FYI on 5G trials interference

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snnet

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#242777 13-Nov-2018 21:53

Just been told today by someone else in the field that if you lose TV3 and others for seemingly no reason and are in the Auckland region (especially if your aerial is aligned to the sky tower transmitter) it's because of the 5G testing. Found this out after a lot of mucking around and head scratching on seemingly perfectly aligned aerials. The other party also found out the hard way. Wish it was put on more notice!

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#2125090 13-Nov-2018 21:59

i'd be interested to know if those claims have been confirmed or is just speculation.

I don't work in the RF space, so i can't speak for any of it. I'm doubtful It's actually causation.

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snnet

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#2125099 13-Nov-2018 22:11

We're not 100% certain but it does seem to correlate apparently. The channels come back when testing has changed/is over

snnet

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#2125102 13-Nov-2018 22:13

Also pretty confident it is the reason as 4G also caused interference which is why we opt to use filters or filtered equipment now

[edit]

I was doubting myself although I really couldn't understand why this was happening when I had perfectly aligned the aerials before hand (3 jobs in the same area) and I had direct line of sight to the sky tower so it wasn't adding up. Ended up calling around others in the field and they were all experiencing issues. One guy had spent the weekend testing with different filters and all sorts of things but couldn't get the signal back. Ended up coming back by itself and the interference had disappeared from the meter (before it would spike at a certain frequency). He'd called around and someone at the manufacturer where most of the equipment comes from had said it was because of the 5G testing. Not saying it's a permanent thing when it's switched on but it is/was happening during testing. Just thought I'd put it out there incase people are wondering and searching why this is happening as it hasn't been very open so far.

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#2125127 13-Nov-2018 22:45

Do you know what frequency band is being used for 5G testing?

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sbiddle

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#2125235 14-Nov-2018 07:18

kiwiharry: Do you know what frequency band is being used for 5G testing?

mmWave (28GHz) and some indoor testing in 3.5GHz due to existing rights holders in the band. These will be the two primary bands used for 5G in New Zealand.

There is no possible way 5G testing in either band either could cause interference in the 500MHz and 600MHz bands used for TV unless there was a harmonic created by poorly filtered equipment.

LTE on the other hand does use the 700MHz band so theoretically could cause some issues in some areas if not filtered correctly with a poor setup and bad coax and connectors. It's for this reason filters exist to eliminate 700MHz interference.

I'm certainly unaware of any such issues (and have been to 5G working group meetings) but @knoydart would be able to confirm whether any issues have occured with 4G in New Zealand.

knoydart

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#2125241 14-Nov-2018 07:27

There have been a handful of residential DTV installations which have had wide band mast head antenna amplifiers removed from their installations, but no massive spike occurred post 2014 (when the 700 MHz band 28 LTE services went live).

There has been an outdoor trial of 5G technology (using both 3.5 and 28 GHz), but that was in Wellington CBD.

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#2125247 14-Nov-2018 07:46

I’ve had quite a few, one fairly recently in Kent Tce Wellington after a new cellsite came on.

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#2125253 14-Nov-2018 08:10

Brunzy: I’ve had quite a few, one fairly recently in Kent Tce Wellington after a new cellsite came on.

Did a filter sort it?

snnet

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#2126681 14-Nov-2018 15:48

Harmonics are indeed the issue introduced. If not 5G then it's something else they're doing at the sky tower which was causing issues with DVB-T/2

Equipment with 4G filtering did not prevent this

hio77

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#2126695 14-Nov-2018 16:01

snnet:

Harmonics are indeed the issue introduced. If not 5G then it's something else they're doing at the sky tower which was causing issues with DVB-T/2

Equipment with 4G filtering did not prevent this

Could be a ton more things transmitting from the skytower.. cell panels are far lower than that

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snnet

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#2126707 14-Nov-2018 16:12

hio77:

snnet:

Harmonics are indeed the issue introduced. If not 5G then it's something else they're doing at the sky tower which was causing issues with DVB-T/2

Equipment with 4G filtering did not prevent this

Could be a ton more things transmitting from the skytower.. cell panels are far lower than that

Sure, could be, but this is just what I was told. Apparently the person telling me had asked around sky comms and that's the answer he got. It's not necessarily the frequency being interfered with it's the harmonics throwing a wobbly.

sbiddle

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#2126724 14-Nov-2018 16:47

snnet:

hio77:

snnet:

Harmonics are indeed the issue introduced. If not 5G then it's something else they're doing at the sky tower which was causing issues with DVB-T/2

Equipment with 4G filtering did not prevent this

Could be a ton more things transmitting from the skytower.. cell panels are far lower than that

Sure, could be, but this is just what I was told. Apparently the person telling me had asked around sky comms and that's the answer he got. It's not necessarily the frequency being interfered with it's the harmonics throwing a wobbly.

If this was the case then @knoydart should be aware of it.

Brunzy

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#2126730 14-Nov-2018 17:01

sbiddle:
Brunzy: I’ve had quite a few, one fairly recently in Kent Tce Wellington after a new cellsite came on.

Did a filter sort it?

Sure did, at the input of the amp. I’d have liked to put one at the Antenna too, but roof access is via an apartment balcony and they weren’t home.
I haven’t been back so all must still be ok.
Unusual symptoms, there was all sorts of rubbish on the Speccie which went away when I removed the power from the Satellite Amp , and I initially thought there was some AC from the supply which I’ve had lots of before, but when I replaced it the issue came back.

ResponseMediaNZ

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#2126820 14-Nov-2018 21:13

snnet:

hio77:

snnet:

Harmonics are indeed the issue introduced. If not 5G then it's something else they're doing at the sky tower which was causing issues with DVB-T/2

Equipment with 4G filtering did not prevent this

Could be a ton more things transmitting from the skytower.. cell panels are far lower than that

Sure, could be, but this is just what I was told. Apparently the person telling me had asked around sky comms and that's the answer he got. It's not necessarily the frequency being interfered with it's the harmonics throwing a wobbly.

If there was issues with skytower and harmonics there would be alot more of us complaining that have RF gear up on the tower.
If its a major issue then you need to be logging this with RSM as interferance (At time of posting RSM is down for maintaince so cant post the link)

Also if there was poorly filtered gear on skytower JDA and Broadcast would know about it pretty fast, we all self monitor and 99% of us are good tenants up there on the comms levels.

I know of new RF gear being switched on but thats in the 400-440 TD Band

snnet

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#2126836 14-Nov-2018 21:32

All I was posting was what I was being told. I was getting calls for a couple of days non stop from a lot of people about it. I've talked to others in the field who have experienced the same thing. It's not a figment of my imagination, I'm not trying to blame someone specifically or something specifically, as I said it's what I've been told as being the reason for the whacky harmonics and that's all I can say about it because that's all I know about it. It seems to have settled down now, for now, whatever it was.

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