A Sky, cable and digital tv forum. Digital TV Banter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » Digital TV Banter forum » Digital TV Newsgroups » uk.tech.digital-tv (Digital TV - General)
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

uk.tech.digital-tv (Digital TV - General) (uk.tech.digital-tv) Discussion of all matters technical in origin related to the reception of digital television transmissions, be they via satellite, terrestrial or cable. Advertising is forbidden, with no exceptions.

4G filter measurement



 
 
Thread Tools Display Modes
  #1  
Old March 9th 13, 06:09 PM posted to uk.tech.digital-tv,uk.tech.broadcast
Jim Lesurf[_2_]
external usenet poster
 
Posts: 4,326
Default 4G filter measurement

I've just done a quick measurement on the SAC AE5100 filter that I bought
from CPC as a "4G filter". Results at...

http://jcgl.orpheusweb.co.uk/temp/AE5100.png

I wonder how representitive this will be of all the other filters that will
now doubtless flood onto the market... Not an encouraging thought...

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Ads
  #2  
Old March 9th 13, 07:43 PM posted to uk.tech.digital-tv,uk.tech.broadcast
Bill Wright[_2_]
external usenet poster
 
Posts: 9,381
Default 4G filter measurement

Jim Lesurf wrote:
I've just done a quick measurement on the SAC AE5100 filter that I bought
from CPC as a "4G filter". Results at...

http://jcgl.orpheusweb.co.uk/temp/AE5100.png

Useless then, on either graph. But why are they different?

I wonder how representitive this will be of all the other filters that will
now doubtless flood onto the market... Not an encouraging thought...


There's going to be a run on snake oil. Stock up now.

Here's a bit of background:

https://dl.dropbox.com/u/11023364/Fi...%201%20Feb.pdf
https://dl.dropbox.com/u/11023364/Fi...02%20March.pdf

This was written before 4G became an issue. If you look at the lefthand
side of p124 you will see the words:
"The response is maintained perfectly up to channel 37, after which it
falls off quite quickly. At channel 40 the attenuation is 12dB, and
above channel 42 itís 18dB or more." Now that was a good quality filter,
costing £20.

Suppose channel 37 is actually channel 60. The test would then read "The
response is maintained perfectly up to channel 60, after which it falls
off quite quickly. At channel 63 the attenuation is 12dB, and above
channel 65 itís 18dB or more."

Now suppose we change channel 37 to channel 58.The test would then read
"The response is maintained perfectly up to channel 58, after which it
falls off quite quickly. At channel 61 the attenuation is 12dB, and
above channel 63 itís 18dB or more."

In most cases 12dB is not going to be enough. A little thought about
these figures will show you that filters are not going to solve the
problem for those who watch TV on channels 58, 59, and 60.

Bill
  #3  
Old March 9th 13, 10:35 PM posted to uk.tech.digital-tv
[email protected]
external usenet poster
 
Posts: 1,245
Default 4G filter measurement

On Sat, 09 Mar 2013 19:43:12 +0000, Bill Wright
wrote:

Jim Lesurf wrote:
I've just done a quick measurement on the SAC AE5100 filter that I bought
from CPC as a "4G filter". Results at...

http://jcgl.orpheusweb.co.uk/temp/AE5100.png

Useless then, on either graph. But why are they different?


That's the same plot isn't it? Just an expanded axis.
Not a very effective filter but nonetheless there will be many
marginal locations where it will be adequate.

An employee of a well-known site operator tells me that 4G test
transmissions have been going on for many weeks. But he couldn't or
wouldn't say which sites were involved so I don't know if they were in
ch.60 areas.
  #4  
Old March 10th 13, 12:18 AM posted to uk.tech.digital-tv
Bill Wright[_2_]
external usenet poster
 
Posts: 9,381
Default 4G filter measurement

lid wrote:
On Sat, 09 Mar 2013 19:43:12 +0000, Bill Wright
wrote:

Jim Lesurf wrote:
I've just done a quick measurement on the SAC AE5100 filter that I bought
from CPC as a "4G filter". Results at...

http://jcgl.orpheusweb.co.uk/temp/AE5100.png
Useless then, on either graph. But why are they different?


That's the same plot isn't it?

Oh, so it is. Must try to not post when the wife is nagging that 'we'll
be late'.

Bill
  #6  
Old March 10th 13, 09:47 AM posted to uk.tech.digital-tv,uk.tech.broadcast
Brian Gaff
external usenet poster
 
Posts: 7,250
Default 4G filter measurement

In the olden days, people designing services and where to put them in the
spectrum knew what they were doing and the limitations of equipment for
domestic use. it seems to me that recently, and possibly starting around
when pagers first appeared, this talent has been lost in favour of the idea
that we will allocate where we want to and let the industry fix the issues.
So if you have a 4G smartphone and you live in the shadow a tv transmitter
tha uses ch59 at reasonable power, does your phone get deaf and not work one
wonders.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Bill Wright" wrote in message
...
Jim Lesurf wrote:
I've just done a quick measurement on the SAC AE5100 filter that I bought
from CPC as a "4G filter". Results at...

http://jcgl.orpheusweb.co.uk/temp/AE5100.png

Useless then, on either graph. But why are they different?

I wonder how representitive this will be of all the other filters that
will
now doubtless flood onto the market... Not an encouraging thought...


There's going to be a run on snake oil. Stock up now.

Here's a bit of background:

https://dl.dropbox.com/u/11023364/Fi...%201%20Feb.pdf
https://dl.dropbox.com/u/11023364/Fi...02%20March.pdf

This was written before 4G became an issue. If you look at the lefthand
side of p124 you will see the words:
"The response is maintained perfectly up to channel 37, after which it
falls off quite quickly. At channel 40 the attenuation is 12dB, and above
channel 42 itís 18dB or more." Now that was a good quality filter, costing
£20.

Suppose channel 37 is actually channel 60. The test would then read "The
response is maintained perfectly up to channel 60, after which it falls
off quite quickly. At channel 63 the attenuation is 12dB, and above
channel 65 itís 18dB or more."

Now suppose we change channel 37 to channel 58.The test would then read
"The response is maintained perfectly up to channel 58, after which it
falls off quite quickly. At channel 61 the attenuation is 12dB, and above
channel 63 itís 18dB or more."

In most cases 12dB is not going to be enough. A little thought about these
figures will show you that filters are not going to solve the problem for
those who watch TV on channels 58, 59, and 60.

Bill



  #7  
Old March 10th 13, 09:59 AM posted to uk.tech.digital-tv,uk.tech.broadcast
David Woolley[_2_]
external usenet poster
 
Posts: 550
Default 4G filter measurement

Brian Gaff wrote:

So if you have a 4G smartphone and you live in the shadow a tv transmitter
tha uses ch59 at reasonable power, does your phone get deaf and not work one
wonders.


The phone will have been designed with the presence of TV transmissions
on adjacent channels in mind.

I believe there is an element of frequency division multiplexing in LTE,
so the phone will probably choose a frequency that is less badly affected.
  #8  
Old March 10th 13, 10:00 AM posted to uk.tech.digital-tv,uk.tech.broadcast
David Woolley[_2_]
external usenet poster
 
Posts: 550
Default 4G filter measurement

Bill Wright wrote:
Jim Lesurf wrote:
I've just done a quick measurement on the SAC AE5100 filter that I bought
from CPC as a "4G filter". Results at...

http://jcgl.orpheusweb.co.uk/temp/AE5100.png

Useless then, on either graph. But why are they different?

I wonder how representitive this will be of all the other filters that
will
now doubtless flood onto the market... Not an encouraging thought...


There's going to be a run on snake oil. Stock up now.

Here's a bit of background:

https://dl.dropbox.com/u/11023364/Fi...%201%20Feb.pdf
https://dl.dropbox.com/u/11023364/Fi...02%20March.pdf

This was written before 4G became an issue. If you look at the lefthand
side of p124 you will see the words:
"The response is maintained perfectly up to channel 37, after which it
falls off quite quickly. At channel 40 the attenuation is 12dB, and
above channel 42 itís 18dB or more." Now that was a good quality filter,
costing £20.

Suppose channel 37 is actually channel 60. The test would then read "The
response is maintained perfectly up to channel 60, after which it falls
off quite quickly. At channel 63 the attenuation is 12dB, and above
channel 65 itís 18dB or more."

Now suppose we change channel 37 to channel 58.The test would then read
"The response is maintained perfectly up to channel 58, after which it
falls off quite quickly. At channel 61 the attenuation is 12dB, and
above channel 63 itís 18dB or more."

In most cases 12dB is not going to be enough. A little thought about
these figures will show you that filters are not going to solve the
problem for those who watch TV on channels 58, 59, and 60.

Bill


  #9  
Old March 10th 13, 10:02 AM posted to uk.tech.digital-tv,uk.tech.broadcast
David Woolley[_2_]
external usenet poster
 
Posts: 550
Default 4G filter measurement

Jim Lesurf wrote:
I've just done a quick measurement on the SAC AE5100 filter that I bought
from CPC as a "4G filter". Results at...

http://jcgl.orpheusweb.co.uk/temp/AE5100.png

I wonder how representitive this will be of all the other filters that will
now doubtless flood onto the market... Not an encouraging thought...


Will LTE base stations necessarily be site cleared for the whole LTE
allocation? It might be that those in marginal areas for the higher DTT
channels may only be site cleared for the higher end of the LTE downlink
allocation.
  #10  
Old March 10th 13, 10:11 AM posted to uk.tech.digital-tv,uk.tech.broadcast
hwh[_2_]
external usenet poster
 
Posts: 62
Default 4G filter measurement

On 3/10/13 10:59 AM, David Woolley wrote:
Brian Gaff wrote:

So if you have a 4G smartphone and you live in the shadow a tv
transmitter tha uses ch59 at reasonable power, does your phone get
deaf and not work one wonders.


The phone will have been designed with the presence of TV transmissions
on adjacent channels in mind.

I believe there is an element of frequency division multiplexing in LTE,
so the phone will probably choose a frequency that is less badly affected.


I'm afraid not. If the operator has 5 MHz up and down, there is nothing
to choose from.

gr, hwh
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT. The time now is 12:38 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.SEO by vBSEO 2.4.0
Copyright ©2004-2019 Digital TV Banter.
The comments are property of their posters.