Distance between dish and receiver

[Billet]

I've tried searching but this seems easier. If I manage to get my new dish what is the maximum distance I could have between the dish and the receiver, in old money please!!!!

Regards

[Robbo]

Up to 30m should be OK with good quality cable.

39 inches = 1m


How far do you need it?, In new money please.

Robbo

[Billet]

Touche Robbo

My house is listed so I have to be carefull, I have a 90cm and 60cm setup on the side of the house, they cannot be seen from the road. However I want to fit a 1.2cm dish. I would probably have to put it on one of the outbuildings and these are between 30 and 40 metres, I can't put it on the ground as the hedge is to high, well I suppose I could mount it on the surface with a long pole. What do you think?

Regards

[Robbo]

It depends how long the pole needs to be, scaffold pole will flex if it is too long. Mine is on an 8ft pole buried in about 2ft, and it's OK.

You might get away with 40m with wf100, but to be on the safe side, you should use wf125 instead. It is more expensive but has less attenuation.

Actually the attenuation of 40m of wf125 has as close as damn it the same attenuation as 30m of wf100.

(http://www.cai.org.uk)



( I like to flick between feet and metres)

[Billet]

Thats good info, I have just had another look and the only option really is on top of the stables 35 mtrs.

Thanks Robbo

[satelliteman]

Just to add to that, you can run up to 60mts of 1mm type cable (wf100) Max without too much signal loss. If your using a bigger dish then even better as you will have more signal at the front end, assuming your picking up strong satellites that is.

P.S, I have managed 70Mts from a Z2 (60cm) and it were spot on.



EDIT:
0.3dB loss @ 2150 Mhz per 1 mtr
0.3 x 70 mts = 21dB loss.
80cm dish receiving 80dB
80dB - 21dB = 59dB
Min signal @ receiver is 52dB c/N of 12dB

Over this a pre-amp will be required

[Robbo]

Crikey, I didn't realize you could 'get away' with it that long, although I presume this would only be the case for a strong satellite like 28E or Hotbird or something. Also if you start adding Diseqc switches or motors into the equation plus connectors, this would futher reduce the margin. What sort of power level ( or dBuV) would you be getting from 26E(mbc) with your penta SM?

[satelliteman]

Robbo,

Level: 72.5dBuV on Fox Movies & 68.2dBuV on Mbc
Bit Error Rate: Marginal although produces a good picture. 2E-4 before Viterbi is considered to be acceptable but Mbc beam is around 4E-3.

For example Astra28: Level approx 78dBuV and BER >4E-5

2E-4 = 2 errors in every 10,000 bit of data

DiSEqC switch will lose around 2dB and a motor around the same quoted @ 2150mhz

[Andyman]

hi
I used to have a triax td 88 with a cambridge .6db lnb on 1 west analogue
about 10 years ago wired with 34 metres with rg6 copper on aluminium air spaced cable. No problems except for downpours (that always seemed to start about 11.00pm!).
Now going for a 1m dish, better lnb and 40m of wf100 cable and diseq motor. Do you think a digital signal would make much difference over such a cable run.

[satelliteman]

Well RG6 is not good enough for today's satellite. It's only rated up to 1000Mhz and although it was used years ago, DVB-S & DVB-S2 requires quality cabling such as copper to copper benchmarked but they still sell it.

Technically, if you double the dish size, you will have a gain 3-4dB increase. 'IF' pre-amps can be used on long cable runs and LNb's with lower noise figures to improve to overal performance