Visiosat bisat - loss of signal during bad weather

[ozumo]

On Amazon I found a Humax one:
HUMAX Green Power Quad LNB, 4 Subscribers, Satellite Universal LNB, Energy Saving, 4-Way LTE Filter, Weather Protection Housing, Gold-Plated F-Sockets, for Digital TV in HD, Full HD and 4K UHD

The Humax should do the job but is quite pricey, at least you can return it easily. We don't have an associated retailer.

 

[Bamboccio]

Thank you - I bought it and changed it only to figure out that the issue persists and I now have some bad signal also on vertical transponders. It is raining now but somehow the signal oscillates from what is in the photo to 0. This seems to happen only on HB and in the multiswitch I have Astra 19.2 and 28 which both work fine so I assumed that this is not a multiswitch issue also given that I have another receiver with a separate cable and multiswitch which has the same issue. I have not taken a photo of the new LNB but basically it is same as it was before which I re-attach here.
Someone before seemed to say that it was an issue of the height of the LNB. What I am now sure why the signal show as strong as that in my Technomate and then it breaks.
Any ideas?

 

[ozumo]

I would suspect cable/connectors/switches, are you able to get a receiver & TV close to the dish and use a short cable to connect directly to the LNB? 15dB, if correct, should be more than plenty for stable video.

 

[Bamboccio]

I

I would suspect cable/connectors/switches, are you able to get a receiver & TV close to the dish and use a short cable to connect directly to the LNB? 15dB, if correct, should be more than plenty for stable video.

Thank you! I cannot bring a receiver up there
What puzzles me is that I have exactly the same issue with 3 different connection points which use different cables and different switches so the only thing in common is the LNB and I have now changed it so I am guessing that the issue can only be one of bad height / skew of the LNB given that the other LNB for Astra provides a good signal.
Am I missing something?

 

[ozumo]

The next thing I would try would be to connect the receiver directly to the LNB rather than going through a switch. 15dB means you have a margin of over 7db compared to the minimum required for lock so it could be some kind of intermittent interference. On some feeds from 7°E I get interference from a local mobile phone tower that causes the receiver to lose and regain signal a couple of times a second.

 

[Bamboccio]

Thank you - I will try the direct connection. How did you manage to identify that you ad the interference? I see the image breaking or stopping but only on HB not Astra.

 

[ozumo]

I used my SDR and compared the signals I could see to this Ofcom document that lists the frequencies used by mobile operators:

https://www.ofcom.org.uk/siteassets/resources/documents/manage-your-licence/mobile-wireless-and-broadband/2.3-3.4-ghz/frequency-allocations-mobile-and-broadband-below-5-ghz-june-20242.pdf

It was the IF frequencies (that the LNB sends to the receiver) that were affected rather than the transponder frequencies.

 

[Bamboccio]

Thank you. I am not sure. I have been looking all day already and I had long periods of good signal but I also had some random breaks. At some point it stopped as I started watching HB on 2 receivers at the same time which may have been just a coincidence. At the moment it works ok, it will be interesting to see if breaks also during a sunny day.

 

[Channel Hopper]

I was in West London around the same time as the past few posts, it wasn't raining, just misty.

Which postcode ?

 

[Analoguesat]

Tweak the skew of the lnbs. Facing the dish the lnbs ahould be twisted clockwise a bit so the connector on the bottom of the lnb is at about "7 o'clock"

 

[Bamboccio]

I was in West London around the same time as the past few posts, it wasn't raining, just misty.

Which postcode ?

Yes misty in W10.

 

[Bamboccio]

Tweak the skew of the lnbs. Facing the dish the lnbs ahould be twisted clockwise a bit so the connector on the bottom of the lnb is at about "7 o'clock"

Thank you. I will try that too but I seem to remember that going further clockwise would loose some more signal at least according to my Technomate.

 

[Bamboccio]

The plot thickens. I have attached one cable between LNB and decoder and left the other 2 cables going via the switches. Initially I had no signal with the switches and the direct connection and now I have signal in both: the switched one breaks and I am checking the direct one.

 

[Bamboccio]

After testing the signal breaks on the switched connection not on the direct.
For info I have 3 switches one is 2way and 2 are 4 ways and all have the issue on HB and not Astra.
It also seem that one of the switched connection is worst than the other and when the receiver are both in it causes the other switched connection to also go off.

 

[Bamboccio]

Thank you @ozumo I now can see that the switches were out of their casing so they got wet and hence probably started to fail. I will change them all. Does it sound a decent diagnosis and plan?

 

[a33]

I now can see that the switches were out of their casing so they got wet and hence probably started to fail.

Sometimes letting them dry for a day or so is enough, for them to function properly again.
Hopefully things aren't oxydized (or how do you spell that?), and damaged, yet.

Greetz,
A33

 

[ozumo]

Thank you @ozumo I now can see that the switches were out of their casing so they got wet and hence probably started to fail. I will change them all. Does it sound a decent diagnosis and plan?

Yes although it still seems a little strange how only Hotbird is affected on each of the DiSEqC switches.

 

[Bamboccio]

Yes that was my feeling and that they all failed at the same time and in fact if you did not suggested it I would have not tested the direct connection LNB receiver. I have now ordered the new switches so we will see. Once again really really thank you!

 

[Bamboccio]

Sometimes letting them dry for a day or so is enough, for them to function properly again.
Hopefully things aren't oxydized (or how do you spell that?), and damaged, yet.

Greetz,
A33

Today was a dry day and the problem persists so I have gone ahead and bought new ones - thank you!

 

[a33]

Today was a dry day and the problem persists so I have gone ahead and bought new ones - thank you!

OK.
You could let your old ones dry longer (can you easily open them?), and keep them for later trying/checking.
They wouldn't be the first that come out unharmed, in the end....

Greetz,
A33