How big a dish should I buy (and other advice please) Forums

haylingchrist

Hi,

I'm putting together a satellite system for use on my van but I'm not sure what size dish to go for.

Having dug around it seems to me that going much over about 65 cm will only gain me at most another 100 miles of reception on the fringes and will be harder to align. Will going up to 85cm say, be worth the extra aggro?

We freecamp and move most days so the dish will be on the roof and ease of alignment is at least as important as fringe reception. I plan to make a mount incorporating a compass and spirit level. With both these 'zero'd out' when correctly aligned I think it should be simple to regain 'yesterdays setting' which should be pretty close unless we've driven a long way. The other idea I have is to use a quad LNB and permanently attached a (weatherproofed and battery powered) sat finder to the back of the dish. With one output spare the other two will be used for TV and an Internet down link (the main reason for all this)

I've prototyped most of this using a £99 kit from AVC which includes ' standard zone 1 minidish', but am short of much real experience so would welcome any input.

AVC broadband is on the Astra 'South Beam'

Chris
PS There's no way I'm spending £2000 on an auto seeking jobbie....

gaspode · Moderator

Sounds to me that you don't need much help from here, the battery powered sat-finder on a spare LNB sounds a good idea, have you tried it yet?
I wouldn't think that you will gain much by using a dish bigger that 65cm and a larger dish will also be harder to align. We used a 55cm mini-dish last year and picked up the Astra south beam very strong in France, Germany and northern Italy, also managed to pick up the narrow beam around Lake Maggiore although we lost it in some parts of France & Germany.

MicknPat

Chris,

Have a look here

PhilM

Hi Chris, I have used the minidish as far south as Sicily on several occasions as well as Vienna in the East and find that most channels except BBC and ITV of course are obtainable. Channel 4 gets a bit iffy if the weather is bad. I generally take an 80cm with a low noise LNB these days to improve BBC and ITV reception, but find that they are still lost once over the Alps or south of Barcelona.
Phil.

DABurleigh

Chris,

I'd keep with your AVC minidish; its beamwidth will be noticeably wider than an 85cm dish so easier to align and less prone for loss of signal due to wind or moving about in & out of the van if on the roof. In lots of Scotland, NW & W Ireland, and the French/Spanish border, for example, it will get dodgy, especially in heavy rain.

You say keep it on the roof but one advantage of a manually aligned dish on a tripod is that it is easy to move around the ground adjacent to the van to obtain a direct line of sight to the satellite when you are screened by trees.

Presumably the meter has a power switch; don't think mine has.

Tighten the clamps so that only moderate force on the dish edge move it, but static friction is enough to hold it there. Once peaked up, tighten the clamps carefully; with an 80+ cm dish you can easily go way off the peak as you tighten things up.

Dave

chellaman

Hi All,
Where satellite signal strength is concerned, it is essential to use the best quality cable, and a dish/LNB combination which is matched.
Apart from this, it is a common misconception that replacing, for example, a 0.6dB LNB with a 0.4 dB will have a large effect on signal strength. This is untrue because the change in dB is logarithmic and this would give an increase of less than 1%.
However, broadly speaking, signal increases directly with dish surface area.
So, an 85 cm dish would increase strength by 70%, and 80cm by 50%!
The name of the game, providing all else is OK, is DISH SIZE.
Size DOES matter!!!
Personally, I've never had a problem with the tuning or stability of an 80cm dish. Unlike my 2.4 metre dish in Spain!

DABurleigh

"Size DOES matter!!! "

Not beyond "big enough" it doesn't Wink

Dave

PhilM

IMO it's not much use having a high quality cable if your LNB is noisy. A 0.3dB LNB is, again IMO, gives much better performance than a 0.6dB. I expect someone more knowledgable than I will query your assertions.
Phil.

haylingchrist

Thanks for all your input (not quite sure what the overall recommendation on dish size is though Smile

A few responses:

- A lot of what I know came from satelliteforcaravans - great site.

- I don't want a tripod because it doesn't fit with my wild camping ethos. And anyway if I put one up in may of the car parks we camp in in the alps, the next ski-bus would probably run it over Smile

. My other objection is just the faff of all that connecting/disconnecting.

- I've got to make the bat powered sat finder yet - I'll just put it a sat finder in a tupperware box with a couple of 9v batteries and a switch. What's stumping me is I don't know the polarity of the electrical feed on the coax. I could put a multimeter on it but I haven't got round to it yet and I'm scared of ruining the reciever. Will keep you posted.

- Dish/LNB matching concerns me. How do you tell? I suspect the LNB which came with the (oval) minidish won't work well with a round 65/80 cm one. I want to replace the dish because I need a folding arm one to mount well on the roof. I suspect I could get a bigger dish but no better performance which is partly what prompted my original post.

Chris

PhilM

Hi Chris, you can usually slide the LNB back and forth along the arm, there is often a couple of inches to play with. I set mine using the Sat Meter, skew also needs setting from time to time depending on your location. The small changes are difficult to see on a meter so I adjust very small amounts at a time and tune for max signal quality on the receiver.. Looking towards the dish the LNB generally needs rotating to around 10/11 degrees clockwise to start with then minor adjustments from there if necessary.
Phil.