I have usefull length of Belden 9248 RG-6 75 ohm Co-ax is this any good
for Satellite dish connection?

Ta.

--
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http://gymratz.co.uk/hot-seat.htm - Live web-cam!
TRADE PRICED SUPPLEMENTS for Personal Trainers or individual purchase.
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In article , Pet
writes
I have usefull length of Belden 9248 RG-6 75 ohm Co-ax is this any good
for Satellite dish connection?

Ta.


Yes....
--
Tony Sayer

From http://www.satcure.co.uk/accs/page8.htm

SATDS is low cost, very flexible and ideal for making short connecting leads
and for runs around the house. The main drawback is that it's easily crushed
and kinked. Because of its aluminium and copper shield, it's very
susceptible to damage in damp conditions and it's more "lossy" than other
cable which uses only copper so using it for long runs outddors is to be
discouraged.

CT100 and H109 are slightly more robust but still susceptible to kinking.
Being stiffer, they are not as good as SATDS (RG6) for looping between
equipment. However, losses are lower than SATDS and they survive outdoors
better.


probably ok, but this suggests CT100 is better for the long run to the dish.

"Pet" wrote in message
...
I have usefull length of Belden 9248 RG-6 75 ohm Co-ax is this any good
for Satellite dish connection?

Ta.

--
http://gymratz.co.uk - UK's best bodybuilding supplements,gym equipment.
http://gymratz.co.uk/hot-seat.htm - Live web-cam!
TRADE PRICED SUPPLEMENTS for Personal Trainers or individual purchase.
http://trade-price-supplements.co.uk

tony sayer wrote:

I have usefull length of Belden 9248 RG-6 75 ohm Co-ax is this any good
for Satellite dish connection?

Ta.

Yes....

Sorry, forgot to mention, Probabally looking at connecting to a
"multiswitch" in the loft then running to differrent rooms in the house.
I presume losses will be insignificant as a multiswitch presumably
amplifies signal as well?


--
http://gymratz.co.uk - UK's best bodybuilding supplements,gym equipment.
http://gymratz.co.uk/hot-seat.htm - Live web-cam!
TRADE PRICED SUPPLEMENTS for Personal Trainers or individual purchase.
http://trade-price-supplements.co.uk

In article , a
writes
From http://www.satcure.co.uk/accs/page8.htm

SATDS is low cost, very flexible and ideal for making short connecting leads
and for runs around the house. The main drawback is that it's easily crushed
and kinked. Because of its aluminium and copper shield, it's very
susceptible to damage in damp conditions and it's more "lossy" than other
cable which uses only copper so using it for long runs outddors is to be
discouraged.

CT100 and H109 are slightly more robust but still susceptible to kinking.
Being stiffer, they are not as good as SATDS (RG6) for looping between
equipment. However, losses are lower than SATDS and they survive outdoors
better.


probably ok, but this suggests CT100 is better for the long run to the dish.


Reckon that its all a bit academic for domestic use where cable runs
aren't likely to be that long.

Try it and see, either it will work or it won't but I reckon you'd have
to have very long runs for it not to work, and try not to crush it


--
Tony Sayer

On Thu, 26 Aug 2004 11:05:51 GMT, Pet wrote:

tony sayer wrote:

I have usefull length of Belden 9248 RG-6 75 ohm Co-ax is this any good
for Satellite dish connection?

Ta.

Yes....

Sorry, forgot to mention, Probabally looking at connecting to a
"multiswitch" in the loft then running to differrent rooms in the house.
I presume losses will be insignificant as a multiswitch presumably
amplifies signal as well?

You need to look carefully at the specs.

Many of them have UHF input as well as from the LNB and a separate
gain control for the UHF.

In general, they don't make an increase in the satellite signal level
as such, but amplify the signals to the extent necessary to
compensate it being potentially split N ways.
Some switches have an increasing amplification with increasing
frequency to compensate in part for the cable characteristics. There
may be an adjuster.

Look at

http://www.spaun.de/html/sms_9801_nf.html

as an example of this

The point is that multiswitches are meant to be more or less plug and
play with standard quattro LNBs and CT100 cable



..andy

To email, substitute .nospam with .gl

Andy Hall wrote:


Look at

http://www.spaun.de/html/sms_9801_nf.html

as an example of this

The point is that multiswitches are meant to be more or less plug and
play with standard quattro LNBs and CT100 cable

Thanks Andy.
Well, I've already run the trickiest length of the stuff this evening.
As it's (RG6) primarily used for transmission of RF rather than just RX
I am assuming it should have minimal losses compared to CT100. besides,
maximum distance of each run will be around 10 m and Dish to
Multiswitch will be about 3 to 4 m max.

Hopefully I'l be OK.

--
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http://gymratz.co.uk/hot-seat.htm - Live web-cam!
TRADE PRICED SUPPLEMENTS for Personal Trainers or individual purchase.
http://trade-price-supplements.co.uk

"Pet" wrote in message
...

As it's (RG6) primarily used for transmission of RF rather than just
RX I am assuming it should have minimal losses compared to CT100.
besides, maximum distance of each run will be around 10 m and Dish
to Multiswitch will be about 3 to 4 m max.

The attenuation of the stuff that the cable TV industry calls 'RG6'[1] is to
all intents and purposes the same as CT100 / WF100 etc. - about 30 dB per
100m at the upper end of the SAT IF band (2.2 GHz or so).

In applications like yours, where the cable lengths are fairly short, loss
in the cable is the least of your worries - there's about 55 dB gain in the
typical LNB and the system will happily stand 20 dB or more loss between the
LNB and the set-top- box without any ill effect on signal quality. Other
cable properties are more important than attenuation: screening factor and
accuracy of impedance are the main two. DVB-S uses high-symbol-rate QPSK
modulation and reflections (due to mismatches) in the IF cable will cause
inter-symbol interference and a loss of signal quality [2][3]. This is the
usual cause of 'missing channels' in systems where there are several of
joints and bits'n pieces in the cable run. For the same reason it's vitally
important to use good quality (preferably crimp) F connectors and make sound
braid connections in the coax.

The other issue you get when combining LNB outputs and off-air UHF on to a
single cable - as in a multiswitch or 'loftbox'[4] system - is degradation
of the UHF C/N ratio due to the amplified wideband noise present at the LNB
output. Multiswitches and loftboxes include sharp cut-off highpass filters
to mitigate this effect, but the performance of the filters in different
products varies considerably - so filter performance is often a more
important selection criterion than gain/loss.


[1] Which is nothing much like 'proper' RG6/U to MIL-C-17.

[2] Unlike the DVB-T and DAB systems where the use of COFDM makes
the system highly reflection tolerant.

[3] Preferably use a cable 'benchmarked' under the CAI scheme - see
http://www.cai.org.uk/asp/bmcables.asp

[4] Regd. trademark of Global, but actually becoming rather like
'Hoover'.

--
Andy

On Fri, 27 Aug 2004 12:03:29 +0100, "Andy Wade"
wrote:

For the same reason it's vitally
important to use good quality (preferably crimp) F connectors

Good quality and F Type connectors are two descriptions which do not
belong in the same sentence. Designed to be as cheap as possible F
type connectors have succeeded beyond the wildest imagination of
their designers. If there is a worse RF connector (other than the TV
co-ax plug) I am yet to see it.

--
Peter Parry.
http://www.wpp.ltd.uk/

Peter Parry wrote:
On Fri, 27 Aug 2004 12:03:29 +0100, "Andy Wade"
wrote:

For the same reason it's vitally
important to use good quality (preferably crimp) F connectors

Good quality and F Type connectors are two descriptions which do not
belong in the same sentence. Designed to be as cheap as possible F
type connectors have succeeded beyond the wildest imagination of
their designers. If there is a worse RF connector (other than the TV
co-ax plug) I am yet to see it.

3.5mm mono plug?
(as used on my "FM" ISA radio card.)
It never really worked.

On Fri, 27 Aug 2004 18:50:11 +0100, Peter Parry
strung together this:

Designed to be as cheap as possible F
type connectors have succeeded beyond the wildest imagination of
their designers. If there is a worse RF connector (other than the TV
co-ax plug) I am yet to see it.

But, for the mass market they're easily available and reasonably
foolproof, (well not really but they're easier to put together than
co-ax plugs). For 'non-critical' RF installations I use F connectors
in preference to co-ax connectors.
--

SJW
A.C.S. Ltd

On 28 Aug 2004 13:55:19 GMT, Ian Stirling
strung together this:

3.5mm mono plug?

Spot on they are, I've got one on the back of one of the TV's in the
van. Works a treat(ish)!
--

SJW
A.C.S. Ltd

On Sat, 28 Aug 2004 20:12:37 +0100, Lurch
wrote:


But, for the mass market they're easily available and reasonably
foolproof, (well not really

Is that Latin for "not at all"? You only need to look at the damn
things and they fall off.

but they're easier to put together than
co-ax plugs). For 'non-critical' RF installations I use F connectors
in preference to co-ax connectors.

What always amuses me is the various satellite people who witter on
about the qualities of one cable versus another (identically
specified) one and then stick these abominable terminations on the
end.

--
Peter Parry.
http://www.wpp.ltd.uk/

In article , Peter Parry
writes
On Sat, 28 Aug 2004 20:12:37 +0100, Lurch
wrote:


But, for the mass market they're easily available and reasonably
foolproof, (well not really

Is that Latin for "not at all"? You only need to look at the damn
things and they fall off.

but they're easier to put together than
co-ax plugs). For 'non-critical' RF installations I use F connectors
in preference to co-ax connectors.

What always amuses me is the various satellite people who witter on
about the qualities of one cable versus another (identically
specified) one and then stick these abominable terminations on the
end.



Which one are U calling the abominable termination? surely not the F
plug?....
--
tony sayer

On Sun, 29 Aug 2004 10:50:34 +0100, tony sayer
wrote:


Which one are U calling the abominable termination? surely not the F
plug?....

On consideration I can see your point - to grace the piece of
tinplated scrap sold as an "F Plug" with the description termination
is unjustifiable.

--
Peter Parry.
http://www.wpp.ltd.uk/

In article , Peter Parry
writes
On Sun, 29 Aug 2004 10:50:34 +0100, tony sayer
wrote:


Which one are U calling the abominable termination? surely not the F
plug?....

On consideration I can see your point - to grace the piece of
tinplated scrap sold as an "F Plug" with the description termination
is unjustifiable.


Well in my 'umble opinion as a radio comms engineer, I reckons that the
abomination is the Belling Lee co-ax plug. The F type is better in many
ways. So I suppose that all the cable networks that use F types should
have used the BL co-ax plug then?......
--
Tony Sayer

On Sun, 29 Aug 2004 12:49:50 +0100, tony sayer
wrote:


Well in my 'umble opinion as a radio comms engineer, I reckons that the
abomination is the Belling Lee co-ax plug. The F type is better in many
ways.

That's a bit like saying having you arm amputated with no anaesthetic
is nicer than having your leg amputated in similar circumstances.
The statement may be true but it doesn't paint the whole picture.

So I suppose that all the cable networks that use F types should
have used the BL co-ax plug then?......

No, any one of the proper RF connectors, TNC, BNC even FME would be a
vast improvement on either of the apologies for a plug that you
mentioned.

--
Peter Parry.
http://www.wpp.ltd.uk/

In article , Peter Parry
writes
On Sun, 29 Aug 2004 12:49:50 +0100, tony sayer
wrote:


Well in my 'umble opinion as a radio comms engineer, I reckons that the
abomination is the Belling Lee co-ax plug. The F type is better in many
ways.

That's a bit like saying having you arm amputated with no anaesthetic
is nicer than having your leg amputated in similar circumstances.
The statement may be true but it doesn't paint the whole picture.

No...

So I suppose that all the cable networks that use F types should
have used the BL co-ax plug then?......

No, any one of the proper RF connectors, TNC, BNC even FME would be a
vast improvement on either of the apologies for a plug that you
mentioned.

So what's the problem with it then?,

And yes, it isn't a N type, but then again their overkill for domestic
applications....

--
Tony Sayer

"Peter Parry" wrote in message
...

No, any one of the proper RF connectors, TNC, BNC even FME would be a
vast improvement on either of the apologies for a plug that you
mentioned.

No they wouldn't - anyway getting them in 75 ohm versions and sizes to fit
the foam and 5-cell dielectric cables used in the TV distribution world
would be difficult.

I disagree fundamentally with your premise. The Type-F connector is an
example of good engineering, in that it achieves (or can achieve) excellent
performance at very low cost. It _is_ a proper RF connector. Perhaps
you've only encountered the cheapest nastiest sort. Take a look at the 'F'
series products offered by companies like Cabelcon (Denmark), Gilbert (USA),
PPC (USA), Tratec (Netherlands) and others.

Good crimp F-connectors give excellent screening factors (90 dB+) and can
provide excellent impedance matching ( 20 dB return loss to above 2 GHz).
The fact that, for the smaller cable sizes, the cable inner conductor acts
as the centre pin of the plug means that the male side of the connection
inherently provides a good impedance match and cost is minimised. Matching
performance is primarily determined by the internal design of the female
connector, which is usually part of equipment. There are two principal
types of inner contact design in use - the original flat leaf spring type,
which are generally OK up to 860 MHz (top of the UHF TV band) and the round
cage jack type which are suitable for use up to 2 GHz + (top of the
satellite first IF band).

You do need to be very careful when choosing adapters between F and other
connector series, some of which display very poor return losses (high SWR)
and others of which are OK.

The 'F' interface is quite respectable - it's standardised in IEC 60169-24
and Agilent supply a calibration kit (85039B) characterised up to 3 GHz for
use with their vector network analysers:
http://we.home.agilent.com/USeng/nav...880331/pd.html.

--
Andy

On Sun, 29 Aug 2004 14:42:01 +0100, "Andy Wade"
wrote:


I disagree fundamentally with your premise. The Type-F connector is an
example of good engineering,

It is a good example of cost engineering - designing something for as
low a production cost as possible whilst maintaining the minimum
level of performance you can get away with. Exactly the same design
criteria and standards as the Belling Lee (IEC) TV connector.

Perhaps you've only encountered the cheapest nastiest sort.

The cable pin versions are all cheap, that was the design aim. The
consequence of meeting that aim is that they are nasty.

There are variants of the F type with centre pins which are capable
of the sort of performance you would expect of a proper connector.
The Amphenol pin F type is an example and as they say "...it became
increasingly obvious that existing low performance F receptacles
could not be used in high speed cable modems and customer interface
units"

Good crimp F-connectors give excellent screening factors (90 dB+)

I seriously doubt if a cable pin F type connector can achieve
anything like this figure at 1GHz.

and can
provide excellent impedance matching ( 20 dB return loss to above 2 GHz).

A VSWR of 1:1.22 is not achievable with a plug using a wire centre
conductor. Typically a BNC connector will exhibit a VSWR of 1 :1.1
(26dB RL) at 2GHz.

F connectors using the cable core are one plug where you cannot get
data sheets because the performance is inherently unpredictable as
half the plug is made out of the cable.

The fact that, for the smaller cable sizes, the cable inner conductor acts
as the centre pin of the plug means that the male side of the connection
inherently provides a good impedance match and cost is minimised.

It actually means you have a bent copper pin. Copper corrodes and
copper oxide acts as a rectifier - just what you don't need in an RF
plug. You also get centre conductor nicks, bending, dielectric
migration and metal fatigue. None of these help the performance at
all.

The 'F' interface is quite respectable

It is adequate as a higher frequency version of the Belling Lee (IEC)
co-ax connector. As something designed down to a price of pennies
each its mechanical and RF properties are just what you would expect
for the price you pay.

- it's standardised in IEC 60169-24

So is the Belling Lee plug so that isn't a terribly high
recommendation :-).

It's a cheap and nasty device which is exactly why you only find it
in consumer equipment where cheap outweighs nasty.


--
Peter Parry.
http://www.wpp.ltd.uk/

It's a cheap and nasty device which is exactly why you only find it
in consumer equipment where cheap outweighs nasty.



So have you had a lot of problems with these then?, because I've used
them over the years and haven't!.

After all, they are used in "domestic" applications and compared to the
belling lee co-ax are a better connector in that even if they do use the
centre conductor at least there is one less thing to go wrong.

Just "how" many aerial installers solder the centre conductor or even
just "crimp" it with a pair of side cutters?. Even the outer braiding
can be screwed onto the connector which is much better then the usual
way the BL is used.

So why did satellite receiver manufactures chose to standardise on the F
then?.

After all I couldn't even imagine domestic gear using BNC, TNC, or N or
7/16th types now, could U...


If you want a really useless abomination of a connector then the PL259
is the one(
--
Tony Sayer

On Mon, 30 Aug 2004 14:23:41 +0100, tony sayer
strung together this:

If you want a really useless abomination of a connector then the PL259
is the one(

Still not as bad as the BL though, I haven't had a PL259 fall off a
bit of cable before because it felt like it.
--

SJW
A.C.S. Ltd

On Mon, 30 Aug 2004 14:23:41 +0100, tony sayer
wrote:


So why did satellite receiver manufactures chose to standardise on the F
then?.

Its the cheapest connector on the market.

If you want a really useless abomination of a connector then the PL259
is the one(

It does hold together though - and to be fair it was designed in the
late 30's when "UHF" was anything over 100MHz. Its top frequency is
only 300MHz and its quite depressing to see kit supposedly working at
a GHz with these connectors.


--
Peter Parry.
http://www.wpp.ltd.uk/

On Mon, 30 Aug 2004 17:46:02 +0100, Peter Parry
wrote:

On Mon, 30 Aug 2004 14:23:41 +0100, tony sayer
wrote:


So why did satellite receiver manufactures chose to standardise on the F
then?.

Its the cheapest connector on the market.

If you want a really useless abomination of a connector then the PL259
is the one(

It does hold together though - and to be fair it was designed in the
late 30's when "UHF" was anything over 100MHz. Its top frequency is
only 300MHz and its quite depressing to see kit supposedly working at
a GHz with these connectors.

Actually nearly 2GHz for satellite IF.

In the U.S., where F connectors etc. are used for cable TV, it also
deskills the termination exercise. I somehow doubt that a lot of
the individuals doing this work would have a high success rate with
BNC and TNC et al. connectors.





..andy

To email, substitute .nospam with .gl

On Mon, 30 Aug 2004 19:55:20 +0100, Andy Hall
wrote:

On Mon, 30 Aug 2004 17:46:02 +0100, Peter Parry
wrote:

It does hold together though - and to be fair it was designed in the
late 30's when "UHF" was anything over 100MHz. Its top frequency is
only 300MHz and its quite depressing to see kit supposedly working at
a GHz with these connectors.

Actually nearly 2GHz for satellite IF.

Think we might be getting mixed up - I was referring to the "UHF
Plug" (PL259) when referring to a top frequency of 300 MHz.

In the U.S., where F connectors etc. are used for cable TV, it also
deskills the termination exercise.

Which was one of its design aims.

I somehow doubt that a lot of
the individuals doing this work would have a high success rate with
BNC and TNC et al. connectors.

Many don't do too well with what they have. An elderly neighbour of
ours was told by the highly skilled CAI member aerial destructor that
she couldn't get digital TV because, as he told me, there were "not
enough decibels being received and they were interfering with each
other so you need a system amplification installation and new cable
installed" (and here is your bill so far for GBP150).

As our aerial (propped up on the attic water tank 10 years ago to see
if it would work and it's going to be fixed properly one day honest)
works perfectly this puzzled me until a quick look showed the skilled
fitter had pointed the aerial about 25deg out at the Kodak Building
rather than the transmitter. This actually does give the strongest
signal on the idiotbox measuring device he was using but is useless
as it also includes numerous out of phase reflections. 10 minutes
work got a perfectly good signal (and I did enjoy telling the
installers exactly what they could do with their bill).

--
Peter Parry.
http://www.wpp.ltd.uk/

In article , Peter Parry
writes
On Mon, 30 Aug 2004 14:23:41 +0100, tony sayer
wrote:


So why did satellite receiver manufactures chose to standardise on the F
then?.

Its the cheapest connector on the market.

Yes it is cheap but its a well engineered design. I ask you again have
you had problems with it?.

If you want a really useless abomination of a connector then the PL259
is the one(

It does hold together though - and to be fair it was designed in the
late 30's when "UHF" was anything over 100MHz. Its top frequency is
only 300MHz and its quite depressing to see kit supposedly working at
a GHz with these connectors.


Yes well we are agreed on that!.......
--
Tony Sayer

On Mon, 30 Aug 2004 22:39:14 +0100, Peter Parry
wrote:



Think we might be getting mixed up - I was referring to the "UHF
Plug" (PL259) when referring to a top frequency of 300 MHz.

Ah, sorry, lost the plot.



Many don't do too well with what they have. An elderly neighbour of
ours was told by the highly skilled CAI member aerial destructor that
she couldn't get digital TV because, as he told me, there were "not
enough decibels being received and they were interfering with each
other so you need a system amplification installation and new cable
installed" (and here is your bill so far for GBP150).

Even as an explanation to a lay person, that's bogus.

AIUI, the critical factors are the carrier to noise ratio (because
DTTV carrier is NdB below the analogue (typically adjacent) carriers
and the bit error rate.

The elderly person might be confused by the introduction of BERT into
the discussion but even so.....



As our aerial (propped up on the attic water tank 10 years ago to see
if it would work and it's going to be fixed properly one day honest)
works perfectly this puzzled me until a quick look showed the skilled
fitter had pointed the aerial about 25deg out at the Kodak Building
rather than the transmitter. This actually does give the strongest
signal on the idiotbox measuring device he was using but is useless
as it also includes numerous out of phase reflections. 10 minutes
work got a perfectly good signal (and I did enjoy telling the
installers exactly what they could do with their bill).

Hmmm. As I would have thought that he would have got a lower error
rate reading by pointing the antenna at the transmitter, presumably he
was using a simple signal strength meter.

It's going to be interesting to see how these characters get on when
and if there are no analogue transmissions where they could at least
look for multipath reception on the picture.




..andy

To email, substitute .nospam with .gl

Peter Parry wrote:

The cable pin versions are all cheap, that was the design aim. The
consequence of meeting that aim is that they are nasty.

Not necessarily nasty, but I think we'll have to agree to differ on this.

There are variants of the F type with centre pins which are capable
of the sort of performance you would expect of a proper connector.
The Amphenol pin F type is an example and as they say "...it became
increasingly obvious that existing low performance F receptacles
could not be used in high speed cable modems and customer interface
units"

Note the word "receptacles" in there which makes it clear they're
referring to the female side of the interface, which (as I've already
said) is what primarily determines the RL/VSWR performance.

Good crimp F-connectors give excellent screening factors (90 dB+)
I seriously doubt if a cable pin F type connector can achieve
anything like this figure at 1GHz.

Well you're wrong: they can, and do. Here's some evidence
http://www.cabelcon.dk/download/screening.PDF.

A VSWR of 1:1.22 is not achievable with a plug using a wire centre
conductor.

Why not? - RF-wise the male F connector amounts to an open cable end
with a flange attached to the outer conductor.

Here's an example of a good-quality F back-back female coupler:
http://www.cabelcon.dk/F81hq.htm. IME the RL specs on that page are not
exaggerated.

Typically a BNC connector will exhibit a VSWR of 1 :1.1
(26dB RL) at 2GHz.

A good one might, but there are plenty of grotty BNC connectors about.

F connectors using the cable core are one plug where you cannot get
data sheets because the performance is inherently unpredictable as
half the plug is made out of the cable.

Data sheets for the the female connectors would be more pertinent, but I
agree they're not always available. But armed with a VNA and the HP cal
kit, measurements aren't too difficult.

It actually means you have a bent copper pin. Copper corrodes and
copper oxide acts as a rectifier - just what you don't need in an RF
plug. You also get centre conductor nicks, bending, dielectric
migration and metal fatigue. None of these help the performance at
all.

Well I'd agree they aren't suitable for use in aggressive atmospheres
where corrosion would be likely to be a problem. In practice though in
TV distribution systems I've never known this to be a problem, other
then in outdoor applications where the sealing has failed and water has
got in. Most real-world problems arise from faulty installation or poor
crimping, leading to bad connection in the outer conductor, not the
inner. (And of course we're not considering transmission applications
here with significant RF power, where passive intermod might be a problem.)

It is adequate as a higher frequency version of the Belling Lee (IEC)
co-ax connector. As something designed down to a price of pennies
each its mechanical and RF properties are just what you would expect
for the price you pay.

Its RF properties can be excellent, especially given what you pay.

It's a cheap and nasty device which is exactly why you only find it
in consumer equipment where cheap outweighs nasty.

You'll find lots of F-connectors on the capital plant side in CATV and
SMATV systems, etc. - so it's not strictly limited to consumer applications.

My list of worse RF connectors:

- RCA phono (aka Cinch) - used as a UHF connector in some TV tuners and
modulators; now that *is* nasty;

- miniature version of the Belling Lee - remember those?

- Type-UHF (PL259 etc.) [/ibid./]

- the old Pye plug.

--
Andy

On Mon, 30 Aug 2004 23:13:10 +0100, tony sayer
wrote:


Yes it is cheap but its a well engineered design. I ask you again have
you had problems with it?.

I try to avoid anything to do with them. Every time I get involved
with the damn things I know what is going to happen - you touch the
cable and the connector self destructs. Sometimes looking at them
hard is enough to make the cable jump out.

One local installer of these things seems to use his teeth to crimp
them and a passing breeze makes them fall apart. Another sort which
seems popular around here has what I presume is a crimp skirt made of
tinplate the thickness of aluminium foil and about 3mm in depth.
Needless to say it has the breaking strain of a jellybaby.

--
Peter Parry.
http://www.wpp.ltd.uk/

On Tue, 31 Aug 2004 10:08:12 +0100, Andy Wade
wrote:

Peter Parry wrote:

A VSWR of 1:1.22 is not achievable with a plug using a wire centre
conductor.

Why not? - RF-wise the male F connector amounts to an open cable end
with a flange attached to the outer conductor.

Because the impedance is very dependent upon the geometry of the
inner and outer conductors - and a bit of copper wire sticking out
the end doesn't stay absolutely straight nor round. Moreover the
oxidation of the copper introduces regions of variable conductivity,
and worse, small amounts of rectification. All these factors degrade
the VSWR.

Here's an example of a good-quality F back-back female coupler:
http://www.cabelcon.dk/F81hq.htm. IME the RL specs on that page are not
exaggerated.

Those are specifications for a fixed coupler - the figures are those
I would expect for any such device (even a PL259 coupler!!) as its
only a tube with a fixed inner.

Typically a BNC connector will exhibit a VSWR of 1 :1.1
(26dB RL) at 2GHz.

A good one might, but there are plenty of grotty BNC connectors about.

That figure is a fairly representative one for BNC/TNC, even fairly
cheap ones will achieve it.

Data sheets for the the female connectors would be more pertinent, but I
agree they're not always available. But armed with a VNA and the HP cal
kit, measurements aren't too difficult.

The reason the data sheets are not available is that the performance
is inconsistent. This is inevitable if you have something where the
plug is partially constructed on site. I agree you can always do
real measurements - but I doubt if that happens very much.

Well I'd agree they aren't suitable for use in aggressive atmospheres
where corrosion would be likely to be a problem. In practice though in
TV distribution systems I've never known this to be a problem,

It isn't a problem because you are rarely working at the limits of
performance. It does mean the connectors are not suitable for
situations where consistent performance is a critical issue.

Most real-world problems arise from faulty installation or poor
crimping, leading to bad connection in the outer conductor, not the
inner.

I wouldn't disagree with that :-).

My list of worse RF connectors:

- RCA phono (aka Cinch) - used as a UHF connector in some TV tuners and
modulators; now that *is* nasty;

Ah, yes I had rather forgotten that one although I never considered
it to be anything other than a poor audio connector!



--
Peter Parry.
http://www.wpp.ltd.uk/

"Andy Hall" wrote
| The elderly person might be confused by the introduction of BERT
| into the discussion but even so.....

I can imagine, especially if her Bert died in the war ...

Owain

In article , Peter Parry
writes
On Mon, 30 Aug 2004 23:13:10 +0100, tony sayer
wrote:


Yes it is cheap but its a well engineered design. I ask you again have
you had problems with it?.

I try to avoid anything to do with them. Every time I get involved
with the damn things I know what is going to happen - you touch the
cable and the connector self destructs. Sometimes looking at them
hard is enough to make the cable jump out.

Well are we talking about the same thing then Peter?.

That doesn't seem to be a very scientific answer

One local installer of these things seems to use his teeth to crimp
them and a passing breeze makes them fall apart. Another sort which
seems popular around here has what I presume is a crimp skirt made of
tinplate the thickness of aluminium foil and about 3mm in depth.
Needless to say it has the breaking strain of a jellybaby.

Well perhaps the ones I've used in the past must be of sterner stuff.

Tell U what I'll give a M8 of mine a bell who works for ntl cable and
see what he thinks of them. And he's not one to mince words!...
--
Tony Sayer

In article , Peter Parry
writes
On Tue, 31 Aug 2004 10:08:12 +0100, Andy Wade
wrote:

Peter Parry wrote:

A VSWR of 1:1.22 is not achievable with a plug using a wire centre
conductor.

Why not? - RF-wise the male F connector amounts to an open cable end
with a flange attached to the outer conductor.

Because the impedance is very dependent upon the geometry of the
inner and outer conductors - and a bit of copper wire sticking out
the end doesn't stay absolutely straight nor round. Moreover the
oxidation of the copper introduces regions of variable conductivity,
and worse, small amounts of rectification. All these factors degrade
the VSWR.

You seem to have a hatred of these devices. They as I've said are not N
or TNC's etc but I do think that you have a very bad bias!.

After all every sky receiver has one of these hanging on the back and I
don't think they are falling over in droves?.

Here's an example of a good-quality F back-back female coupler:
http://www.cabelcon.dk/F81hq.htm. IME the RL specs on that page are not
exaggerated.

Those are specifications for a fixed coupler - the figures are those
I would expect for any such device (even a PL259 coupler!!) as its
only a tube with a fixed inner.

Is the absolute VSWR of one of these really relevant in the TV system?..

Typically a BNC connector will exhibit a VSWR of 1 :1.1
(26dB RL) at 2GHz.

A good one might, but there are plenty of grotty BNC connectors about.

That figure is a fairly representative one for BNC/TNC, even fairly
cheap ones will achieve it.

Data sheets for the the female connectors would be more pertinent, but I
agree they're not always available. But armed with a VNA and the HP cal
kit, measurements aren't too difficult.

The reason the data sheets are not available is that the performance
is inconsistent. This is inevitable if you have something where the
plug is partially constructed on site. I agree you can always do
real measurements - but I doubt if that happens very much.

Well I'd agree they aren't suitable for use in aggressive atmospheres
where corrosion would be likely to be a problem. In practice though in
TV distribution systems I've never known this to be a problem,

It isn't a problem because you are rarely working at the limits of
performance. It does mean the connectors are not suitable for
situations where consistent performance is a critical issue.


Price?....


Most real-world problems arise from faulty installation or poor
crimping, leading to bad connection in the outer conductor, not the
inner.

I wouldn't disagree with that :-).

Me neither!..

My list of worse RF connectors:

- RCA phono (aka Cinch) - used as a UHF connector in some TV tuners and
modulators; now that *is* nasty;

Ah, yes I had rather forgotten that one although I never considered
it to be anything other than a poor audio connector!



Well a lot of they are around too!....
--
Tony Sayer

On Tue, 31 Aug 2004 22:46:14 +0100, tony sayer
wrote:


You seem to have a hatred of these devices.

Correct :-)

They as I've said are not N
or TNC's etc but I do think that you have a very bad bias!.

Correct.

After all every sky receiver has one of these hanging on the back and I
don't think they are falling over in droves?.

This is a recommendation? Every TV set has a Belling Lee plug, they
don't fall over in droves but its still an 'orrible connector.

It does mean the connectors are not suitable for
situations where consistent performance is a critical issue.

Price?....

Cheapest of all, I agree. However, is the cost of plugs an important
factor in any installation? You can buy F type connectors for about
10p each or less, however I doubt if you would use those plugs. You
only need one poor connector and an hour or so fault finding wipes
out the cost saving of the cheap plugs.

Ah, yes I had rather forgotten that one although I never considered
it to be anything other than a poor audio connector!

Well a lot of they are around too!....

Agreed - but I still don't consider it to be an RF connector :-)

--
Peter Parry.
http://www.wpp.ltd.uk/

In article , Peter Parry
writes
On Tue, 31 Aug 2004 22:46:14 +0100, tony sayer
wrote:


You seem to have a hatred of these devices.

Correct :-)

They as I've said are not N
or TNC's etc but I do think that you have a very bad bias!.

Correct.

After all every sky receiver has one of these hanging on the back and I
don't think they are falling over in droves?.

This is a recommendation? Every TV set has a Belling Lee plug, they
don't fall over in droves but its still an 'orrible connector.

Well from the way you put it these are falling to bits as soon as anyone
looks at them, which isn't true. If any installers have difficulty
terminating the F plug then perhaps they should be *terminated* from the
job....

It does mean the connectors are not suitable for
situations where consistent performance is a critical issue.

Price?....

Cheapest of all, I agree. However, is the cost of plugs an important
factor in any installation? You can buy F type connectors for about
10p each or less, however I doubt if you would use those plugs. You
only need one poor connector and an hour or so fault finding wipes
out the cost saving of the cheap plugs.

OK then. An N type will cost a few quid now can you really see domestic
grade manufacturers using them?. No I don't think so. The F is a simple
inexpensive way to do a simple undemanding job. Which they are quite
good at.

We use connectors on transmission equipment that cost around 80 odd quid
a go, which are very good for what they do but domestic users aren't
likely to be dealing with kilowatt's of RF:!.

As to domestic grade equipment give me an F over the Belling Lee pox any
day..


Ah, yes I had rather forgotten that one although I never considered
it to be anything other than a poor audio connector!

Well a lot of they are around too!....

Agreed - but I still don't consider it to be an RF connector :-)

No...

But then again how many domestic users would use XLR grade??
--
Tony Sayer

On Wed, 1 Sep 2004 09:38:24 +0100, tony sayer
wrote:

In article , Peter Parry
writes

Well from the way you put it these are falling to bits as soon as anyone
looks at them, which isn't true.

It is in my case - maybe they know I don't like them.

If any installers have difficulty
terminating the F plug then perhaps they should be *terminated* from the
job....

Well I can certainly think of some who that would be appropriate for
- especially the person around here who crimps them with his teeth
and uses sticky tape to hold them in place.

OK then. An N type will cost a few quid now can you really see domestic
grade manufacturers using them?.

I would have considered BNC or TNC to be a more appropriate
alternative.


--
Peter Parry.
http://www.wpp.ltd.uk/

On Wed, 01 Sep 2004 12:33:38 +0100, Peter Parry
wrote:

On Wed, 1 Sep 2004 09:38:24 +0100, tony sayer
wrote:

In article , Peter Parry
writes

Well from the way you put it these are falling to bits as soon as anyone
looks at them, which isn't true.

It is in my case - maybe they know I don't like them.

If any installers have difficulty
terminating the F plug then perhaps they should be *terminated* from the
job....

Well I can certainly think of some who that would be appropriate for
- especially the person around here who crimps them with his teeth
and uses sticky tape to hold them in place.

OK then. An N type will cost a few quid now can you really see domestic
grade manufacturers using them?.

I would have considered BNC or TNC to be a more appropriate
alternative.

But can you see the average Sky installer being able to make off a BNC
connector properly? Most of them can just about manage to nail the
dish on your front door and run.

..andy

To email, substitute .nospam with .gl

On Wed, 01 Sep 2004 14:06:20 +0100, Andy Hall
wrote:


But can you see the average Sky installer being able to make off a BNC
connector properly? Most of them can just about manage to nail the
dish on your front door and run.

There you are then - secondary advantage would be to force a raising
of standards of Sky installers :-).

--
Peter Parry.
http://www.wpp.ltd.uk/

In article , Peter Parry
writes
On Wed, 01 Sep 2004 14:06:20 +0100, Andy Hall
wrote:


But can you see the average Sky installer being able to make off a BNC
connector properly? Most of them can just about manage to nail the
dish on your front door and run.

There you are then - secondary advantage would be to force a raising
of standards of Sky installers :-).


And then we will see the advent of either porcine aviation or perpetual
motion machines that do useful work)

In the meantime thanks be for someone inventing a plug that even an
orthodenticaly challenged person can put on!...
--
Tony Sayer