Possible satellite signal interference.

K

Keepalive213

New Member
My Satellite Setup
Astra 28.2, Saorsat
My Location
ROI
Hi everyone first time poster from the western parts of the ROI.
I have a query about suspected satellite signal interference, Astra 2, Free-to-air satellite channel reception.
Triax TD64 dish (normally an ideal size for this location), mounted about 14ft high with no trees, obstacles etc in the way.
New LNB, I have also tried a second new one of a different brand.
Horizon hdsm usb sat meter, regularly used and working well, recent transponder list update from Horizon site.
VH and HH both reading high 90%s as normal.
VL locks on, up to around 40% (normally high 90% as well) and intermittently shoots up to 70 / 75% before dropping again.
HL will not lock on, display flashes quickly like it is trying to lock on but no beep, something seems to be preventing it from doing so.

Did a satellite scan using a generic FTA receiver and picked up 110 channels instead of the usual 370 (approx)

Surroundings... There are 3 phase power cables literally running through the garden.
If I was to look up at an angle of approx 45 degrees from bottom of dish, the cables are at a distance of about 20m away. Basically the dish faces right into them.
There is a transformer approx 50m away, there is a buzzing noise but I cant say for sure if its cable or transformer.

Across the bay around 6 miles away there is a hill which has a similar elevation, maybe a bit higher.
There would be lots of transmissions coming from that location.
6 storey aviation radar station.
Saorview terrestrial tv transmitter.
Line of site broadband transmissions, 2 - 50mbps
Mobile phone and 4g mobile broadband, up to 90 mbps.

Any ideas or potential solutions much appreciated.
 
Welcome to the forum

If its worked ok before and isnt working now something has changed. Now it could be external interference, especially if something in the set up of the electrical cables or transmitters ha sdegraded or is damaged. But then again it could be

damaged coax cable
water ingress into cable
failing lnb (unlikely as you have tried a second one)
failing receiver (again unlikely as you have tried various receivers.

Can you set up a temporary shield of some sorts - soemething using metal corrugated panels would do to lash up a temporary block. Put it between the dish & the potential interference. Just make sure it cant blow away if the wind gets up suddently!

If youu seriously suspect the external masts / electrics relocate the dish to shield it from the worst of the interference

A websdr dongle on a laptop running sdr# with a short wire anttena might give you an indication of where any potential interference is coming from if its local.
 
Hi a
Analoguesat said:
Welcome to the forum

If its worked ok before and isnt working now something has changed. Now it could be external interference, especially if something in the set up of the electrical cables or transmitters ha sdegraded or is damaged. But then again it could be

damaged coax cable
water ingress into cable
failing lnb (unlikely as you have tried a second one)
failing receiver (again unlikely as you have tried various receivers.

Can you set up a temporary shield of some sorts - soemething using metal corrugated panels would do to lash up a temporary block. Put it between the dish & the potential interference. Just make sure it cant blow away if the wind gets up suddently!

If youu seriously suspect the external masts / electrics relocate the dish to shield it from the worst of the interference

A websdr dongle on a laptop running sdr# with a short wire anttena might give you an indication of where any potential interference is coming from if its local.
Click to expand...

Hi thanks for the reply.
All cables are in good condition, dish and LNBs are new.
I replaced a rusty dish and salt laden LNB which had not worked iin some time due to their condition.
With my Horizon meter and new hardware this signal problem is evident.
The corrugated sheet idea is a no go as the dish is relatively high, in a very windy location and on a very nice house!
Relocating the dish would not work as I did signal tests on all possible sides and have found the same issue.
 
Presumably you are confident you are on Astra 2? If so what angle is the lnb rotated at?, perhaps a photo from the front of the dish will help
 
What is the elevation on the dish?? (XX number of degree elevation off of the ground) Anything around 15 degrees or lower would/could be a problem with RFI from a ground terrestrial RF source, local airport approach radar, anything in the 12 GHz band or a harmonic or the satellite signal it's self bouncing off something, this would/could cause a phase cancellation on the main signal.

You said you had problems with salt corrosion on the dish, this may also affect the system ground on the coax, an un-grounded or bad ground on the coax/system can cause all sorts of problems.
 
From memory , the footprint of Astra 2 in Eire/ROI is better than the extremes of Scotland, expect 15 degrees would be the absolute minimum.
 
Op here, thanks for all the replies.
I am definitely confident I am on Astra 2 as I have aligned many hundreds of dishes here on the Atlantic coast.
The 2 Lnbs which I tried were Triax and Inverto and both readings were the same.
As regards the salt, all old equipment has been removed and replaced with new stuff.
I have been installing satellite dishes for 9 years and have never come across a situation like this before, so I think ill just consider it unexplainable and hope I dont encounter it again.
 
Thinking out the box - could you cut down a something like a big coffee can and use it as a temporary shield. If nothing else it might give you an idea of if the interference is directional. Cut a hole in the bottom and you can slide it over the arm and move it up and down as an rf blocker.
 
Analoguesat said:
Thinking out the box - could you cut down a something like a big coffee can and use it as a temporary shield. If nothing else it might give you an idea of if the interference is directional. Cut a hole in the bottom and you can slide it over the arm and move it up and down as an rf blocker.
Click to expand...

I will try that next time I am in the area, incidentally I did test an LNB wrapped in several layers of aluminium foil but it didn't help.
 
Keepalive213 said:
Hi a


Hi thanks for the reply.
All cables are in good condition, dish and LNBs are new.
I replaced a rusty dish and salt laden LNB which had not worked iin some time due to their condition.
With my Horizon meter and new hardware this signal problem is evident.
The corrugated sheet idea is a no go as the dish is relatively high, in a very windy location and on a very nice house!
Relocating the dish would not work as I did signal tests on all possible sides and have found the same issue.
Click to expand...
You weren't trying during the sun outage were you?
 
dmaavrigdo said:
You weren't trying during the sun outage were you?
Click to expand...
That I dont know, but I did install 2 new dishes half a mile away from the troublesome one on the same day, with no trouble.
The storms here are relentless, 70 - 80 mph again today. Its an ill wind that.....
 
The London area is just starting the outage for Astra 4A at 4.8 East if anyone wishes to check. (11.43 to 11.57, peaks at 11.50)
 
Just to confirm that at the outage time I got no loss of signal from 4A stronger transponders , using the steerable 80cm dish upstairs. The signal level from the Elanvision display did lot change from the usual 70% either, which I thought was strange.
 
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