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NealSullivan
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211MHz and 219 MHz

Anybody know what other equipment sits at the 219MHz channel... I always have a reasonably noticeable post-RS errors on the 219MHz channel... It's listed on WIKI as licensed for whitespace use, is that the old VHS/etc channel for the rf link between AV equipment and TV.. Is this likely to be someone close watching old tapes?
It's not too problematic but I would like to know.. There's 00000's of errors a day where there are only a few at 211 and virtually zero above.. A router reset brings it back to channel 1-8 so it can't be that bad...
The service is OK, just a question.. Best network in the UK
Best regards,
NEAL

 

[MOD EDIT: Subject heading changed to assist community]

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Message 2 of 28
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Re: 211MHz & 219 MHz

Hi NealSullivan,

Thanks for your post on the Forum. I have run checks on your connection, and both your SuperHub and local network segment (219MHz) look good.

RS errors aren't normally a problem unless they show a rapid increase over a short space of time. Keep an eye on this and let us know if you see any changes or have any performance problems.

 

Kind regards,


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Sephiroth
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Re: 211MHz & 219 MHz


NealSullivan wrote:

Yeah, thanks for the support.... I did put some LED lights in here without the ferrite rings and the switching noise was was audiable all up VHF on my FM radio for 40meters..
dBm/mv/snr/etc I am well versed as I used to work fixing and calibrating radar... Gimme a decent Tektronics scope/alalyser and some adapters and probes I'd find all the ingresses and fix my whole cmts spur for fun..

A shame I can't drive I'd apply for a virgin job.. I know (cisco) IOS/eth/IP/.1x/.1p/.1q/.11 etc backwards too but transport'd let me down..

Nice to hear from you Kippies, have a good un :-)
NEAL

Averaging 1600 signal/noise I recon just about today... I'll wait for the lights to switch on tonight! :-)

RxMER (dB) 33.49 32.87 31.92 33.27 33.38 33.72 32.41 31.14


Those numbers are out of spec and you will lose packets as per the post-RS error count.  VM need to investigate and fix that.

 

Seph - ( DEFROCKED - My advice is at your risk)

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Sephiroth
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Re: 211MHz & 219 MHz


NealSullivan wrote:

Thanks Seph, what should they be to be in spec?

The big packet losses are on-and-off... Whenever VM have a look they're ok, but being in another timezone probably puts most engineers out of sync with when it Is happening...

I'm not convinced DAB is at these frequencies anymore, weren't they just the trials? 
*Nodrogd* can you put an authority stamp on this? :-?

10B211.648 MHzLocal ensembles; small scale DAB trial

is the wiki entry...
http://en.wikipedia.org/wiki/Digital_radio_in_the_United_Kingdom


Downstream SNR (aka RxMER) should be better than 34.5 dB.  At that level you will see lots of pre-RS errors.  The majority of people are seeing 38 to 40 dB and that's what VM would ultimately strive for in a given area when upgrading it.

Tech support are scripted that 34 dB is the lower threshold.  It's bad down at that level.

 

Seph - ( DEFROCKED - My advice is at your risk)

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cje85
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Re: 211MHz & 219 MHz

Each downstream channel provides approximately 50Mb, so there's a total of 400Mb for you and other customers nearby connected to those channels. The symbol rate isn't related to the speed provided.


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Message 2 of 28
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Re: 211MHz & 219 MHz

Hi NealSullivan,

Thanks for your post on the Forum. I have run checks on your connection, and both your SuperHub and local network segment (219MHz) look good.

RS errors aren't normally a problem unless they show a rapid increase over a short space of time. Keep an eye on this and let us know if you see any changes or have any performance problems.

 

Kind regards,


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Superuser
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Re: 211MHz & 219 MHz

Firstly, don't worry too much about post-RS errors. These are errors that have been recovered by the decoding process & are not affecting your service too much. An increase in pre-RS errors (non recovered data) is more sinister, & needs to be looked at.

VM's system should be watertight against ingress from Freeview TV & DAB radio frequencies, all of which are re-used by VM. However, despite it being against VM's T & C's some people will make their own alterations to VM's cabling, which then allows ingress & affects all their neighbours connections. Anything to avoid a callout fee.

For info, 211 Mhz is actually the top of VHF Band III (the band now used for DAB radio). UHF TV starts at a much higher frequency (471 Mhz or Ch21 UHF). VHS recorders used to operate at around 610Mhz (Ch37)

su1718.jpgCable customer since 1993. Services: FH TV, Sky Sports & Movies (2xV6), Talk Anytime Phone, VIVID 350, Virgin PAYG Mobile

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Dave_cq
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Re: 211MHz & 219 MHz


nodrogd wrote:

Firstly, don't worry too much about post-RS errors. These are errors that have been recovered by the decoding process & are not affecting your service too much. An increase in pre-RS errors (non recovered data) is more sinister, & needs to be looked at.

 


I always thought it was the other way round ... that post-RS errors were the errors that the Reed-Soloman process had failed to correct (non recovered data) and so were the more significant.

 

********* SuperHub 2ac - Asus rt-ac68u Router - Vivid 100Mbps **********

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NealSullivan
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Re: 211MHz & 219 MHz

I think I know you've got that backwards NoDrog.... Thanks anyway
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NealSullivan
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Message 6 of 28
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Re: 211MHz & 219 MHz

We're back on channels 9-16 things seem a lot less choppy on IPlayer...
Thanks to either human or ranging intervention I'm down to about 2post errors every 10 seconds.. More what I'd be expecting....

I don't suppose the UK LED Street lights communicate in the high VHF band do they.. Or a harmonic...? I get a wealth of radio noise where there's one 10feet from the house from the power switching, enough to throw an FM radio and Wifi as unusable too
The world is full of noise, amazing when you look... I'll get a highband spectrum analyser one day and actually have a look! :-)

Thanks for the change
NEAL  LE5 1 :-)

 

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Message 7 of 28
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Re: 211MHz & 219 MHz

In addition to the information provided above (and yeah its post you need to be more concerned about), you SNR SHOULD give you a clue as to whether its external interference affecting your WAN side connection. Low SNR= more noise.

So if SNR is fine and pre and post are piling up, its something else. If your using Wifi, yes street lights will chuck out interference in that part of the spectrum (as will most electrical kit). But so will those lovely energy saving bulbs...

http://www.wirebiters.com/fluorescent-lights-mess-wifi-signal/

 

 


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NealSullivan
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Message 8 of 28
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Re: 211MHz & 219 MHz

Yeah, thanks for the support.... I did put some LED lights in here without the ferrite rings and the switching noise was was audiable all up VHF on my FM radio for 40meters..
dBm/mv/snr/etc I am well versed as I used to work fixing and calibrating radar... Gimme a decent Tektronics scope/alalyser and some adapters and probes I'd find all the ingresses and fix my whole cmts spur for fun..

A shame I can't drive I'd apply for a virgin job.. I know (cisco) IOS/eth/IP/.1x/.1p/.1q/.11 etc backwards too but transport'd let me down..

Nice to hear from you Kippies, have a good un :-)
NEAL

Averaging 1600 signal/noise I recon just about today... I'll wait for the lights to switch on tonight! :-)

RxMER (dB) 33.49 32.87 31.92 33.27 33.38 33.72 32.41 31.14

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Sephiroth
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Re: 211MHz & 219 MHz


NealSullivan wrote:

Yeah, thanks for the support.... I did put some LED lights in here without the ferrite rings and the switching noise was was audiable all up VHF on my FM radio for 40meters..
dBm/mv/snr/etc I am well versed as I used to work fixing and calibrating radar... Gimme a decent Tektronics scope/alalyser and some adapters and probes I'd find all the ingresses and fix my whole cmts spur for fun..

A shame I can't drive I'd apply for a virgin job.. I know (cisco) IOS/eth/IP/.1x/.1p/.1q/.11 etc backwards too but transport'd let me down..

Nice to hear from you Kippies, have a good un :-)
NEAL

Averaging 1600 signal/noise I recon just about today... I'll wait for the lights to switch on tonight! :-)

RxMER (dB) 33.49 32.87 31.92 33.27 33.38 33.72 32.41 31.14


Those numbers are out of spec and you will lose packets as per the post-RS error count.  VM need to investigate and fix that.

 

Seph - ( DEFROCKED - My advice is at your risk)

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NealSullivan
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Message 10 of 28
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Re: 211MHz & 219 MHz

Thanks Seph, what should they be to be in spec?

The big packet losses are on-and-off... Whenever VM have a look they're ok, but being in another timezone probably puts most engineers out of sync with when it Is happening...

I'm not convinced DAB is at these frequencies anymore, weren't they just the trials? 
*Nodrogd* can you put an authority stamp on this? :-?

10B211.648 MHzLocal ensembles; small scale DAB trial

is the wiki entry...
http://en.wikipedia.org/wiki/Digital_radio_in_the_United_Kingdom

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