HX50 in Afghanistan pointing issues (HX W6)

A colleague and I are both having issues pointing our 1.2m Prodelin dishs to Hughes HX W6 (two separate setups).  We are both novices and are self-installing.  Below is some background info:

Lat/Long: 34.4N, 70.3E
EL: 24.8
AZ: 242
POL: 48.2
LNB receive type: unknown

Bentley Walker sent me this:
Symbol Rate: 5000000
LNB 22KHz Switch: Off
DVB Mode: DVB S2 ACM
Frequency Band: KU/QPSK
Receive Pol: Vertical
Transmit Pol: Horizontal
VSAT return: inbound
Transmit Radio: 2 watt

We have set the elevation (with an inclinometer), done sweeps on the azimuth and rotated THE ENTIRE DISH to the correct polarization.  Additionally, we've set the LNB to vertical polarization (to the side) while keeping the 5-0-5 and the single notch away from the feed arm.  

THE PROBLEM: Last night, i pointed the dish to a signal of 27.  After reading some of the posts on the forum, i changed the LNB receive type to Pure and restarted the modem.  After it restarted, and without touching the dish, the signal dropped to 15.  I changed it back, restarted and the signal remained 15.  Now i'm completely lost and don't know what to do next.  Any suggestions?

Just in case there is a misunderstanding about where to measure beam elevation on this 1.2m Prodelin dish with the mode-matched feed.  This photo should help: This example shows it set to 48 deg beam elevation.

Anyone without an inclinometer can make one like that above by printing out this page Inclinometer

Tell us the make and model number of the LNB you have.

Tell us the receive frequency you have configured in the modem.

With the LNB set to "Pure" try swinging the dish again to find the satellite.

Changing the LNB settings will make some LNBs (INVACOM SPV 30 or 31) switch between different local oscillator frequencies.

The satellite downlink frequency minus the LNB  local oscillator frequency = the modem frequency.

For example:
Satellite down  = 11.3805 GHz
LNB LO frequ    = 10.000 GHz  
Modem tuning  =    1.3805 GHz = 1380.5 MHz (actually input to the HX modem as 13805, in units of 100kHz )

Example LNBs:
NJR2784   LO = 10 GHz
NJR2744   LO = 10.75 GHz
NJR2754   LO = 11.3 GHz

Invacom SPV-50 LO= 10 GHz
Invacom SPV-60 LO= 10.75 GHz
Invacom SPV-70 LO= 11.3 GHz

Invacom SPV-30 LO=9.75 or 10.6 GHz (switched 13/19V)
Invacom SPV-31 LO=10 or 11.3 GHz (switched 13/19V)

Read more: NJR LNBs   Invacom LNBs

If you have anomalies with the receive signal then it may be that the LNB cable connections need attention.  

Always power off at the mains wall switch before interfering with the coax cables or the low voltage multi-way connector between the power supply module and the modem.

Regarding the coax cables and the F connectors.  The centre wire pin should stick out 1.5mm proud of the rim.  The braid sheath should make good contact with the plug outer.  There must be no fragments of braid copper foil or wire shorting out the cable.  When screwing in the centre pin should slide smoothly into the hole and not push back the cable end within the plug.  Use firm finger tightness only, even if it hurts your fingers a bit but do make sure it is properly screwed in.  Don't use a wrench and damage the LNB or modem internally.  Do not get the coax cables crossed over.  You may wish to do all testing and adjustment with just the receive cable connectced until you have the best signal.

Once you have found the satellite the signal level will go above 30 up to near 100, and you then need to spend at least 30 minutes peaking up.  Peaking up is more difficult than finding the satellite.

Best regards, Eric.

Sir

We don't normally use the Invacom LNB for Afghan, it is usually a High Band NJRC for Sesat and a Low Band for W6, can you email in the morning the type of LNB and which satellite you are aiming for. Are these systems you bought directly from Bentley Walker or where did you buy them from ?

We will help you to get on line so please email me soon as you can  anthony@bentleywalker.com

Best Regards

All,  I am excited to report that i've successfully peaked up at 93 percent signal. 

A few lessons learned:
-Use the printout inclinometer.  I originally used an electronic one that's calibration must have been off.  Sometimes the simplest method is the best

-With the LNB and feed horn staying in the same position (vertical pol, 505 and single tick on top), I rotated the BUC 90 degrees anticlockwise as looking at the dish from the LNB.

I have seen a lot of posts involving changing the nominal polarization of the LNB, but very few involving the polarization of the BUC.   I guess this is what the manual was referring to as "horizontal polarization".  Straight out of the box, one could disconnect the feed horn, rotate the entire LNB/BUC setup 90 degrees and then re-attach the feed horn so the 505 and single tick were still opposite the feed arm.  I don't know if this is proper, but it's what worked for me.  We'll see what happens after i try to commission the modem.

Again, thanks to everyone who helped...I really appreciate it.  This forum is a HUGE asset to anyone trying to install a dish.

I'm going to make my LNB's look like the above one today and see if that fixes our problems. Ours is supposed to be Vertical Pol, however currently its set to Horizontal.

In refrence to the above post by Eric Johnstron... On the picture of the LNB... is the coax wire to the r/h side of the screen the recieve or transmit?  I have the same LNB on a HN7000 receiver and when it was moved from one site to the other both ends (with the markings) were stripped clean when the wires were removed.  TYIA.

Eric, aren't the transmit polarization descriptions reversed on those two photos? To me the upper transmitter - with the bolt holes facing left (or right) - I'd call vertical TX. The lower transmitter - with the bolt-holes facing up (or down), I'd call horizontal TX.

I say that because - other than the Osiris TG model that you show in those photos - most Hughes TRIAs bolt either directly to the feedarm, or to their cradle and then to the feedarm. That means the bolt holes will by design be either facing down or up. In the non-TG configurations, the default TX polarization must be horizontal. To go vertical in other than the TG cradle requires a vertical shim.

Consider the photo of my "pure" Osiris: and note the bolt positions. What you're looking at is the H/H configuration. Along with Chinon, Isis, Anubis TRIAs, it can't rotate in its cradle (like the Osiris-TG), meaning that they're of a fixed TX polarization  And in my part of that world, that fixed polarization defaults to horizontal. Switching TX polarization requires the insertion of a vertical shim.

//greg//

Quote:
No sir, that TG rig is actually my hot spare. It's configured H/H in that photo, just in case something goes wrong with the "pure" OSIRIS that I'm currently using on a H/H access. You've interpreted the photo incorrectly. The broad faces of that silver w/g section are in fact horizontal. Externally, it's 14.6mm wide, 8.7mm high.

The LNB is electrically switched; 18v for H, 13v for V. But if I had to move to a transponder where a vertical uplink was required, I'd have to physically install a 90 degree hardware shim.

HughesNet consumer grade uplinks in North America are Horizontal by default. Business/enterprise grade on the other hand, can be either H or V (depending upon GOS). But even then - with the exception of TG type TRIAs - a 90 degree shim must be installed for Vertical uplinks.

Now. That said, what do you think the chances are that Hughes deploys different transmitters to your part of the world? They're awful hard to read once installed, but - if you wish - we can compare Hughes part numbers. Because a situation where the two of us were offering conflicting info to enquiring members, simply wouldn't do.

//greg//