Changing down from 1m to 80cm

[Tony B2]

I need to replace my Jaeger 128 H2H motor, which is currently (not) driving a 1m dish - I forget which make now as the dish has been up more than 11 years, probably Lenson Heath.

I would like to stick with a 36V H2H motor which probably means Jaeger again (128G or 99G ?). Looking at mounting options it looks as if I will need to replace the dish too, as the current one seems totally incompatible with the 99G configuration. So, could I ask for a recommendation on replacing a 1m aluminium dish? Whilst I am up there, I might as well replace the LNB (a very cheap one in place currently).

So, I am thinking maybe a Triax 80cm, plus 0.2db LNB, as I might not need to get another 1m dish? Would I lose much in going from a fairly old 1m dish and cheap LNB, if I go to a good quality (and clean) 80cm dish with a modern/good quality LNB?

Basically, I am interested in receiving from 28E to 5W, and I live in Southern England. Before the motor problems I could pick up everything I wanted (BBC HD, Prem HD, CMore HD - at least when FTA). Did not suffer too many problems in rain, but tended to have noticeable dropouts in windy conditions - and the whole thing needs to be fairly light - as it is on quite a long pole.

Many thanks in advance!

[kmc]

the orbital 80cm dish is excellent and apparently the dark gold lnb 0.1 is superb
regards
kmc

[Dreamcatcher]

Seems odd that you need to make a drastic change when all has been ok for 11 years.


Those 20cm between 80cm and 1m can make all the difference sometime. It's good to get a good spec LNB but there's no substitute for dish area when it comes to a quality signal.

[Tony B2]

Well, I have to say that things have not been that good with the current set up, over the last year and a half.

Numerous E-2 error codes on the V-box, and miscounting, resulting in frequent re-setting of satellite positions. I did change the reed sensor, and although I could live with this, now after some flakey months of operation the motor refuses to move the dish at all, although I can hear the motor working. So I guess that the mechanism has seized and/or the gears have worn out, or been stripped.

So, rather than try to fix the motor (again) I thought I would cut my losses and fit a new one, for a quiet life! Then when I look at mounting interfaces, I can see that the dish limits my options a bit, and after 11 years it is a bit less than pristine.

So, I am prepared to start with a clean sheet, so long as I get good performance and a couple of years (hopefully more) trouble free operation.

If it is necessary to go for a Triax (or whatever) 1 m then I will, but I had hoped that LNB performance improvements, and a much cleaner/newer dish would make up for the smaller size.

[Mickha]

I have read reports of a Fracarro Penta 85 bringing in some good results, a satellite enthusiast tried it against a Triax 88 and it beat it.

[tr8.]

sorry to say but size is everything when it come to dish's
The lnb can give cleaner ( less noise) but not realy any more signal, or if any more no more than the odd % as opposed to reducing the dish surface area by over 20%. If you had any sats you used that were weak and/or effected by weather you will almost certainly lose them by reducing size.
If you go only for the main sats it wont make any difference 19e 13e etc

[Keano]

I have read reports of a Fracarro Penta 85 bringing in some good results, a satellite enthusiast tried it against a Triax 88 and it beat it.

Yep its a good dish, i replaced my 110cm televes dish with the 85cm fracarro back in the spring and never looked back since.

OK i did lose a couple of channels on 26.0e that were borderline with the 110cm and I can no longer pick up 11862V on 7.0w but overall the fracarro is a superb dish I can't recommend it enough.

I use a quad titanium lnbf with it.

[Glenn_911]

Try the Gregoriaan dish 0.9 with SNF-031 LNB and all your problems are gone.

This dish receive the same like a 1.2 Offset.

Enjoy


Glenn_911

[olaus]

sorry to say but size is everything when it come to dish's
The lnb can give cleaner ( less noise) but not realy any more signal, or if any more no more than the odd % as opposed to reducing the dish surface area by over 20%. If you had any sats you used that were weak and/or effected by weather you will almost certainly lose them by reducing size.
If you go only for the main sats it wont make any difference 19e 13e etc

Hi m8s,
I would say that you reduce the area with 1x1 - 0.8x0.8 = 36% and not 20%, but OK, 36% is more the 20% as you wrote!
/Regards

[paulw]

Amazing!! Right answer but wrong method!! :)

Dish sizes are for the diameter of the dish.
Need to use dish radius for calculating area.
(You can leave out the pies since they will cancel out!)

Area difference (0.5 x 0.5) - (0.4 x 0.4) = 0.09

Fractional difference = Area difference / Area of old dish
= 0.09 / 0.25
= 0.36
Which gives a percentage difference of 36%.

The reason you got the correct answer is that by using diameters
your dish areas are 4 times too large. However, to calculate the
fractional difference you need to divided the area difference by
the area of the original dish, i.e. divide by 0.25. Dividing by 0.25
is the same as multiplying by 4. Since your areas were 4 times
too large but you didn't multiply by 4 to obtain the fractional
difference, you ended up with the correct value.

Your method works provided the original dish diameter is
1 metre but not if it is some other size, say 0.9m.


Regards,
paulw