SatSig topic:

iDirect 3000 problem, low RX

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Dec 15^th, 2011 at 6:49pm

Hello, I'm from Argentina. I'm trying to point an iDirect 3000 series to Intelsat 707. The problem is that I can´t get more than 5 volts with iSite or Console. I'm using a modem with the 6.0.9.1 version and the OPT is 6.0.9.3. I don´t know what else to do. I know that I have DC to the LNB, I already check the frequencies. Is it a problem version, maybe and old version?? Thank you.

Dec 16^th, 2011 at 4:49pm

Maybe polarisation. If Ku band, have you set the initial named polarisation and then adjusted it?
What name polarisation and by how much adjustment amount ? Adjustment amount will be about 10 deg clockwise, as viewed from behind the dish and facing forwards towards the satellite in the sky. What is your receive polarisation name lat/long or town ?

Maybe wrong satellite. You are presumably peaked up on some satellite. Does the +5v go down if you move the antenna slightly sideways, either way ?
Note and measure and mark the exact position now, so you can always get back to this satellite.
Do you get readings at the other adjacent satellites along the orbit either way? The other satellites are in a gently sloping line, tilted at about 10 deg down to the right.

Maybe wrong tuning. What is the satellite downlink carrier frequency ? What is the model number/local oscillator frequency of your LNB ? What is the receive L band tuning you have set (in options file)?.

Best regards, Eric.

Dec 16^th, 2011 at 5:46pm

It's not a polarisation problem, I'm using an OMT with Rx H y Tx V. When I move the dish to the right and left I have a slow down in the 5v. I can find another satellites but they have less than 5v (at least 2v). About the tunning, well I'm using a DRO and last night I try with a PLL. The frequency in the OPT it's 10.75 GHz in both LNB and PLL. I configured the values in the OPT file and the rx freq in L band it's 1 GHz, or 1.2GHz. I mean, the values match with the BW of the modem and the BW of the LNB. The model of the LNB is: NJR2744HH and the PLL is: NJR2535H.
I have a question...does the modem has to be somehow "activated" in the NOC's database??. I only want to have Rx, Tx doesn't matters to me.

Dec 16^th, 2011 at 6:17pm

If your wanted carrier is wider than 6 Msps then the DRO LNB will probably do OK. The modem receiver may lock to the carrier even with an error as high as +/-900 kHz. But, make sure you have the receive acquisition range set wide enough in the options file.

If your wanted carrier is small, say less then 2 Msps, then the PLL LNB is needed.

In the options file you need to set the L band receive carrier tuning frequency. This, when added to the LNB local oscillator gives the actual satellite downlink frequency. Ask the NOC what is the satellite downlink frequency, then subtract 10750 MHz and the answer is the tuning frequency for you to use in the options file.

Example:
Satellite downlink frequency 11875 MHz.
( minus ) LNB local oscillator frequency 10750 MHz.
( = ) Modem tuning frequency 1125 MHz or rx_freq = 1125000000

I can't see any reason why the options file needs to include the LNB local oscillator frequency.

While you ask the NOC find out what is the downlink polarisation name. If your polarisation name is "Vertical" and you have +10 deg clockwise adjustment applied then the LNB arm will be sticking out sideways, slightly up if on the left side or slightly down if on the right hand side, as viewed from behind the dish and facing forwards towards the satellite in the sky. If your polarisation name is "Horizontal" and you have +10 deg clockwise adjustment applied then the LNB arm will be sticking upwards and slightly to the right, as viewed from behind the dish and facing forwards towards the satellite in the sky.

Ask the NOC for a fresh up-to-date options file, saying what LNB you are using. This will make sure you also have the bit rate and FEC set correct.

Your modem will need to be registered at the hub if you are to transmit.

Best regards, Eric.

Dec 17^th, 2011 at 6:32am

Hello Eric, today I saw the satellite. I could get an iDirect modem x3 Evolution. The thing is that, although I could find it; I won't be to able to hold the modem (only for a few days). I'm using an iDirect LNB PLL with two bands. do you have any suggestions about what can I change in my old modem to make it see Rx??. Another thing, I need to be able to enter by hyperterminal and I dont have the iDirect login (it's not iDirect). The procedure to change the iDirect login password (root password), is the same that in the iDirect 3000 series??.

fis load Linux
exec -c "root=/dev/mtdblock2 console=ttyS1,9600 single"
--- and when it appears the /# prompt I have to enter passwd...
Thank you

Dec 17^th, 2011 at 8:29am

I suggest you contact the NOC for advice about a suitable model of iDirect modem, software version, type of LNB and matching options file.

I am not aware that an iDirect modem can control a dual band LNB, so as to switch it from one band to another using voltages (say +13V or +19V) or tone (22kHz on/off). All iDirect modems are intended to be used with simple, single band, LNBs, as far as I am aware.

The modem tuning, set in the options file, needs to be the satellite frequency minus your LNB local osc frequency, for Ku band systems. See my message above for example calculation.

If you have a PLL type LNB find out if it is internal or external reference. If external reference, then the options file will need the 10 MHz reference turned on, thus: odu_rx_10_mhz = 1

I don't know about password etc.

Best regards, Eric.

Dec 18^th, 2011 at 7:47am

Eric, the LNB it's an iDirect Universal PLL with and input freq: 10.7-11.7ghz / 11.7-12.75ghz and the local freq it's 9.75/10.6ghz +- 370 khz. About the internal or external reference of 10 mhz, I already saw that, the thing is that, n the 3000 sries I didn't have to put the reference, but in the x3 it comes in up that value "1". So, the PLL it's using that 10 MHz reference. I can't contact with the NOC, a couple of friends of mine provided me with this equipments to make a few test and I cant get in touch with the NOC. I solved the problem with the pass. Thank you Eric, I will tell how this works...

Dec 18^th, 2011 at 8:30pm

Your LNB might be one of these:

DiSEqC 22 KHz Tone Universal Ku-Band PLL LNB (P/N: E0001110-0001)

Manual Switch Universal Ku-Band PLL LNB (P/N: E0001106-0001)

Local Frequency
[Low band] 9.75 GHz
[High band] 10.60 GHz

Input Frequency Range
[Low band] 10.70 to 11.70 GHz
[High band] 11.70 to 12.75 GHz

Output Frequency Range
[Low band] 950 to 1,950 MHz
[High band] 1,100 to 2,150 MHz

If the 22kHz tone version: high level tone On= high band.
I don't know how to turn tone on/off using options file. Note that this type of LNB is referred to in the context of the "Evolution" series iDirect modems.

If the manual version you turn a switch: cross means low band, in-line means high band.

Read more: https://www.idirect.net/~/media/Files/Spec%20Sheets/iDiProductShtPLLLNBs08103.as...

There is no mention of an external reference being required, so try with the 10 MHz reference supply from the modem turned off.

Best regards, Eric.

Dec 24^th, 2011 at 5:13am

Thank you Eric, but in the x3 series we don't the option of "set" values in the OPT; it might because the configuration (i'm not so sure). This LNB model uses the 10 MHz reference, anyway the projecto works so thank you very much.