thaiconm 5 reception
Currently set up a 2.4m c band dish in Bundaberg hoping to get Thaicom 5 "h" channels. Elev at 6 degrees and magnetic around 266 degrees with a clear sky view.
I am using a programmable sat finder SF-500 and have set all the frequencies.
The LNB is Zinwell dual polarity ZCF-D21B
I set the local oscillator frequency in the sat finder to 5150 mhz.
First attempt showed nothing what-so-ever and I was wondering if the supply to the sat finder might be the problem.
It came with a 13volt supply but one some further reading I see the LNB is fed with 18 volts during normal operation from the receiver to switch the polarity from vertical to horizontal.
So query is, should I rig up a supply to give this voltage (18v) to the sat finder ??
Input says it's range is 13 to 18v.
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Originally Posted by bluejets
It would have a Buck/Boost circuit to change from H/V on Transponder selection polarity. 18 H/13V .Address: Bundaberg qld
Latitude: -24.8654°
Longitude: 152.3487°
Satellite: 78.5E THAICOM 5
Elevation: 6.0°
Azimuth (true): 276.9°
Azimuth (magn.): 266.6°
You can click and drag the marker
Seems OK on Global Beam.
Those meters will actually work on a supply voltage of 12V.
When you select H polarisation, it passes 18V to the LNB.
You need to set the polarisation to horizontal.
6 deg elevation is a big ask though.
I have managed to get Thiacom5 and I'm in N.E. Vic with a clear view of the sky in that direction. Being up on a hit helps alsoIs this a new installation? You need to lock on to a sat first and find out what it is and then work your way down the clark belt to Thiacom5.
Leroy
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ok...well, I have the manual for the sat finder and it does not make any mention of any internal voltage booster for the dual polarity switching.
I was aware that the receivers will do this though.
The sat finder is programmable so it will "lock" on to the sat in question as long as the frequencies etc. are entered properly.
So no real need as far as I can see to go chasing the "belt".
It is a new install though, and it had me puzzled as to why I was not getting any signal what-so-ever.
The voltage seemed to be the most obvious. I'll keep at it....Thanks
Sat finder works fine on Optus D2 and the free channels there on my other KU dish.
Last edited by bluejets; 14-07-13 at 08:33 PM.
Lucky you!Being up on a hit helps also
@bluejets, my sat-finder recharges at 24V and supplies the LNB with the required 13/18 volts when selected. Yours should too.
Can you check the voltage on the output terminal of your sat-finder with a multimeter?
Small errors in elevation, azimuth and offset are made worse at the extreme West and East of a polar setup. Your dish may be near-enough for satellites 'above' you, but can be out of alignment for very low satellites.
I suspect your sat finder is working fine and you just need to fine-tune your Az-El and offset adjustments on your dish mount.
Doesn't appear to have this. It was supplied with a plug pack (13v) connects to receiver input. There is an optional jack for up to 18v. ... manual is here ....Lucky you!
@bluejets, my sat-finder recharges at 24V and supplies the LNB with the required 13/18 volts when selected. Yours should too.
Can you check the voltage on the output terminal of your sat-finder with a multimeter?.
I will check output though.Thanks
If in doubt, power the meter directly from the decoder set to a horizontal channel.
This will ensure it is supplied with 18VDC.
ok...good idea..thanks.
Did a couple of tests today and the sat finder meter does indeed give a higher voltage when "H" polarity is selected.
This was using the power supply that came with the meter.
Levels under no-load were 17v and 20v.
I imagine these will drop a bit under load to give the required switching level to the LNB.
Other results were a signal strength of 69%.
However the quality remained at zero with occasional flashes on the meter without dish movement up to 72%.
Not sure what that means other than signal is somewhat weak..??
Last edited by bluejets; 17-07-13 at 10:30 AM.
Have you adjusted the LNB skew and focal distance?
Fluctuations of signal quality that severe can also be associated with signal path obstruction, eg: a tree branch moving in the breeze.
Yes.....adjusted the skew to 64 degrees. This can be a little confusing depending on which instructions one reads but I think I have it right.
Focus is set at the 36 mark on the lnb case...Correct?? Dish is Joysky 2.4m ST-75 as far as I can gather.
Adjusted anti-clockwise
i.e looking from the back of the dish towards the satellite anticlockwise 64 degrees from where the termination was originally pointing straight down.
According to dishpointer I should have a clear view, the nearest obstruction is a house roof some 94 metres away and it shows required clearance at 9.4m.
So I'm ok there I believe. Next one is a tree at 143 metres and clearance requirement of 14.3 metres. Tree would be maybe 7m I'm guessing.
That's about it.
Dish is mounted with it's centre approx. 5 metres above the ground.
I imagine the ground level is the point of reference for dishpointer measurements.
Last edited by bluejets; 17-07-13 at 03:11 PM.
The figures on dishpointer etc are a starting guide only.
You still need to make the adjustments looking at a meter with a signal quality scale, or displayed on a screen from your decoder.
Remember to pause for a second after making very small adjustments for your meter/decoder to 'catch up' as signal measurements in them are not in real time.
G'Day.
Just a couple of misconceptions that you have:-
Skew is quoted when viewing from front of dish.
There is an inbuilt buck/boost circuit to select H/V depending on H/V selection of the meter.
You must not use the Power pack at the same time as the decoder.
It is imperative that the dish track the Clarke Belt if you want more than one satellite.
The adjustments are minute and critical with respect to each other.
Some grist for the mill.
bluejets, you are going to have to swing the dish a bit mate. There's no way you can hit a satellite bang-on with just a 'static' adjustment.
The whole idea of the sat finder is to let you know when your hit the satellite while you're swinging the dish.
Sorry if this is too obvious, but you haven't mentioned that you are actually adjusting the dish at all.
Don't worry too much about skew at this stage, it can be tweaked later when you find the satellite, but as B4Life mentioned it's adjusted looking at the back of the LNB towards the dish.
This means you're close. Adjust your dish, until you should get a stable/peak quality reading.
This is where plain English and peoples view can differ. For me , "viewing from the front of the dish" means looking into the LNB and the concave section of the dish.G'Day.
Just a couple of misconceptions that you have:-
Skew is quoted when viewing from front of dish.
There is an inbuilt buck/boost circuit to select H/V depending on H/V selection of the meter.
You must not use the Power pack at the same time as the decoder.
It is imperative that the dish track the Clarke Belt if you want more than one satellite.
The adjustments are minute and critical with respect to each other.
Some grist for the mill.
So is this the same when dishpointer and others quote an anti-clockwise rotation?
(Edit) Looks like I might have the skew around the wrong way going by comments here.
I believe I already quoted that I found that the sat finder had an internal boost circuit so I started new tests based on that knowledge.
I am an electrician so know better than to connect to 2 differing supplies simultaneously so no problem there.
Just on the one satellite so should be no need for "tracking set-up" as far as I can see. Would this be a fair assumption..?
Last edited by bluejets; 17-07-13 at 07:25 PM.
Yes ...been moving the dish and the flashes may, as you say, be because I'm moving things too quickly without waiting for a meter update.
Thanks...I'll try again tomorrow.
Yes, looking 'into' the (concave) dish is from the front and that is where LNB skew is referenced. eg: you are looking at the rear of the LNB, because the front of the LNB is pointing into the centre of the dish.
Although obvious, when you make LNB adjustments, you'll be blocking the signal path as you can only reach the LNB from the front/side, so after making adjustments, move clear and check the signal strength and quality.
Aligning a dish for a fixed position is not as critical as aligning a motorised dish.
Yes, but all those other figures don't amount to a tinker's arse, unless your mast is plumb and you are pointing correctly !
Reflect that you are trying to focus on a satellite, about the size of a bus, over 40,000 Kms away, to within one degree.
No problem, it is easy if you are cognisant of the fundamentals.
Sounds like you're all over it like wet paint.
I take it your satfinder/receiver is programmed for one of the 'global' horizontal beams? Such as, 3440H, 3480H, 3520H, 3551H etc.
Maybe some kind C-bander, could suggest the strongest Thaicom5 transponder frequency for the East-coast? May help a bit.
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