SatSig topic:

modem linkstar always restart when connected to bu

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Jun 10^th, 2010 at 9:38am

dear all,

i hope my topic it's not repost

my friend at east indonesia have trouble with the modem linkstar, the trouble come when the modem connected to buc, the modem always restart, any one know why?

we was pointing using rx first after rx power have good value (-43) so we shutdown the modem and connceted modem to buc, but after the modem connected to buc, the modem always restarting ( the sat led at modem never fast blinking, after boot up the modem will restart)

Jul 21^st, 2010 at 8:15pm

Hello dear,
if you using RG11 Cable then please change it to RG6 caz the RG11 is more ohms then RG6 ... and how much Watt is yout BUC. if all of these not done then change the BUC + contact with HUB and give them the BUC model to change the model for you link ...

Jul 22^nd, 2010 at 7:25am

Hello,

It does not sound like a cable problem.

The procedure you have taken is good: With BUC disconnected point the dish to the satellite, after getting good Rx signal turning off the terminal and connecting the BUC.

I think you should contact your NOC and work it out with them. For my opinion, it sounds like the terminal is trying to connect to the hub and is getting continuos reset command from the HUB, maybe there is an issue with the version or the parameters configured into the terminal. Anyway, at this stage you must work it out with your hub operator.

As it was mentioned, about different cable types:
Both RG6 and RG11 are 75 Ohm. The difference is that signal loss on RG6 is higher than on RG11. Typically (but not always), it is recommended to use RG6 for distance of cable run of up to 50m and RG11 for cable run of 50m to 100m or so.

Kind Regards,
Nimrod

Jul 22^nd, 2010 at 8:39am

Warnings:
Always power off before doing anything with the coax cables.
Never get the coax cables crossed over.

RG-6 type
Connector used: type F (male).
Impedance: 75 Ohm
Recommended for IFL lengths up to 100 ft.
Maximum length is 200 ft with external power supply and 2W C-band or 1W/2W Ku-band BUC.
Maximum length is 150 ft with external power supply and 5W C-band or 4W Ku-band BUC.

RG-11 type
Connector used: type F (male).
Impedance: 75 Ohm
Recommended for IFL lengths between 100 – 250 ft.
Maximum length is 250 ft with 2W C-band or 1W/2W Ku-band BUC.
Maximum length is 250 ft with external power supply and 5W C-band / 4W Ku-band BUC.

RG-8 (75 Ohm) Low Loss Cable
Connector used: type F (male).
Impedance: 75 Ohm
Recommended for IFL lengths between 200 – 300 ft.
Maximum length is 300 ft with 2W C-band or 1W/2W Ku-band BUC.

Signal attenuation per 100 ft:
RG-6 approx 11.1dB @ 950 to 1450 MHz
RG-11 approx 4.1dB @ 950 to 1450 MHz
RG-8 (75 Ohm) approx 3.3dB @ 950 to 1450 MHz

Regarding the resetting problem, I wonder what is the power setting in the config text line.

If your -t transmit power setting is too high then at the instant that your modem first transmits the BUC will be overdriven and its power supply current will go abnormally high, causing a high current in the modem power supply and making it trip off and reset.(and maybe damage it)
Try with -t -60. This sets the modem transmit output power to its lowest level -30dBm. Each -t step is 0.5 dB. If that stops the resetting then increase the level progressively e.g. -t -55 and so on till your transmit signal is strong enough to get through to the hub.

You might also get the overcurrent / reset effect if you are using a 5W BUC and don't have an external power supply. You can damage the modem doing this.

The maximum input level into a BUC is typically -20 dBm. Do not exceed this. Read the BUC specification if you can.
e.g.
Modem output power setting -t -30, means level = -15 dBm.
Cable loss 10 dB
Input level to BUC = -25 dBm.

Best regards, Eric.

Jul 29^th, 2010 at 4:36am

the problem solve when my engineer cut the cable form 30meter to 20meter, maybe its was poor cable i use, thx for u'r opinion and solution that given to me,

1question againt Cheesy

what recomended cable for linkstar no i use Belden Rg6 9116 with 60%
so i change no to comscope F690BV 90%, but the vendor suggest SAT660BV, wich one i must choose, or you can recomended the best cable ?

Sep 1^st, 2010 at 7:48pm

check is your linkstar modem software is upgraded from hub site if not it will not sync and if the modem not sync it restarts again n again after 10 min this is it's default setting.