Offset Dish for Sky Digital

[Finio]

Currently using a 1.2 M curcular dish. Neighbour has an old Portugese dish which is 1.2 wide but 1,4 in height. It also has a shorter feedhorn. Would it be worth trying this dish out? I have an Inverto Silvertech Quad LNB.

Biggest problems with 2B North best quality about 20% with 2D at 45%

Thanks

 

[rolfw]

Are we to assume that you are not in East anglia as your details state Finio?

 

[Finio]

Yes now in Malaga.

 

[rolfw]

OK, depends on the quality of the offset dish, at that size, they normally out perform a prime focus though.

 

[Finio]

Thanks for that. The dish I have is newish the other dish is older but looks in good nick. My dish is 1.2M the possible replacement is 1.2 by 1.4 high. As I am not a maths type is this much bigger and does the stubbier feedhorn make any odds?

Thanks for answering

 

[benidormgary]

My rusty maths suggest that it has about 16-17% more surface area.If its free,go for it!

 

[Finio]

Thanks. Will try and have a go with it this afternoon.

 

[Finio]

OK, depends on the quality of the offset dish, at that size, they normally out perform a prime focus though.

Is the spare dish 1.2 wide 1.4 tall the Prime Focus and are you saying my current 1.2 offset usually outperforms?

thanks

 

[benidormgary]

A "Prime" (or sometimes called "Direct")focus dish is perfectly round,and has 3 support legs(for the LN equi-distant spaced around the outer edge.

An "Offset" dish is usually taller than it is wider(but its the other way round for bog-standard Sky dishes).These normally only have one arm at the bottom to take the LNB,but the bigger offset dishes (usually over 1.2 mtrs.) have 3 support arms-,two at the side of the dish,and one at the bottom.

Your newly-aquired offset dish should out-perform your original prime focus dish as has been suggested,if it is set up correctly and with the right choice of LNB. Hope this helps.

 

[Finio]

Thanks for the feedback. Going to try it this afternoon and will report back.

 

[PoloMint]

You probably wont get all that much better than 20-30% quality on 2A North in the Malaga area with a 1.2m offset. Are you east or west of Malaga? (west normally has better reception, which is odd as it is further south and so further outside the official footprint)

The skew (twist) of the LNB is critical, a small fraction can make the difference between 10% and 30% quality. Remember the digibox takes a few seconds to update its signal reading (if you are using that as a signal meter).

 

[Finio]

East of Malaga. I get the test channel at 40%. C5 is the strongest 2B North transponder at 20% from 8am -12pm. The 2A South beam comes in at 100%. I have a problem where I live if I put up a bigger dish so have to work with what I have. the strange thing is that when the original installation was done it was all 100% OK. This problem with 2b North started last Oct!

 

[Finio]

Sorry was talking about 2B North. I have no probs with any 2a channels.

 

[Finio]

9.30pm local here in Spain 40k east of Malaga.

Astra 2D - 95%

Astra 2A North - 35%

Astra 2A South 95%

Astra 2B South 95%

Astra 2B North 10% (C5 strongest transponder)

Using Inverto Quad 1.2 M offset Dish. I have three digiboxes all about the same signals coming through. Am I missing something here?

 

[PoloMint]

I'm afraid that could just be the limit of your dish.

I have family about 60KM west of Malaga, they have a 1.2m offset and Panasonic 30 digibox. This used to get everything with no problems, then slowly 2B north beam channels started to break up.

Last time I was out there channel 5 was only there during the daytime (went in the evening/night), the same for some of the music channels on the same beam. 2A North and 2D are fine in all but the worst weather conditions.

This didn't seem to be a problem with their dish, and the neighbours noticed the same thing at around the same time (with their own dish). However there are reports of people to the east of Malaga (further east than you) who have no problems with a 1.2m offset.

2B north is the weakest beam in your part of Europe, unfortunately it may be just a little too weak for the popular 1.2m offset dish.

 

[Finio]

Sounds familiar actually. I will try an alternative dish which I am cleaning up tonight. Its slightly bigger and I can swap up. Thanks for the input.

 

[Finio]

Have installed the slightly larger dish but it seems to have disorientated a couple of my digiboxes. I cannot get C4 & C5 at all now! Have done a search in MANUAL TUNING and they both give a 30% signal and then find channels listed as being on other transponders.

Any thoughts anyone?

 

[rolfw]

What LNB is on the dish?

 

[Finio]

Inverto Silvertech Quad swapped with Sharp Dual LNB but same problems. Its like the box has been zapped or something

 

[Finio]

The wierdest bit is that 12070 and 12304 both horzontal on Astra 2b north have been my problem transponders. These boxes gave me decent readings in MANUAL TUNING and I thought that I'd cracked it. Search results then gave me channels off another transponder!!!