TVI while the wind blows

[VK7HH]

An interesting problem which some of you may have experienced?

I have a Diamond X-200 on top of my roof which is on the same mast as my TV antenna.

I have a 5.8GHz WiFi link dish on the same mast. The X-200 is about 1m space vertically above the WiFi dish and the TV antenna is the lowest just above the roof, but about 2m below the X-200.

Anyway, while not transmitting and the wind blows, I can see the X-200 moving and the my TV signal pixelates. Only on heavy gusts it is visible. The TV antenna doesn't move at all.

We have LOS to the TV towers, they run in VHF portion of the band on Mt.Wellington.

Anyone else come across this?

Hayden

[VK4TI]

An interesting problem which some of you may have experienced?

I have a Diamond X-200 on top of my roof which is on the same mast as my TV antenna.

I have a 5.8GHz WiFi link dish on the same mast. The X-200 is about 1m space vertically above the WiFi dish and the TV antenna is the lowest just above the roof, but about 2m below the X-200.

Anyway, while not transmitting and the wind blows, I can see the X-200 moving and the my TV signal pixelates. Only on heavy gusts it is visible. The TV antenna doesn't move at all.

We have LOS to the TV towers, they run in VHF portion of the band on Mt.Wellington.

Anyone else come across this?

Hayden

I assume it's a digital signal , it would be interesting to measure the swing induced on the supporting mast by the dish etc . If you digital signal is not uber powerful then the shift in wind driven alignment may be sufficient to cause the pixilisation . The tv antenna here is inside the roof and runs about 55% on channel 11 , a good wind can cause some momentary pixilisation .
Barry

[VK6ADF]

Does anyone else in your vicinity have the same pixelation? Might not be your end but maybe the transmitter system has a wind induced problem. Distant tree's in line with signal moving in the wind another idea.. I live in a black spot area and can have my TV monitoring the signal level and watch my signal (and almost everyone else in town has trouble in my case) go from over 50% to zero and stay there for many seconds then back up to over 50% in an instant on bad days, and perfect picture no drop outs other days. I hate digital TV...watch a lot more DVD's now.

[VK7HH]

I assume it's a digital signal , it would be interesting to measure the swing induced on the supporting mast by the dish etc . If you digital signal is not uber powerful then the shift in wind driven alignment may be sufficient to cause the pixilisation . The tv antenna here is inside the roof and runs about 55% on channel 11 , a good wind can cause some momentary pixilisation .
Barry

Yes digital - no analogue anymore in Tasmania since April this year. The dish is a small 300mm Ubiquiti dish, not a lot of wind loading and the mast doesn't move visibly in the wind - the X-200 does.
The signal is 10 out of 10 quality and 10 out to 10 signal. When the pixelation occurs the quality drops to 5 then back up to 10. The signal stays the same.

I've only had the issue since putting the X-200 up - it is quite interesting. Perhaps the Copper co-linear elements inside the fibreglass radome are moving inside creating wideband noise or something? There is another translator LOS from here in the high 600MHz region, but I need to figure out how to remove all my existing channels from the TV and only program from the translator. The TV antenna incidentally is a log periodic, excellent antennas.

Does anyone else in your vicinity have the same pixelation?

Don't think so.

Might not be your end but maybe the transmitter system has a wind induced problem.

That could be possibly - the towers regularly cop 100km/h + winds, but how far does a 130m concrete tower move in the wind?

[VK4APN]

The signal is 10 out of 10 quality and 10 out to 10 signal. When the pixelation occurs the quality drops to 5 then back up to 10. The signal stays the same.

We have had digital only in this part of world for a year or 2 now. At least 3 people I know had issues in the early days with TOO much signal causing drop outs/pixelation etc. In each case it was solved by reducing/attenuating the signal level to digital tuner. There is some explanation regarding this on one of the DTV sites. Some one more learned than I may care to elaborate?

Doesn't explain the vibration issue tho.

[VK4TI]

An interesting problem which some of you may have experienced?

I have a Diamond X-200 on top of my roof which is on the same mast as my TV antenna.

I have a 5.8GHz WiFi link dish on the same mast. The X-200 is about 1m space vertically above the WiFi dish and the TV antenna is the lowest just above the roof, but about 2m below the X-200.

Anyway, while not transmitting and the wind blows, I can see the X-200 moving and the my TV signal pixelates. Only on heavy gusts it is visible. The TV antenna doesn't move at all.

We have LOS to the TV towers, they run in VHF portion of the band on Mt.Wellington.

Anyone else come across this?

Hayden

Right now I am suffering some considerable digital pixelisation across most channels , conditions are low wind and 30c however I can watch the signal climb to very high levels and then pixelate , the antenna is inside our clay tile roof and to be sure it is not a simple temp thing hosed the tiles , no improvement but interesting watching .

[VK5PJ]

Hi Hayden,
I think your problem may be a bit simpler than expected. I would suspect you have a mechanical defect in the TV antenna that is being triggered by bending of the pole when the wind hits the collinear.

I would be looking at the join of the coax to the BALUN and where the BALUN connects to the aluminium element. Get up on the roof and push on the pole to simulate the wind and look closely at the TV antenna to see what moves. It may be even a hairline crack in an element.

If possible have some one in the house to yell out when it goes faulty (do not use a hand held as it will probably overload the TV rx and mask the problem) and if you can, give everything a wriggle to check what causes the fault.

Regards,
Peter, vk5pj

[VK3BJM]

I think Peter's suggestion is an excellent one.

Rather than shouting, use a mobile phone with a corded or bluetooth headset. A lot easier, and leaves both hands free.

Hayden, you didn't mention if it was occurring to every channel, but I guess we've all assumed this is the case?

73,
Barry
VK3BJM

[VK7HH]

Hi Peter,
Yes I''m going to get up there and figure out what is happening. The coax runs down the boom to the end of the antenna where termination occurs.

Could be a hairline crack - the log antennas have thin elements that can be easily damaged.

Happening on all channels yes.

[VK5PJ]

Hope it works out Hayden
please let us know how it goes, I live in a fring area for TV and since digital has gone in have spent countless hours and over a thousand dollars on trying to get a relaible signal. Still not there yet, we get fade outs from ABC channels all the time and a lot of pixelation on the others.

About to get depserate and try a passive repeater on a nearby high spot to see if I can get a releiable free to air signal. We have a VAST satelite receiver but we want to use our multi channels hard disk recorder as well.

Regards,
Peter, vk5pj