| Author |
Message |
Stephen
Guest
|
 Posted:
Sat Dec 03, 2005 9:00 am Post subject:
Picking up Sky Digital with a 3 foot long spring |
|
|
I think it is true to say that an ordinary TV aerial has a signal collecting
area roughly equal to a satellite dish of diameter equal to the front to
back length of the TV aerial. (The virtual aperture of a Yagi array is
approximately equal to it's front to back length.)
Since the signals from the Sky satellite are very strong by satellite
standards, and we can sometimes "get away with murder" when lining up Sky
dishes, couldn't we use a Yagi for Sky?
It would have to be very long in terms of the number of elements, giving
rise to a very narrow beam width, but this would be no narrower than the
satellite dish beam width we are used to. It would also have to accept both
horizontal and vertical polarisation, but rather than go to the trouble of
making an elaborate miniature Yagi with up to a hundred "plus signs" (one
for each element) why not use a long spring, like conventional aerials for
circularly polarised VHF signals from satellites? The diameter would be half
a wavlength, about half an inch, and the pitch between turns would be a
quarter wavelength, about a quarter of an inch, while the length should be
about the same as the diameter of an equivalent dish, say 90cm or 3 feet to
be on the safe side, so the spring would have over 100 turns. The vertical
and horizontal components of the signal should still be separable at the end
of the spring, just stick it to the front of a conventional LNB.
Does anyone know if thie crazy sounding idea might actually work? It could
help people who live in conservation areas etc, and can't use a conventional
dish. |
|
| Back to top |
|
 |
Jim Watt
Guest
|
| Posted:
Sat Dec 03, 2005 9:08 am Post subject:
Re: Picking up Sky Digital with a 3 foot long spring |
|
|
On Sat, 3 Dec 2005 03:00:26 -0000, "Stephen"
<stephen@junkmail.sptv.demon.co.uk> wrote:
| Quote: | I think it is true to say that an ordinary TV aerial has a signal collecting
area roughly equal to a satellite dish of diameter equal to the front to
back length of the TV aerial. (The virtual aperture of a Yagi array is
approximately equal to it's front to back length.)
Since the signals from the Sky satellite are very strong by satellite
standards, and we can sometimes "get away with murder" when lining up Sky
dishes, couldn't we use a Yagi for Sky?
It would have to be very long in terms of the number of elements, giving
rise to a very narrow beam width, but this would be no narrower than the
satellite dish beam width we are used to. It would also have to accept both
horizontal and vertical polarisation, but rather than go to the trouble of
making an elaborate miniature Yagi with up to a hundred "plus signs" (one
for each element) why not use a long spring, like conventional aerials for
circularly polarised VHF signals from satellites? The diameter would be half
a wavlength, about half an inch, and the pitch between turns would be a
quarter wavelength, about a quarter of an inch, while the length should be
about the same as the diameter of an equivalent dish, say 90cm or 3 feet to
be on the safe side, so the spring would have over 100 turns. The vertical
and horizontal components of the signal should still be separable at the end
of the spring, just stick it to the front of a conventional LNB.
Does anyone know if thie crazy sounding idea might actually work? It could
help people who live in conservation areas etc, and can't use a conventional
dish.
|
There is a commercial product available, see picture at
http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=SE00465&N=411
LX2000 Digital Satellite Antenna
The LX2000 digital satellite antenna provides a unique alternative to
the parabolic dish in digital television reception. It is discrete and
unobtrusive and is installed in the same fashion as a dish. The LX2000
antenna will receive all the satellite transmissions that a Zone 1
dish is capable of receiving. Performance compares favourably with
dishes of 55cm area
Unique, discrete appearance
Simple installation, minimum assembly
Straightforward alignment
Manufactured from non-ferrous material and will not rust
Ideal for aggressive environments
Virtually indestructible
Weight: 2.25kg
Dimensions (LxD): 940x120mm
Order Code SE00465
price each 110.49
--
No use to me, but it exists and if it was a lemon CPC would not
stock it ....
--
Jim Watt
http://www.gibnet.com |
|
| Back to top |
|
|
Walt Davidson
Guest
|
| Posted:
Sat Dec 03, 2005 3:31 pm Post subject:
Re: Picking up Sky Digital with a 3 foot long spring |
|
|
On Sat, 03 Dec 2005 09:23:04 +0100, Jim Watt <jimwatt@aol.no_way>
wrote:
| Quote: | There is a commercial product available, see picture at
http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=SE00465&N=411
LX2000 Digital Satellite Antenna
The LX2000 digital satellite antenna provides a unique alternative to
the parabolic dish in digital television reception. It is discrete and
unobtrusive and is installed in the same fashion as a dish. The LX2000
antenna will receive all the satellite transmissions that a Zone 1
dish is capable of receiving. Performance compares favourably with
dishes of 55cm area
Unique, discrete appearance
Simple installation, minimum assembly
Straightforward alignment
Manufactured from non-ferrous material and will not rust
Ideal for aggressive environments
Virtually indestructible
Weight: 2.25kg
Dimensions (LxD): 940x120mm
Order Code SE00465
price each 110.49
|
This is extremely useful information, because under current UK
legislation a householder is only allowed to have ONE satellite dish
without special planning permission. Because of this rule, I was
forced to take down my Sky Digital dish. It would seem that I could
replace it with this antenna, because the law relates specifically to
"dishes" and this is not a dish, by any stretch of the imagination!
Thanks, Jim!
--
Walt Davidson Email: g3nyy @despammed.com |
|
| Back to top |
|
|
Michael Chare
Guest
|
| Posted:
Sat Dec 03, 2005 4:43 pm Post subject:
Re: Picking up Sky Digital with a 3 foot long spring |
|
|
"Jim Watt" <jimwatt@aol.no_way> wrote in message
news:s5l2p1to41j021k4jfmdalaarkjem37k8s@4ax.com...
| Quote: | On Sat, 3 Dec 2005 03:00:26 -0000, "Stephen"
stephen@junkmail.sptv.demon.co.uk> wrote:
There is a commercial product available, see picture at
http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=SE00465&N=411
LX2000 Digital Satellite Antenna
The LX2000 digital satellite antenna provides a unique alternative to
the parabolic dish in digital television reception. It is discrete and
unobtrusive and is installed in the same fashion as a dish. The LX2000
antenna will receive all the satellite transmissions that a Zone 1
dish is capable of receiving. Performance compares favourably with
dishes of 55cm area
--
No use to me, but it exists and if it was a lemon CPC would not
stock it ....
|
See:
http://www.hometheaterhifi.com/volume_10_4/pulsat-lx-2000-satellite-antenna-12-2003.html
--
Michael Chare
|
|
| Back to top |
|
|
Jim Watt
Guest
|
| Posted:
Sat Dec 03, 2005 4:59 pm Post subject:
Re: Picking up Sky Digital with a 3 foot long spring |
|
|
On Sat, 03 Dec 2005 09:31:10 +0000, Walt Davidson
<g3nyy@despammed.com> wrote:
| Quote: | This is extremely useful information, because under current UK
legislation a householder is only allowed to have ONE satellite dish
without special planning permission. Because of this rule, I was
forced to take down my Sky Digital dish. It would seem that I could
replace it with this antenna, because the law relates specifically to
"dishes" and this is not a dish, by any stretch of the imagination!
|
What a good idea !
Its much more rampant than a dish.
You could paint it red and inscribe the words 'up yours'
Its been around for a while, and although others may have
it slightly cheaper, CPC have an excellent service and
online catalogue.
If you get one, let us know how you get on with it.
--
Jim Watt
http://www.gibnet.com |
|
| Back to top |
|
|
Donald
Guest
|
| Posted:
Sat Dec 03, 2005 5:08 pm Post subject:
Re: Picking up Sky Digital with a 3 foot long spring |
|
|
On Sat, 3 Dec 2005 03:00:26 -0000, "Stephen"
<stephen@junkmail.sptv.demon.co.uk> wrote:
| Quote: | Since the signals from the Sky satellite are very strong by satellite
standards, and we can sometimes "get away with murder" when lining up Sky
dishes, couldn't we use a Yagi for Sky?
|
My neighbour picks up Sky satelite using a bent knitting needle!
Been doing it for years. Reception is perfect. |
|
| Back to top |
|
|
Irma Troll
Guest
|
| Posted:
Sat Dec 03, 2005 5:08 pm Post subject:
Re: Picking up Sky Digital with a 3 foot long spring |
|
|
Jim Watt wrote:
| Quote: | On Sat, 3 Dec 2005 03:00:26 -0000, "Stephen"
stephen@junkmail.sptv.demon.co.uk> wrote:
I think it is true to say that an ordinary TV aerial has a signal collecting
area roughly equal to a satellite dish of diameter equal to the front to
back length of the TV aerial. (The virtual aperture of a Yagi array is
approximately equal to it's front to back length.)
Since the signals from the Sky satellite are very strong by satellite
standards, and we can sometimes "get away with murder" when lining up Sky
dishes, couldn't we use a Yagi for Sky?
It would have to be very long in terms of the number of elements, giving
rise to a very narrow beam width, but this would be no narrower than the
satellite dish beam width we are used to. It would also have to accept both
horizontal and vertical polarisation, but rather than go to the trouble of
making an elaborate miniature Yagi with up to a hundred "plus signs" (one
for each element) why not use a long spring, like conventional aerials for
circularly polarised VHF signals from satellites? The diameter would be half
a wavlength, about half an inch, and the pitch between turns would be a
quarter wavelength, about a quarter of an inch, while the length should be
about the same as the diameter of an equivalent dish, say 90cm or 3 feet to
be on the safe side, so the spring would have over 100 turns. The vertical
and horizontal components of the signal should still be separable at the end
of the spring, just stick it to the front of a conventional LNB.
Does anyone know if thie crazy sounding idea might actually work? It could
help people who live in conservation areas etc, and can't use a conventional
dish.
There is a commercial product available, see picture at
http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=SE00465&N=411
LX2000 Digital Satellite Antenna
The LX2000 digital satellite antenna provides a unique alternative to
the parabolic dish in digital television reception. It is discrete and
unobtrusive and is installed in the same fashion as a dish. The LX2000
antenna will receive all the satellite transmissions that a Zone 1
dish is capable of receiving. Performance compares favourably with
dishes of 55cm area
Unique, discrete appearance
Simple installation, minimum assembly
Straightforward alignment
Manufactured from non-ferrous material and will not rust
Ideal for aggressive environments
Virtually indestructible
Weight: 2.25kg
Dimensions (LxD): 940x120mm
Order Code SE00465
price each 110.49
--
No use to me, but it exists and if it was a lemon CPC would not
stock it ....
|
Tesco sell lemons and they are in stock because I have just bought one
to go with my gin and tonic.
Irma |
|
| Back to top |
|
|
No-One
Guest
|
| Posted:
Sat Dec 03, 2005 5:08 pm Post subject:
Re: Picking up Sky Digital with a 3 foot long spring |
|
|
| Quote: | This is extremely useful information, because under current UK
legislation a householder is only allowed to have ONE satellite dish
without special planning permission. Because of this rule, I was
forced to take down my Sky Digital dish. It would seem that I could
replace it with this antenna, because the law relates specifically to
"dishes" and this is not a dish, by any stretch of the imagination!
Thanks, Jim!
--
Walt Davidson Email: g3nyy @despammed.com
|
I read that this law has been changed in the last month or so to allow 2
dishes. |
|
| Back to top |
|
|
spiney
Guest
|
| Posted:
Sat Dec 03, 2005 5:08 pm Post subject:
Re: Picking up Sky Digital with a 3 foot long spring |
|
|
WARNING Adrian is useless (but I support his right to post).
Satellite "antenna".
A yagi design is not viable for sat Ku band, since at that frequency
the elements are too small, and anyway you won't get enough gain, and
it would need to be impractically long, and then in any case you
couldn't have a 1Ghz bandwidth!
The LX200 is a "dielectric antenna", as commonly used in microwave
system. From reports, it isn't as good as a standard lnb with a 43cm
minidish, but is usable for Sky.
An alternative, for ku band, is a phased array aerial, as was
originally used in British Satellite Broadcasting's prematurely
designed and ill-fated "squarial". |
|
| Back to top |
|
|
Jim Watt
Guest
|
| Posted:
Sat Dec 03, 2005 5:08 pm Post subject:
Re: Picking up Sky Digital with a 3 foot long spring |
|
|
On Sat, 3 Dec 2005 10:43:11 -0000, "Michael Chare"
<MunderscoreNEWS@chareDOTorg.uk> wrote:
| Quote: | http://www.hometheaterhifi.com/volume_10_4/pulsat-lx-2000-satellite-antenna-12-2003.html
|
Love the bit "From the maximum signal direction, the strength trails
off significantly when the LNB is displaced more than about one inch
from the optimum setting."
my experience here is that a 1/8th turn on the elevaton screw on
my dish makes all the difference in receiving Channel 5 or not.
--
Jim Watt
http://www.gibnet.com |
|
| Back to top |
|
|
Bill Wright
Guest
|
| Posted:
Sat Dec 03, 2005 5:08 pm Post subject:
Re: Picking up Sky Digital with a 3 foot long spring |
|
|
"spiney" <sparkistuf@hotmail.co.uk> wrote in message
news:1133612185.052831.52420@o13g2000cwo.googlegroups.com...
| Quote: | WARNING Adrian is useless (but I support his right to post).
A yagi design is not viable for sat Ku band, since at that frequency
the elements are too small, and anyway you won't get enough gain, and
it would need to be impractically long, and then in any case you
couldn't have a 1Ghz bandwidth!
|
Interestingly, the bandwidth required is roughly 22% of centre frequency,
pretty well the same as UHF Group A. So a yagi could be designed with enough
bandwidth, without having the severe compromises that a 'wideband' design
suffers. Just a small point of information, Mr Spiney. It's best to be
accurate.
Bill |
|
| Back to top |
|
|
Adrian
Guest
|
| Posted:
Sat Dec 03, 2005 5:08 pm Post subject:
Re: Picking up Sky Digital with a 3 foot long spring |
|
|
spiney wrote:
| Quote: |
Satellite "antenna".
A yagi design is not viable for sat Ku band, since at that frequency
the elements are too small, and anyway you won't get enough gain, and
it would need to be impractically long, and then in any case you
couldn't have a 1Ghz bandwidth!
The LX200 is a "dielectric antenna", as commonly used in microwave
system. From reports, it isn't as good as a standard lnb with a 43cm
minidish, but is usable for Sky.
An alternative, for ku band, is a phased array aerial, as was
originally used in British Satellite Broadcasting's prematurely
designed and ill-fated "squarial".
|
Warning for inexperienced readers: spiney has established a well-earned
reputation on this newsgroup for making statements which are false and/or
misleading. He repeats these and dismisses attempts to explain his errors
and falsehoods. He also has a track record of making false statements about
individuals, and then ignoring invitations to back up his allegations -
thus indicating that he knows what he says about them is false.
For the above reasons readers are advised to regard what he says as being
likely to be unreliable/false/worthless, and note that many of the people
here with relevant technical experience regard his postings with contempt
and irritation. |
|
| Back to top |
|
|
Walt Davidson
Guest
|
| Posted:
Sat Dec 03, 2005 5:08 pm Post subject:
Re: Picking up Sky Digital with a 3 foot long spring |
|
|
On Sat, 3 Dec 2005 10:43:11 -0000, "Michael Chare"
<MunderscoreNEWS@chareDOTorg.uk> wrote:
Hmmmmm.
I am rather less enthusiastic now, having read this (somewhat
unscientific) report. It seems the tests were carried out on Astra 1
analogue signals.
In particular, the antenna seems rather cheaply constructed ...
especially when you look at the price, which is well in excess of
GBP100. When spending that amount of money, I do not expect the
product to be held together with duct tape!
--
Walt Davidson Email: g3nyy @despammed.com |
|
| Back to top |
|
|
Andy Luckman (AJL Electro
Guest
|
| Posted:
Sat Dec 03, 2005 5:08 pm Post subject:
Re: Picking up Sky Digital with a 3 foot long spring |
|
|
In article <ibu2p1h9tpltki68sv1no347kj0sr0t1c9@4ax.com>, Jim Watt
<URL:mailto:jimwatt@aol.no_way> wrote:
| Quote: | If you get one, let us know how you get on with it.
|
Last time I tried to order one from my distributers, I was told they are not
being ordered in again due to the number of returns.
--
AJL Electronics (G6FGO) Ltd : Satellite and TV aerial systems
http://www.classicmicrocars.co.uk : http://www.ajlelectronics.co.uk |
|
| Back to top |
|
|
Adrian
Guest
|
| Posted:
Sat Dec 03, 2005 5:08 pm Post subject:
Re: Picking up Sky Digital with a 3 foot long spring |
|
|
Andy Luckman (AJL Electronics) wrote:
| Quote: | In article <ibu2p1h9tpltki68sv1no347kj0sr0t1c9@4ax.com>, Jim Watt
URL:mailto:jimwatt@aol.no_way> wrote:
If you get one, let us know how you get on with it.
Last time I tried to order one from my distributers, I was told they
are not being ordered in again due to the number of returns.
|
CPC have them on offer for £97.50 + VAT, order code SE0046503
--
Adrian A |
|
| Back to top |
|
|
|
|
|
|
FAQ
Memberlist
Register
Profile
Log in to check your private messages
Log in