Anyone out there using a televes Avant HD or Televes Avant 5?
Stephen
I've been reading the downloaded instruction manual for the Televes Avant HD
(Its an improved version of the Televes Avant 5)
Its claimed to be suitable for single dwelling units.
Reading the specifications, it states: that the optimum input margin is 60
to 105dBµV and that the output level can be regulated to 96 to 111dBµV (it
has automatic gain control to ensure the output levels remains constant even
when the input signals vary.)
As I understand it, the suitable DTT level signals is 40 to 60dBµV. Analogue
is 60 to 80dBµV, but lets neglect that due to the impending switch over.
Lets assume this Televes Avant HD woudl be used to combine 3 UHF aerials, a
DAB and a FM aerial, plus CCTV and be used to feed a 16 output Multswitch.
Assuming no UHF gain in the multiswitch and neglecting cable losses, this
means the input UHF signal required to the Multiswitch is of the order of 52
to 72dBµV, to ensure that 40 to 60dBµV was arriving at the wall plates.
(12dB gain is needed to power 16 outlets)
Assuming the Televes Avant HD's output can be set to 96BµV, which is the
lowest output level, that is still 24 to 44dB higher than the required UHF
input level of 52 to 72dBµV of the multiswitch.
So:
(a) am I missing something?
(b) Is Televes claim questionable?
(c) do I need to insert a passive attenuator of 24 to 44dB between the
launch amp and the multiswitch?
(d) can DTT/freeview tuners really cope with 84dBµV instead of 40 to 60dBµV?
As a side point, the Noise figure of the Televes Avant HD is 9dB. . . . . .
Stephen.
Bill Wright
> Hi All,
>
> I've been reading the downloaded instruction manual for the Televes Avant HD
> (Its an improved version of the Televes Avant 5)
>
> Its claimed to be suitable for single dwelling units.
>
> Reading the specifications, it states: that the optimum input margin is 60
> when the input signals vary.)
>
The signals at the outlets of any amplified system shouldn't be lower
than 50dBuV.
Analogue
> is 60 to 80dB�V, but lets neglect that due to the impending switch over.
>
> Lets assume this Televes Avant HD woudl be used to combine 3 UHF aerials, a
> DAB and a FM aerial, plus CCTV and be used to feed a 16 output Multswitch.
> Assuming no UHF gain in the multiswitch and neglecting cable losses, this
> means the input UHF signal required to the Multiswitch is of the order of 52
> to 72dB�V, to ensure that 40 to 60dB�V was arriving at the wall plates.
> (12dB gain is needed to power 16 outlets)
If the switch has zero gain each of the outputs will be at the same
level as the input, more or less.
>
> Assuming the Televes Avant HD's output can be set to 96B�V, which is the
> lowest output level, that is still 24 to 44dB higher than the required UHF
> input level of 52 to 72dB�V of the multiswitch.
>
> So:
>
> (a) am I missing something?
> (b) Is Televes claim questionable?
> (c) do I need to insert a passive attenuator of 24 to 44dB between the
> launch amp and the multiswitch?
> (d) can DTT/freeview tuners really cope with 84dB�V instead of 40 to 60dB�V?
I don't use programmable units of that kind because I find them
inflexible and not cost effective, so my experience is limited to
servicing systems where they HAVE been used. That experience has
reassured me that I am wise not to use them.
However, I think I can say that the Avant series seems to me to be well
over the top for a one-switch system. It appears to be designed as the
launch amp for a large system, with a low gain high output amp following
it; or alternatively as a stand alone unit for a small (60 outlet)
system. A multiswitch is in effect one outlet as far as the Avant is
concerned. Most switches do have a bit of overall gain on the
terrestrial port, by the way, so the outputs are perhaps 4dB above the
input.
Some idea of the minimum output levels you need for UHF DTT:
--at the wallplate 50dBuV
--at the switch output 55dBuV upwards, depending on cable length.
Remember cable deteriorates, so for CT100 work on 2.8dB/10m at 860MHz.
The outlet will lose a bit of course.
-- at the switch input: as above minus a bit for switch gain if it has any.
You can feed 75dBuV or even more into a DTT tuner as long as it isn't
accompanied by anything stronger, such as analogue at 95dBuV.
If you use the Avant I think you should run it at its optimum input and
output levels, then attenuate down to a suitable input level for the
switch. Don't starve it of signal to get the output down; the internal
noise will show up badly if you do.
Hope this helps.
Bill
Stephen
The situation I have is that currently I have aerials for Sandy Heath and
for Oxford.
All the muxes are OK for Oxford, analogue is ropey.
The converse is true for Sandy Heath though, analogue is great, muxes 2, A C
& D are rubbish due to the notch filter effect created by the TPO'ed trees.
Sandy Heath is the first of the four recieavble TX's at my house to start a
HD service.
(The other two are Waltham and Sutton Coldfield. I have a hill between me
and Sutton Coldfield and there is a metal comms tower between me and
Waltham)
So looking at DTG's website, Sandy will be using UHF 21, 24 and 27 for the 3
PSB muxes, and Oxford will continue for a little while longer using UHF's
29, 34, 48, 51, 52 and 68. Eventually the 3 COM muxes at Sandy Heath will
use 48, 51 and 52 after Oxford has DSO'ed.
So I was looking into combining part of Group A from SDH to get the 3 PSB
muxes and combine it with Oxford's six muxes. I can't find a aerial group
combiner that can do this satisfactorily.
There will at be Muxes 7 and 8 launching at some point in the future. So I
was looking into programmable cluster filters and launch amps for my
multiswitch. The only two I can see that would be of any use is the Televes
Avant HD and the Fracarro SIG 008 unless anyone else has any suggestions?
Stephen.
"Bill Wright" <bi...@invalid.com> wrote in message
news:ifne38$b2e$1...@speranza.aioe.org...
> Stephen wrote:
>> Hi All,
>>
>> I've been reading the downloaded instruction manual for the Televes Avant
>> HD (Its an improved version of the Televes Avant 5)
>>
>> Its claimed to be suitable for single dwelling units.
>>
>> Reading the specifications, it states: that the optimum input margin is
>> 60 to 105dBµV and that the output level can be regulated to 96 to 111dBµV
>> (it has automatic gain control to ensure the output levels remains
>> constant even when the input signals vary.)
>>
>> As I understand it, the suitable DTT level signals is 40 to 60dBµV.
>
> The signals at the outlets of any amplified system shouldn't be lower than
> 50dBuV.
>
> Analogue
>> is 60 to 80dBµV, but lets neglect that due to the impending switch over.
>>
>> Lets assume this Televes Avant HD woudl be used to combine 3 UHF
>> aerials, a DAB and a FM aerial, plus CCTV and be used to feed a 16 output
>> Multswitch. Assuming no UHF gain in the multiswitch and neglecting cable
>> losses, this means the input UHF signal required to the Multiswitch is of
>> the order of 52 to 72dBµV, to ensure that 40 to 60dBµV was arriving at
>> the wall plates. (12dB gain is needed to power 16 outlets)
> If the switch has zero gain each of the outputs will be at the same level
> as the input, more or less.
>
>>
>> Assuming the Televes Avant HD's output can be set to 96BµV, which is the
>> lowest output level, that is still 24 to 44dB higher than the required
>> UHF input level of 52 to 72dBµV of the multiswitch.
>>
>> So:
>>
>> (a) am I missing something?
>> (b) Is Televes claim questionable?
>> (c) do I need to insert a passive attenuator of 24 to 44dB between the
>> launch amp and the multiswitch?
>> (d) can DTT/freeview tuners really cope with 84dBµV instead of 40 to
>> 60dBµV?
Bill Wright
> So looking at DTG's website, Sandy will be using UHF 21, 24 and 27 for the 3
> PSB muxes, and Oxford will continue for a little while longer using UHF's
> 29, 34, 48, 51, 52 and 68. Eventually the 3 COM muxes at Sandy Heath will
> use 48, 51 and 52 after Oxford has DSO'ed.
>
> So I was looking into combining part of Group A from SDH to get the 3 PSB
> muxes and combine it with Oxford's six muxes. I can't find a aerial group
> combiner that can do this satisfactorily.
Taylor Transmitters
Ask Karen for a filter order form and fill it in as follows.
Qty 1 (Oxford)
TCFL6 with one common input for channels 29, 34, 40, 48, 51/52 and 68.
The ch40 is a spare that you could retune if things change.
Qty 1 (Sandy)
TCFL4 with one common input for channels 21, 24, 27 and 39. The ch39 is
a spare that you could retune if things change.
Qty 1 TD2-4F splitter (combiner)
Thro loss on above totals 10dB so be prepared to use low gain preamps on
each aerial feed.
See
http://www.wrightsaerials.tv/articles/domestic-rf-distribution-4.pdf
http://www.wrightsaerials.tv/articles/satellite-distribution-pp21-30.pdf
(page 3)
Bill
Stephen
and how much would this little lot cost me?
Also how much flexibility is there for retuning should Arquiva start playing
"musical chairs" at the Tx'es?
Also will there be room to add additional filters for when Muxes 7 and 8
start from Oxford and Sandy Heath respectively?
?
"Bill Wright" <bi...@invalid.com> wrote in message
news:ifnkem$qi6$1...@speranza.aioe.org...
Stephen
> TCFL6 with one common input for channels 29, 34, 40, 48, 51/52 and 68. The
> ch40 is a spare that you could retune if things change.
These are the old pre-DSO allocations, the new allocations are: 53, 55, 57,
59, 60, 62 from the 28th September 2011..... can the TCFL6 be retuned or
would a new one be required?
> Qty 1 (Sandy)
> TCFL4 with one common input for channels 21, 24, 27 and 39. The ch39 is a
> spare that you could retune if things change.
There are some interim parking channels as well, which is UHF 31.
Regards,
Stephen
Bill Wright
> Chers Bill,
Oh, to see Cher's name and mine so close together! I've come over all
unnecessary...
>
> and how much would this little lot cost me?
website. About �140 at a guess.
>
> Also how much flexibility is there for retuning should Arquiva start playing
> "musical chairs" at the Tx'es?
>
> Also will there be room to add additional filters for when Muxes 7 and 8
> start from Oxford and Sandy Heath respectively?
The diagram on p3 of
http://www.wrightsaerials.tv/articles/satellite-distribution-pp21-30.pdf
shows how to use two filters with the signals from one aerial. The 6dB
tap can be a splitter if you like.
Bill
Bill Wright
>> Qty 1 (Oxford)
>> TCFL6 with one common input for channels 29, 34, 40, 48, 51/52 and 68. The
>> ch40 is a spare that you could retune if things change.
>
> These are the old pre-DSO allocations, the new allocations are: 53, 55, 57,
> 59, 60, 62 from the 28th September 2011..... can the TCFL6 be retuned or
> would a new one be required?
You could retune
68 to 62
51/52 to 59/60
48 to 57
but after that you might struggle.
Bill
Stephen
taking onboard Bill's comments:
so if we work backwards from from a wall outlet figure of 55dBµV,
at the multiswitch outputs we would need 58dBµV (allowing for 3dB loss in a
10m cable run)
Please correct me if I am wrong, but am I to understand that the 5x16
multiswitch will have a UHF amp of 13dB gain or so as I had thought that if
you split a signal 16 ways, you'd end up with 16 output signals, all 12dB
lower than the original single input signal? (if there was no internal
amplifier, that would obviously justify a UHF launch amplifier. Also the
fewer amplification stages, the less noise?)
So that means the input UHF signal levels at the multiswitch need to be
around 60dBµV.........
if we set the Avant to its optimum gain and have an output of 110dBµV, that
means we need an attenuator of 50dB between the Avant and the
multiswitch.....
applying 50dB of attenuation would certainly sort out the 9dB noise
introduced by the Avant...... ::-)
Stephen.
Richard Russell
> You could retune 68 to 62, 51/52 to 59/60, 48 to 57
Is it practical to retune one of these filters without a spectrum
analyzer?
Richard.
http://www.rtrussell.co.uk/
Bill Wright
> OK,
>
> taking onboard Bill's comments:
>
> so if we work backwards from from a wall outlet figure of 55dBµV,
>
> at the multiswitch outputs we would need 58dBµV (allowing for 3dB loss in a
> 10m cable run)
Allow 1dB for the wallplate, 2dB if its diplexed.
>
> Please correct me if I am wrong, but am I to understand that the 5x16
> multiswitch will have a UHF amp of 13dB gain or so as I had thought that if
> you split a signal 16 ways, you'd end up with 16 output signals, all 12dB
> lower than the original single input signal?
Inside the multiswitch the process of adding the VHF/UHF signals to the
satellite signals is lossy. But you don't need the think about any of
that, honestly. All you need to do is read the gain figure on the label
and add it into your sums. Treat the switch as a black box, like I do.
(if there was no internal
> amplifier, that would obviously justify a UHF launch amplifier. Also the
> fewer amplification stages, the less noise?)
See below
>
> So that means the input UHF signal levels at the multiswitch need to be
> around 60dBµV.........
That would be a reasonable level. A bit higher than I'd use, unless the
downleads were 20m or so...
>
> if we set the Avant to its optimum gain and have an output of 110dBµV, that
> means we need an attenuator of 50dB between the Avant and the
> multiswitch.....
As I said, the Avant is not suitable for feeding one switch. In my opinion.
>
> applying 50dB of attenuation would certainly sort out the 9dB noise
> introduced by the Avant...... ::-)
No it wouldn't, because all that amplification would degrade the s/n
ratio irreversibly, and attenuation wouldn't improve it.
Incidentally the reason I advocate a level of 50dBuV+ for 64QAM on a
system is that in practice the BER is never as good from a system as it
is from an aerial with a strong signal because of system noise, and you
don't want to let receiver noise get anywhere near worsening it. Then
there's the fact that people use shit flyleads, loop the signal though
several receivers and an antique VCR or three before letting the poor
old telly have a sniff of it.
Bill
Bill Wright
Everyone will say 'No!' but actually, if you're pushed, you can, if you
have a meter that reads signal strength on DTT and genuinely measures
the level across the mux in a series of samples. If it just reads in the
middle of the mux, that's maybe not so good, I dunno. Although these
filters don't tune very narrowly, and even if you were to tune all three
stages to the centre on the channel the results wouldn't be bad; just
maybe 3 or 4dB fall off at the edges. Ideally you stagger tune slightly
to get the mux flat. I wouldn't like to tune a filter to accept two or
more adjacent channels like that though. You could it but it would be a
lot of pratting about.
The way I do it for what it's worth is with an analyser and a noise
generator.
Taylors will retune them for you, and so will I for the price of a pint.
By the way Teldis sell these same filters. Also see
http://www.polytron.de/Prospekte/KanalfilterE.pdf
Bill
Stephen
> Stephen wrote:
>> OK,
>>
>> taking onboard Bill's comments:
>>
>> so if we work backwards from from a wall outlet figure of 55dBµV,
> That was 50dBuV
>
>>
>> at the multiswitch outputs we would need 58dBµV (allowing for 3dB loss in
>> a 10m cable run)
> Allow 1dB for the wallplate, 2dB if its diplexed.
>
>>
>> Please correct me if I am wrong, but am I to understand that the 5x16
>> multiswitch will have a UHF amp of 13dB gain or so as I had thought that
>> if you split a signal 16 ways, you'd end up with 16 output signals, all
>> 12dB lower than the original single input signal?
> Inside the multiswitch the process of adding the VHF/UHF signals to the
> satellite signals is lossy. But you don't need the think about any of
> that, honestly. All you need to do is read the gain figure on the label
> and add it into your sums. Treat the switch as a black box, like I do.
So essentially there is a UHF amplifier incorporated, designed to compensate
for the splitting 16 ways though?
> Then there's the fact that people use shit flyleads, loop the signal
> though several receivers and an antique VCR or three before letting the
> poor old telly have a sniff of it.
Amen Brother!
When ever I buy a new piece of TV related gear, I throw the piece of coiled
up UHF string thats packaged in a plastic bag straight into the bin!
I then make my own fly leads using CT100 cable, using either F connectors or
a Nickel plated steel Belling Lee with a PTFE insert, as this allows me to
solder the centre pin without melting the PTFE, cheaper versions use
polyethylene which melts easily with a soldering iron or have aluminium pins
which are a pig to solder to.
In fact, the two Freeview twin tuner PVR's that I have, originally had a
short 5cm long flying co-ax lead running from the output of the 1st tuner to
the input of the second tuner. Those short links also went in the bin.
I had the sense to run 6 co-axial leads from the loft to the lounge, did the
same for the master bedroom, and again for the second bedroom, as well as 4
Cat5e ehethernet cables to each room.
So, in the lounge there's 4 CT100 fly leads from the wall plates, one for
the freeview integrated TV, two for the Thomson Twin tuner PVR.and 1 for
the Nebula Freeview card in the lounge PC. (The PC is also connected to the
TV set via HDMI.
In the master bedroom, theres four fly leads, one for the single tuner
freeview DVD recorder, two for the Twin tuner Hitachi PVR and one for the
analogue TV set.
For completeness, I soldered a 75 ohm resistor into a BL plug and used these
to terminate the unused outputs of the tuners on both PVRs.
Regards
Stephen.
.
> Bill
>
Graham.
"Bill Wright" <bi...@invalid.com> wrote in message news:ifnkem$qi6$1...@speranza.aioe.org...
It surprises me that Taylor kit still uses B-L connectors. Wouldn't you feel more comfortable in an all
f-type environment up to the domestic outlet plate?
--
Graham.
%Profound_observation%
Bill Wright
>
>> and add it into your sums. Treat the switch as a black box, like I do.
>
> So essentially there is a UHF amplifier incorporated, designed to compensate
> for the splitting 16 ways though?
It compensates for the splitting and also the combining with the
satellite signals. As a matter of interest, some early switches were
designed to be powered entirely from the receivers, and they didn't
amplify the VHF/UHF signals at all. The through loss was perhaps 20dB
for a six-way switch, a lot more than the loss of a simple six way split.
>
> I then make my own fly leads using CT100 cable, using either F connectors or
> a Nickel plated steel Belling Lee with a PTFE insert, as this allows me to
> solder the centre pin without melting the PTFE, cheaper versions use
> polyethylene which melts easily with a soldering iron or have aluminium pins
> which are a pig to solder to.
But it can be done. We make hundreds of flyleads (it's a long story;
don't ask) and we solder quite happily without melting the PTFE (if
that's what it is). We use good heatsinks and a quick technique. And
Loktite (don't ask).
>
> In fact, the two Freeview twin tuner PVR's that I have, originally had a
> short 5cm long flying co-ax lead running from the output of the 1st tuner to
> the input of the second tuner. Those short links also went in the bin.
Short links can be made from 5mm coax from the RG59 family with solid
dielectric and heavy braid screening. This cable would be too lossy for
long runs but for a few cm it works fine. Interconnects on factory-made
head-ends are often made like that.
>
> I had the sense to run 6 co-axial leads from the loft to the lounge, did the
> same for the master bedroom, and again for the second bedroom, as well as 4
> Cat5e ehethernet cables to each room.
A man after my own heart.
Bill
Bill Wright
Bill
Stephen
After some more research on the net,
I found another headend clusterfilter amplifer that appears to do similar to
a Fracarro SIG 8008 and the Televes Avant 5/HD
Its the Triax TMB 10C (there are other versions, ending in A, B, S and CU
instead of C.) and is available from HDSL or Amazon for 288 quid inc VAT and
free P&P.
Anyone got any experience with the Triax TMB 10C?
Regards
Stephen.
"Stephen" <i.wan...@spam.com> wrote in message
news:Tq-dnTKduq_uZ73Q...@brightview.co.uk...