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NSS7 downlink C and Ku signals in Libya

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Ex Member
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Mar 6th, 2007 at 6:28pm  
Hi All ..

i have been trying to point at NSS7 and no secuessi have tried everything possible so my final thoughts came to the localtion problem ..
so this is my location
N 24.2022
E 23.2926
my Evolation is 380 M above sea level ..

can any one confirm to me if i could get a signal on this location ??
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« Last Edit: Mar 7th, 2007 at 5:22pm by Admin1 »  
 
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Eric Johnston
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Reply #1 - Mar 6th, 2007 at 10:52pm  
It looks hopeful.  The detailed coverage maps are here:
http://www.satsig.net/global-teleports/north-africa-coverage.htm

The downlink power in eastern Libya is about 4 - 5 dB below the beam peak.  What size dish are you using and what carrier frequency, symbol rate and polarisation are you trying to receive.  I should be able to see your downlink.  I am in the same coverage at the beam peak, so I will see what is the margin here.
wxw
Best regards, Eric.
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Reply #2 - Mar 7th, 2007 at 12:29pm  
thank you very much for ur reply ...

the NOC told me that there is a sun outage at this time of the year so there will be alot of interference and it will be ended at 14:00 GMT.. so i have to wait for this .

in the other hand my specfications is :
Dish: 1.2M prodlien .. LNB: NJR 2184 HW .. the uplink centre frequency is 6131.9 MHz .. the downlink is 3906.9Mhz .. Symbol rate: 10197.136 ..

and i am pointing on another downlink  11572 which is very good in other places but here it is only giving me 51 dbuv before it gave me about 56 - 55 dbuv

.... thank you
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Eric Johnston
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Reply #3 - Mar 7th, 2007 at 5:08pm  
For C band operation, a 1.2m dish is probably too small unless the service provider is paying extra for more transponder power than is the fair share of the transponder resource.  Think in terms of 1.8m minimum for C band operation, preferably 2.4m or 3.7m or 4.5m diameter.

For your Ku band reception, have a look at the downlink contours and see if the reduction can be related to the locations and contours.  It should be noted that in the edge region of the beam, the contours are only approximate and that level will vary rapidly from one place to another.   The contours vary with frequency as well as with small satellite movement, so it is not possible to be very precise.

A reduction from 55 dBuV to 51 dBuV is an 8 dB reduction in signal power, which I agree is much more than expected.

Sun noise occurs when the satellite crosses over the sun.  This happens in spring and autumn, in each case for several consecutive days at the same time each day.
On the first and last days, when the satellite grazes across the edge of the sun, you may hardly notice the noise increase, which lasts a few seconds.  On the middle day when the satellite goes right across the equator of the sun, the noise increase is the greatest and you may have a short outage.   It depends on dish size, frequency etc.

Best regards, Eric
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« Last Edit: Mar 7th, 2007 at 6:11pm by Admin1 »  
 
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Reply #4 - Mar 8th, 2007 at 8:14am  
thanks Eric alot for ur help and ur replys ...

for the time being i secusses to activate the modem but with the usual problem which is that the modem is working on the max power  my compresion point  -14 db ..they told me that i have to change the dish from 1.2 m to 1.8m and they left it activated until then..
 
anyway ... i want to ask about the isolation .. what is it excatly and why they counting on it .. because on other satiellite i am doing only the 1db com. point test ..
so what is this Isolation and what affect it and what effect it has on my signal  cuz sometimes when the isolation is good the signal dropes down and the oppiset ..

thanks all
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