SatSig topic:

No voltage AM22 Andrews 1.2m dish iDirect 3100

(Read 10326 times)

Jul 25^th, 2007 at 6:27am

I am a soldier in iraq trying to set up internet for my platoon. I have an idirect 3100 system coupled with an andrews 1.2m dish pointed at am22 and i cannot get any voltage 0.0

I have pointed the dish in every conceveable azmuth, angle and polar but still no voltage. the Lnb and buc are properly situated and the dish has a clear sky view

No matter what I should be getting some voltage through, right? Suggestions please before my platoon kills me for wasting their money.

Thanks B

Jul 25^th, 2007 at 8:36am

do you get DC power at the end of your cable, just before the LNB? (you need to check it with a voltmeter).

Jul 26^th, 2007 at 6:10pm

i tested the cable and i get AC voltage but no DC voltage. so what does that mean?

Jul 26^th, 2007 at 7:46pm

I'm not iDirect trained, but typically - if you're truly seeing AC volts on the coaxial cable center conductor - that's bad.

Are you trying to use a inline satellite signal detector? Or are you relying on the modem for information? If a signal detector, they usually derive operating power from the modem via the RECEIVE cable center conductor. Outdoor end of the modem receive cable goes on one side of the meter, pigtail cable connects the other side with the LNB.

When checking for voltage on the outdoor end of the modem cable, set the multimeter to detect DC volts. Put one meter probe on the center conductor, the other on the threaded connector. You should typically see somewhere between 13 and 20 volts. But that only tells ya that there's voltage being provided to the LNB (and to the meter when it's installed inline).

After verifying operating voltage, you THEN put the meter inline. Then go by the needle deflection and/or sound of the sat meter to gauge receive signal strength from the satellite.

//greg//

Jul 27^th, 2007 at 6:50pm

i have been using the modem's pointing application to attempt to get on the satellite but it has yet to shwo any voltage.

i have used a voltmeter and was able to get 4 volts AC from my LNB while it was pointed at am22 but that is as high as i was able to get and still with no reading from my modem application (Isite) pointing tool.

Jul 28^th, 2007 at 3:16pm

Dear Nathan,

I think that you should contact your service provider and ask for their very dear support; they should not just sell you a service they should also try to help you. I think that there is a possiblity to fix the problem but there are several tests that are needed to be completed and the best way to carry it out is by direct contact over the phone or messenger or so.

If your provider cant help you with this troubleshooting please contact me offline and I will try to help you further on.

Good luck,
Nimrod

Jul 28^th, 2007 at 7:10pm

The iSite pointing application will not give a reading if you have a firewall turned on, make sure all firewalls are off to use the application.

Jul 30^th, 2007 at 9:21am

hmmm i tunred the firewall off and still nothing from the pointing application. i am able to work with the modem just fine but still get no signal reading.

Aug 1^st, 2007 at 4:19pm

Check the LNB cable and LNB DC power supply voltage.

Verify that the cables are not crossed over. Disconnect the transmit BUC cable at the modem for the time being.

One end of the receive cable should go to the receive RX IN connector on the modem. The other end to the small LNB module at the antenna. At both ends, the centre pin of the coax cable should stick out 2mm, beyond the surrounding rim. The braid of the cable should make good contact inside the F connector plug. Look, with a magnifying glass if necessary, that there are no tiny fragments of braid wire shorting the connections. When you connect the plug make sure the pin goes in smoothly and does not push back the cable itself. The pin is best rounded slightly at the tip and possibly twisted quarter of a turn as it is pushed in so that it really goes deep into the hole.

With the indoor end connected, and taking great care not to short circuit the outdoor end, measure the DC voltage at the end of the cable where it connects to the LNB. You should get something like 19 volts DC with positive on the centre pin. The purpose of this voltage supply is to make the LNB work. This LNB supply voltage (and its value) is not the noise power/signal quality voltage displayed on the iSite screen.

If you get no DC volts at the LNB end of the cable then you have a cable disconnection or the iDirect modem is not putting out an LNB supply voltage.

I believe the iSite display shows noise power at low levels and thus detects any and all satellites (yellow volts 2 to 12 volts). If it is red (0 to 2 volts) then you may have the LNB disconnected, with not even the noise floor of the LNB being received. Once the signal being received matches the configuration file the signal display value will increase significantly (now green 12 to 24 volts) showing that the demodulator has locked onto the correct carrier and thus the correct satellite and polarisation is being received. The display (green 12 to 24 volts) is now signal quality.

Once we know that you have managed to get the LNB powered ON we can then work on trying to find the satellite. What polarisation have you been told to receive by your service provider ?

Best regards, Eric.

Aug 2^nd, 2007 at 7:56pm

Dude,

Heres the deal. Your polorization is probably off. Start at 0 and see if you get different voltage readings at the az/el location you got 4 volts, if stronger or weaker than its your polorization. Second if that isnt the case take a inclometer and put it on the feed support boom of your antenna and take a real elevation reading. I spent 2 days looking for the bird because i put my offset into isite and decided to set my dish at the angle isite gave me. dont do that, verify elevation and then take your el reading using a inclometer or a pocket transit. if you dont have either go find the 31's and borrow theirs. laterz....

Aug 2^nd, 2007 at 10:41pm

I agree with the advice above, however if you are really getting AC voltage rather than DC voltage at the end of the coax that comes from the modem and connects to the LNB - you have a more serious problem - like a bad modem. If the modem is putting out AC instead of DC on the coax and you've connected it to the LNB, the LNB may be damaged by now.

Test the voltage right out of the connector on the back of the modem. It should be DC, and it should be about the same at the end of the cable on the LNB side when you connect the cable to the modem. The polarity setting will definitely affect what iSite shows you, but the modem should not be sending AC current out.

Aug 2^nd, 2007 at 11:02pm

One scary thought I had was that the earth potential might be significantly different between the indoor location and the outdoor location. It is not unheard of for there to be many volts AC (at 50 or 60 Hz) between locations, particularly when the soil is dry sand.

I am now always wary of even touching the outdoor end of an IFL cable and check its voltage to local ground or to my hand before touching it. Where I work you can also get sparks (harmless to humans) off the end of such free ended cables (and gates and fences) due to induced RF voltages from nearby, like overhead, MF transmitter antennas.

One dubious solution to mains loops is to isolate the entire LNB/BUC/Feed assembly from the outside earth by insulating at the yoke clamp. This resolves high earth currents along the outers of the IFL cables but breaks all the rules about lightning protection, earthing at the antenna and at the building interface. Maybe on a site with insulating ground the best plan is to join all metal structures (buildings, containers, shelters, antenna bases etc) with fat earth cables. A fat earth cable between the indoor rack earth and the antenna base is a safe solution.

I've not heard from Nathan ?

Amended (I received email this morning):

Nathan has the wrong type of LNB and his service provider is now sending him the correct type.

Best regards, Eric.

Aug 8^th, 2007 at 11:39pm

That's really interesting!

May 7^th, 2008 at 11:01pm

did u try telnetting the modem open the telnet in the in the tree directory type in paswords n stuff leave the command prompt box open goto ant pointing and start ....monitor voltage thru that box(cmnd prompt)

Sep 15^th, 2008 at 4:51pm

You need to check the option file for the modem and make sure it is set to provide LNB power.

Sep 25^th, 2008 at 9:58pm

Dear...

before you start the pointing from the ISte telnet to the modem and type this command:

rx enable on

and then start the pointing and see if you get any good values.

also what's the type of your LNB? PLL or DRO LNB?
this could show if you need the 10MHz to be enabled in your option file or not.

also what's the version of the package file you are using on this 3000 modem?? sometimes this happened because of a bad upload or corrupted package file to the modem, so check all these possabillity and try to swap your cables between TX and RX and see if you can find any results...

regards..