Signal Quality Unstable

[trinidex]

I have the following setup:

14ft mesh BUD
Chapparal CBand Feedhorn
Eagle Aspen 17degree C-Band LNB SLT12017
Pansat 2500A

I'm pointed at G4R, Tx13 (Networks).

During the day, I get a signal quality that jumps between 33% and 45%, gradually as the evening comes around, the quality starts to drop. By 7PM the channels are "out" more than they are "in", and the quality is around 15%

By 10PM the channels are watchable, quality up to 40% and climbing as the night goes on.

I'm hoping someone has some suggestions on how to resolve this, or at least what could be causing it.

TIA

 

[Mr Tony]

satellite wobble (the satellite may drift) Where ya located?

Otherwise you may need to "nudge" your dish a little east or west

I have a 6 foot dish (aimed at G4 for the nets) and the signals for mine jump between 40-45 during the day and 35-42 at night. I have a Pansat 1500 (little brother to the 2500) and I'm in Minnesota. I can get the nets fine but the New Mexico chuch channel (KCHF on 3790 H) I only get at a 15...If I nudge the dish west KCHF comes in at 50 but nets go to only 30

Its weird when the signal is 15 you don't get them in. I get a stable picture all the way down to 15-16 quality...ROCK SOLID even on 30 quality

 

[trinidex]

Location...Location...Location

I'm located in the Caribbean, I forgot that part (sorry). West of Barbados, actual location:Longitude : 61° 22' 0" W Latitude : 13° 15' 0" N

I'll try nudging when the signal is low and see what happens.

Someone else had suggested skew, any thoughts on that?

Thanks for the tip.

 

[Mr Tony]

yes skew is very important, especially when you are so far off your true south satellite (the satellite at your longitude)

For me, skew is only +5 so its not much

Good luck

 

[Greg Mueller]

This is a long shot....

It might be that during the day the sun shines on your mount/dish and the metal expands and causes the dish to actually look at a different part of the sky (a smidge) compared to when it cools down at night.

This info comes from my experience in my astronomy hobby. During the night as the tube of the telescope cools it shrinks and you have to refocus. Many of the top end scopes now use carbon fiber tubes so there is less temperature change as compared to aluminum or steel

 

[trinidex]

expanding & contracting

hmmm... interesting. It certainly does get hot here (30c).

In that case, peaking the dish at night should bring the picture in right? if that is right, it'll be an easy test.

Thanks!

This is a long shot....

It might be that during the day the sun shines on your mount/dish and the metal expands and causes the dish to actually look at a different part of the sky (a smidge) compared to when it cools down at night.

This info comes from my experience in my astronomy hobby. During the night as the tube of the telescope cools it shrinks and you have to refocus. Many of the top end scopes now use carbon fiber tubes so there is less temperature change as compared to aluminum or steel

 

[trinidex]

skew question

righto, so I may need to adjust the skew (not easy as the feedhorn does not have a polarizor )

What can I expect to happen if I adjust the skew, should the quality increase? become more stable?

Thanks!

yes skew is very important, especially when you are so far off your true south satellite (the satellite at your longitude)

For me, skew is only +5 so its not much

Good luck

 

[Mr Tony]

So I assume the dish is fixed at G4 then?

If you manually have to adjust the skew at the dish, the signal will fluxuate as you move the skew. Find the best option. For me, when I skew it, the signal goes from 0 to 30 and stays stable. As I get closer to the peak spot, then it goes up to 45 or so. Another option is the focal distance (moving the LNB in and out from the feedhorn)

It wont get to 30C here until June....but it was 30 last night (30F that is)

 

[trinidex]

Update...

Last night was a better night, didn't have any problems until the end of NCIS

The dish was fixed, but I motorised it today. Nudging it east/west has not stabilised the quality.

I have a Chaparral feedhorn with polarizer so I'm gonna try installing it.

So I assume the dish is fixed at G4 then?

If you manually have to adjust the skew at the dish, the signal will fluxuate as you move the skew. Find the best option. For me, when I skew it, the signal goes from 0 to 30 and stays stable. As I get closer to the peak spot, then it goes up to 45 or so. Another option is the focal distance (moving the LNB in and out from the feedhorn)

It wont get to 30C here until June....but it was 30 last night (30F that is)

 

[trinidex]

Further update...

So tonight was okay until around 8:30PM EST
Symptons: bad pixelation and quality level between 0% and 30%

I'm wondering if the 2500A "caches" the data stream, why? well, when watching the quality level, it would suddenly drop to "UNLOCK" but there would still be a picture, then a few secs later, the picture would freeze, then "No Signal, Bad or Scrambled Channel" message.

If it does "cache" data stream, it is not helpful when peaking

So that is the latest, quality between 0% (UNLOCK) and 30%

I really hope someone has an idea

 

[Mr Tony]

Trindex
I really don't know what to tell you. I just went through the chanenls (8:00 CDT) and left it on CBS for 7 minutes with the signal screen up on my Pansat 1500 and the signal stayed between 42-45...did not devaite off of those numbers.

The only difference between the 2500 & 1500 is the 2500 has UHF remote and AC-3 output.

 

[Mr Tony]

well I watched NBC for over an hour (watched Dateline) on 3 different recievers and all were stable

Pansat & Buzz were between 42-45 the whole hour (the Pansat I had the signal screen on for 5 minutes at a time) and the Neosat was at 50 (but that signal likes to read high)

If it goes out at specific times, it has to be something like you're on the fringe and the satellite moves out of your area at a specific time

 

[rainmaker]

your lnb may have become temp senstive to check when you have good signal put ice or something cool on the lnb and see if you loose quality or when you have no signal heat lnb with hair dryer and see if quality gets higher.

 

[Greg Mueller]

Further update...
So tonight was okay until around 8:30PM EST
Symptons: bad pixelation and quality level between 0% and 30%

I'm wondering if the 2500A "caches" the data stream, why? well, when watching the quality level, it would suddenly drop to "UNLOCK" but there would still be a picture, then a few secs later, the picture would freeze, then "No Signal, Bad or Scrambled Channel" message.

If it does "cache" data stream, it is not helpful when peaking

So that is the latest, quality between 0% (UNLOCK) and 30%

I really hope someone has an idea
Reply With Quote

Sounds exactly like the weak signal strength of 129 here on the west coast.

 

[trinidex]

Update and thanks...

--Thanks--First off, a big thanks for all the replies and suggestions. Further thanks to Iceberg for the testing - it's appreciated.

RE: the LNB being temperature sensitive, although possible, it is a new, practically unused (only for testing) unit, so I'm thinking (hoping) it isn't that.

--Update--
So this morning, I went to change the feedhorn, and noticed that the exisiting feedhorn wasn't straight in the scalar ring. I couldn't undo the locking grub screw (wouldn't budge), so I realigned it with my trusty multi-purpose adjustment tool aka: hammer

I now have a steady 42%-45%, and no more dramatic jumps, so I am a happy camper

I'll see what happens tonight.

 

[Mr Tony]

--Update--[/B]
So this morning, I went to change the feedhorn, and noticed that the exisiting feedhorn wasn't straight in the scalar ring. I couldn't undo the locking grub screw (wouldn't budge), so I realigned it with my trusty multi-purpose adjustment tool aka: hammer

I now have a steady 42%-45%, and no more dramatic jumps, so I am a happy camper

I'll see what happens tonight.

ah yes, the old reliable hammer

Mine was the same way...30-32 and then I moved it a little bit in the scaler rings and STEADY 42-45.

Let us know how it works out tonight

 

[rainmaker]

--Thanks--First off, a big thanks for all the replies and suggestions. Further thanks to Iceberg for the testing - it's appreciated.

RE: the LNB being temperature sensitive, although possible, it is a new, practically unused (only for testing) unit, so I'm thinking (hoping) it isn't that.

--Update--
So this morning, I went to change the feedhorn, and noticed that the exisiting feedhorn wasn't straight in the scalar ring. I couldn't undo the locking grub screw (wouldn't budge), so I realigned it with my trusty multi-purpose adjustment tool aka: hammer

I now have a steady 42%-45%, and no more dramatic jumps, so I am a happy camper

I'll see what happens tonight.

when all else fails grab the hammer.LOL

 

[voomvoom]

I've almost reverted to using my power tools at times. 12 gauge shotgun. But, so far I haven't had to use it yet. I sure have given it some thought from time to time.

Al

 

[trinidex]

Apparent Success!

Well it seems we are good to go

Last night, between 8PM and 10PM the quality was erratic as previous nights, BUT it was jumping between 30% & 45% and the signal didn't unlock.

So it seems that it was a combination of fringe reception (especially weak at those times) and a mis-aligned feedhorn.

Thanks to everyone for your feedback and suggestions.

 

[Mr Tony]

Cool. Glad it worked out. Hopefully it only gets better