African Satellite World and Sat Gear

[Majay]

How much is the splitter switch?

 

[flybird]

Splitter switch

H & V splitters are expensive however if all channels have the same polarity you can use a simple KSH. 200 splitter. H and V splitter would require a twin LNB for effective switching between the 2 polarities. So the best option then is the twin LNBF.

 

[Tony Stark]

am only left with be-in fatafeat and City 7 TV.nilesat is becoming unfavourable as days go by.

I feel you. MTV is gone, am only left with Dubai One, Fox Mux, CNN, Aljazeera and BBC, good thing I have my Bein. Pondering seriously about the next way forward...

 

[bra.kop]

On 7e some channels are behaving in a manner that its not encouraging.can someone translate the meaning on frequency 11554,11533 hosting the discovery channels,animal planet and investigation channel.Am worried

i guess its poor signal tried to translate it from turkish to english but i couldnt get a clear sentence.lets give it time.

 

[jonathantich]

i guess its poor signal tried to translate it from turkish to english but i couldnt get a clear sentence.lets give it time.

Its back.Was bad signal

 

[FTA-Nash]

More on Mr. Dongra's 2.4m Offset Dish Fabrication

All,
This is additional information to the post by Dongra (https://www.jamiiforums.com/tech-ga...lite-world-and-sat-gear-542.html#post11570281) on 5[SUP]th[/SUP] January 2015. Mr. Dongra had promised to share the measurements we used. Here they are.

The Dish from Mr. Subbi came without any of its metal parts (LNB arms, neck support structure, stand, etc). Hence we had an uphill task figuring out how to fabricate these. To start with, we used the following simple formula for calculating the Focal length (i.e., length of LNB arm) as:

Focal length = (Width x Width x Width) / (16 x Depth x Height)

In the case of the off-set dish we had: Height = 270 Cm; Width = 250 Cm; Depth = 22 Cm

Therefore, Focal length = (250 x 250 x 250) / (16 x 22 x 270) = 164.4 Cm
Hence the Focal length given by Mr. Subbi of 165Cm, was fairly accurate. We also decided to go by his LNB side support arm length of 197Cm.

CALCULATING THE OFFSET ANGLE:

According to the measurements on the dish:
AB = 270 Cm = distance across dish from top to bottom (HEIGHT)
BF = 165 Cm = distance of bottom of dish to focal point [i.e., size of LNB arm]
AF = ……. = distance of top of dish to focal point
P = 22 Cm= maximum perpendicular distance from the chord to the dish (or DEPTH).

The offset angle ‘theta' can be calculated using the following formula:
Angle theta = (1/2) x asin(8P/AB) = 0.5 x asin[(8 x 22) / 270] = 20.68 Degrees

This angle of approximately 21 Degrees is comparable to that of the Eurostar 130Cm which is usually between 21 and 22 degrees.

Now that we had found the Offset angle (20.68 Degrees) above;

Offset Angle = asin [(AF - BF) / AB]

Now to calculate the distance AF = distance of top of dish to focal point ......................

From the formula: Angle theta = (1/2)*asin(8P/AB) = 20.68 Degrees,

Also:
20.68 Degrees = asin [(AF - BF) / AB] = asin [(AF – 165)/270

Sin20.68 = (AF – 165)/270 and therefore AF = 260.35

Ideally, this should be the correct length between the top of the Dish and the tip of the LNB focal arm (of 165Cm) in order to achieve an offset angle of 20.68 Degrees.

Therefore, we went ahead to use these measurements for the fabrication of the LNB arm and its support arms.


THEN CAME THE DILEMMA !!

Once this was done; after installing the dish, we started by tracking 5E and got a very strong quality of 85% for the DW TV Transponder. Next we tried 7East. Then we realized that the LNB was not in the right focal position since it was collecting little signal from 7 East.

To overcome this, we decided to bring down the LNB arm and the two side supports and make them adjustable so that we could play around with the arms during the tracking process! Also, thw wind factor was real trouble since the 100Kg or so dish structure plus its metal was shaking at slight provocation. Note that the 3-inch pipe stand structure (anchored by twelve M-10 Roll-bolts on the concrete base) was very firm.

SHOUTS OF JOY !!

Days later, after re-fabrication of the arms and making extra back supports to act as wind break, finally, we managed to track the 7East Europe beam using Focal length of 157Cm instead of 165Cm; and LNB side support arms of 196Cm instead of 197Cm. This effectively altered the Offset Angle.

However, all apart from three TPs are streaming in stable at quality of 78%. The 3 weak ones are scratching at 40% as indicated by Mr. Dongra (11534 V 30000; 11575 V 30000; 11617 V 30000). This means that further minor adjustments can be done to arrive at the original factory Focal position. Next we added other LNBs for 7W, 5E and Amos5.

Attached below find extra photos with measurements we used. Pardon for lots of mathematics above.

 

[heviejob]

More on Mr. Dongra’s 2.4m Offset Dish Fabrication

All,
This is additional information to the post by Dongra (https://www.jamiiforums.com/tech-ga...lite-world-and-sat-gear-542.html#post11570281) on 5[SUP]th[/SUP] January 2015. Mr. Dongra had promised to share the measurements we used. Here they are.

The Dish from Mr. Subbi came without any of its metal parts (LNB arms, neck support structure, stand, etc). Hence we had an uphill task figuring out how to fabricate these. To start with, we used the following simple formula for calculating the Focal length (i.e., length of LNB arm) as:

Focal length = (Width x Width x Width) / (16 x Depth x Height)

In the case of the off-set dish we had: Height = 270 Cm; Width = 250 Cm; Depth = 22 Cm

Therefore, Focal length = (250 x 250 x 250) / (16 x 22 x 270) = 164.4 Cm
Hence the Focal length given by Mr. Subbi of 165Cm, was fairly accurate. We also decided to go by his LNB side support arm length of 197Cm.

CALCULATING THE OFFSET ANGLE:

According to the measurements on the dish:
AB = 270 Cm = distance across dish from top to bottom (HEIGHT)
BF = 165 Cm = distance of bottom of dish to focal point [i.e., size of LNB arm]
AF = ……. = distance of top of dish to focal point
P = 22 Cm= maximum perpendicular distance from the chord to the dish (or DEPTH).

The offset angle ‘theta’ can be calculated using the following formula:
Angle theta = (1/2) x asin(8P/AB) = 0.5 x asin[(8 x 22) / 270] = 20.68 Degrees

This angle of approximately 21 Degrees is comparable to that of the Eurostar 130Cm which is usually between 21 and 22 degrees.

Now that we had found the Offset angle (20.68 Degrees) above;

Offset Angle = asin [(AF - BF) / AB]

Now to calculate the distance AF = distance of top of dish to focal point ......................

From the formula: Angle theta = (1/2)*asin(8P/AB) = 20.68 Degrees,

Also:
20.68 Degrees = asin [(AF - BF) / AB] = asin [(AF – 165)/270

Sin20.68 = (AF – 165)/270 and therefore AF = 260.35

Ideally, this should be the correct length between the top of the Dish and the tip of the LNB focal arm (of 165Cm) in order to achieve an offset angle of 20.68 Degrees.

Therefore, we went ahead to use these measurements for the fabrication of the LNB arm and its support arms.


THEN CAME THE DILEMMA !!

Once this was done; after installing the dish, we started by tracking 5E and got a very strong quality of 85% for the DW TV Transponder. Next we tried 7East. Then we realized that the LNB was not in the right focal position since it was collecting little signal from 7 East.

To overcome this, we decided to bring down the LNB arm and the two side supports and make them adjustable so that we could play around with the arms during the tracking process! Also, thw wind factor was real trouble since the 100Kg or so dish structure plus its metal was shaking at slight provocation. Note that the 3-inch pipe stand structure (anchored by twelve M-10 Roll-bolts on the concrete base) was very firm.

SHOUTS OF JOY !!

Days later, after re-fabrication of the arms and making extra back supports to act as wind break, finally, we managed to track the 7East Europe beam using Focal length of 157Cm instead of 165Cm; and LNB side support arms of 196Cm instead of 197Cm. This effectively altered the Offset Angle.

However, all apart from three TPs are streaming in stable at quality of 78%. The 3 weak ones are scratching at 40% as indicated by Mr. Dongra (11534 V 30000; 11575 V 30000; 11617 V 30000). This means that further minor adjustments can be done to arrive at the original factory Focal position. Next we added other LNBs for 7W, 5E and Amos5.

Attached below find extra photos with measurements we used. Pardon for lots of mathematics above.

View attachment 216569 View attachment 216570 View attachment 216571 View attachment 216572 View attachment 216573 View attachment 216574 View attachment 216575 View attachment 216576 View attachment 216577 View attachment 216578

There goes true ASAS.

 

[bubbastunna]

More on Mr. Dongra’s 2.4m Offset Dish Fabrication

All,
This is additional information to the post by Dongra (https://www.jamiiforums.com/tech-ga...lite-world-and-sat-gear-542.html#post11570281) on 5[SUP]th[/SUP] January 2015. Mr. Dongra had promised to share the measurements we used. Here they are.

The Dish from Mr. Subbi came without any of its metal parts (LNB arms, neck support structure, stand, etc). Hence we had an uphill task figuring out how to fabricate these. To start with, we used the following simple formula for calculating the Focal length (i.e., length of LNB arm) as:

Focal length = (Width x Width x Width) / (16 x Depth x Height)

In the case of the off-set dish we had: Height = 270 Cm; Width = 250 Cm; Depth = 22 Cm

Therefore, Focal length = (250 x 250 x 250) / (16 x 22 x 270) = 164.4 Cm
Hence the Focal length given by Mr. Subbi of 165Cm, was fairly accurate. We also decided to go by his LNB side support arm length of 197Cm.

CALCULATING THE OFFSET ANGLE:

According to the measurements on the dish:
AB = 270 Cm = distance across dish from top to bottom (HEIGHT)
BF = 165 Cm = distance of bottom of dish to focal point [i.e., size of LNB arm]
AF = ……. = distance of top of dish to focal point
P = 22 Cm= maximum perpendicular distance from the chord to the dish (or DEPTH).

The offset angle ‘theta’ can be calculated using the following formula:
Angle theta = (1/2) x asin(8P/AB) = 0.5 x asin[(8 x 22) / 270] = 20.68 Degrees

This angle of approximately 21 Degrees is comparable to that of the Eurostar 130Cm which is usually between 21 and 22 degrees.

Now that we had found the Offset angle (20.68 Degrees) above;

Offset Angle = asin [(AF - BF) / AB]

Now to calculate the distance AF = distance of top of dish to focal point ......................

From the formula: Angle theta = (1/2)*asin(8P/AB) = 20.68 Degrees,

Also:
20.68 Degrees = asin [(AF - BF) / AB] = asin [(AF – 165)/270

Sin20.68 = (AF – 165)/270 and therefore AF = 260.35

Ideally, this should be the correct length between the top of the Dish and the tip of the LNB focal arm (of 165Cm) in order to achieve an offset angle of 20.68 Degrees.

Therefore, we went ahead to use these measurements for the fabrication of the LNB arm and its support arms.


THEN CAME THE DILEMMA !!

Once this was done; after installing the dish, we started by tracking 5E and got a very strong quality of 85% for the DW TV Transponder. Next we tried 7East. Then we realized that the LNB was not in the right focal position since it was collecting little signal from 7 East.

To overcome this, we decided to bring down the LNB arm and the two side supports and make them adjustable so that we could play around with the arms during the tracking process! Also, thw wind factor was real trouble since the 100Kg or so dish structure plus its metal was shaking at slight provocation. Note that the 3-inch pipe stand structure (anchored by twelve M-10 Roll-bolts on the concrete base) was very firm.

SHOUTS OF JOY !!

Days later, after re-fabrication of the arms and making extra back supports to act as wind break, finally, we managed to track the 7East Europe beam using Focal length of 157Cm instead of 165Cm; and LNB side support arms of 196Cm instead of 197Cm. This effectively altered the Offset Angle.

However, all apart from three TPs are streaming in stable at quality of 78%. The 3 weak ones are scratching at 40% as indicated by Mr. Dongra (11534 V 30000; 11575 V 30000; 11617 V 30000). This means that further minor adjustments can be done to arrive at the original factory Focal position. Next we added other LNBs for 7W, 5E and Amos5.

Attached below find extra photos with measurements we used. Pardon for lots of mathematics above.

View attachment 216569 View attachment 216570 View attachment 216571 View attachment 216572 View attachment 216573 View attachment 216574 View attachment 216575 View attachment 216576 View attachment 216577 View attachment 216578

then 180 cm prime dish is better off

 

[FTA-Nash]

then 180 cm prime dish is better off

Well, depends on your location. Our installation was done at Nairobi. North of Equator, a 90Cm will work satisfactorily. Also, if you get the focal point right for the 240Cm, it will pull in much more signal than the 180Cm Prime Focus. 13 months ago, I installed a 180Cm PF plus star-gold Fuji in Rongai (15Km south of Nairobi) for 7E and still could not get stable signal for the three weak TPs: 11534 V 30000; 11575 V 30000; 11617 V 30000. Even the discoveries were scratching. Also, note that around December, reception of the 7E European beam is stronger around Nairobi compared to May-August period.

 

[abu i-man]

More on Mr. Dongra’s 2.4m Offset Dish Fabrication Focal length = (Width x Width x Width) / (16 x Depth x Height)In the case of the off-set dish we had: Height = 270 Cm; Width = 250 Cm; Depth = 22 CmTherefore, Focal length = (250 x 250 x 250) / (16 x 22 x 270) = 164.4 CmHence the Focal length given by Mr. Subbi of 165Cm, was fairly accurate. We also decided to go by his LNB side support arm length of 197Cm.CALCULATING THE OFFSET ANGLE:According to the measurements on the dish:AB = 270 Cm = distance across dish from top to bottom (HEIGHT)BF = 165 Cm = distance of bottom of dish to focal point [i.e., size of LNB arm]AF = ……. = distance of top of dish to focal pointP = 22 Cm= maximum perpendicular distance from the chord to the dish (or DEPTH).The offset angle ‘theta’ can be calculated using the following formula:Angle theta = (1/2) x asin(8P/AB) = 0.5 x asin[(8 x 22) / 270] = 20.68 DegreesThis angle of approximately 21 Degrees is comparable to that of the Eurostar 130Cm which is usually between 21 and 22 degrees.Now that we had found the Offset angle (20.68 Degrees) above;Offset Angle = asin [(AF - BF) / AB]Now to calculate the distance AF = distance of top of dish to focal point ......................From the formula: Angle theta = (1/2)*asin(8P/AB) = 20.68 Degrees,Also:20.68 Degrees = asin [(AF - BF) / AB] = asin [(AF – 165)/270Sin20.68 = (AF – 165)/270 and therefore AF = 260.35Ideally, this should be the correct length between the top of the Dish and the tip of the LNB focal arm (of 165Cm) in order to achieve an offset angle of 20.68 Degrees.Therefore, we went ahead to use these measurements for the fabrication of the LNB arm and its support arms.

Bruh!!!!Respect!

 

[holycow]

More on Mr. Dongra's 2.4m Offset Dish Fabrication

All,
This is additional information to the post by Dongra (https://www.jamiiforums.com/tech-ga...lite-world-and-sat-gear-542.html#post11570281) on 5[SUP]th[/SUP] January 2015. Mr. Dongra had promised to share the measurements we used. Here they are.

Wonder what's keeping you from doing a mould for the 2.4m dishes. Your ASAS is beyond help.

 

[SAT2]

Wonder what's keeping you from doing a mould for the 2.4m dishes. Your ASAS is beyond help.

FTANash

which particular channels of digiturk are you receiving without crack may you list on this big investment.

 

[ten over ten]

FTANash

which particular channels of digiturk are you receiving without crack may you list on this big investment.

Nice!!!
How much was the total investment on the entire project?
Trying Hard not to think of investing in it but ASAS wining :A S 109::A S 109:

 

[denosang]

what kind of cards can the 4950H accept

 

[findout]

More on Mr. Dongra's 2.4m Offset Dish Fabrication

All,
This is additional information to the post by Dongra (https://www.jamiiforums.com/tech-ga...lite-world-and-sat-gear-542.html#post11570281) on 5[SUP]th[/SUP] January 2015. Mr. Dongra had promised to share the measurements we used. Here they are.

The Dish from Mr. Subbi came without any of its metal parts (LNB arms, neck support structure, stand, etc). Hence we had an uphill task figuring out how to fabricate these. To start with, we used the following simple formula for calculating the Focal length (i.e., length of LNB arm) as:

Focal length = (Width x Width x Width) / (16 x Depth x Height)

In the case of the off-set dish we had: Height = 270 Cm; Width = 250 Cm; Depth = 22 Cm

Therefore, Focal length = (250 x 250 x 250) / (16 x 22 x 270) = 164.4 Cm
Hence the Focal length given by Mr. Subbi of 165Cm, was fairly accurate. We also decided to go by his LNB side support arm length of 197Cm.

CALCULATING THE OFFSET ANGLE:

According to the measurements on the dish:
AB = 270 Cm = distance across dish from top to bottom (HEIGHT)
BF = 165 Cm = distance of bottom of dish to focal point [i.e., size of LNB arm]
AF = ……. = distance of top of dish to focal point
P = 22 Cm= maximum perpendicular distance from the chord to the dish (or DEPTH).

The offset angle ‘theta' can be calculated using the following formula:
Angle theta = (1/2) x asin(8P/AB) = 0.5 x asin[(8 x 22) / 270] = 20.68 Degrees

This angle of approximately 21 Degrees is comparable to that of the Eurostar 130Cm which is usually between 21 and 22 degrees.

Now that we had found the Offset angle (20.68 Degrees) above;

Offset Angle = asin [(AF - BF) / AB]

Now to calculate the distance AF = distance of top of dish to focal point ......................

From the formula: Angle theta = (1/2)*asin(8P/AB) = 20.68 Degrees,

Also:
20.68 Degrees = asin [(AF - BF) / AB] = asin [(AF – 165)/270

Sin20.68 = (AF – 165)/270 and therefore AF = 260.35

Ideally, this should be the correct length between the top of the Dish and the tip of the LNB focal arm (of 165Cm) in order to achieve an offset angle of 20.68 Degrees.

Therefore, we went ahead to use these measurements for the fabrication of the LNB arm and its support arms.


THEN CAME THE DILEMMA !!

Once this was done; after installing the dish, we started by tracking 5E and got a very strong quality of 85% for the DW TV Transponder. Next we tried 7East. Then we realized that the LNB was not in the right focal position since it was collecting little signal from 7 East.

To overcome this, we decided to bring down the LNB arm and the two side supports and make them adjustable so that we could play around with the arms during the tracking process! Also, thw wind factor was real trouble since the 100Kg or so dish structure plus its metal was shaking at slight provocation. Note that the 3-inch pipe stand structure (anchored by twelve M-10 Roll-bolts on the concrete base) was very firm.

SHOUTS OF JOY !!

Days later, after re-fabrication of the arms and making extra back supports to act as wind break, finally, we managed to track the 7East Europe beam using Focal length of 157Cm instead of 165Cm; and LNB side support arms of 196Cm instead of 197Cm. This effectively altered the Offset Angle.

However, all apart from three TPs are streaming in stable at quality of 78%. The 3 weak ones are scratching at 40% as indicated by Mr. Dongra (11534 V 30000; 11575 V 30000; 11617 V 30000). This means that further minor adjustments can be done to arrive at the original factory Focal position. Next we added other LNBs for 7W, 5E and Amos5.

Attached below find extra photos with measurements we used. Pardon for lots of mathematics above.

View attachment 216569 View attachment 216570 View attachment 216571 View attachment 216572 View attachment 216573 View attachment 216574 View attachment 216575 View attachment 216576 View attachment 216577 View attachment 216578

Perfect !

 

[FTA-Nash]

Wonder what's keeping you from doing a mould for the 2.4m dishes. Your ASAS is beyond help.

Mostly, it is more of lack of sufficient time. If time allows in late 2015, can try modifying a 130Cm Eurostar Offset by adding a 2 Ft Iron sheet section around the upper part to increase the diameter to 130 + 60 + 60 = 250Cm Dish. To support this, a network of light Iron or aluminium bars / tubes will be fixed at the back of the dish. In addition, Longer LNB arms needed .... Just food for thought .......

 

[FTA-Nash]

FTANash, which particular channels of digiturk are you receiving without crack may you list on this big investment.

Check the TPs listed on: Digiturk on Eutelsat 7A at 7.0°E - LyngSat

All Non-HD channels on the following TPs are stable and watchable at Signal of 75 – 85% and Quality of at least 78%:
10762 V 30000 (all open at Q83%);
10804 H 30000 (All HD, scrambled; Q80%);
10804 V 29900 (BBC Knowledge, Nat-Geo People, E2, Fox sports, etc. at Q83%);
10845 H 30000 (TRT HD; others here are HD and non-watchable for now);
10845 V 30000 (Mezzo, VH1, Extreme sports; BBC Ent; MCM Top; Fashion TV; etc. at Q83%);
10887 H 30000 (HD, scrambled; 78%);
10887 V 30000 (HD, scrambled; 78%);
10928 H 30000 (Aljazeera Eng; TV5; BBC; CNN; Euro-news; France-24; etc at Q80%);
10928 V 30000 (TRT1; others – HD – scrambled; Q78%)
11456 V 20050 (All open, Q78%);
11471 H 30000 (Disney Junior; Minika-Go; MTV-Hits; etc. at Q80%);
11492 V 30000 (Baby TV; Idman Azerbaycan; etc at Q78%);
11513 H 29900 (MTV Europe; E! Europe; Eurosport 2; etc at Q79%);
11554 H 30000 (Nickelodeon; Invest. Discovery; Discovery Chan; Discovery Sc.; Duck Tv; etc at Q78%);
11596 H 30000 (Nickelodeon Junior; Eurosport News; etc at Q78%);
11637 H 30000 (MGM Channel; Baby First; Bloomberg TV; etc. at Q78%);
11668 V 30000 (HD, scrambled; 78%);

The following four TP are fluctuating between 39% - 78% Quality:
11534 V 30000 (Animal Planet; Cartoon Network; etc);
11575 V 30000 (Bloomberg; Blue Hustler; Playboy; etc);
11617 V 30000 (Nat Geo; Nat Geo Wild; History; 46 Radio Channels; etc.);
11678 H 30000 (Eurosport International; Disney Channel; etc.);

 

[FTA-Nash]

Nice!!!
How much was the total investment on the entire project? Trying Hard not to think of investing in it but ASAS wining :A S 109::A S 109:

Let me give you only a rough estimate here:

Purchase Dish from Dar: KSh.8,000

Transport Dish from Dar to Nrbi: KSh.10,000

Metal Fabrication costs (materials, bolts, nuts and Welder labour) plus transporting within 15Km from Nairobi: Sh.22000

Hiring extra hands to help fix dish stand, hold 100Kg final structure; and other manual work: Sh.3000;

Purchase LNBs (1 Inverto, 3 Starlife); cables; connectors; horse-clips; other accessories: Sh.4000

Total cost will be not less than Sh.40,000;
Might spend more if you hire a Jamii-Forum member to assist in Tracking: [Cost to be negotiated];

 

[bra.kop]

Check the TPs listed on: Digiturk on Eutelsat 7A at 7.0°E - LyngSat

All Non-HD channels on the following TPs are stable and watchable at Signal of 75 – 85% and Quality of at least 78%:
10762 V 30000 (all open at Q83%);
10804 H 30000 (All HD, scrambled; Q80%);
10804 V 29900 (BBC Knowledge, Nat-Geo People, E2, Fox sports, etc. at Q83%);
10845 H 30000 (TRT HD; others here are HD and non-watchable for now);
10845 V 30000 (Mezzo, VH1, Extreme sports; BBC Ent; MCM Top; Fashion TV; etc. at Q83%);
10887 H 30000 (HD, scrambled; 78%);
10887 V 30000 (HD, scrambled; 78%);
10928 H 30000 (Aljazeera Eng; TV5; BBC; CNN; Euro-news; France-24; etc at Q80%);
10928 V 30000 (TRT1; others – HD – scrambled; Q78%)
11456 V 20050 (All open, Q78%);
11471 H 30000 (Disney Junior; Minika-Go; MTV-Hits; etc. at Q80%);
11492 V 30000 (Baby TV; Idman Azerbaycan; etc at Q78%);
11513 H 29900 (MTV Europe; E! Europe; Eurosport 2; etc at Q79%);
11554 H 30000 (Nickelodeon; Invest. Discovery; Discovery Chan; Discovery Sc.; Duck Tv; etc at Q78%);
11596 H 30000 (Nickelodeon Junior; Eurosport News; etc at Q78%);
11637 H 30000 (MGM Channel; Baby First; Bloomberg TV; etc. at Q78%);
11668 V 30000 (HD, scrambled; 78%);

The following four TP are fluctuating between 39% - 78% Quality:
11534 V 30000 (Animal Planet; Cartoon Network; etc);
11575 V 30000 (Bloomberg; Blue Hustler; Playboy; etc);
11617 V 30000 (Nat Geo; Nat Geo Wild; History; 46 Radio Channels; etc.);
11678 H 30000 (Eurosport International; Disney Channel; etc.);

is it 4922 0r 4950 receiver?

 

[Gich]

More on Mr. Dongra's 2.4m Offset Dish Fabrication

All,
This is additional information to the post by Dongra (https://www.jamiiforums.com/tech-ga...lite-world-and-sat-gear-542.html#post11570281) on 5[SUP]th[/SUP] January 2015. Mr. Dongra had promised to share the measurements we used. Here they are.

The Dish from Mr. Subbi came without any of its metal parts (LNB arms, neck support structure, stand, etc). Hence we had an uphill task figuring out how to fabricate these. To start with, we used the following simple formula for calculating the Focal length (i.e., length of LNB arm) as:

Focal length = (Width x Width x Width) / (16 x Depth x Height)

In the case of the off-set dish we had: Height = 270 Cm; Width = 250 Cm; Depth = 22 Cm

Therefore, Focal length = (250 x 250 x 250) / (16 x 22 x 270) = 164.4 Cm
Hence the Focal length given by Mr. Subbi of 165Cm, was fairly accurate. We also decided to go by his LNB side support arm length of 197Cm.

CALCULATING THE OFFSET ANGLE:

According to the measurements on the dish:
AB = 270 Cm = distance across dish from top to bottom (HEIGHT)
BF = 165 Cm = distance of bottom of dish to focal point [i.e., size of LNB arm]
AF = ……. = distance of top of dish to focal point
P = 22 Cm= maximum perpendicular distance from the chord to the dish (or DEPTH).

The offset angle ‘theta' can be calculated using the following formula:
Angle theta = (1/2) x asin(8P/AB) = 0.5 x asin[(8 x 22) / 270] = 20.68 Degrees

This angle of approximately 21 Degrees is comparable to that of the Eurostar 130Cm which is usually between 21 and 22 degrees.

Now that we had found the Offset angle (20.68 Degrees) above;

Offset Angle = asin [(AF - BF) / AB]

Now to calculate the distance AF = distance of top of dish to focal point ......................

From the formula: Angle theta = (1/2)*asin(8P/AB) = 20.68 Degrees,

Also:
20.68 Degrees = asin [(AF - BF) / AB] = asin [(AF – 165)/270

Sin20.68 = (AF – 165)/270 and therefore AF = 260.35

Ideally, this should be the correct length between the top of the Dish and the tip of the LNB focal arm (of 165Cm) in order to achieve an offset angle of 20.68 Degrees.

Therefore, we went ahead to use these measurements for the fabrication of the LNB arm and its support arms.


THEN CAME THE DILEMMA !!

Once this was done; after installing the dish, we started by tracking 5E and got a very strong quality of 85% for the DW TV Transponder. Next we tried 7East. Then we realized that the LNB was not in the right focal position since it was collecting little signal from 7 East.

To overcome this, we decided to bring down the LNB arm and the two side supports and make them adjustable so that we could play around with the arms during the tracking process! Also, thw wind factor was real trouble since the 100Kg or so dish structure plus its metal was shaking at slight provocation. Note that the 3-inch pipe stand structure (anchored by twelve M-10 Roll-bolts on the concrete base) was very firm.

SHOUTS OF JOY !!

Days later, after re-fabrication of the arms and making extra back supports to act as wind break, finally, we managed to track the 7East Europe beam using Focal length of 157Cm instead of 165Cm; and LNB side support arms of 196Cm instead of 197Cm. This effectively altered the Offset Angle.

However, all apart from three TPs are streaming in stable at quality of 78%. The 3 weak ones are scratching at 40% as indicated by Mr. Dongra (11534 V 30000; 11575 V 30000; 11617 V 30000). This means that further minor adjustments can be done to arrive at the original factory Focal position. Next we added other LNBs for 7W, 5E and Amos5.

Attached below find extra photos with measurements we used. Pardon for lots of mathematics above.

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Hats of my brother. This is acute ASAS. Enough respect.