Another Afghanistan Thread

[wikun]

Here we go... First off, this is my first post and so hello to everyone. I have searched and read all of the AFN threads on the site, but I am still at a loss for sat service. I am a commo, but I am a radio guy not really a Sat guy. My setup is a 1.5 meter dish (inverted as instructed for a better look angle) I guess if you invert the dish, you will be staring at a 27.5 degree look angle vice a 13 degree look angle with the dish right side up. I have a Cisco D9865 decoder. The settings have been matched to the AFN website that all the posts have referenced. I have my lnb connector cocked to the 4 o'clock position. I have gone up, down, left and right. I am going to post pictures of my setup. The thing that I want to know now, is first, with the antenna inverted, the armature is on the top, the "bend" should be bent up or should the bend sag in toward the center of the dish? I hope that makes sense. Next in the advanced menu of the decoder, if you go to rf status, it is saying the polarization is horizontal. Should I be concerned with this or am I in to deep in the menu? Is the polarization set in the decoder on this model or by turning the lnb? I am going to post pictures up soon. Also I cannot get the decoder to beep. I was told this model beeps to aid in sat acquisition. Is this true?

 

[rolfw]

Not quite sure why you would need to mount the dish upside down (unless it's to keep the profile down), just makes alignment slightly more tricky. With the offset on average being 26 degrees or so on an offset dish, when mounted the correct way up, the dish face will be only slightly off the vertical for a 27 degree elevation.

Look forward to seeing the photos, not sure what you mean about the LNB arm sagging.

 

[DragonSat]

I align AFN every day. Theres your issue!!!!!!!!!!! AFN is now Vertical since last September

AFN is 12.341 V. 27500 FEC 3/4. pointed at 9E

From your location
Elecation 19 Degrees (So dish points sligtly below vertical 26-19 gives 7 degrees toward the ground)
Azimuth 249 Degrees (Magnetic bearing)
Skew 53 Deg clockwise (As looking at the dish)

You need to set both Vertical and 13V LNB Voltage. Set for X-Over Band, not LO1 or 2. In case in the future the NIT tables are updated with additional transponders in the low band.

Also a 1.5m dish is the minimum, for your location. It will work no problem if well aligned

 

[Channel Hopper]

Not quite sure why you would need to mount the dish upside down (unless it's to keep the profile down), just makes alignment slightly more tricky.

The inversion (on an offset dish) allows a low elevation satellite to be viewed without the dish surface having a large negative elevation angle (or hit the post). The height of the overall system can also be reduced dramatically.

Which 1.5m antenna are you using, is it one of those quick deploy units, and is it receive only or a modified receive transmt version ?

On a receive/transmit dish the The 'bend' normaly sags away from the dish, on a receive only it is almost always into the dish.

 

[Vipersan]

I'm most confused by this ...
But as Rolf says ..setting up with dish inverted makes the job trickier ..
Why not flip the dish right side up ..during the set up ..?
Once you have the signal locked ..then ...if its a 'profile' thing as Rolf suggests...you can invert the dish again ..and you will then have only two adjustment to make ...ie change of elevation ...and skew
Position E > W will remain unaltered..
Also ..do make sure you have clear line of sight to open sky in the rough direction of the 'bird' you are after ..
It makes me wonder if you do ...simply because you are going to such lengths to possibly mask the dishes profile..??
rgds
VS

 

[Channel Hopper]

It all depends on where the dish is installed. WInd loading for example on a quick deploy unit can damage the mounting system if set vertically. Then there is the possibility of fixed cable lengths on some 'all in one' antenna systems.

 

[DragonSat]

Another option, but again depends on your equipment. Is to use the Global beam from 63.5E. Its C-Band though.

 

[rolfw]

The inversion (on an offset dish) allows a low elevation satellite to be viewed without the dish surface having a large negative elevation angle (or hit the post). The height of the overall system can also be reduced dramatically.

I appreciate why people may invert the dish, but from the initial post, it seems that the dish has been inverted because that's what others have done, at 21 degrees elevation according to dishpointer, the dish face will only be 5 degrees off vertical leaning forward (assuming 26 degree offset).

 

[Channel Hopper]

The video below suggests the angle of dangle would be somewhat further than 10 degrees if the dish was installed 'upwards'

[video=youtube;1JCmjNKY25o]http://www.youtube.com/watch?v=1JCmjNKY25o[/video]

It could of course be pointing to another satellite, but I can see there are additional supports from the post to the backplate, and these are bolted in the inverted position to give a good equilateral set of angles for maximum rigidity. The dish itself does look cheap though (Patriot ?)

 

[ralphmagno]

wow,
this is the strangest thing i have ever seen.
why in the world would they want to mount the dish upside down????
look at the web site on afn alignment the dish is right side down.
the arm has to be at the bottom and not the top.
how is anyone going to get the elevation correct following the markers on the side if the dish is up side down?
since you have noexperience in afn install and you have no test equipment mount the dish correctly and set the elevation in the ball park and then move the dish right and left a tad.
ralph

 

[Topper]

wow,
this is the strangest thing i have ever seen.

Not in the MIddle East it is not

 

[Channel Hopper]

I appreciate why people may invert the dish, but from the initial post, it seems that the dish has been inverted because that's what others have done, at 21 degrees elevation according to dishpointer, the dish face will only be 5 degrees off vertical leaning forward (assuming 26 degree offset).

22 degrees is the minimum angle recommended by Patriot for their dish faces, the offset angle of their 1.5m dish is almost 29 degrees.

 

[rolfw]

That would I guess explain the inversion, however we are making an assumption that the dish is a Patriot and also that the OP is in the centre of Helmand and not further South, as then the elevation could be 24 degrees or more.

 

[DragonSat]

I am not so sure why seeing an inverted dish is strange. Many military satellite installations are done this way with offset dish's and low look angles.
When I was in Afghan it was an everyday occurrence to see these. Even in the UK you see them on permanent low angle dishs. Not seen one in Italy yet though

 

[Channel Hopper]

That would I guess explain the inversion, however we are making an assumption that the dish is a Patriot and also that the OP is in the centre of Helmand and not further South, as then the elevation could be 24 degrees or more.

True, but the Patriot PTX antenna was the one recommended by AFRTS back in 2007, and even though the brand is now part of the Cobham group, it is still the only approved Ku 1.5m I know of that can be supplied in bulk.

I will check on the documents I have in the archives

 

[DragonSat]

Did this get resolved?

 

[Robbo]

22 degrees is the minimum angle recommended by Patriot for their dish faces, the offset angle of their 1.5m dish is almost 29 degrees.

Just noticed a mistake in that document.

NOTE: The elevation look angle range reaches down to approx. 22 degrees
above horizon. If the antenna needs to “look” lower than this the antenna can
be re-assembled in the inverted as shown by repositioning the 4 bolts attaching
the Back Ring to the Back Angle Supports. To adjust Elevation angle the reference
angle for the face of the dish will be the satellite elevation angle minus the offset angle
degrees.

.

That should be plus ​if inverted I think.

 

[Channel Hopper]

Possibly the reason Patriot are no longer in the business.

 

[jncsk8r]

I hate to bump this thread but I too am now stuck in the AFN Afghanistan nightmare. I am on a small combat outpost, on top on a hill in Khost City, Afghanistan. Clear view of the sky in all directions. If you look on dishpointer.com i'm at a latitude of 33.3458° and a longitude of 69.9086° EXACTLY. Trying to shoot the 9E EUTELSAT 9A. I have matched the settings from AFNs site exactly in the decoder. Double and triple checked. Our dish is mounted inverted as well, LNB arm coming down from the top of the dish. I have two LNBs that meet the universal LNB criteria and fall within the range listed in other AFN Afghanistan threads. The thing is, everything worked OK until about 3-4 days ago. So I've been tasked with sorting it all out. Prior to adjusting anything I marked the dish settings so I could always go back, but no matter what Az I set or Elv I use the reciever seems to report signal from about 44 - 47 maybe 50 if my hands are around the LNB. No quality and certainly no lock. The settings I was given from dishpointer are as follows: EUTELSAT KA-SAT 9A - Distance: 40001km - Elevation: 15.6° - Azimuth (true): 253.0° - Azimuth (magn.): 250.6° - LNB Skew [?]: 53.0°. I just really don't get what's going on here and why no matter what I do (aside from unplugging the LN the reciever just reads anywhere from 44-47 for signal. Can someone suggest something that maybe I'm missing. I understand that larger dishes are harder to aim, and ours is pretty large, about from hand to hand wide. Thanks in advance!

SFC Carlson

 

[Channel Hopper]

Do you have a spare LNB to try ?

Have you checked the cable connections (all of them) ?