Unacceptable Hard Drive Noise From HDR 2000T?

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Unacceptable Hard Drive Noise From HDR 2000T?

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Faust

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As I found out to my cost though Graham I couldn't get away with losing 4db on COM7/8.

The really odd thing about this though is that I can still get the local mux 36 I think, which shows 'This is Birmingham' which is on even lower power than COM7/8 even when it's 'high pressure' weather and COM7/8 have gone off the cliff.

I have tried a 5db to 20db attenuator (just in case the signal was 'too strong'). This made the problem worse. I will just sit it out until the frequency is shut down. I've got Freesat so all is not lost.

| Sat 28 Apr 2018 14:37:00 #21 |
grahamlthompson

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Faust - 1 minute ago »
As I found out to my cost though Graham I couldn't get away with losing 4db on COM7/8.
The really odd thing about this though is that I can still get the local mux 36 I think, which shows 'This is Birmingham' which is on even lower power than COM7/8 even when it's 'high pressure' weather and COM7/8 have gone off the cliff.
I have tried a 5db to 20db attenuator (just in case the signal was 'too strong'). This made the problem worse. I will just sit it out until the frequency is shut down. I've got Freesat so all is not lost.

The difference is the local mux isn't part of a SFN so not affected by adjacent transmitters using the same UHF carriers.

| Sat 28 Apr 2018 14:39:32 #22 |
Luke

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Faust - 3 hours ago »
The really odd thing about this though is that I can still get the local mux 36 I think, which shows 'This is Birmingham' which is on even lower power than COM7/8

The local muxes are broadcast using QPSK modulisiation. QSPK is far more robust than the QAM modulisation used for the other multiplexes. The modulisation used is so robust compared to the other muxes that it makes a direct comparison of power levels alone meaningless.

| Sat 28 Apr 2018 18:07:41 #23 |
Faust

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grahamlthompson - 8 hours ago »

Faust - 1 minute ago »
As I found out to my cost though Graham I couldn't get away with losing 4db on COM7/8.
The really odd thing about this though is that I can still get the local mux 36 I think, which shows 'This is Birmingham' which is on even lower power than COM7/8 even when it's 'high pressure' weather and COM7/8 have gone off the cliff.
I have tried a 5db to 20db attenuator (just in case the signal was 'too strong'). This made the problem worse. I will just sit it out until the frequency is shut down. I've got Freesat so all is not lost.

The difference is the local mux isn't part of a SFN so not affected by adjacent transmitters using the same UHF carriers.

I was talking to an aerial fitter a couple of weeks ago from the Stoke on Trent area. He was telling me they are having some real issues with COM7/8 in Stoke. Apparently they have been advising people they need to switch from a Group A aerial to a wideband (mainly Log Periodic like I have had fitted).

However, even when they have fitted new aerials customers still can't get COM 7/8. The fitter was saying that in Stoke part of the city can only get a signal from the Fenton transmitter whereas the other half can use either Fenton or the main transmitter at Sutton Coldfield. The fitter thinks that the SC transmitter may be causing interference for those using Fenton and Fenton is causing interference for those on SC.

Whether that is true or not I couldn't say, though I know Fenton is a relay for SC. A quick search shows COM 7 Fenton on C32 (562.0MHz) and COM 8 on C34 (578.0MHz) whereas Sutton is on COM 7 C55 (746MHz) and COM 8 on C56 (754MHz)

| Sat 28 Apr 2018 22:56:01 #24 |
A1944

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Fenton changed to 55/56 in early March.

| Sat 28 Apr 2018 23:45:35 #25 |
Faust

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A1944 - 14 hours ago »
Fenton changed to 55/56 in early March.

So does this then put Fenton relay on the same frequencies as Sutton Coldfield COM 7 C55 (746MHz) and COM 8 on C56 (754MHz) and if so would that cause interference with each other despite one being Horizontal and the other Vertical?

| Sun 29 Apr 2018 14:14:14 #26 |
grahamlthompson

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Faust - 56 minutes ago »

A1944 - 14 hours ago »
Fenton changed to 55/56 in early March.

So does this then put Fenton relay on the same frequencies as Sutton Coldfield COM 7 C55 (746MHz) and COM 8 on C56 (754MHz) and if so would that cause interference with each other despite one being Horizontal and the other Vertical?

That's the SFN bit (Single Frequency Network). The plan is that all com 7 and com 8 mux will move to the same frequencies for a period.

http://www.telecomabc.com/s/sfn.html

There will be some areas where the two interfere with each other (mush areas) and I guess they will get larger under high pressure uplift conditions.

All my channels are in a SFN group. It works fine for me because of geographic location. The others in the group are in completely different directions so are much weaker even if you aligned an aerial on them.

| Sun 29 Apr 2018 15:18:00 #27 |
Faust

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grahamlthompson - 13 minutes ago »

Faust - 56 minutes ago »

A1944 - 14 hours ago »
Fenton changed to 55/56 in early March.

So does this then put Fenton relay on the same frequencies as Sutton Coldfield COM 7 C55 (746MHz) and COM 8 on C56 (754MHz) and if so would that cause interference with each other despite one being Horizontal and the other Vertical?

That's the SFN bit (Single Frequency Network). The plan is that all com 7 and com 8 mux will move to the same frequencies for a period.
http://www.telecomabc.com/s/sfn.html
There will be some areas where the two interfere with each other (mush areas) and I guess they will get larger under high pressure uplift conditions.
All my channels are in a SFN group. It works fine for me because of geographic location. The others in the group are in completely different directions so are much weaker even if you aligned an aerial on them.

Well I would imagine that Fenton and SC would be synchronised as Fenton is a relay of SC. The other safeguard re: cross interference is the aerial itself. I have had a Log Periodic fitted which is supposed to have a narrow acceptance angle thus minimising cross-interference and yet COM 7/8 has become very hit and miss for our property.

One day it can be signal strength 90 quality 100 the next day it's pulsing between SS 0 SQ 0 to SS 65 SQ 70 in a matter of almost milliseconds causing total picture absence or picture breakup.

I certainly daren't set any programmes to record from channels 55 and 56 due to the unpredictable reception.

| Sun 29 Apr 2018 15:39:00 #28 |
grahamlthompson

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Faust - 3 minutes ago »

grahamlthompson - 13 minutes ago »

Faust - 56 minutes ago »

A1944 - 14 hours ago »
Fenton changed to 55/56 in early March.

So does this then put Fenton relay on the same frequencies as Sutton Coldfield COM 7 C55 (746MHz) and COM 8 on C56 (754MHz) and if so would that cause interference with each other despite one being Horizontal and the other Vertical?

That's the SFN bit (Single Frequency Network). The plan is that all com 7 and com 8 mux will move to the same frequencies for a period.
http://www.telecomabc.com/s/sfn.html
There will be some areas where the two interfere with each other (mush areas) and I guess they will get larger under high pressure uplift conditions.
All my channels are in a SFN group. It works fine for me because of geographic location. The others in the group are in completely different directions so are much weaker even if you aligned an aerial on them.

Well I would imagine that Fenton and SC would be synchronised as Fenton is a relay of SC. The other safeguard re: cross interference is the aerial itself. I have had a Log Periodic fitted which is supposed to have a narrow acceptance angle thus minimising cross-interference and yet COM 7/8 has become very hit and miss for our property.
One day it can be signal strength 90 quality 100 the next day it's pulsing between SS 0 SQ 0 to SS 65 SQ 70 in a matter of almost milliseconds causing total picture absence or picture breakup.
I certainly daren't set any programmes to record from channels 55 and 56 due to the unpredictable reception.

They have to be sychronised, the issue is down to the guard interval and location. As the link explains the system works by unwanted channels being recognised as from the same transmitter but arising from a reflected signal (reflected signals arive a little later). This gives ghosting on analogue systems. The system breaks down when the reciever can't tell which is the wanted one.

| Sun 29 Apr 2018 15:47:12 #29 |
Faust

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grahamlthompson - 3 hours ago »

Faust - 3 minutes ago »

grahamlthompson - 13 minutes ago »

Faust - 56 minutes ago »

A1944 - 14 hours ago »
Fenton changed to 55/56 in early March.

So does this then put Fenton relay on the same frequencies as Sutton Coldfield COM 7 C55 (746MHz) and COM 8 on C56 (754MHz) and if so would that cause interference with each other despite one being Horizontal and the other Vertical?

That's the SFN bit (Single Frequency Network). The plan is that all com 7 and com 8 mux will move to the same frequencies for a period.
http://www.telecomabc.com/s/sfn.html
There will be some areas where the two interfere with each other (mush areas) and I guess they will get larger under high pressure uplift conditions.
All my channels are in a SFN group. It works fine for me because of geographic location. The others in the group are in completely different directions so are much weaker even if you aligned an aerial on them.

Well I would imagine that Fenton and SC would be synchronised as Fenton is a relay of SC. The other safeguard re: cross interference is the aerial itself. I have had a Log Periodic fitted which is supposed to have a narrow acceptance angle thus minimising cross-interference and yet COM 7/8 has become very hit and miss for our property.
One day it can be signal strength 90 quality 100 the next day it's pulsing between SS 0 SQ 0 to SS 65 SQ 70 in a matter of almost milliseconds causing total picture absence or picture breakup.
I certainly daren't set any programmes to record from channels 55 and 56 due to the unpredictable reception.

They have to be sychronised, the issue is down to the guard interval and location. As the link explains the system works by unwanted channels being recognised as from the same transmitter but arising from a reflected signal (reflected signals arive a little later). This gives ghosting on analogue systems. The system breaks down when the reciever can't tell which is the wanted one.

RE: guard interval it's 1/16 for both COM 7/8. What is going to happen in 2020/21 with these muxes? Do we know what frequencies these channels will occupy?

| Sun 29 Apr 2018 18:54:32 #30 |