Need a KU Band light weight 4W BUC

To be more specific, I need a NJT5017F.  Must be able to ship to APO address.

Eric, I think that our max C/N was around 5db.  This was at -5db of transmit power on the modem.  The test was done during fairly clear weather.

When I was with TS2 they had us transmitting at max 0.0 tx power and we still only got about 4.5 C/N.  This also greatly reduced our receive SNR.

I'm positive that the dish is pointed as well as it can be.  I haven't check to see if it is warped.  But I'll try anything at this point.  The current dish I have doesn't allow for adjustments as shown in the link you provided but I do have a spare dish that has that type of set up.  If I find that my dish is warped I will swap it out.

Thanks for the help

It's hard for me to speak to what the hub is or isn't doing.  Partly because of lack of experience.  I do know that I've tried service with two different Hubs and both have complained about my TX signal.

I can speak to the fact that I've shortened and re terminated all of my cables at least 3 times.  They are approximately 20ft in length and have no shorts. (tested with multimeter)

I tried the string test like you mentioned and the dish is not distorted at all.  The strings actually just touch one another.

I will ask about reducing uplink bit rate.

I was comparing my BUC/LNB assembly to that of another spare we have.  I have some pictures if you have time to look at them.  One is from a Bentley Walker system and ours is from TS2.  The LNB's are different (we have been using the NJR2784H the other is NJR2754H) but I believe the BUCs are compatible (using NJT5037F the spare is P/N 1025739).  The Bently Walker assembly looks a lot different and has a much larger feed on the front.  Not sure if this is based on how it sits in front of the dish or not.  Anyway, if it's possible to mix/match these assemblies to fix our problem let me know.  You may even be able to tell me if ours is assembled incorrectly. 

Otherwise I'm going to get a 6W BUC.

When testing we started with an initial power setting of -15 dBm but as soon as the terminal was in data transfer it would slowly creep to it's max power setting of -5.  Same symptom with TS2.  Initial power was -8 and would go to 0.0 dBm.

Not sure where to go from here.  Should I request another test with much lower power?  I have the other dish that goes with the assembly that came with a larger feed.  That's why I was curious if I could just swap out the LNB and try that set up.  You can just look at the other ODU and tell that it is better hardware.

I also have a spare iDirect 3100.  Is there a way to tell if my modem has been damaged other than trying the spare and seeing if that gives better performance?

We were constantly having interference issues with our current setup pointing to NSS6.  Our azimuth had us pointing in the direction of at least 10 other terminals.

Is there something configured at the HUB that tells the modem to increase it's power?  I have been under the impression that the modem has an initial TX setting and that once it is 'in network' that it was supposed to increase to max power.  Shows how much I know.

I have another system not far from here (same hardware) that does the same thing.  Starts at -8 and creeps to -2 dBm.  I've not had any problems with it though and it keeps a constant 8-9C/N.

Quote:


As Eric mentioned above, there are prescribed UCP (Uplink Control Parameters) for each network inroute group (whether it is a single carrier or bundled multiple carriers).  

All modems operating in an inroute are instructed to meet a certain TDMA Nominal C/N, at the line cards.   In most cases the default is 9dB for Ku (lower for other bands).  Which is why your nodes are operating at 8-9dB.   With a configured 9dB in mind for the UCP, if bursts from a single remote or several remotes operating in that inroute arrive high or low (ex: 10.5dB or 6.5db) the NMS will issue them power offset in an effort to get them back to 9dB (9 dB is what is cosndiered the center of the sweet spot...in most cases the sweet spot is normally 1dB wide but centered on 9dB...therefore the sweetspot for Ku actually covers from 8.5 to 9.5db.).  It CAN be made wider (say 2dB) at the risk of mild acquistion CRC Errors (they are common with a sweet spot that is too wide...but easily diagnosed by the hub). If you look in the control panel for each remote you will see that their upstream SNR remains centered on the UCP Sweet spot (the TDMA nominal value set by the HNO).

With the above in mind, getting a 1dB compression test is a must.  A good 1dB compression test will identify your max power limits (read: for your operating location, and your RF components)  thus preventing the NMS from issuing power offsets to the point where you saturate the BUC and the signal/carrier becomes distorted (saturation will yield Hub traffic CRC errors).   Power offsets are common when  the Hub and/or the remote site(s) are under weather.  The NMS will ONLY up the power to a specific node, if THAT remote site is under weather.  It is site/remote specific (one site under weather will not cause the NMS to adjust power on the entire inroute group/all of the modems).  However, if the Hub side comes under weather, then obviously the NMS will issue power offsets to the entire inroute group to bring them all up on power due to the attn of the downlink - as seen by the e/s hub.

Just wanted to close out this post and let everyone know that we are finally up with a stable service.  We never did figure out what was wrong with our TS2 terminal nor why 3 different service providers couldn't get it to work.  We haven't found anything wrong with the hardware???

We are now on a Bentley Walker system, using the same 3w BUC on AM22.  Our tx power usually averages -19dBm but can vary between -20 and -16 depending on the weather.

Thanks for all of the help!