Quad LNB on 60cm circular dish

eamonnq

I recently installed a quad LNB on a 60cm circular dish, but it would appear that some of my channels are breaking up badly, while others work perfectly well.

Was just wondering if the quad lnb would be better on an 80cm dish, or would I be better off replacing it with a Sky type dish, with the quad LNB ?

Tony

what model/make of LNB did you install ? Did you adjust the skew IE turning the LNB in the holder?

eamonnq

Tony wrote: »

what model/make of LNB did you install ? Did you adjust the skew IE turning the LNB in the holder?

http://cgi.ebay.ie/ws/eBayISAPI.dll?ViewItem&item=130516036908&ih=003&category=60838

Thanks for the reply it is that type of LNB, and we did adjust the skew. A lot of the channels are working perfectly but some are not watchable at all.

Tony

That lnb will only work on an oval sky minidish as the feedhorn is not suited to a circular dish. You need to change either the dish or the lnb to get it working correctly.

eamonnq

Thanks again,

Was afraid you might say something like that!!

Zardoz

Tony wrote: »

That lnb will only work on an oval sky minidish as the feedhorn is not suited to a circular dish. You need to change either the dish or the lnb to get it working correctly.

Thats generally the case but oddly enough I have a Quad Sky Lnb working away perfectly on a 60cm Smart oval dish .
I'm actually getting a far stronger signal with this setup than I did with my old minidish .:)

eamonnq

Zardoz wrote: »

Thats generally the case but oddly enough I have a Quad Sky Lnb working away perfectly on a 60cm Smart oval dish .
I'm actually getting a far stronger signal with this setup than I did with my old minidish .:)

Yes but I would imagine the fact that the dish I am using is circular, would be the difference.

Zardoz

eamonnq wrote: »

Yes but I would imagine the fact that the dish I am using is circular, would be the difference.

Meant to clarify my dish is quite circular ,its slightly higher than wider.
http://www.tvtrade.ie/smart-60cm-satellite-dish.html
Sky Minidish is oval,much wider than higher .

eamonnq

Zardoz wrote: »

on a 60cm Smart oval dish .
I'm actually getting a far stronger signal with this setup than I did with my old minidish .:)

Ah you see you caught me out when you said OVAL

Zardoz

eamonnq wrote: »

Ah you see you caught me out when you said OVAL

Well if you must know almost every dish is oval ,they are not circular .
One dimension is always longer than the other.
Sky minidish is much wider than it is higher.
Your "circular" dish is most likely slightly higher than it is wider .

Anyway I am digressing,what Tony said is correct ,you need a universal quad lnb to get good reception.:)

eamonnq

Zardoz wrote: »

Thats generally the case but oddly enough I have a Quad Sky Lnb working away perfectly on a 60cm Smart oval dish .
I'm actually getting a far stronger signal with this setup than I did with my old minidish .:)

Apologies again, but I thought you said yours was working away perfectly with a SKY QUAD LNB ??

Zardoz

eamonnq wrote: »

Apologies again, but I thought you said yours was working away perfectly with a SKY QUAD LNB ??

Yes,mine does work perfectly .Stronger signal than before and no break up in heavy rain on the weaker channels.
Did you try varying the focal distance,i.e vary the distance of the lnb from the dish face to peak the signal ,it makes a big difference.

eamonnq

Ah now you are getting way too technical for me now!!

I will have a go and twisting the dish and turning the lnb and varying the focal distance, and see how it goes!!

Thanks for the suggestions.

Liameter

Sky LNBs are designed to "see" an area which is predominantly oval - wider than its height.

Standard LNBs are designed to "see" a roughly circular dish. In other words, when you look at the dish through the LNB clamp, the dish looks circular.

More info: http://www.satcure.co.uk/tech/lnb.htm#oval

STB

eamonnq wrote: »

Ah now you are getting way too technical for me now!!

I will have a go and twisting the dish and turning the lnb and varying the focal distance, and see how it goes!!

Thanks for the suggestions.

Or just buy a Sky/Raven Dish on adverts for feck all (less than €20).

It will save the self head wrecking.

eamonnq

I thought the head-wrecking part of it was the best bit!!

I have a few other variables to bring into the equation still (dodgy connections on the cable ? , cheap cable ? f to coax adaptors being used on 2 of the feeds, a splitter to take both sat and rf into another room, magice eyes on the coax etc !!),


Am only starting with the head wrecking.........!!

but it might be time to just replace the dish, as Sky Sports was breaking up during the match last night!!!

swoofer

Dont give up too easily and waste money. As you replaced the lnb yourself then you can access the dish so here are a few tips.

1. Did you make a note of the old LNB position BEFORE you removed it!! I know no one does.

2. The lnb has to have a skew set for sky so looking from the front the lnb should be twisted to the left, not a lot. Now you know what skew is. This affects signals on horizontal and vertical.

3. The next bit is the focal length. The lnb has a collar so before you tighten completely you should move lnb towards the dish or away from dish and you have to watch the signal meter. The aim is to get lnb fine tuned. NB You need to check a vertical channel and a horizontal one as well.

4. When you put the heavier lnb on the dish arm the weight means the lnb droops ever so slightly but it does. You now have to change elevation on dish ie either move up or down.

NB very important you have all leads connected correctly, not 2 many bends and the f connectors cut correctly with no loose earth wire touching centre core.

To do all above you really need tv and sat receiver near dish.

And f to coax adaptors are a no no, have straight feeds ie no joins. Best cable is wf100.

And when you start on splitters you are into the whole hog. Why have splitters if you have 4 feeds from dish??

gb--

STB

eamonnq wrote: »

I thought the head-wrecking part of it was the best bit!!

I have a few other variables to bring into the equation still (dodgy connections on the cable ? , cheap cable ? f to coax adaptors being used on 2 of the feeds, a splitter to take both sat and rf into another room, magice eyes on the coax etc !!),


Am only starting with the head wrecking.........!!

but it might be time to just replace the dish, as Sky Sports was breaking up during the match last night!!!

Okay but what Tony from satellite.ie told you earlier is true. Using a Sky Quad LNB on a circular dish is not recommended. The Sky Quad LNBs are designed for those raven dishes which are wider horizontally than they are vertically, so the LNB concentates as such.

What you could do then for experimental purposes. Forget Skew etc for a sec. Put the box on a channel that is causing problems normally a weak transponder. You say Sky Sports is breaking up, put it on that channel, now view the Signal Strength and quality on screen. Now first try ever so slightly adjusting the dish elevation (give it afew secs for the box to cop this - if the monitor is not beside you get someone to shout the %s !!). You should then be seeing some changes in the signal readings. Obviously you are trying to reach as high % as you can on both level readings. When its the best you can get it, lock the elevation down and do the same with the positioning left or right. That should get you your highest readings. If its still bad you then go to skew and adjust that.

You are obviously at the threashold that it is breaking up and the signal may be improved by the paragraph above.

eamonnq

Tried a bit of this and a bit of that, and HEY PRESTO!! everything is bang on now!!

Have Satellite, UHF aerial (for DTT) splitters, adaptors combiners, distribution amp, magic eyes, RF modulator and all sorts of bits and pieces connected in some strange way but it is working!!!

Thing is a mess of wires in about 3 different rooms, and I will have to tidy it up at some stage !!

Thanks for all the suggestions!!

swoofer

Glad you are sorted and thanks for letting us know.

gb--

Tony

+1 Glad to hear its working. Its good that you came back to say its fixed as many do not unfortunately (does that make me sound old and grumpy ?)

eamonnq

Tony wrote: »

+1 Glad to hear its working. Its good that you came back to say its fixed as many do not unfortunately (does that make me sound old and grumpy ?)

It's fixed until I can find something else to add into the equation!!Maybe an RF modulator from a CCTV camera into the mix somewhere!!??

Hmmmmm............or an output from the satelite box to a CCTV web server??!!

Thanks again for the help