amc 9 83 w classic tv here

[tvropro]

Yeah, G3 issues....right there with ya bud :rant:
I agree, there are a lot of factor we just dont have the information about. We can only speculate from observation, but you would think any engineer worth his salt would know the fine line this signal is riding. Another 'speculative' observation is that since uplink/downlink ERP is proportionally related, and a TP has finite output for a given bandwidth, I'm still of a mind that someone is comming in pretty hot, and hogging the available power output of the TP at times. That makes the problem double if the 'hog' is also the one that is adjacent to 11735 powerstarving all other active signals (who else is there full time?) and causing capture problems too. The offending signals arent listed on Lyngsat, so who knows exactly what they are really running at, given that the STBs will lock them in a pretty wide range, all the way passed (above) the RTN signal.
I dunno. It is very annoying when it happens.
I dont see RTN getting picked up for a sub here. The local NBC has THiS and LTV for subs. The CBS and ABC affiliates both use one sc for delayed broadcasts of the main channel programming (what a waste) and the ABC station has the Accuweather feed (more usless crap tv) on their -3 sc. Fox, MY and CW dont have any sc that I've seen, but I cant see independents picking up an independent for a sc feed. ION has it's usual sc multiplex, as does PBS. I dont see Houston getting the RTN channels on OTA.
Even though they ended up in questionably the crappiest spot in the satellite spectrum, you are right, all things (Equitably, punny huh!) considered we should be thankful for what we do have.. I just cant beleive that the affiliates' engineers havent questioned the poor margin of error for threshhold receiption.
If it's not twice as good as it needs to be then it's only half as good as it should be. Let their signal jump to LEO-1 and I'll bet some heads will roll somewhere!

I still would like to know who runs Leo and what is the purpose of 24/7 color bars?

 

[Tron]

I really need to try an experiment... use a Digitrans commercial receiver to tune in RTV. I bet there will be absolutely no problem, and the reason is that, in many cases, the tuners in these cheap consumer FTA receivers just aren't good enough to isolate these two signals. The problem with this experiment is that I'm having no problem receiving RTV on my Visionsats. The experiment would work better in a system where there was a reception problem with RTV.

 

[B.J.]

.....Another 'speculative' observation is that since uplink/downlink ERP is proportionally related, and a TP has finite output for a given bandwidth, I'm still of a mind that someone is comming in pretty hot, and hogging the available power output of the TP at times. That makes the problem double if the 'hog' is also the one that is adjacent to 11735 powerstarving all other active signals (who else is there full time?) and causing capture problems too. The offending signals arent listed on Lyngsat, so who knows exactly what they are really running at, given that the STBs will lock them in a pretty wide range, all the way passed (above) the RTN signal.
...

If one signal on a transponder puts out too much power, yes, it can hog the power and make things difficult for the other signals on the transponder. This is a problem on amateur radio transponders. However this is NOT the problem on TP-1 on AMC9. The signals on this transponder are all about the same strength. And as I mentioned before, if anything, the RTN signal is probably the strongest signal on the transponder (I say this even though the 11729 signal looks to be equal or a very small amount higher, however the apparent signal strength of the 11729 signal has contributions from both the 11735 and 11723 signals, while the 11735 only has additional contributions from the 11729. So the nearly equal appearance makes me believe that the 11735 is the strongest signal on the transponder. Worst case is that it is equal to it's 2 nearest neighbors. But the LEO signal is definately not hogging the transponder.

One interesting thing that probably has nothing to do with any of the issues discussed here, is that the transponder 1 on AMC9 is supposed to be 36 MHz wide, centered at 11720, so it extends from 11702 - 11738. And the 11735 signal has an SR of 4440, so it's bandwidth will be approximately 4.44 MHz (a bit more), putting it from 11732.8 - 11737.2 . This means that the RTN signal is the last signal on that transponder, so it will never get any interferrence on the high side, other than cross polarization or adjacent sats. I'm not sure if there are any other implications with respect to being on the edge of a transponders bandpass or not.

 

[pedrogarcia]

If it is a case of co frequency interference there is plenty of transponder space RTN could ask for with a higher frequency

 

[B.J.]

If it is a case of co frequency interference there is plenty of transponder space RTN could ask for with a higher frequency

Why would they spend more money to switch to another transponder? I'm guessing that their real customers are not having any problems at all. It's not a problem for them. It's only a few hobbiests that are having problems. They're going to find the cheapest price for a transponder that will do the job for them.

 

[melgarga]

BJ,
Without access to a spectrum analyzer the speculation was based on TP theory of operation and DVB capture effect observations. A spectrum analyzer doesnt care if there is a lock, just that rf is present or not as it sweeps the bandwidth, so it is a true indication of relative power distribution. Another factor that led me to such unscientific speculation is that the behavior is not consistant nor can be anticipated by time of night/day, week/weekend or any other measureable factor. The event seems to be totally random in nature. Since the path, frequencys, distance, and dish positions are all fixed variables, the next 'major' unknowns are the uplink/downlink power allocation factor, and the actual bandwidth usage. According to your measurements, the amplitude seems to be equally distributed for all intents and purposes. Do you have the resolution in your equipment to determine the bandwidth of the signals? Actual would be best, but a measureable relative indication may be useful.
Your comment about being at the edge of the TP is a good one, and no I hadnt give it any consideration. According to your measurements bandpass or rolloff issues dont appear to be present, given your all things being relatively equal data.
I would be real curoius what any of the affiliate downlink engineers think of this marginal setup. I've proven (to myself at least) that having higher gain does not appear to alleviate the juimp to the "stronger" signal. (My nominal Q for a locked 11735 is 69-72 on the Primestar, and for LEO-1 it is 87-90, but we know Q is not raw rf, but is BER and misbehaved adjacent signals can affect it's neighbors error rate.) In fact the higher gain seems to benifit the stronger signal in that I can get an11735 lock with less gain (Primestar), and it will do nothing but jump to LEO-1 when switched over to the larger array (BUD). Speaking in tv dx'ing terms, I equate it to 'nulling out' a stronger station on a directional array even though the antenna position is not pointed in the direction for best gain on the desired station. I'm not physically moving dishs in this case of course, just lowering the gain by switching arrays and it seems to even the playing field for the 11735 signal.
As level of difficulty goes,it cant be that difficult for them to flip to the opposite polarity, have all the affiliates spin their LNBs 90 degrees, and pick up 25-30 db's of cross polariazation isolation. I know if I was a station engineer and saw what I do see I would have concerns about signal integrity and reliability.
Cavity based bandpass or notch filtering for single station receiption at the downlink is a realistic possibility as well. Without cracking the books, I dont know how tight you can get stuff at these freq's though. Anything that puts the undesirables down on the skirt, even at the cost of 6-10 db on the peak would be a good single channel setup. The top end loss could be compensated for with a high gain array.
Talk about a Mad Scientist project for watching TV......"How to build and tune your own microwave bandpass/notch cavity array"..........although the S2 guys might benifit from just such a system.....hmmmmmm
Maybe a poll is in order regarding who has RTN as a sub channel OTA in their area. It would be interesting to see what the stations have for TVRO equipment and what if any issues they may have identified. Someone within reasonable travel range could visit the station and see if the engineer would be willing to be interviewed or possibly give a tour. (Remember Anole's famous words - Take lots of pics!)
Sometimes I have to remind myself, It's not about the kill, it's about the hunt......lol

 

[melgarga]

Tron,
I've intentionally side stepped the whole "This box is better than the that one" thing in this issue because selectivity wise they are all pretty much created equal, that is, the comsumer grade units I know about.(sensitivity in a whole 'nother thing) I cant speak to the design of the commercial units, but unless they have a dual (or more) conversion frontend, or some sort of frequency driven track-tuning (think Bearcat) they are pretty much equal too.
At appx 1Ghz wide, you could shove an 18 wheeler thru the front end of these things sideways. The tuner chip extracts the QPSK modulation and send it to the DVB VPU for final demux and display formating without any additional (external at least) downconversion. So where would you engineer in any add'l bandpass/selectivity filtering, especially to get less that 2-3 mhz passband with a single conversion receiver that has a 1Ghz wide front end? It isnt possible as far as I can tell.
I could see possibly limiting the capture range of the freq&SR seek/lock functions, but for a blind scan capable receiver that would either impair it's ability to capture signals in the size steps it uses, or make it painfully slow to step thru the possible combinations, possibly both. Then it still may refuse to lock the explicit desired freq if the offending freq is wreaking enough havoc (ie encrouching on bandwidth)with the desired signals BER.
I'm with you tvropro, just who is the LEO1 outfit and why are they sucking down the solar cells with just a colorbar pattern? The least they could do is put something on there we can watch.........If not some programming of social redeeming value, then maybe......I'm thinking Malibu Beachcam.....
Come to think of it, didnt this issue crop up about the time the Fiz was doing hero worship to Capt Midnight?.........hmmmm....then that Minnesota Nazi put him out on the curb............j/k couldnt resist
Nazis in Minnesota.....hmmmmm. Isnt that like Omish in Iran?????

 

[Dee_Ann]

I will bet that most of you know this already and I'm really the least qualified person here to even comment on this subject but, I lost RetroTV too and now all I see are those stupid colored bars and that nasty squealing sound.

When I press the info button it says the channel name is Video-1 and it says the provider is "TandbergTV"

So whoever TandbergTV is must be the culprits behind this rude behavior.
I googled it and this is what I found, TANDBERG Television : World leaders in video compression & digital systems - TANDBERG Television

Maybe someone can send them a nice email and ask them to stop being so rude and ruining things for everyone with their useless nonsense?

 

[guapoharry]

Fine, all of the consumer units suck. So, it's pointless to consider why some work better than others.

Yet, for a given dish / LNBF some of my receivers get RTV and one does not. (Pansat 2500A)

If it's not selectivity, maybe it's AGC. Or maybe, it's some software algorithm.

Perhaps it's because my Pansat 2500 is too stupid to look at chunks of frequency less than 8mhz when doing a scan.

Consider this: when scanning, suppose there are two signals inside a 8 mhz sample, how does the software know which freq. to look at?

In watching my 2500A, I see that it starts at IF 950 and goes up by 8. So then, I figured: What LNBF LO could I set the receiver at so a scan starts at 11735?

11735-950-10750=35 35/8=4 remainder 3

So, I set the LO to 10750+3=10753. And my Pansat 2500A blind scanned in RTV for the first time!

If your STB doesn't offer adjustable steps, try changing your LO a little!

BTW, if someone figured this out already, please advise so my head doesn't explode...

PS, after looking at a table of freq's that increment by 8 mhz from 11700, my model of two freqs inside a sample might not have been correct. But maybe the tuners on these consumer units are not accurate... Whatever...it worked for me...

 

[melgarga]

Sounds like you may have found a solution, for your setup at least. Mine is more a question of consistancy, or actually a lack thereof. If you move your LO back to the correct value after capturing the signal does it always find RTN, or does it start jumping to the LEO1 signal? I have had receiption on the threshehold so close that changing from east feed to west feed or vice versa, making the rx unlock and relock, the LEO signal will jump in sometimes or I get no a/v at all with 90 + on the Q meter.
I'm going to have to try the LO shift thing next time I have any trouble out of it.
Watching the blindscan freq. display, the 6000 moves in 8 mhz steps as well. I always thought it 'ramped' from one point up 8 mhz then reset the 'bar' and ramped up the next 8 mhz. How else would it display a freq value it found between the 8 mhz steps?
Your experiment seems to indicate that it takes samples a 8 mhz intervals and depends on the wide frontend to allow for capture of signals not on the 8 mhz boundries.
Nothing I've looked at schematic wise would indicate they have an AGC system, not like one that we are familiar with in analog receiption anyway. Who knows what goes on inside those LSI tuner and DVPU chips.

 

[hwm]

Same dish/lnb 3 receivers test results:

The same dish and LNB were used for all 3 receivers. The dish and LNB are painstakingly peaked on 83W / AMC9.

Dish: Winegard DS-2076 76cm offset Ku band dish.

LNB: DMS International Standard Ku JSC321S 0.3 dB rated

Neusat SP-6000 Standard: Will not lock onto the 11735 transponder at all. No amount of blind scanning or manual entry of frequency and symbol rate data would get a lock on 11735. Tried TP freqency of 11740 as suggested by others on this forum, in addition to 11735. It would get the NBC color bars and the LEO1 transponders without issues at 60- 80% Q.

Captiveworks CW-700S: Found the 11735 transponder with blind scan first try. Signal quality varies from 30- 45%. Picture breakup threshold is 25- 28 on this receiver, so signal was lost on cloudy days, and at night. NBC Color bars at 80% Q.

Conaxant Mini: (Recently purchased new in the box for $46 delivered on eBay!) This receiver allows the frequency stepping while blind scanning to be selected at 2, 4 , 6 or 8 MHz. I chose 2 Mhz and scanned AMC9. It found the 11735 transponder and gets 60- 70% indicated signal quality. Clouds do not knock it out, and it continues to get 11735 / RTV even in the middle of the night. No noticeable dropouts of RTV signal in over a weeks use. NBC Color bars at 95% Q.

My admittedly non-expert conclusion: There is a big difference in consumer grade satellite receivers.

 

[Tron]

When I press the info button it says the channel name is Video-1 and it says the provider is "TandbergTV"

So whoever TandbergTV is must be the culprits behind this rude behavior.
I googled it and this is what I found, TANDBERG Television : World leaders in video compression & digital systems - TANDBERG Television

Tandberg is the manufacturer of the uplink equipment, they have nothing to do with the organization that is using it. They manufacture encoders, receivers, and other commercial satellite equipment. It says Tandberg because that is the default label if the uplinker does not customize the service name info, kind of like how a wireless network may have the default name of "Linksys" or "Netgear" if it is not customized by the owner of the router.

 

[melgarga]

Some good observations hwm. Did you try to manually input any freq/sr combos higher or lower than 11735/4444 on the Neusat and see if it would lock RTN on a single TP scan? That works with the CS 6000 when it refuses to lock RTN, sometimes. Others have had similar luck.
BTW, I read once somewhere never buy an STB that starts with "N". You results, and other stuff I've read seem to support that statement.
I've read good stuff about the Mini, so $46 delivered is a steal. Congrats! I'm SD unit poor ATM (3 STBs and 2 PCI cards) but I wouldnt pass on one of those if I saw one for that price.
One thing, you might set the Mini for 8 mhz steps and do it again, that would be closer to an apples to apples comparison. I dont expect any change in the result, but it does make the test criteria closer to equal. (Be sure to re-run all the STB/combos together since the realtime signals seem to arbitrarally vary.)
Like I said, good lab test/observation style execution and report, did you note all your criteia and results in cronological order in your spiral??? (naaa.... that just for the eggheads.....) '
As well as it appears the Mini performed, I dont think it can be qualified as a commercial grade receiver, but your test does re-affirm there are performance differences on the subject from one STB to the other.
So the question is, is it sensitivity or selectivity? The one that was the poorest performer in the lock test, also was the one with the worst sensitivity.
Like the proverbial Tootsie Pop....."The world may never know...."

EDIT - I meant 11744/4444 but didnt catch the error until now

 

[Dee_Ann]

Tandberg is the manufacturer of the uplink equipment, they have nothing to do with the organization that is using it. They manufacture encoders, receivers, and other commercial satellite equipment. It says Tandberg because that is the default label if the uplinker does not customize the service name info, kind of like how a wireless network may have the default name of "Linksys" or "Netgear" if it is not customized by the owner of the router.

Oh! Ok. Well I knew I don't know what I'm talking about. Ya know? LOL!

 

[Keith Brannen]

Did anyone ever see any programming on that? All I ever see is color bars. RTN needs to boost there power so they can splatter back on them.

I actually saw a news feed on Leo-1 within the last month. It didn't last long (can't even remember what it was about)!

Interestingly, today RTN is stronger than it has been in a long time. Normally, it has been around 30, while today it is bouncing around the mid 30s up to the mid 40s. Meanwhile, Leo-1 which normally is 60s or better, is doing the same bouncing as RTN at the same levels.

Too bad I didn't have two receivers to see if when one peaked the other was at the low end.

Of course, it just starting raining and now both are hovering in the low 30s!

EDIT: The rain stopped, it's cleared up a bit, and both are fairly stable in the low/mid 40s.

 

[Dee_Ann]

OMG!!! OMG!!! I got RTV back and with 100 / 100 signal! Woohoo!

I had to go out and mess with the stupid dish but it's back! Yay!!! @party@party@party@party@party@party

 

[Mr Tony]

might have to try the 6 footer later with the KU LNB

 

[melgarga]

OMG!!! OMG!!! I got RTV back and with 100 / 100 signal! Woohoo!

I had to go out and mess with the stupid dish but it's back! Yay!!! @party@party@party@party@party@party

Did you use that new fangled meter with the custom software or did you go out and 'eyeball' it in like a pro.....
100/100. Wow, what does the Coolsat 6000 show for level/quality?
I've got a new project for you Dee, if you have a clear LOS to the east/southeast...(i'm glad I'm not a tree that's in your way....)
Hispasat at 30.0W

 

[tvropro]

I'd like to see a picture of that 100/100. What size dish do you have 15 foot? I think the meter is extremely loose.

 

[Dee_Ann]

Did you use that new fangled meter with the custom software or did you go out and 'eyeball' it in like a pro.....
100/100. Wow, what does the Coolsat 6000 show for level/quality?
I've got a new project for you Dee, if you have a clear LOS to the east/southeast...(i'm glad I'm not a tree that's in your way....)
Hispasat at 30.0W

Well, yes, and, no.

I tried to used that fancy-schmancy new La-de-da meter but to no avail.
I ended up putting that little cheapie squeal meter my neighbor gave me.
He had previously taught me how to use it. So really the fancy meter was just giving power to the little squeal meter.

I don't think I have the birdog programmed properly, yet. I'll have to try different options then save the settings that work, now that I am totally on the right satellite. I don't know how that dish moved but it did. It was tight on the pole, I had to use a wrench to adjust it.

It's also very touchy about clouds. We have been having a lot of nasty weather lately and the picture goes in and out. I can look out the window when the picture goes out and see dark rain clouds over head. As they pass and the sky opens up again the picture comes back..

As for the 100 / 100, well that's dropped down to 90 / 100 now. If it falls below 80 / 100 the picture starts going on and off. How it's getting these numbers I have no idea, it's what shows up when I press the info button on the remote.

I'm thinking that I may have better luck when (IF) I can ever put up that big dish on a motor. This stuff is soooooo touchy. Rain or even rain laden clouds really mess it up easy. This is definitely a clear skies only project.

Oh, I looked at that dishpointer.com site and there are trees dead square in the way. And they are well within the neighbor's yard, they are HIS pecan trees. I dare not touch them. All I can do is hope that the next hurricane takes care of them. He's a nice neighbor that brings me BBQ plates sometimes. I like the free BBQ. I will leave his trees alone.

I think though, that there is one other thing I can try. I'll get back with you on it. What's on that satellite anyway? It sounds like Spanish, which I don't understand, I'm a mono-language girl. Never took other languages in school, back then they were optional.