Digital TV - DIY articles

The draft DIY digital TV intro article is he

http://wiki.diyfaq.org.uk/index.php?title=Digital_TV

Feel free to add to it directly (or post stuff here...)

Doing that one prompted a bit of a revamp or the TV aerial one - I have
added some tips on DIYing these - but you may be able to think of mo

http://wiki.diyfaq.org.uk/index.php?title=TV_aerial

A bit that was in there - but seemed out of place was on VHF aerials.
That is now waiting for some embellishment to turn it into a proper
article. (I am not sure how realistic its claims are anyway - never
having tried using a TV aerial for radio). Any thoughts?:

http://wiki.diyfaq.org.uk/index.php?title=VHF_aerial

(Could probably do with some sections on dimple dipoles, yagi, and the
(in)famous halo etc).

There is one on aerial plugs:

http://wiki.diyfaq.org.uk/index.php?...V_aerial_plugs

Another on cable:

http://wiki.diyfaq.org.uk/index.php?...for_TV_aerials

And finally one one amps:

http://wiki.diyfaq.org.uk/index.php?...rial_amplifier

(note, due to spammers some of these articles are only editable if you
create yourself an account on the DIY wiki first)

--
Cheers,

John.

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| John Rumm - john(at)internode(dot)co(dot)uk |
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"John Rumm" wrote in message
et...
The draft DIY digital TV intro article is he

http://wiki.diyfaq.org.uk/index.php?title=Digital_TV

Feel free to add to it directly (or post stuff here...)

Doing that one prompted a bit of a revamp or the TV aerial one - I have
added some tips on DIYing these - but you may be able to think of mo

http://wiki.diyfaq.org.uk/index.php?title=TV_aerial

A bit that was in there - but seemed out of place was on VHF aerials. That
is now waiting for some embellishment to turn it into a proper article. (I
am not sure how realistic its claims are anyway - never having tried using
a TV aerial for radio). Any thoughts?:

http://wiki.diyfaq.org.uk/index.php?title=VHF_aerial

(Could probably do with some sections on dimple dipoles, yagi, and the
(in)famous halo etc).

There is one on aerial plugs:

http://wiki.diyfaq.org.uk/index.php?...V_aerial_plugs

Another on cable:

http://wiki.diyfaq.org.uk/index.php?...for_TV_aerials

And finally one one amps:

http://wiki.diyfaq.org.uk/index.php?...rial_amplifier

(note, due to spammers some of these articles are only editable if you
create yourself an account on the DIY wiki first)

Yes it's coming along nicely now.
One typo and one factual
1 "*Personally* Video Recorders"
2 name the additional channels that a FTV card will decode

Also explain that an ex-Sky subscription card is in effect a FTV card.

I think there is a need to explain more fully the differences between
the two Freesats, I think you need to separate it from the SKY heading.

--
Graham.

%Profound_observation%

Graham. wrote:

Yes it's coming along nicely now.
One typo and one factual
1 "*Personally* Video Recorders"

ta - fixed

2 name the additional channels that a FTV card will decode

Added link to wikipedia article on this (moving target, so may as well
let some one else keep up! ;-)

Also explain that an ex-Sky subscription card is in effect a FTV card.

Yup, good point

I think there is a need to explain more fully the differences between
the two Freesats, I think you need to separate it from the SKY heading.

What, add "Freesat from sky" as a separate heading you mean?

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"John Rumm" wrote in message
et...


http://wiki.diyfaq.org.uk/index.php?title=TV_aerial
This is a very impressive document. Good sound practical advice. I hope you
don't mind a few suggestions.

De-typoed:
Small set-top aerials vary in performance from poor to useless in most
areas. In strong signal locations one may be ok for a portable TV. The
advantages are minimal cost, no installation, and portability.

De-typoed:
In practice roof mounting gives a much stronger and better quality signal
than a loft aerial. A loft aerial will be quite satisfactory in many cases,
but not always. Rooftop is of course less convenient and more expensive.
Outdoor aerials, poles and cables have limited life, so the expense is
repeated over time.

Error:
Baluns
Nearly all TV aerials are described by the manufacturer as 75 ohm aerials,
yet nearly all are really designed as 300 ohm aerials, with construction
details reducing this to some degree, but not to 75 ohm. Connecting a 300
ohm aerial to 75? cable causes loss of gain, tendency to reflections, and
some degree of degradation of signal quality.
Better aerials have a small balun inside that transforms the 300 ohm signal
to a genuine 75 ohm feed. All CAI approved aerials have this.

In fact even cheap aerials are designed to match to 75ohm feeder. (More or
less). A folded dipole with no parasitic elements would match to 300 ohm.
Once you start adding elements the characteristic impedence drops. The balun
(in this case) usually converts 75 ohm balanced to 75 ohm unbalanced.
However some manufacturers use the balun design to tweak the matching, so
the dipole terminals might not be quite 75 ohm. The old baluns for VHF FM
actually did convert 75 to 300 or vice versa, as well as converting balanced
to unbalanced.

De-typoed:
a.. Don't choose a position where it will have your eye out every time you
climb through the loft hatch!
De-typoed:
a.. If more than one location is available, do a survey at each position to
see which is best. The easiest chimney to get to might not offer the best
results!
De-typoed:
Height is important - raising an aerial as little as a metre
De-typoed:
If multipath (i.e. ghosting) is a problem, try a more directional aerial,
and try different bearings. It may be preferable

Bill

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember John Rumm
saying something like:

A bit that was in there - but seemed out of place was on VHF aerials.
That is now waiting for some embellishment to turn it into a proper
article. (I am not sure how realistic its claims are anyway - never
having tried using a TV aerial for radio). Any thoughts?:

http://wiki.diyfaq.org.uk/index.php?title=VHF_aerial

It's true enough.

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Graham." saying
something like:

Also explain that an ex-Sky subscription card is in effect a FTV card.

Istr, if a card has been blocked by Sky for non-payment, it will not
work at all.

John Rumm wrote:


(Could probably do with some sections on dimple dipoles, yagi, and the
(in)famous halo etc).

It certainly should. Then I could find out what on eath they are...


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

"The Medway Handyman" wrote in message
...
John Rumm wrote:


(Could probably do with some sections on dimple dipoles, yagi, and the
(in)famous halo etc).

It certainly should. Then I could find out what on eath they are...


I thought they were sexual positions myself - almost made being a radio
amatuer an attractive proposition )


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

In article , Bill Wright
scribeth thus

"John Rumm" wrote in message
net...


http://wiki.diyfaq.org.uk/index.php?title=TV_aerial
This is a very impressive document. Good sound practical advice. I hope you
don't mind a few suggestions.

De-typoed:
Small set-top aerials vary in performance from poor to useless in most
areas. In strong signal locations one may be ok for a portable TV. The
advantages are minimal cost, no installation, and portability.

De-typoed:
In practice roof mounting gives a much stronger and better quality signal
than a loft aerial. A loft aerial will be quite satisfactory in many cases,
but not always. Rooftop is of course less convenient and more expensive.
Outdoor aerials, poles and cables have limited life, so the expense is
repeated over time.


Around 20 odd years?.. Seems unnecessary to make that point IMHO.

Might put some off an otherwise proper way to do it..

Error:
Baluns
Nearly all TV aerials are described by the manufacturer as 75 ohm aerials,
yet nearly all are really designed as 300 ohm aerials, with construction
details reducing this to some degree, but not to 75 ohm. Connecting a 300
ohm aerial to 75? cable causes loss of gain, tendency to reflections, and
some degree of degradation of signal quality.
Better aerials have a small balun inside that transforms the 300 ohm signal
to a genuine 75 ohm feed. All CAI approved aerials have this.

Waaaay over the top for Joe public to take in .. better that

"the aerial needs to contain a balun which makes it work more
efficiently...

--
Tony Sayer

In article , Grimly
Curmudgeon scribeth thus
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember John Rumm
saying something like:

A bit that was in there - but seemed out of place was on VHF aerials.
That is now waiting for some embellishment to turn it into a proper
article. (I am not sure how realistic its claims are anyway - never
having tried using a TV aerial for radio). Any thoughts?:

http://wiki.diyfaq.org.uk/index.php?title=VHF_aerial

It's true enough.

Yes but although the VHF aerial adds to the cost, like a TV aerial its a
very good -investment- (a dirty word in the UK;!), to improve the
performance of the equipment connected to it......
--
Tony Sayer