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NJT5017F and DirecWay compatibility Question

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Jan 29th, 2008 at 2:17pm  
I am trying to set up a DirecWay based system in Iraq and wondering if there are any compatibility issues between a NJT5017F Transmitter (4W BUC) and DirecWay 6000 systems.

I received the satellite and ODU separately and had to "find my own modem" so I am testing it with a current DW6000.

The problem is I receive a Tx Code of 13 when I try to Range the system to NSS6.

I receive a 99 signal strength using the following:
- Channel Master (Andrew) 1.8m Antenna (Type 183)
- LNB: NJR2784H (P/N 1024572-0001. Shown on Hughes list)
- BUC: NJT5017F (4W BUC)
- DW6000

I am pointed at NSS6 (from Iraq at 110mag, 23.94 elevation)

I have tried:
1. Adjusting Lat / Long values through Telnet. I am EXACTLY on from both Map and GPS (it was slightly previously, but the unit had no issues on W1)
2. Reconnecting the connections on the BUC and indoor unit (modem)

? Will any Polarity change fix this? Is it possible to have a 99 signal and the Tx Polarity be incorrect?

Which leaves:
- Bad BUC
- DW6000 cannot output 4W required
- Moisture inside ODU

Any help would be appreciated at this point I am unsure what the issue is.

Alex
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Reply #1 - Jan 29th, 2008 at 3:25pm  
I believe the problem may be the 13.05 GHz local oscillator freq of the NJT5017F. The DW6000 assumes the BUC and LNB use the same LOF. If your LNB is in fact Hughes approved, it likely uses a 10.75 GHz LOF (http://bipcorp.com/bip2/product_pdf/NJR2784H_rev02M.pdf isn't specific). You set the RX frequency in during the registration/commissioning process. There is no operator input for TX frequency.

My guess is that the NJT5017F is simply not compatible with the rest of the hardware.

//greg//
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« Last Edit: May 10th, 2015 at 1:14pm by Admin1 »  

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Reply #2 - Jan 29th, 2008 at 5:12pm  
Are there any other Modems which are compatible or allow Transmit Frequency adjusment?

The Dish (with feed cone and waveguide), BUC and LNB all came together.

To verify, there is another identical "backup" which was unused as well with the same hardware. It is strange there are two exact setups with the same hardware which won't work with DirecWay. Perhap they were designed for use on a higher end system.



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Eric Johnston
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Reply #3 - Jan 29th, 2008 at 5:25pm  
Ask your service provider what receive frequency and receive nominal polarisation you are supposed to be using and ask for advice about using a non-standard BUC.

A 10 GHz local oscillator LNB, like NJR2784H, may be suitable for you if it matches the particular downlink frequency you are trying to receive.  Subtract 10 GHz from the downlink frequency and see if your modem can be tuned to the result of the calculation.  Your successful reception of a signal sounds promising.

LNBs with other local oscillator frequences, like 9.75, 10.6, 10.75 or 11.3 GHz are available, if required.  The most recent Hughes HX kit comes with an Invacom LNB which is 22kHz tone switchable 9.75 or 10.6 GHz.

Greg is right to query that the standard 13.05 GHz local oscillator of the NJT5017F may not be the same as that used in the Hughes device.  I don't know.   There seems little information around about how the Hughes modem and transmit module interwork.  Apart from the unknown upconverter local oscillator frequency there is a need for a reference (10 , 50 MHz perhaps) and the possibility of FSK configuration and status communications between the units. With no knowledge I would suggest leaving disconnected so as to avoid possible interference to others.

I am concerned that the DW6000 indoor unit may be unable to put out sufficient DC power (48 watts) to power the NJT5017F BUC.  The DW6000 or its power module or its connectors may overheat and be a fire hazard.  If it struggles to supply adequate DC power to the BUC there is the further problem that the output may be distorted and chirped and interfere with adjacent carriers.

Best regards, Eric.
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Reply #4 - Jan 29th, 2008 at 5:59pm  
Per IPdish, when aiming at NSS-6 I am supposed to use the following settings (when entered through Telnet)

Satellite Channel Frequency: 16700  (<x100 KHz>)
Receive Symbol Rate: 5000000
Viterbi Rate: 3 (for 3/4)
LNB Polarization: 0 (Vertical)
Tx Polarixation: 0 (Horizontal)
DVB Program Num - User: 20500
DVB Program Num - DNCC: 0

Previously, on W1 the DW6000 was set at:
Satellite Channel Frequency: 16156
Receive Symbol Rate: 30000000 (Sps)
Virterbi Rate: 5 (for 5/6)

The LNB Part Number is listed on the Hughes part list as compatible (1024572). And by the receive signal so far, I am confident that piece of the puzzle is a non-issue.

As for the BUC, its frequency or power requirements make for the issues.

I have a separate dish aimed at W1 (.98m) which was part of the same setup the DW6000 I am using came from. I can get that working if need be, but I was attracted to the promised non-existant Download caps of IPdish through their Dubai NOC. I am trying to other option to "just" buy a new modem (if the whole setup works) instead of having to buy a whole new setup.

Tell me if I am crazy, but trying to get Soldiers access 400 mb goes fast between 10-12 people (just to be throttled).  The recent Hughes restriction of hardware to service providers it was purchased through is annoying.

Are there any Specifications on the local frequency of compatible BUCs? How much do they run (with shipping to Iraq a key factor). However, if I begin to replace component the advantage of "only having to buy the modem" goes away, and dealing with download restrictions becomes reality.

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Reply #5 - Jan 30th, 2008 at 2:09pm  
I think I have figured out which system the Satellite antenna (with BUC and LNB) was originally used for.

They are selling a 4W BUC which came from an "iDirect" package.

Thus I think the antenna is inteded for use with iDirect and not with DirecWay. (It's compatibility with Linkstar is unknown).

Now the next question is:
What is better Hughes, iDirect or Linkstar, with trying to get the best price, but maintain minimal download caps (which result in throttling).
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« Last Edit: May 10th, 2015 at 12:52pm by Admin1 »  
 
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Eric Johnston
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Reply #6 - Jan 30th, 2008 at 3:09pm  
My opinion ---
Hughes, iDirect or Linkstar are all excellent technical solutions.  Hughes HX and Linkstar-S2 have DVB-S2 type outlinks and are thus efficient.   Hughes HX has adaptive return links.  iDirect is based on a strong IP networking design and has mesh potential.

The service you get will depend very much on the people who run the hubs and their balance of quality versus price and how much profit they wish to make, if any.   Any hub can work very well to not at all, depending on the people who operate and configure it and the way they help customers with installations.  The marketing/sales people are also important as far as perception is concerned.  It is wrong to raise expectations above what can be actually provided.  This is the reason the word "unlimited" is virtually banned, by me, from use in this forum - but people still try it on from time to time.

Hughes has a history of very large hubs and mass market low cost hardware, but this brings devolved  customer interfaces where you can never get to talk to the hub engineer.  The new HX hub, managed by Bentley Walker is a refreshing change.  You get talk to the people who can actually help you.  

iDirect has several hundred hubs ranging from those managed by teams of perhaps 20 people to those operated by one man from home via a remote PC.  The technology is fine but the support you get will vary, also the ability to make special arrangements involving extra hub equipment or software.

Linkstar/Wildblue/Tooway/DOCSIS are generally big time hubs like Hughes and are often interrelated with the satellite owners and VSAT is a way to use up their satellite capacity.

Some networks offer very cheap services.  Beware of severe congestion and the company going bust in a few months time.  The most expensive services involve dedicated trunking capacity, suitable for phone shops, large internet cafes, businesses, ISP and cell phone nodes.

Regarding cost and throttling.   The basic fact is that is costs so much to put 1 Mbit/s through the satellite.  I guess you want similar high speeds, but only for a very small proportion of the time.  Your need, per PC, is only about 15kbit/s down and 4kbit/s up on average and this is all you can afford to pay for.  What you would like is 1 or 2 Mbit/s down whenever you want it.  It is not easy to marry up these apparantly conflicting requirements.  The solution is some kind of fair access policy to make sure that the amount of Mbytes that you actually download does not deviate too far from the proportion of the total costs that you are paying.  Fair use quotas like 180 Mbytes per 8 hours at the top speed, followed by lower speeds for the remainder of the 8 hours are typical, with different values according to how much money you contribute.  VoIP, file sharing, video and audio activities are expensive to provide compare with typical web browsing and emails.

As a very rough guide, you should be paying at least $70 per month per PC you have connected.

I know all the above is moderatly controversial, so welcome to further comments below please.

Best regards, Eric.
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