Attenuator blows up 2 Freesat boxes

J

joddle

Specialist Contributor
Messages
517
My Satellite Setup
2x Pace 2600 C1 (in a box just in case) , 3 x Humax HD Foxstat (2 of which in store as spares) . 3x Manhatten Plaza - Pasat 2.4 PF dish mounted on flat roof with Invacom C120 quad LNB .
My Location
Massanassa, Valencia, Spain
And now to cap it all - I decided to look at the previous Humax which had failed - it was the first to go but I kept it as it had a new power supply which I though may be good if one of the others blows as they seem to do - Same cleaning and drying with a hairdryer and tentative turn on again - and yes - a fully working box again. it seems those old Humax LNB short protection circuits really do their job and the arcing experienced with both boxes to do with water ingress - and even that did not destroy the LNB power supply :)
 
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Lazarus

Lazarus

Tout Rond Bon Oeuf
Staff member
Messages
25,496
My Satellite Setup
80cm Motorised.
Several small Dishes.
Much else.
My Location
North York Moors
Splendid!

I have two Humax boxes: Long may they remain spark free :D
 
jeallen01

jeallen01

Specialist Contributor
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3,701
My Satellite Setup
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My Location
Somewhere in England (possibly?)!
FWIW, it might be a good idea to replace at least the final metre or so of cable to the LNB with foam-filled WF100 (or similar) cable (instead of air-spaced stuff) as that should pretty much pretty much prevent the chance of water getting into the rest of the cable to the box. OTOH, if the rest of the cable is already well-soaked with water then that won't help. Best solution is obviously to replace all the cable with WF100-type cable, and make sure that there is a drip-loop just outside the wall through which it enters the building.

Also, make sure that all the F-connectors outside the building are well-waterproofed with self-amalgamating tape - "automatic" practice for me and most of the forum members, but unfortunately not for many "professional" installers:-doh. Could be one of the reasons that, in 25 yrs, I've never had a water-ingress issue with multiple sat Rx setups.;)
 
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J

joddle

Specialist Contributor
Messages
517
My Satellite Setup
2x Pace 2600 C1 (in a box just in case) , 3 x Humax HD Foxstat (2 of which in store as spares) . 3x Manhatten Plaza - Pasat 2.4 PF dish mounted on flat roof with Invacom C120 quad LNB .
My Location
Massanassa, Valencia, Spain
Thanks for the advice Jeallen but I have now already re-cabled - of course your comment on using amalgamating tape is very valid. The water ingress was not due to any joints or incorrect setup but to the split in the feed cable - I must however remember to check more regularly as here the sun gets very hot indeed and so exposed cables suffer far more than in the UK.
 
jeallen01

jeallen01

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My Satellite Setup
See Signature
My Location
Somewhere in England (possibly?)!
...- I must however remember to check more regularly as here the sun gets very hot indeed and so exposed cables suffer far more than in the UK.
From what I have read black cable resists UV degradation better than the white stuff (OTOH, can't confirm that as it's never been hot enough for long enough! :()
 
Menorca Man

Menorca Man

Member
Messages
91
My Satellite Setup
Sky+ HD (2GB Amstrad DRX890) + Generic 1.65m x 1.5m offset with Opticum LQP-04H Quad LNB
My Location
Ciutadella de Menorca
From what I have read black cable resists UV degradation better than the white stuff (OTOH, can't confirm that as it's never been hot enough for long enough! :()
On the other hand, a black cable will absorb the heat of the sun more than a white cable and therefore may cause internal degradation of the insulation (i.e. melting!).
 
jeallen01

jeallen01

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My Location
Somewhere in England (possibly?)!
MM

You are probably right on the heat absorption issue, but that's what "received wisdom" from reading says.

Best solution is probably to protect the cables against strong sunlight with some sort of cover wherever practicable - wherever possible, mine are hidden behind things in the garden (fences, trelliswork and so on).
 
M

Mickha

Super Moderator
Staff member
Messages
5,390
One solution I used, for my parents installation, was an old garden hose pipe, no longer used, but in good condition, I fed the cable through the hose pipe, and ran this from dish to near the installation point, ensuring I did a loop, to stop water ingress, and sealed the ends, to stop insects gaining entry.
It's cheap, for me free, and does a good job.
 
J

joddle

Specialist Contributor
Messages
517
My Satellite Setup
2x Pace 2600 C1 (in a box just in case) , 3 x Humax HD Foxstat (2 of which in store as spares) . 3x Manhatten Plaza - Pasat 2.4 PF dish mounted on flat roof with Invacom C120 quad LNB .
My Location
Massanassa, Valencia, Spain
A regular check is now on my schedule and this week I found another suspect piece of cable but on a different feed. Looks like it will split at any time now as I can see the shape of the braid through the outer insulation - again on a very exposed section and subject to the heat. Already I have moved most of the main feeds to a place where they get little direct sun but the part on the PF dish itself running up to the LNB is what is hardest to protect and where most of the damage seems to be occurring. I may try binding the cables to the LNB arm with a split sheath but that will still leave the most vulnerable bits, i.e. where they loop round to connect to the Invacom LNB
 
jeallen01

jeallen01

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3,701
My Satellite Setup
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My Location
Somewhere in England (possibly?)!
Can you not cover the last bit to the LNB with some smaller sheathing or "zipper-tubing"( both come in various diameters) - or even a length of corrugated flexible trunking?
 
J

joddle

Specialist Contributor
Messages
517
My Satellite Setup
2x Pace 2600 C1 (in a box just in case) , 3 x Humax HD Foxstat (2 of which in store as spares) . 3x Manhatten Plaza - Pasat 2.4 PF dish mounted on flat roof with Invacom C120 quad LNB .
My Location
Massanassa, Valencia, Spain
Can you not cover the last bit to the LNB with some smaller sheathing or "zipper-tubing"( both come in various diameters) - or even a length of corrugated flexible trunking?
Yes that's worth considering - thanks
 
A

a33

Specialised Contributor
Messages
497
My Satellite Setup
XSAT410
Rebox RE-9000
My Location
NL
From what I have read black cable resists UV degradation better than the white stuff
From what I know, it's not the SUN HEAT but indeed the SUN RAYS that degrade the plastic of the cable, because of certain additives in it that are sensitive to those sun rays.

Usually (but not always!) black cables have less of those additives, and are therefore more resistant to sun damage, as @jeallen01 wrote. In the specs of some cables I've seen mentioned, that they are made especially for outdoor use.

Covering the cable with a garden hose pipe or something else is indeed also a good trick to prevent the direct influence of sun rays.

The same sensitiveness to sun rays applies to tie wraps, by the way. Black ones are better sun-resistant than other colours.
In mediterranium circumstances: use black tie wraps! :)

greetz,
A33
 
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