: Unknown
timestamp: August 25, 2022, 08:58:33 am
content: Quote from: e100 on August 25, 2022, 08:31:03 amProbably? Even if you were using one of these in the city, your device will automatically adjust it's gain levels anyway in order to comply with limits (to a degree). These kinds of networks are designed with "absolutely worst case" in-mind. Even if you're flying in a commercial aircraft, cell hopping every few seconds, the networks can cope with that (your device, however, may not).In Australia, you can actually purchase active cellular repeaters, without the need for an application or a licence:https://www.cel-fi.com. You literally just buy it and install it. The Cel-Fi products have been approved for use by all the carriers and the Australian Communications and Media Authority (ACMA), which is Australia's version of the FCC.Back in the "old days", you used to have to apply to your cellular carrier for approval to have a repeater and they would supply it to you, provided you ticked all their boxes. Cellular coverage issues in Australia are fairly uncommon though. There are some edge cases (like my local fire brigade station) where 4G/5G doesn't penetrate enough indoors or underground. I've also seen some hard-core campers install these Cel-Fi repeaters in their 4WD/caravans for when they go "out bush" so they can have some kind of data connectivity where it's normally not possible with just a handset.

author: Kleinstein
author_rank: Super Contributor
timestamp: August 25, 2022, 09:42:01 am
content: Quote from: e100 on August 25, 2022, 08:31:03 amYou may technically violate the EIRP limits (that is a higher sensindg power in one direction than allowed by the licience). However who really cares in those very remote areas where the next person is likely miles away.Early GSM cell phones for car installation had a higher power level (8 W compared to 2 W for the handheld ones). So there is at least some headroom or a littel more antenna gain.The reduction in the sending power would only work if the signal is strong, so likely not in area were you need such help.Besides the S/N limitation that can be improved on with the better antenna: The phone standards also have a limit in the signal roundtrip delay. So there is a hard limit to how far the antenna can work. To improve on this they would need to find a way for the relevant cell towers also to work with more delay.