Thread: Montana PBS Cure

Many of us have experienced problems while trying to receive a stable Montana PBS that doesn't do a SQ 75 (or whatever) to 0 dance causing pixelation, freeze-ups, etc. Most recently posted here: http://www.satelliteguys.us/free-air...ble-catch.html (see my comments on page 2 as to what I experienced).

Anyhow, the weather was unseasonably warm a couple of days ago, so I decided to replace the LNB (a Digiwave standard linear) with one of my many spares to see if one would give a better signal to help alleviate the SQ yo-yo dance. My SQ for Montana PBS (when I could glimpse it before it did a dance, or on the rare times that it locked in) has always been in the 70s to high 80s.

I decided first to try one of my Fortec Star universal LNBs (I bought several during the beginnings of my FTA, before I realized the extent of my addiction, and the general need for standard linears). Checked the SQ on the other transponders on 125, levels were around the same (some a tiny bit lower). BUT... Montana PBS, which had been glitchy minutes before the change, was now locked without any problems! No matter what I did (changed channels, turned off/on the receiver, etc.) it always acquired a lock, and held!

It has now been almost two days since the switch, and still it locks (and holds) and doesn't do the dance (except the odd time for a second or two when I first go to the channel, usually when coming from a different satellite). Was able to watch the Saturday night British comedies for the first time in a long time without any glitches. I am a happy camper!

Anyhow, for any others experiencing the same problems, if you can, switch out the LNB, and see whether a different one can make a difference. Of course, YMMV.

1.2m dish, invacom LNBF. no problems ever!!

I don't know why people expect good things to occur with DVB-S2 signals when they have $10-15 asian **** LNB(F)'s....

Which dish and what model Invacom LNBF are you using?

Originally Posted by skysurfer

1.2m dish, invacom LNBF. no problems ever!!

I don't know why people expect good things to occur with DVB-S2 signals when they have $10-15 asian **** LNB(F)'s....

My ku dishes have the original Primestar LNBs on them and everything works fine....till I hit the Montana transponder. Then I get a brief pixelated image & the box re-boots. Every time.

Sent from my DROIDX using SatelliteGuys

Fortec Star 1.2m dish (self-modified to get better performance than the standard install) and a Invacom QPH-031 LNBF.

I also have the Invacom LNB... the SNH-031, and I have no problems at all. The signal is low, but I get a watchable picture all the time, and I use a 76 cm dish.

Originally Posted by Andrew K

...The signal is low, but I get a watchable picture all the time...

I can say the same regarding reception of LPB on 87W. It seems with DVB-S2 that very low measured signal quality (10-15%) still delivers visually clear reception once the receiver locks onto the signal. Normally on my S9 with a DVB-S signal, I need at least 45% or higher to watch a station reliably.

[QUOTE=skysurfer;2746412]1.2m dish, invacom LNBF. no problems ever!!

I don't know why people expect good things to occur with DVB-S2 signals when they have $10-15 asian **** LNB(F)'s....[/QUOTE

Maybe a more expensive LNB will be better but I'd think like most digital devices LNB's either work or they don't. Isn't the difference between price ranges going to be sensitivity and ability to discriminate and pass on the signal with minimal signal loss? If you are in a fringe reception area for the same dish set up and cable run maybe one LNB will give you better Q than another but if you are solidly in a desired footprint do you get much bang for the buck if the difference is say 76% Q instead of 74%. Seems like dish aiming and dish design will be much more important for weaker signals than the LNB cost or brand will be, especially for a sat that has the dish highly skewed. I've found dish tweaking for Montana PBS to change the skew just a wee bit resulted in a much stronger signal and even if I dropped a few percent of Q at the eastern end of the arc, my cheap Fortec lnb is just fine.

Maybe the answer is that some may need a more expensive LNB (assuming better but that is another discussion) if they are geography challenged, have long cable runs etc. but not all of us need to go that route and can use "cheap" just fine.

I am surprised that anyone would have trouble with Montana PBS. I pull this signal down with a quality reading of 96-97% indicated on the meter of my AZBox Premium Plus. I have a 1.2 M GeoSat PRO dish with an Invacom QPH-031 LNBF and a DG-380 motor.

The LNBF itself is not exactly a major factor in the equation. Almost all LNBFs work exceptionally well. A $6 vs a $120 LNBF changes the quality very little. The higher dollar LNBFs are usually more expensive because they are providing you with added features like multiple outputs or C + L band or low + high Ku band capabilities, etc. Unless your LNBF is pure junk right off the shelf, there is little difference in the reception.

The important factor here is three fold, possibly four. The first is the size and geometry of the dish. Second is how well the LNBF is matched to the dishes physical geometry. Third is the IRD's tuner quality. AND the most important of all is the alignment of the dish and motor tracking of the arc.

I have always utilized the Invacom QPH-031 LNBFs, so I never questioned the reception. I always concentrated on the size of the dish and the alignment of the dish and motor. When I tried a less expensive LNBF, I noticed very little change in signal reception quality. Some actually improved the signal.

Getting the LNBF and the dish geometry to match are important. Sometimes the focal distance is extremely important. Sometimes the two are so well matched that the focal distance does not seem to make a great deal of difference. You will discover this as you simply experiment with your components.

The dish size is important here, but so is the actual geometry of the dish. A 75cm Winegard dish is excellent, but I found the larger 1 M Winegard to be extremely selective (more difficult to align as it seemed to focus too tightly). The larger dish could increase the signal quality substantially, but was extremely touchy to align. Being much heavier, it proved to be a poor choice for a motorized system in my opinion. If the dish is highly focused, then you must be especially critical of your alignment and arc tracking. My 1.2 M GeoSat PRO dish proved to be much more reliable. It was not so focused that it became unforgiving if it were not precisely aligned and it was not so heavy that the motor couldn't handle it.

I have compared the 75 cm Winegard and the 1.2 M GeoSat PRO closely. I would recommend either highly. But, I would rate the 1 M Winegard as a poor choice for a motorized system as the alignment does become so critical. There are other sized dishes in between that I have not experimented with, so I cannot provide an evaluation of them.

The tuner within the IRD has a lot to do here. If it is of good quality, it proves itself. If it is not, they often adjust the meter to make it appear better by numbers or scaling that is not accurate. A receiver with a poor tuner and a falsely scaled meter can be very deceiving (which is why we do not compare apples to oranges).

In summary, there are quite a few factors that you must be aware of and the most critical is the actual dish (and motor) alignment. The LNBF is one of the lesser factors here. Most all LNBFs provide acceptable performance, even if they are only priced at $12.

Just keep all of my statements in mind when you are setting up your system and selecting components.

RADAR