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Focal Distance

Messages
33
Likes
1
Location
Larnaca, Cyprus
My Satellite Setup
Sky+HD box (Amstrad DRX890),
Sky box (Pace 2600CI),
3.2m primefocus ,C120,
Technomate TM6900,
My Location
Larnaca, Cyprus
#1
Hello there,

Can you please let me know what is the focal distance of a 1.8m Andersen offset dish.
Also, and correct if I am wrong is is right to say to that focal distance of an offset dish is the distance between the inner center of the dish and the feed horn.
Lastly, is the Andersen 1.8m offset dish a good combination with the Andrews feed horn and the C120.

Thanks
 

dxsat

Specialist Contributor
Messages
745
Likes
70
My Satellite Setup
Snap's setup: (In Spain) Humax HDR, Prodelin 1.8m dish + Invacom QDF-031 + CM feed, (In UK) CallFlow VDSL + EE 4G, Sky Q, YouView HD, Mac OSX, iOS
My Location
UK: Tonbridge, Kent. Spain: Madrid.
#2
The Andersen offset 1.8m has a f/d ratio of 0.61, making focal length 1.098 metres.
This should be from the centre axis, as seen by the feed, to the front face of the feedhorn, I believe.
The Andrew offset feed works better than any other on large offset dishes such as yours.
The only problem you might have is adapting the diameter of the feed to the LNB holder on the Andersen.
On some offset dishes such as Gibertini, f/d of 0.66, the best position of the feed is as far back as it will go, exception is on Andrew dishes, where the exact point is clearly defined. In all cases, fine tuning with a meter is essential.
 
Messages
33
Likes
1
Location
Larnaca, Cyprus
My Satellite Setup
Sky+HD box (Amstrad DRX890),
Sky box (Pace 2600CI),
3.2m primefocus ,C120,
Technomate TM6900,
My Location
Larnaca, Cyprus
#3
Hi Snap,

Can you let me know please if the Andrew offset feed can work on an Andersen offset 2.4m dish too?


Thanks
 

dxsat

Specialist Contributor
Messages
745
Likes
70
My Satellite Setup
Snap's setup: (In Spain) Humax HDR, Prodelin 1.8m dish + Invacom QDF-031 + CM feed, (In UK) CallFlow VDSL + EE 4G, Sky Q, YouView HD, Mac OSX, iOS
My Location
UK: Tonbridge, Kent. Spain: Madrid.
#4
If the dish is offset, it will work. You may have to experiment on focal distance by pulling the LNB and feed back and forth.
 

Bale

Member
Messages
33
Likes
1
Location
Larnaca, Cyprus
My Satellite Setup
Sky+HD box (Amstrad DRX890),
Sky box (Pace 2600CI),
3.2m primefocus ,C120,
Technomate TM6900,
My Location
Larnaca, Cyprus
#5
I replaced today on my Andersen offset 1.8m dish the universal twin LNB 0.3dB Horn (invacom) with the Universal Quad LNB 0.3dB C120 and the Andrew offset feed , I was impressed with the results, previously I wasnt able to get the default frequency, now I can, is weak but between the hours 5.30-8.30pm is quite strong, during those times for my suprice I get channel 4 as well, also previously I had some problems with the US channel 5 plus the scifi channel(+1), now I get perfect picture for 24 hours.
I need to ask if I decide to upgrade to some point to an 2.4 Andersen offset dish, will be able to get channel 4 for 24 hours ?.

Thanks
 

iceman

Specialist Contributor
Messages
744
Likes
3
My Satellite Setup
3.0m Motorised Channel Master + 4 fixed dish Amstrad_DRX890C
DM7020s,DM800se
UNOHM EP314 PROMAX TV Explorer
My Location
Kyrenia - NORTH CYPRUS
#6
Bale said:
I replaced today on my Andersen offset 1.8m dish the universal twin LNB 0.3dB Horn (invacom) with the Universal Quad LNB 0.3dB C120 and the Andrew offset feed , I was impressed with the results, previously I wasnt able to get the default frequency, now I can, is weak but between the hours 5.30-8.30pm is quite strong, during those times for my suprice I get channel 4 as well, also previously I had some problems with the US channel 5 plus the scifi channel(+1), now I get perfect picture for 24 hours.
I need to ask if I decide to upgrade to some point to an 2.4 Andersen offset dish, will be able to get channel 4 for 24 hours ?.

Thanks
How is the reception on SKY Two & SKY Three?You should have a picture on these channels between 5.30pm-10.00pm..
They are weaker than Channel 4 and default transponder but they also improve at same times.
I believe 2.4 Andersen will fix Channel 4 reception for you..
I have a friend in Nicosia using a 2.4 offset and his Channel 4 is OK 24/7...
 

bignick

Specialist Contributor
Messages
336
Likes
0
My Satellite Setup
Back in the UK and missing Cyprus!!!
My Location
Aylesbury
#7
Bale said:
I replaced today on my Andersen offset 1.8m dish the universal twin LNB 0.3dB Horn (invacom) with the Universal Quad LNB 0.3dB C120 and the Andrew offset feed , I was impressed with the results, previously I wasnt able to get the default frequency, now I can, is weak but between the hours 5.30-8.30pm is quite strong, during those times for my suprice I get channel 4 as well, also previously I had some problems with the US channel 5 plus the scifi channel(+1), now I get perfect picture for 24 hours.
I need to ask if I decide to upgrade to some point to an 2.4 Andersen offset dish, will be able to get channel 4 for 24 hours ?.

Thanks

I have fitted many Anderson 2.4m and none of them have problems with C4. You should get channel 4 with some to spare!

Nick
 

Bale

Member
Messages
33
Likes
1
Location
Larnaca, Cyprus
My Satellite Setup
Sky+HD box (Amstrad DRX890),
Sky box (Pace 2600CI),
3.2m primefocus ,C120,
Technomate TM6900,
My Location
Larnaca, Cyprus
#8
I do get sky 2 and sky 3 but with breaks-ups, but havent really checked them if there is a specific time period that can get them without problems, how about when channel 4 goes HD in December, will be in the same transporter like channel 4 now? it will be pitty if I upgrade to 2.4m and not to be able to get ch4 HD.

Thanks