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Thread: HELP! Can't for the life of me pick up peripheral sats

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    Exclamation HELP! Can't for the life of me pick up peripheral sats

    Hi Guys,

    I'm a first time sat dish installer who is setting up a C-band dish at home. I've done a lot of homework regarding this topic, but for some reason I cannot get a lock on peripheral satellites.

    My details are as follows:

    City: Perth, Australia
    Latitude: -31.74°
    Longitude: 115.74°

    Dish: 3 metre C-band mesh dish
    LNB: Zinwell C-BAND LNBF D21B 3.4-4.2 Ghz 20°K
    Actuator: 24" heavy duty
    Receiver: Strong SRT 4663X
    Positioner: V-box

    - I have quadshield RG6 cable running directly from my LNB to the reciever (no V-box loop out).
    - Actuator is controlled independently by V-box.
    - LNB has been installed in scalar ring with correct F/D position (0.38) and also with F-connector pointing directly up.
    - rectangular insert block for LNB (?to catch circular polarisation) has been removed
    - Scalar ring has been aligned in the centre
    - Pole is plumb
    - direct line of sight from dish to TV where sat receiver is connected to
    - using sat reciever signal quality to measure signal

    - I'm using the following angles at neutral position of polar mount
    ----- Declination offset: 4.47°
    ----- Polar axis: 32.16°
    ----- Zenith (= decl offset + polar axis): 36.68°
    ----- Elev (= 90 - Zenith): 53.3°

    I'm using an anologue inclinometer for angles. Therefore I've tried to get the above angles set to within 0.5°.

    For directing my polar mount to the North (i.e. Azimuth 0°), I'm using Chinasat 6B's (115.5°) signal quality, initially, as a true north. This sat is at 53° El and 359.6° Az (true north) from my sat position.

    The only other signal's (apart from chinasat) I'm able to get are AsiaSat 3S to my west and AsiaSat4 to my east. I cannot get anything else.

    I've adjusted my mounts North direction by moving the mount east/west to peak on AsiaSat4 and AsiaSat3s.

    After peaking my North direction, the signal for these 2 satellites do not improve with either an upward tilt or a downward tilt of the dish.

    My signal quality level's are as follows:
    - AsiaSat3s (west of me): ~60%
    - ChinaSat (approx directly north of me): ~78%
    - AsiaSat4: ~51%

    I'm using the 'dish setting' in my receiver to select the particular satellites and view their signal quality level. (My signal intensity level is 97% always - so I have a good physical connection between my LNB and my receiver).

    I'm unable to find any other sats apart from the 3. I'm after Insat3A as my prime sat.

    Is there anything I'm doing wrong???

    Any assistance would be appreciated.



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    Wink Skew?

    G'Day Cobber,
    Not that I know a lot about C band, but this comment,
    and also with F-connector pointing directly up.
    has me wondering.
    You should get the same Skew 180 degrees and it is always advisable to have it facing down to minimise any chance of water ingress.
    It also suggests that you do not realise that Skew is dependent to a large extent on longitude. You should set it roughly for your longitude, and then peak it on the signals of interest.
    ie: It should be at zero (down) when at True North.
    The dish rotates with a properly set up motor/jack to compensate for relative East to West differences.
    There are often discrepencies and you may have to make a compromise between the various Satellites. Only minor. More obvious with the Optus Sats and others on the Ku band.

    Try that and let us know,
    Kindest Regards, " The Druid "......
    Last edited by beer4life; 02-08-09 at 09:40 PM.

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    Default Skew

    Quote Originally Posted by beer4life View Post
    G'Day Cobber,
    You should get the same Skew 180 degrees and it is always advisable to have it facing down to minimise any chance of water ingress.
    It also suggests that you do not realise that Skew is dependent to a large extent on longitude. You should set it roughly for your longitude, and then peak it on the signals of interest.
    ie: It should be at zero (down) when at True North.
    Hi The Druidd,

    Thanks for your response.

    Yes I didn't know about getting the same skew at 180 degs. I have the skew pointing directly up when at true North. I assumed that this skew will then change when the dish is moved (and thus rotated) by the actuator, to match the relevent skew needed to pick up signal from the satellite at that respective elevation/azmuth. I assume this is what you meant by "Skew is dependent to a large extent on longitude."

    You should set it roughly for your longitude
    What do you mean by this? I have the skew pointing directly up when at true north.

    I assume that if I rotate my LNB 180degs, then it still shouldn't make any difference as to why I can't pick up peripheral satellites. Is that correct?

    Thanks

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    Default

    The F connector shouldnt be pointing straight up go to dishpointer.com put in your relavant details and you will see the angles and skew for the sat you are searching for adjust your azimuth first elevation second LNB third when doing the final tweak on the LNB you need to move it in or out until you peak the signal and then turn it either way until you peak it figures given on various website are a guide only and change slightly from dish to dish and also from one Lnb to another

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    Wink

    Quote Originally Posted by thefatalrisk View Post
    Hi The Druidd,

    Thanks for your response.

    Yes I didn't know about getting the same skew at 180 degs. I have the skew pointing directly up when at true North. I assumed that this skew will then change when the dish is moved (and thus rotated) by the actuator, to match the relevent skew needed to pick up signal from the satellite at that respective elevation/azmuth. I assume this is what you meant by "Skew is dependent to a large extent on longitude."


    What do you mean by this? I have the skew pointing directly up when at true north.

    I assume that if I rotate my LNB 180degs, then it still shouldn't make any difference as to why I can't pick up peripheral satellites. Is that correct?

    Thanks
    Yes, that's the theory, but you need to rotate it a little as well to peak the signal.
    Also, particularly with the C Band, adjust to peak by moving in and out.
    Let's get that part right first.

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    OK Guys thanks for the responses.

    Looks like my LNB position needs peaking.

    1 more q, would it be best to peak it on the most peripheral sat I can find or the Zenith sat?, or doesn't make a difference?

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    Wink

    Quote Originally Posted by thefatalrisk View Post
    OK Guys thanks for the responses.

    Looks like my LNB position needs peaking.

    1 more q, would it be best to peak it on the most peripheral sat I can find or the Zenith sat?, or doesn't make a difference?
    The one nearest True North to start with, but as I said before, there are slight differences between Sats and a compromise may be necessary.
    Probably best to favor the weakest Sat or the one that you are most interested in if marginal.

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    OK. Playing with the LNB skew considerably increased my signal quality for the 3 satellites I was able to get a signal on.

    Also managed to pick up Measat 3 (on the west) and another one on the east (forgot name).

    My next question is, if I can get a good signal on Measat 3 and AsiaSat 3S, then why can't I pick-up AsiaSat2 which is in-between these 2 sats?

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    Wink No rabbits in that Sat.

    Quote Originally Posted by thefatalrisk View Post
    OK. Playing with the LNB skew considerably increased my signal quality for the 3 satellites I was able to get a signal on.

    Also managed to pick up Measat 3 (on the west) and another one on the east (forgot name).

    My next question is, if I can get a good signal on Measat 3 and AsiaSat 3S, then why can't I pick-up AsiaSat2 which is in-between these 2 sats?

    G'Day Cobber,
    That's like pulling rabbits out of a hat.
    AsiaSat 2 is predominately C Band with some feeds on the Ku band. So unless the feeds are active, you will not find them.
    See here for the Frequencies:-



    Kindest Regards, " The Druid "...............

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    Hi beer4life,

    C-band is what I'm after. They have quite a few channels broadcasted under C-band. Does that mean all their C-band feeds are inactive?

    Another possible suggestion, I'm using my sat receiver to find signals. The dish installation screen that I'm using to find signal quality for a specific satellite ('Dish Setting') has a list of preprogrammed satellites, showing their name, and LNB frequency...

    Is it possible that the transponders frequency and symbol rate for AsiaSat2 in the above 'Dish Setting' screen is set to a feed which is at this time inactive, and therefore I can't pick up AsiaSat2 because I can't pick up that particular feed that it is scanning for?

    Does that make sense?

    Is there a particular screen on the sat receiver which will allow me to measure signal quality from a particular satellite for all transponder frequencies/symbol rates? i.e. for all/any channels?

    Regards

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    Quote Originally Posted by thefatalrisk View Post
    Is there a particular screen on the sat receiver which will allow me to measure signal quality from a particular satellite for all transponder frequencies/symbol rates? i.e. for all/any channels?
    Once you've scanned the satellite and saved the channels, you will see the green circle when you disply the channel info.

    It's only a very rough indication.

    In the initial 'tweaking' stage of dish and LNB alignment, use the green bar graph to obtain the highest reading.

    Accurate signal quality and signal strength can only be measured with a professional meter which displays digital channel power, true BER, MER and noise margin and even then, it's only for a particular frequency on a transponder, not on an individual channel basis, as several channels can be combined on a single frequency.

    My $10K spectrum analyser shows all the above in real time, but you can't expect the same results from a $100 receiver.

    Remember, all receivers need a few (to several) seconds to resond to any adjustments made with a dish or LNB, before they will display the updated changes, so you need to make very small adjustments and wait a bit before making further adjustments. Only expensive real-time instruments will display changes instantly.

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    Wink

    Quote Originally Posted by thefatalrisk View Post
    Hi beer4life,

    C-band is what I'm after. They have quite a few channels broadcasted under C-band. Does that mean all their C-band feeds are inactive?

    Another possible suggestion, I'm using my sat receiver to find signals. The dish installation screen that I'm using to find signal quality for a specific satellite ('Dish Setting') has a list of preprogrammed satellites, showing their name, and LNB frequency...

    Is it possible that the transponders frequency and symbol rate for AsiaSat2 in the above 'Dish Setting' screen is set to a feed which is at this time inactive, and therefore I can't pick up AsiaSat2 because I can't pick up that particular feed that it is scanning for?

    Does that make sense?

    Is there a particular screen on the sat receiver which will allow me to measure signal quality from a particular satellite for all transponder frequencies/symbol rates? i.e. for all/any channels?

    Regards
    Sorry my mistake, I forgot it was C Band that you were on.
    The Transponder Frequencies and the LNB Frequency are entirely different.
    The LNB Frequency is written on the LNB and is to be set the same for all the Satellites. It sets the band of frequencies that come down to your box.
    The Transponder Frequencies differ on each Satellite along with the Symbol rates, FEC, VPid and APid.

    I've had another look at Lyngsat and at the moment there are no Footprint Maps for that Satellite. So unless someone can tell us whether it is receivable in Australia, I can't help you. These maps can be found on the Nav Bar at the top of the Transponder Lists.
    Here is the one for InSat3A @ 93.5E so you know what they look like.


    Last edited by beer4life; 04-08-09 at 11:29 PM.

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    Quote Originally Posted by mtv View Post
    Once you've scanned the satellite and saved the channels, you will see the green circle when you disply the channel info.
    Hi,
    I haven't really found the satellite, so I assume I can't scan it just yet? Can I run the sat scan whilst I'm moving the actuator to see if I can lock onto any channels on the sat?

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    Quote Originally Posted by beer4life View Post

    I've had another look at Lyngsat and at the moment there are no Footprint Maps for that Satellite. So unless someone can tell us whether it is receivable in Australia, I can't help you.
    Yeah, I reliased the dif between transponder and LNB freq.

    I know that AsiaSat2 is accessible from where I'm from (seen it being viewed at a mates house).

    I might try changing the sat scan details to scan for a particular channel (i.e. transponder frequency, symbol rate, FEC, VPid and APid), which I know actually is transmitted by AsiaSat2 and try moving the sat with the actuator to see if I can get those wonderful green bars of signal quality (rather than using the receivers default values for AsiaSat2).
    Last edited by thefatalrisk; 04-08-09 at 11:53 PM.

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    Quote Originally Posted by thefatalrisk View Post
    Hi,
    I haven't really found the satellite, so I assume I can't scan it just yet? Can I run the sat scan whilst I'm moving the actuator to see if I can lock onto any channels on the sat?
    No, you can't scan a transponder if you aren't locked onto it.

    If you are using a receiver to try to locate satellites, you must have an active transponder frequency and correct SR entered on the receiver first, otherwise the bar graph will not show you a reading, even if the dish is on that particular satellite.

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    Quote Originally Posted by mtv View Post
    If you are using a receiver to try to locate satellites, you must have an active transponder frequency and correct SR entered on the receiver first, otherwise the bar graph will not show you a reading, even if the dish is on that particular satellite.
    Excellent!

    Will see how I go tomorrow.

    Thanks for your help guys.

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    Quote Originally Posted by thefatalrisk View Post
    I might try changing the sat scan details to scan for a particular channel (i.e. transponder frequency, symbol rate, FEC, VPid and APid), which I know actually is transmitted by AsiaSat2 and try moving the sat with the actuator to see if I can get those wonderful green bars of signal quality (rather than using the receivers default values for AsiaSat2).
    Agreed, that's the best way to do it.

    If you have the dish aligned correctly to track the arc (Clarke Belt) with the correct info entered into the receiver, you should see it pick up the signal & the bars change green when it comes into view.

    Possibly your dish declination angle may require some adjustment if the arc alignment is out a bit, which would explain why you get some sats and not others.

    As mentioned, the channel details entered need to be currently active, or you won't see them. Also, some transponders are weaker than others on the same satellite and you need to check the channels you are searching for actually have a beam into your area.

    Once again, attention to detail, as very small adjustments can be the difference between getting a reliable signal, no reception at all.

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    Success! It worked. Got the sats i was after.

    Thanks guys!!!!

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    Quote Originally Posted by thefatalrisk View Post
    Success! It worked. Got the sats i was after.

    Thanks guys!!!!
    Good work... well done!

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