DMX741U C/KU LNBF

[C-band]

I would like to say first off I'm a newb to BUD's. I haven't found much info on the DMX741U other than what is on the WSI site and what Lak7 has given me so I though I would share what I have learned. (Thank you Lak7 for your help!) I would imagine it's all out there but being a newb not all of it makes sense.

I recieved a DMX741U yesterday to replace the few week old GeoSat Pro C/KU with a dead C. When I installed the DMX741U I connected my acutrac to KU and noticed my signal jumped UP about 20 points over the GeoSat Pro. I can't say anything about C because I never got a chance to try C on the dead GeoSat Pro from Sadoun.

Ku is 90-93, C is 80-81 both using the Acutrac. (not the reciever)

The DMX741U model has a DiSEqC whereas the DMX741 has a 22KHZ switch.
C is port 1 on the DiSEqC
KU is port 2 on the DiSEqC
KU LNB type : Universal
KU LNB Frequency: 9750/10600

C LNB type: Single
C LNB Frequency: 5150
(these are the settings in my FTA box)

I don't think you can use an external DiSEqC with the 741U. I tried but when I would switch from port to port it acted like it was hanging and drop the signal. I ended up using the internal DiSEqc and it works fine. Any ideas????

There are degree markings on the top of the KU housing. I have those aligned at the 12 o'clock position.

All in all I am very happy with the DMX741U. I still have some tweaking to do. So far I have picked up C at 58W with my 10' unimesh. When I get it all dialed in I think I can go farther. I will report back when I get it all dialed in using the reciever. I don't think I am skewed right.

 

[Anole]

congrats on the new toy:

Get your GeoSat Ck-1 exchanged, and then you can run some comparison tests.
I'm waiting on another member to do some pretty serious side-by-side experiments, but all inputs are great! -
...and remember, it's signal quality that counts.

 

[C-band]

Get your GeoSat Ck-1 exchanged, and then you can run some comparison tests.
I'm waiting on another member to do some pretty serious side-by-side experiments, but all inputs are great! -
...and remember, it's signal quality that counts.

Isn't Linuxman doing some tests?

I had thought about doing an exchange. Then started reading all the RMA stuff, blah, blah, hobbyist item and all that. Seems like a big hassle but I will give it a shot. I do agree that back to back testing should be done for a true comparison. I will be watching for the unbiased results. I was mainly wanting to post the port settings and ask about using an external DiSEqC?

I can say my KU signal quality has went up several points. I still need to tweak the LNB a bit. I have found these are allot more sensitive than I had thought they would be.

 

[Lak7]

I used the BSC621, and switched to the DMX741.
No going back.

There are degree markings on the top of the KU housing. I have those aligned at the 12 o'clock position.

Just make sure your Dish is at your South Sat.
For more precise alignment, pop the Feed Cap off (you have to push it in on one side)
Then stand behind the Dish, look into the Feed, you should see a 1/4" metal bar, that should be straight across - Level, when the Dish is at your True South - Highest Point.

 

[kwhite123]

dmx 741u c/ku lnbf

DMX 741u LNBF think I have everything figured but settings for the 22khz.I only have on and off no auto.not sure if it needs to be on,on the cband side. any help would be appreciated thanx.

 

[beavs2112]

I used the BSC621, and switched to the DMX741.
No going back.


Just make sure your Dish is at your South Sat.
For more precise alignment, pop the Feed Cap off (you have to push it in on one side)
Then stand behind the Dish, look into the Feed, you should see a 1/4" metal bar, that should be straight across - Level, when the Dish is at your True South - Highest Point.

Hi C-Band. I have a DMX741. My personal experience was the initial signal/quality readings were much worse than my old Chaparral CoRotor and Star TRAk LNB. c band was ok but ku sucked. on average my ku quality readings were in the 20% range and when i adjusted for good c reception ku disappeared. Also the C vs Ku skew and focal alignment was really different. It always annoyed me so recently I decided to tackle trying to figure out why. It's not easy to access the LNB on my dish since it's a 10' dish about 15' off the ground. I took the LNB/feedhorn off the dish and popped the front plastic cover and looked inside. Well the reason for my poor signal readings and odd skew was quite obvious. The wire for the Horizontal Ku-side was bent about 20 degrees from where it should be (referenced to the sides of the ku feedhorn and the metal bar lak7 mentioned) and one of the C-band wires was also bent about 10 degrees from where it should be. I fixed the wires by very carefully bending them with needle nose pliers. The LNB was reinstalled and now my ku and c performance has improved enormously. often i see quality readings in the 90-100 % range. so if you do look inside the feedhorn just double check that the c and ku wires are correct. since you're getting good results probably yours are ok but it can't hurt to check.

 

[truckracer]

I had a bsc621. I never could get good ku performance out of it. I put my corotor back on and ku booms in!

 

[Lone Gunman]

Bought a DMX 741U LNBF back a few months ago because I was under the impression that circular feeds could be had with that one and not with the 741. Today I got that 741U out and mounted it on my SAMI and tweaked in the C side of it. Then went to setup to put some numbers in and discovered that this U model has some funky LO numbers for the Ku side? Like 9750/10600 instead of the normal 10750 LO for Ku here in the States?

So I'm thinking that I ordered the WRONG one then??

One question on this LNBF. I did a scan with my Pansat 3500 to see what it would pick up on Cband on 99W. Did both a V scan and an H scan but wound up with all H TPs and no Vs with any matching numbers for that satellite???

So how does this thing differentiate between V and H when it scans because right now it's not?

 

[truckracer]

I remember something about the universal having the 9750/10600 LO. If you don't have it setup in your receivers antenna settings it will yield some off the wall results.

 

[Lone Gunman]

The Pansat that I have this thing connected to has LO settings that match what the LNBF is on the Ku side so that part isn't a problem.

What is a problem however is that it appears to only scan in H TPs when I blind scan with it? I've scanned Cband for H and then VPs but only get H numbers when I'm done, NO Vertical TPs?

I was thinking that since it has both V and H antenna in it that it would just get BOTH polarities at the same time but as I said, the only numbers I get are for H TPs??

Oh, and when I mounted this thing I tweaked on it for about an hour and wound up with 89 S and 99 Q on that 7.5 ft SAMI.

 

[truckracer]

Not sure why the pansat is not registering v tp's. On your blind search menu-under "polarity" are you choosing "all" or "both H and V"? Can you try another receiver?

 

[Lone Gunman]

I've done it all three ways, ie, H scan only, V scan only then BOTH and always get the same results. When I do a BOTH scan, I also get the same TP numbers with a V beside them that I get with an H beside them. After checking on some satellite listing sites all these TPs are actually H with zero V TPs at any time.

And just to clarify, I set this thing up with the "zero" on the little gauge on the end pointed up with the dish looking south. Then I backed up to 99 and tweaked it in cuz there's an analog C channel there and due south of me is a Ku only sat. Not sure I could find it the way things are now with the mover being horked up.

And BTW, didn't get a chance to mess with any of that stuff today. We went and voted then I had to do a system reload on a puter and the Wife had a "honey do" list so satellite stuff got put on the back burner. Yes, even retired people suffer from real life stuff time to time!

 

[truckracer]

LOL sometimes I wish I was retired. Maybe the lnbf is not switching? Iceberg had one like that once. Do you have another one to try?

 

[trommy]

Thanks C Band.A very knowledgable member at another site recomended the 741U over the standard,I think because it has a broader frequency range.Mine should arrive any day now from Hyper...I'll be keeping an eye on this thread.I hope you get it ironed out.G'luck

 

[gordonkearse]

I've been in this hobby since 2004. My first receivers were fortec ultra's during the N1 era. I've still got three of them which work fine.

My basic understanding since then is that standard lnb's are for the American market -- which means they are compatible more with receivers sold in the US.

Universal lnb's were intended for the European market and the receivers which were being marketed there.

I, too, got funky results scanning using universal lnb's. But you'll learn quickly when it comes to spending money.

I started out with the BSC621 standard. I ran it a couple of years and then bought a DMX741 standard. I couldn't tell a lot of difference. But tweaking is essential to getting the best signals!

I love my fta and my newer over-the-air antenna -- mainly because of the HD picture quality. Best of all, its free!!!

I bought a Pansat 9200 used in March. I wouldn't buy one if I were you. They're too expensive to get up and running for DVB-S2 -- even a used one. The only plus is that it will store 10,000 channels, but there aren't 10,000 channels up there.

There are newer receivers out now that cost half as much to get up and going. But I love the S2, too. Lots of it is HD. It scans slowly. Pansats are known as good products. I went on that assumption.

Happy satellite hunting!!! Bang, bang!!!

 

[Lone Gunman]

Thought I had already posted this once but looks like I either forgot to hit the submit button or someone deleted it, which I don't think happened. Just another example of C. R. S. at work!

Ennywho, I found out that the Pansat that I was using on that DMX wasn't switching voltage to make the LNBF switch from H to V. Have two of those receivers so I connected the other one up and sure enough, blind scan found both H and V TPs. So now looks like I got to jtag that other one to see if that will fix that problem since a factory reset didn't help.

That problem is now fixed but I have another. This 741U has Diseq built into switch between C and Ku but there's little in the instructions on how to do that, ie, what setting goes with what? I've tried it with #1 set for Cband and #2 set for Ku but got nothing on Ku. Then I tried it with #1 set for Ku and nothing for C and C works but Ku gives me a bunch of funky numbers with SRs that match Cband TPs and once it finishes I wind up with Cband channels on both, just with "funky" numbers on them from the Ku scan?

So I'm thinking it could be the dish off as I've not really "tweaked" on it as my Analog receiver is screwed up. Got another one coming early next week and I'll be able to eliminate the dish alignment issue but was wondering if someone in here knew exactly what Diseq settings went with what.

Oh, and those "funky" numbers on the Ku scan likely came from the fact that the LO setting for Ku on this "universal" LNBF are 9750/10600 and are set accordingly in the Pansat setup menu.

Anyone got any ideas on this one?

 

[Lak7]

I've tried it with #1 set for Cband and #2 set for Ku but got nothing on Ku.

That is correct.

 

[Flinthill]

Lone Gunman,
Have you been able to get the 741U to work. I'm considering getting one and need to make sure which model to buy.

Flinthill

 

[Lone Gunman]

I've had mixed results with it so far but I'm not exactly sure whether it's the LNBF or my lack of experience with anything but a Corotor II, not that I'm an "expert" at any of this stuff mind you!

The Cband side of it seems to work as well as the Chaparral C only feedhorn with a Cal Amp C LNB that I took off that dish. The Ku side of it is still out to lunch but again, this is a new to me install and I'm still tweaking on it. If I buy another one though I'll probably get the DMX741 instead of the 741 U as the LO settings on the plain 741 are the same as what's used on most other LNBs, ie, Ku is normally 10750. The U model requires the 9750/10600 (Universal) setting which has given me some "funky" numbers from time to time when it did actually work.

So I guess the question is, would I buy another one? Dunno at this point. I need to spend some quality time tweaking on this dish and as soon as my new Vbox X gets here later this week we're gonna do just that.

Oh, and one major plus is that the cost is under $40. Prior to buying this one I was looking at an Invacom and that one was going to cost me around $135.

To Be Continued and Your Mileage May Vary!

 

[Flinthill]

Lone Gunman,
In another thread a fellow said he was having trouble with the DMX741. He didn't say if it was the "U" version or not. You mentioned the Invacom brand as a possible substitute for the WSI unit. I looked at Invacom's site and couldn't find anything that had C and Ku combined. I may have just overlooked it. I'm wondering if you have the model number of the Invacom. I'd like to take a look at it because the brand has a good reputation. I considered the Chaparral "Bullseye II" feedhorn and continue using my Norsat LNBs. But, the price for the Bullseye is somewhere between $400 and $500. Just a little stiff for me!

Flinthill