Band pass filters -- what am I missing?
 

Bob Latham wrote:
In article ,
Bill Wright wrote:
Here's a list of bandpass filters.

http://dl.dropbox.com/u/11023364/bandpass%20filters.doc

Thanks Bill, you sent me this list before and I'm grateful but trying to
order is a pain. I thought the 37-52 Johansson 1107 would be the best for
Sutton but trying to find one - no chance. There are several Martin Turner
web sites but they're all impossible to navigate or order anything on and
nowhere else on the net advertises them.
I'm sure that if you ring up you will find them most helpful. The
website is crap.

Or contact Johansson and ask for a distributor. It doesn't have to be in
the UK.


I've also spent time on the Taylor website looking to buy a TD2-4F and a
few other bits. Their catalogue is terrible and try as I might I couldn't
understand 95% of it. I question if they actually wish to sell anything. I
took it that they were only interested in the professional market
They are. The guy who runs the company won't go into retailing. I don't
know why.

Bill

Band pass filters -- what am I missing?
 

In message , Mark Carver
writes
J G Miller wrote:
On Sunday, August 28th, 2011 at 17:27:25h +0100, Mark Carver wrote:

That's fine, until the UHF channel allocations change !
Hence why I stated an "editable list".

Well, you're almost back to a 'manual tune' procedure then ? In other
words you have to know which transmitter you're using, and what its UHF
allocations are (at present!). In other words you need to be
'technically minded' in order to perform a retune.

so whose do you trust ?
UK Free TV? ;) ;) ;)

Ha ! Please !

It's all a shambles quite honestly.
Totally agree - can you name any other country undergoing
digital switchover which has forced people to do more than
one retune?

No, I don't think I can ?

But has any other country had the same complexity of regional
transmitters and channels? And have they been able to do the changeover
with such a comprehensive avoidance of loss of service?
--
Ian

Band pass filters -- what am I missing?
 

On Sun, 28 Aug 2011 17:04:54 +0000 (UTC), J G Miller
wrote:

On Sun, 28 Aug 2011 16:13:58 +0000, Richard Tobin wrote:

There must be numerous ways that lists of channels for each transmitter
could be provided in a compatible way, for example over MHEG.

Yes but how does the user get the information via MHEG before the
first autoscan on a brand new box?

The autoscan could do an initial "dumb" scan. It would then do an
"intelligent" scan using the MHEG channel data downloaded on the first
scan. On the first scan it could look for the MHEG channel data only and
not populate the channel list.

--
Peter Duncanson
(in uk.tech.digital-tv)

Band pass filters -- what am I missing?
 

"J G Miller" wrote in message
...
On Sun, 28 Aug 2011 16:13:58 +0000, Richard Tobin wrote:

There must be numerous ways that lists of channels for each transmitter
could be provided in a compatible way, for example over MHEG.

Yes but how does the user get the information via MHEG before the
first autoscan on a brand new box?

The box just needs to be able to get the list of channels on the same
transmitter from every channel is finds a signal on.

The box could scan all channels and work out which channels formed sets from
the same transmitter and announce that it had received more than one
transmitter (and tell you the channels and aerial group of each in case you
understood that) and let you choose which to use.

--

Brian Gregory. (In the UK)

To email me remove the letter vee.

Band pass filters -- what am I missing?
 

Ian Jackson wrote:
In message , Mark Carver
writes
J G Miller wrote:

Totally agree - can you name any other country undergoing
digital switchover which has forced people to do more than
one retune?

No, I don't think I can ?

But has any other country had the same complexity of regional
transmitters and channels? And have they been able to do the changeover
with such a comprehensive avoidance of loss of service?

France is similar to us, 6 muxes, and regional variations on FR3. Quite a few
relay stations too AIUI. Of course many analogue services on the Euro mainland
used Band III *&* UHF, and DTT is mostly UHF only (except in Finland where VHF
and UHF is used for DTT) so that must have eased the switchover pain ?.

http://en.wikipedia.org/wiki/T%C3%A9...ique_Terrestre

Spain ended up as UHF only for analogue by the time DSO arrived, but I don't
know how many muxes they have now ?


--
Mark
Please replace invalid and invalid with gmx and net to reply.

www.paras.org.uk

Band pass filters -- what am I missing?
 

"Bill Wright" wrote in message
...
Mark Carver wrote:

Welcome to the world of high power overlapping DTT.

They give us all this bull**** about spectrum being scarce, but what could
be more profligate than transmitting DTT on ten times the necessary power?


There are plenty of places where it will be very useful to have some more
power to give a bit more immunity from unsuppressed motor bikes, weather
bringing in French DTV signals etc.

--

Brian Gregory. (In the UK)

To email me remove the letter vee.

Band pass filters -- what am I missing?
 

Brian Gregory [UK] wrote:
"Bill Wright" wrote in message
...
Mark Carver wrote:
Welcome to the world of high power overlapping DTT.
They give us all this bull**** about spectrum being scarce, but what could
be more profligate than transmitting DTT on ten times the necessary power?


There are plenty of places where it will be very useful to have some more
power to give a bit more immunity from unsuppressed motor bikes, weather
bringing in French DTV signals etc.

Yes regarding the motorbikes, but actually they have overdone it and the
problems caused outweigh the benefits. No regarding French signals,
because that policy would simply lead to escalation. If you want to
avoid interference from abroad the way to do it has an international
agreement to restrict power towards other countries, not have everyone
cranking the power up.

Slightly changing the subject, didn't DSO in some countries involve the
use of the opposite polarization for digi?

Bill

Band pass filters -- what am I missing?
 

In message , Peter Duncanson
wrote

The autoscan could do an initial "dumb" scan. It would then do an
"intelligent" scan using the MHEG channel data downloaded on the first
scan. On the first scan it could look for the MHEG channel data only and
not populate the channel list.


One "official" digital site says that I should get my signals from Dover
which is completely wrong as I cannot get anything from that
transmitter. Another site suggests Crystal Palace but I live in the
shadow of tall buildings if my aerial was pointing that way. I can get
all MUXs from CP but the reception is very variable. I use Bluebell Hill
which is has an unobstructed line of site and gives reliable reception
for all MUXs.

Although my aerial is pointing towards Bluebell Hill I can still get
strong signals from two or three other transmitter. In your scheme,
what is the MHEG information going to do with my channel list, bearing
in mind as an uninformed user without any technical knowledge I
shouldn't need to know any details about transmitters, obstruction etc.?
Assuming the box had information on my location, perhaps with the use of
the post code, then presumably I would be automatically tuned into
Dover!

--
Alan
news2009 {at} admac {dot} myzen {dot} co {dot} uk

Band pass filters -- what am I missing?
 

Bill Wright wrote:

Slightly changing the subject, didn't DSO in some countries involve the
use of the opposite polarization for digi?

Yes, Spain. Some DTT muxes were on adjacent 'taboo' allocations to analogue
(just like here), but AIUI the Spanish broadcasters were concerned about the
analogue carriers swamping out the adjacent DTTs (as happened here, notably
with the Philips On Digital boxes). So, you'd often see two aerials, one H,
the other V pointing at the same Tx, I noticed this on holidays to Santander,
and the Canary Is in '02, '04, and '06. They've DSO'd now, I visited Barcelona
on May, I didn't see any 'double installs' there, so it's doubtful that area
ever used cross pol ? Perhaps the DTT allocations there were in a different
part of the UHF band to analogue ?

--
Mark
Please replace invalid and invalid with gmx and net to reply.

www.paras.org.uk

Band pass filters -- what am I missing?
 

On Sun, 28 Aug 2011 19:59:34 +0100, Alan wrote:

In message , Peter Duncanson
wrote

The autoscan could do an initial "dumb" scan. It would then do an
"intelligent" scan using the MHEG channel data downloaded on the first
scan. On the first scan it could look for the MHEG channel data only and
not populate the channel list.


One "official" digital site says that I should get my signals from Dover
which is completely wrong as I cannot get anything from that
transmitter. Another site suggests Crystal Palace but I live in the
shadow of tall buildings if my aerial was pointing that way. I can get
all MUXs from CP but the reception is very variable. I use Bluebell Hill
which is has an unobstructed line of site and gives reliable reception
for all MUXs.

Although my aerial is pointing towards Bluebell Hill I can still get
strong signals from two or three other transmitter. In your scheme,
what is the MHEG information going to do with my channel list, bearing
in mind as an uninformed user without any technical knowledge I
shouldn't need to know any details about transmitters, obstruction etc.?
Assuming the box had information on my location, perhaps with the use of
the post code, then presumably I would be automatically tuned into
Dover!

For such a plan to be worthwhile the box would need to look at the
strength and quality of the signals received and if necessary offer the
user choices - in terms that the user can understand.

--
Peter Duncanson
(in uk.tech.digital-tv)