How to properly use blind scan

[SATire]

The question is, how to properly use blind scan to find everything possible.

When I do a blind scan, I end up with everything possible that the dish can pick up. If I'm dead on something and there's nothing else around it, then the blind scan should simply reveal everything there is on that satellite.

However, if there's another satellite close enough that the blind scan is picking up channels on more than one satellite, so you end up with a bunch of things that you don't know where they belong.

The only way I know of to clean that mess up is to look at each channel, find out what bird it's supposed to be on and make a note. That takes for ever, isn't worth the effort since one scans now and then for changes.

So my only other option I think, is to make a list of all the TPs which were found, eliminate all of the ones which don't have a signal and that becomes my list for that position/satellite.

Is there a better way? How can I find out all of the TPs on a bird but not end up with the same channels on multiple positions?

BTW, at the moment, I'm using a geosat unit for C only.

Mike

 

[SatelliteAV]

Blind Scan is designed to log all active transponders that your dish is aimed at. Detecting and logging a transponder that is not on the selected satellite is not related to receiver function. A receiver will ignore LNB type and LO frequencies as it is scanning all IF frequencies being sent down the coax from the LNB. Blind scanning transponders from adjacent satellites usually indicates that the dish is either too small or that the dish is not properly aligned.

Sounds like you are already taking the steps to eliminate the transponders that do not belong on the satellite. The only ways to deal with unwanted transponders is to not scan them or to delete them!

 

[Tron]

One of the biggest pains regarding blind scan is the fact that a linear LNBF will pick up some adjacent circular signals if you are close to one of the DBS birds (especially 119W). I usually scan birds that are close to 119W with the "FTA only" option, although I am aware that by doing this I may sometimes miss channels that are, in fact, in the clear.

 

[SatelliteAV]

One of the biggest pains regarding blind scan is the fact that a linear LNBF will pick up some adjacent circular signals if you are close to one of the DBS birds (especially 119W).

You can narrow the IF (frequencies) and the Symbol Rates that are to be scanned in the Blind Scan mode on many receivers. I first saw this option developed by a friend, David McGrath with Fortec Star, on their Lifetime Ultra model. I liked this hobbyist friendly feature so much that we introduced it to the Coolsat brand starting with the 4000 model, and also the Visionsat and the GEOSATpro brands.

Example for North America: If you are using a KU-band, Standard type LNB with an LO of 10750, Make sure that the scan range is set to 950 - 1450MHz (11.7 - 12.2GHz). For a C-Band LNBs with LO of 5150, set the scan range to 950 - 1750MHz. This scan option will avoid scanning frequencies outside of the desired range and also considerably speed up the scan.

 

[Jim S.]

It would be nice if we had more receivers that could be programmed to scan 11700-12200 only. The Solomend doesn't give you any chance to set the range, and the Coolsat I used to use let you set it but you had to set it on each scan by keying in the numbers, which quickly got annoying.

 

[SatelliteAV]

It would be nice if we had more receivers that could be programmed to scan 11700-12200 only. The Solomend doesn't give you any chance to set the range, and the Coolsat I used to use let you set it but you had to set it on each scan by keying in the numbers, which quickly got annoying.

It is quite easy to code, as these parameters are already implemented in Blind Scan capable receivers. It actually takes more time to integrate into the GUI / OSD than it does to make the parameters to include user variables.

 

[SATire]

I only pointed out the receiver because all have slightly different ways of doing the same things. Sometimes, there's a trick with one or another.

The problem is that even when I use sites like lyngsat, it seems that the TPs found aren't always those in the lists and so doing a blind scan reveals the TPs on that bird. Because I ended up doing a blind scan, I also end up with adjacent TPs when birds are close together.

After I do a blind scan, I generally do not save the list but sometimes get lazy and do. I often note down a handful of the TPs found which I don't see in the lists then look them up.
Basically, I'm trying to figure out how to get a fully current up to date list of TPs for the satellite I just tuned into.

Wondered if there was a trick to doing this.

 

[SATire]

Something I've wondered about as I'm sitting there moving the dish back and forth is how the receiver itself could be doing that for me .
Using USALS for example, after getting a starting point, why couldn't the receiver just start working on the adjacent bird, position to where it thinks it should be, then start moving the motor W/E looking for signals. As it finds signals, fine tune into them, have Internet access or a USB port with an updated list of TPs so know when it's hit the right bird, scan all of the channels in. Move on to the next position.

It would be so cool to let it do it's thing and the next morning when you turn on the TV, everything is already there .
Heck, someone could start a little service updating the files that folks would put on their USB key or that the receiver would check regularly over the net and when things changed, would update itself.

I'm day dreaming because I seem to spend way way too much time at this. I just want to watch TV without having to spend days messing with it.

 

[Jim S.]

I don't think you can technically have a complete list of digital transponders, because the symbol rates aren't built into the satellite, they're whatever the uplinker sends.

I'm still puzzled that you're getting so many adjacent satellites. Are you talking about C or Ku, and what size dish are you using?

 

[SATire]

>I'm still puzzled that you're getting so many adjacent satellites. Are you talking about C or Ku, and what size dish are you using?

Nothing unusual, just that I'm using blind scan to try and update my TP list so when the satellites are fairly close together, I seem to pick up nearby signals. I'm using the C-band 742 I think it's called now and the dish is a 6' fortecstar.

 

[SatelliteAV]

I am also confused why your system is picking up transponders from adjacent satellites. Even with a 7.5 dish on C-band, I don't scan any adjacent satellite transponders and I don't recall any adjacent satellite issues when playing around with an offset 1.8m dish either. If the dish is optimize on a single satellite with the LNB properly centered, the FD set and dish tracking the arc, you should not be scanning adjacent satellites.

You shouldn't need to locate satellites using blind scan. I select the satellite and an active transponder frequency found in either The List or on Lyngsat. In DiSEqC 1.2 mode, I drive the dish until the Signal Quality indicates that the dish is on the target satellite, scan that one transponder to verify that the dish is on the correct satellite. If necessary, bump the dish to optimize SQ, delete all transponders from the satellite list then perform a Blind Scan. This provides an accurate transponder list with only active frequencies.

 

[SATire]

I'm glad I asked this question because it indicates that I'm doing something wrong or something in my setup isn't quite right.
I was very much hoping that once I had a starting point, that I could use USALS from that point on but this doesn't seem to work for me. Does it for others?

 

[Jim S.]

I don't use C-band so I can't say for sure what's going on. Unless your dish is just picking up interference because it's too small (do you happen to have a quote for beamwidth for it anywhere?), the usual suspects are that you're aimed between two satellites when you think you're peaked on one, your LNB isn't centered / isn't straight, or your dish is bent.

Let's say I scan 97W Ku and I get all the channels, or most all the channels, from it, but also get one transponder from 95W. (This is easy to recognize, because CCTV is on 95W full-time.) I watch the signal from that transponder from 95W and move the dish west til I get rid of that transponder. Then I scan 97W again and make sure that the one really hot transponder on 99W doesn't show up too. (The S2 Russian transponder that has one channel ITC at the moment.) If it does, I move the dish a tiny bit east, then again check that CCTV hasn't reappeared. Then, I delete all the transponders from my 97W list again and re-scan, because there are plenty of channels to sort through there without any extras.

If you're not trying satellites that have full-time active channels, I can see where this would be a headache to test your alignment.

 

[SATire]

We dropped the dish when it was being installed and I've always wondered if it might be off. I've not done any measurements on it but will next year or will get a replacement dish depending on how things go til then.

 

[AcWxRadar]

I'm glad I asked this question because it indicates that I'm doing something wrong or something in my setup isn't quite right.
I was very much hoping that once I had a starting point, that I could use USALS from that point on but this doesn't seem to work for me. Does it for others?

SATire,

I use USALS exclusively with a Ku-band system (GeoSatPro 1.2M dish and Invacom QPH-031 LNBF).

I set up the dish antenna and the motor using my true south satellite (97W) and entered my latitude and longitude as accurately as I could. There was some number rounding errors to get them to one decimal point, but I don't think that is of great concern. I can use USALS to drive to any satellite within my LOS and it is spot on. I cannot use USALS to drive further than +/- ~59°. It just won't drive past that window edge. There is more travel available from the motor, but I have to use DiSEqC 1.2 to access it.

That being said, I don't have any troubles blind scanning one satellite and picking up TPs from an adjacent satellite.

RADAR

 

[SATire]

I just got my KU dish going again today after taking a quick look and finding the problem in the cable.
I don't have that problem with the KU, only with the C-band dish. Thanks for the tip, that's really useful, especially the point about fine tuning into my LAT/LONG.

 

[SATire]

That's an interesting tip, I wasn't aware of that. I've not spent a heck of a lot of time actually getting to learn these things, been messing with problems mostly. I've set 93W as my default as USALS and see that when I make the others USALS also, the receiver basically just moves the motor to where it should be, more or less. That's pretty cool.

I'll have to mess around with it to figure out how to fine tune it all.

 

[SATire]

Actually, I do have another question on this.
I wasn't aware that I could set a starting point in USALS, then set the next satellite to USALS and it 'should' position itself on it's own.

That seems to have been working up until I made some corrections. For some reason, even though this dish appears to be nice and tight, it's not wobbly or loose, yet when I tune into a channel, sometimes the receiver just plain loses it and I have to correct it again.

So, I got my 93.1W all set up, had a number of others working perfectly using USALS, then one went out so I readjusted and then everything got lost. Since then, I cannot use USALS anymore and have to use DiSEqC to get the signals back. Weird thing is, if I try using USALS to get the signal back, which I do, the second I exit the menu, the position is lost again. The only way I've been able to save them is by using DiSEqC now.

 

[SatelliteAV]

USALS motor control only works with your HH motor / KU band dish . USALS does not work with a VBOX or GBOX with a linear actuator (jack) on you C-band dish. You must use DiSEqC 1.2 motor control with a VBOX or GBOX.