2D Reception in Munich

[paddy]

Originally posted by Old Satellite
A magnetic polariser is used to adjust the incoming signal from the satellite it is normally on a C120 flange. There are still many shops has to where they can be puchased . The problem is that they need from the reciever a magnetic output tyipcally either 50 MA or 100 MA at 5vdc- none of the standard digiboxs are able to provide this output.


Old Satellite

Above quote has just got me a bit worried. I have a 60 cm Nokia dish with matching LNB and get great reception on Astra 2 A & B, but no D with the Irish channels. The decoder is a Panasonic 30. I have now got a 90 cm Philips dish with a C-120 flange, which I was going to fit with a MTI universal LNB I just bought on Ebay. The C-120 feedhorn has "Cahors 76337" embossed on it. Are you saying that the Panasonic Digibox won't send the signal to the LNB to change from H to V?

 

[Old Satellite]

What is fitted to the C120 flange on the Philips dish - is it just a feedhorn- small conical tapered object.

It is normally not a problem to fit C120 Universal LNB providing the feed horn is ok.

Regards

Old Satellite

 

[paddy]

Thank you for your response OS,
At the moment a twin analogue Philips LNC-SC817DS/FL is fitted which I want to replace with the single universal MTI LNB I mentioned. The feed horn looks okay to me. I must correct the Digibox, which is in fact a Panasonic TU-DSB31. I had a local English satellite guy here last autumn to fine tune the Nokia 60 cm dish alignment, which gave me great improvement in bad weather reception on Astra 2A & B. But he reckoned I needed a bigger dish to receive Astra 2D. I just got a bit concerned when I read your post, which interpreted to say that the Digibox would not send the right signal to the C-120 to switch from H to V.
Best regards,
Paddy

 

[Old Satellite]

Lnb change should work from the information that you provide,
I think you will still have problems with your 90 cm on Astra 2 d.

What is your location Paddy ? For many areas of Sweden you need a 1.5 and even a 1.8 to acheive solid reception of the 2d footprint.

Regards

Old Satellite

 

[paddy]

My location is Munich, southern Germany, i.e. miles away from Sweden. The English fellow I mentioned thought 80 cm would do, but I picked up that 90 cm Philips dish from a friend.

 

[rolfw]

We have a couple of members in Munich Paddy, it would certainly appear that the 80cm and better still the 90cm will do the job.

When you have it all set up, post again and I'll include your details in the main post.

 

[Old Satellite]

Sorry I missed the point that you were in Germany, I agree with Rolf the 90 cm should provide reception from Astra 2D

Regards

old satellite

 

[paddy]

Thanks for your reassurance on the dish size. Just a provocative question: Would 60 cm do the job??
The reason I got into this thread was OS' comment on the C-120 feedhorn and the missing signal from the Digibox, but this appears to be a non-issue, am I right?

Best regards,
Paddy

 

[Old Satellite]

60 cm is to small,

There are some good reprots with 80 cm has Rolf confirmed however has you have the 90 cm I would suggest to use - it will provide some receiving margin for signal losses from poor weather condtions etc.

Regards

Old Satellite

 

[paddy]

Thank you OS.
I have received the MTI this morning. It is an AP8-TW and the old feed horn fits. I also have a "Satellite Finder" with a battery power supply, so I might get up on the roof this afternoon. Are there any special points I should keep an eye on?

As I mentioned earlier, your comment about the missing signal from the Digibox got me confused, but I take it this is not going to be a problem. What did you actually mean, when you said

"The problem is that they need from the reciever a magnetic output tyipcally either 50 MA or 100 MA at 5vdc- none of the standard digiboxs are able to provide this output. "

Best regards,
Paddy

 

[paddy]

I have just had a look at the LNBs, on the Nokia (present installation) it says:
Freq. 10.70 - 12.75 GHZ
Lo 9.75 - 10.60 GHZ

On the MTI (proposed new installation) it says:
Freq. 10.70 - 12.75 GHZ

i.e. no LO. Could you please explain to me what that means with regards to Astra 2 reception.
Thanks

 

[rolfw]

The local oscillator down converts the incoming signal to a more manageable frequency, universal LNbs have two LOs, one low 9.750 Ghz and one High 10.600 Ghz, between them they allow you to receive signal in the range 10.700 to 12.750.
This information is expressed differently on different LNBs, but the two you have will be both universal.

Hope that makes sense, I'm sure one of the more erudite members on the board will be able to explain it better.

 

[paddy]

Thanks Rolf, this is what it says on the label of the Nokia LNB, but there is nothing about a LO on the MTI. I thought I better ask the experts first before I start messing around.

 

[Old Satellite]

The problem is that they need from the reciever a magnetic output tyipcally either 50 MA or 100 MA at 5vdc- none of the standard digiboxs are able to provide this output. "




This refers not tot he lNB but to a magnetic poloriser, which is not required for a universal type LNB so dont worry.

regards

Old Satellite

 

[paddy]

Finally got my new installation set up a few weeks ago. Just to recap, this is an old Philips 90 cm offset dish, I think made of aluminium, an MTI AP8-TW single universal LNB, and the Philips feedhorn from the old analogue LNB. I aligned the dish as well as I could with that Satellite Finder I bought on Ebay. Signal strength is about 90 %, and signal quality about 85 %. This drops to about 80 % and 75 % respectively in poor weather. Now here is the problem: Reception of the Irish channels is perfect from about noon until late evening (9 – 10 p.m.), then the picture and sound start to break up and eventually vanish altogether. This normally happens when I want to watch the news or a football match. Hallmark and Eurosport News have mediocre reception even at the best of times. Signal strength and quality levels stay at the 90/85% readings. Does anybody have an idea, what the cause of the problem could be?

 

[rolfw]

Hi Paddy,

The strength and quality readings apply to the default transponder, so will not be particularly helpful. You need to go into the installer's menu, Services/System Setup/0,1,Select/Manual Tuning, then enter the transponder deatails of the errant channel from here http://www.lyngsat.com/dig/skyuk.shtml

You can use this to tweak the skew on the LNB and fine tune the dish.

 

[paddy]

Hi Rolfw,

Thanks for the info. I have fiddled around with all the 2D transponders this afternoon, when reception was good. Readings were extremely variable ranging from about 45 - 65 % for signal strength, and 30- 65 % for quality. By about how many degrees should I skew the LNB? Do you think the hardware combination I have is alright? Do you have an explanation why reception breaks down at night and in the morning?

 

[rolfw]

The skew adjustment will be a suck it and see job Paddy, set the manual tune on one of the weaker transponders and then adjust slightly, try clockwise by a few degrees first.

The night time reception drop off can be caused by several factors, there are a few thread s about it as well, but it is a well documented occurrence.

 

[paddy]

Thanks Rolf, I'll do my best. Are you happy with the hardware I got?

 

[rolfw]

It should be OK Paddy, it may be that the dish needs a general tweak, it certainly won't hurt to give it go.