Minimum Signal Strength

JHet

Hi Guys,

Whats the minimum signal strength you can get away with on a Satellite dish.

Currently only receiving 66%. Dish is mounted low on the ground on a tripod with a couple of bags of sealed 10kg sand/cement mix weighing it down (cheapest heavy thing i could find in woodies!). Signal is coming through a glass balcony. Its an apartment type situation.

I did mount it on the balcony railing using an 8 nut shelly clamp and got 100% signal but I reckon I'd definitely get the neighbours complaining to the management company so I decided to mount a bit lower and see what the best signal I could get was.

Is 66% sufficient to keep a good lock on all channels.

I used Channel 4 as the barometer. 10714 H 5/6 22000

Thanks

Peter Rhea

What's the signal quality like?

Your best bet is just to see if this setup provides reliable viewing with no glitches or breakup, rather than judging by receiver signal readings, which can usually only be 'quantified' by this kind of observation anyway.

SalteeDog

I assume you are referring to signal quality and not strength?

It depends on your receiver, some are more sensitive than others and also different receivers will be calibrated differently.

In my own experience I can get a decent picture at 40% quality but that has no rain margin. 70% is the usual minimum guideline but 66% might be fine.

Best way is to see if you can get a watchable picture during a rain shower on one of the weaker transponder channels. (e.g. 'Popgirl'). If you can get that then your BBCs, ITVs and Channel 4s will be rock solid. Channel 4 is on Astra 1N so is one of the stronger signals.

JHet

Not sure mate. The box I have gives me SNR, AGC, and BER. The SNR is 66%. Can't remember what the others were, but should be able to get those values tonight. I suppose you are right I suppose watching it for a prolonged period of time will be the acid test!

Thanks

SalteeDog

SNR is basically 'Quality' but BER is a useful metric as it measures the error rate in the digital stream. If that reads zero then you are getting a perfect signal. When it goes above 100 or so then it'll be blocky.

In any case - your eyes are the best measure.

zg3409

It depends on the make of box and even the actual box. As said it depends. If it has worked through the heavy rains then you should be OK.

JHet

Checked it last night. Fine on the strong TP's but on the weak ones either no signal or a very week signal. Could't get the likes of Scuzz, Flava all those kind of channels at all really. However all of the BBC's, ITV's and C4's etc which is a lot better than what I did have which was nothing

Hmm to Selfsat or not to Selfsat that is the question? Could probably get away with mounting it a bit higher.

Cheapest I could find including shipping was here.

http://www.amazon.de/dp/B003Q5M1JE/?smid=A25XTIRIYQOTFK&tag=mainseek-new-21&linkCode=asn&creative=6742&camp=1638&creativeASIN=B003Q5M1JE

zg3409

JHet wrote: »

Hmm to Selfsat or not to Selfsat that is the question? http://www.amazon.de/dp/B003Q5M1JE/?smid=A25XTIRIYQOTFK&tag=mainseek-new-21&linkCode=asn&creative=6742&camp=1638&creativeASIN=B003Q5M1JE

Just make sure the dish is the equivalent to a 60cm dish. In central Europe they can get away with much smaller dishes. Ensure you are getting one that is designed for Irish use.

zg3409

Also if buying one of them make sure to get one with at leat two outlets (twin) or quad. A single outlet version cannot be upgraded later, so if you every consider recording a twin should be a must.

JHet

zg3409 wrote: »

Also if buying one of them make sure to get one with at leat two outlets (twin) or quad. A single outlet version cannot be upgraded later, so if you every consider recording a twin should be a must.

Yeah the one I linked to is a quad, I wouldn't consider anything else to be honest for the reasons you mentioned.

How would I establish if the unit was designed for Irish use? I thought the Selfsat was just a generic product that could be used anywhere with good signal strength.

zg3409

There are different size models. The one you linked to is:
Selfsat H 30 D4 Flat Antenna

According to:
http://www.conrad-uk.com/ce/en/product/943060/Selfsat-H-30-D4-Flat-Antenna

is equivalent to a 55cm dish.

The version you should use for Ireland is:
CAMOS SELFSAT FLAT ANTENNA HD21D4

which is equivalent to a 60 - 65 cm

There is a good variety of options on that page incuding a chair mounted version (depends on the angle where you live)

You may get away with the smaller size, depending on where in the country you live, but Sky Ireland would not recommed it.

There is also a squish dish brand available too. You also need to consider they will not look as neat as their photos, when you add brackets, multiple coax cables etc.

JHet

Thanks a mill mate for the info and on educating me on whats the right size for Ireland .

Wow thats quite expensive .....kinda verging into the territory where its nearly not worth it. hmm I wonder if I could get away with mounting my zone 2 a little higher. I'm based on the Sandyford industrial estate so signal is pretty good overall, its just the awkward way I'm having to mount it thats causing the loss.

zg3409

The angle of the signal arriving in sandyford is 20 degrees, so you should be able to mount the dish quite low,

SalteeDog

Chances are that 90% of what you will watch is fine. The ones you might miss are CNBC, Bloomberg News, Horror and Horror +1 and a few kids channels (Popgirl, Kixx, TinyPop). Almost everything else is religion, shopping and girls in their underwear looking bored while waiting for hapless punters to call.

zg3409

Well if he is getting problems on some channels, chances are during heavy rain, like we had at the weekend, other channels will freeze.

watty

The signal strength needed depends on symbol rate of "transponder", the FEC and the modulation type (QPSK, or on DVB-S2 which APSK settings).

It also depends on location as some locations have more interference.

It depends on what rain margin you want.

Also a smaller dish is more affected by solar noise especially for an hour a day in spring and autumn.

JHet

Ideally I would like to retain singal during rainy periods yes.

Forgive my ignorance now, but given the fact that no rain would actually fall on the dish itself help my situation?....or is it a case that the rain affects the frequency bands themselves.

What would your opinion be on the flat dish solutions in this area?

I found another but I'm guessing this would be too small for Ireland to get good signal quality on all tp's.
http://www.amazon.co.uk/Micro-Flat-Antenna-Integrated-White/dp/B003Z6Q57I

zg3409

JHet wrote: »

I found another but I'm guessing this would be too small for Ireland to get good signal quality on all tp's.
http://www.amazon.co.uk/Micro-Flat-Antenna-Integrated-White/dp/B003Z6Q57I

According to:
http://www.elv-downloads.de/Assets/Produkte/10/1011/101144/Downloads/101144_MFlat440single_data.pdf
it's gain is:
"Benefit: 32,90 respectively 34,80 dBi" so the gain looks OK

It's size is quoted as:47.5 x 47.5 cm WHICH IS NOT SMALL. I don't think this dish is small at all.

A model I suggested before is 517 x 277 x 58mm
http://www.conrad-uk.com/ce/en/product/943060/Selfsat-H-30-D4-Flat-Antenna

Just because it is flat does not mean it is small.

Have a look here at transparent dishes, squish dishes and square dishes:
http://www.satellitesuperstore.com/fixed-dishes.htm#clear60

smaller/clear is probably your requirements rather than necessarily flat.

If the signal is going to pass through a glass balcony railing then you may need to go bigger than you currently have.

zg3409

JHet wrote: »

Forgive my ignorance now, but given the fact that no rain would actually fall on the dish itself help my situation?....

No

JHet wrote: »

or is it a case that the rain affects the frequency bands themselves.

The satellite is in Space, to your South, 39,410km from Sandyford. As the signal gets close to Ireland it passes through clouds, mist rain etc. It arrives at a 20 degree angle so it passes through a lot of atmosphere. Very, very heavy rain affects the signal. There is ALWAYS a compromise made.

Sky decided on a particular size dish for Ireland knowing full well it would only work 99.99% of the time. In situations where you really need a smaller dish a 40cm dish will work 99.9% of the time. For camping etc, an even smaller than 40cm dish can be used.

If there are heavy rainclouds to your south, even if it not raining where you are then the signal will drop. As Watty says some channels are stronger than others, so you generally find some channels drop out more easily than others.

JHet

Cheers fellas.

I must post up a pic of the way it is currently.

watty

All available "flat" dishes are optimistic about gain and none are suitable outside of South East / Waterford area.

Many have integral LNBFs that can't be changed. So you are stuck with what ever number of outputs are built in. If the LNB fails the entire unit has to be replaced.

Regular dishes it is easy to change the LNB. 65cm to 85cm recommended depending on location. (Only a few extreme SW or NW locations need 85cm).

For Multifeed (more than one satellite) 80cm to 110cm depending on location or if the satellites are too far apart a large Wave Frontier T90 or two dishes.


The smaller dishes might only be 80% to 90% or even 40% for a week at a time.

For camping if it's something to do because it's raining the camping dishes are no use in Ireland. They are only good for SE England or Local National Services in Germany or similar.