Getting All TPs from a Satellite 101W SES1 C

[cyberham]

Here's a challenge for troubleshooting. With my fixed 7.5-foot Perfect dish, I can receive most of the transponders from 101W SES 1. But...not all at the same time. To get the Weigel mux, I have to position azimuth, elevation, LNBF placement just so. When successful, I can get SQ 72% and the channels are clear. But to get most other transponders, I must very slightly adjust azimuth or elevation or LNBF placement or a combination. This would be easy if I had an actuator but instead it means running to the dish to tweak manually.

I believe this is likely due to my dish being worn (a couple of mesh tears), and probably a little out of perfect shape. My question is what is a practical remedy for this? On many other satellites, the transponders are so strong that this issue doesn't really matter.

 

[mikekohl]

Here's a challenge for troubleshooting. With my fixed 7.5-foot Perfect dish, I can receive most of the transponders from 101W SES 1. But...not all at the same time. To get the Weigel mux, I have to position azimuth, elevation, LNBF placement just so. When successful, I can get SQ 72% and the channels are clear. But to get most other transponders, I must very slightly adjust azimuth or elevation or LNBF placement or a combination. This would be easy if I had an actuator but instead it means running to the dish to tweak manually.

I believe this is likely due to my dish being worn (a couple of mesh tears), and probably a little out of perfect shape. My question is what is a practical remedy for this? On many other satellites, the transponders are so strong that this issue doesn't really matter.

Check and see if your cross pole polarity isolation is peaked so that you get max signal on desired polarity. Switch to other polarity and check for presence of previous signal from desired polarity. Rotate the LNBF for a full null on that signal. There is a greater null when minimizing an unwanted signal, as compared with peaking same signal on proper polarity. Everything else that you are doing is correct...you could check to see that the LNBF is placed dead center with equal spacing length on each support leg, and tweak left/right as well as up/down for centering of feed, followed by peaking the elevation and azimuth. Once you have gone through all of these things, make a list of all transponders on both polarities of 101, and then do the same for 99 as well as 103 West. See if there is any possibility that a weaker TP on 101 is within 10 MHz or so of a working TP on either 99 or 103. If 99 or 103 have a strong signal, it might be smoking your desired TP on 101. Changing the illumination (or focal distance) slightly in or out might bring up your levels on 101, while dropping the strength a bit from undesired satellite(s). Same concept as using a former RP-1 or RP-2 feed from ADL (no longer made), which had better isolation from other signals when compared to the Chaparral CoRotor design or ADL's own adjustable RP-3 feedhorn. Seavey Engineering also had great isolation on their feedhorns back in the day. Since you are using an LNBF already, it is simpler to do the above tests to see where the imbalance may be coming from, and in some cases you might also use tin foil or aluminum mesh on the feedhorn/LNBF or even the perimeter of the scalar plate to keep other sidelobes in check. As you said from the beginning, using an undersized reflector does have its compromises and limitations, but using similar techniques to those that were successful in the past at keeping terrestrial interference out of the feedhorn area or the dish edge itself could also be explored. Enjoy your challenge! Mike

 

[one_db_compression]

Here's a challenge for troubleshooting. With my fixed 7.5-foot Perfect dish, I can receive most of the transponders from 101W SES 1. But...not all at the same time. To get the Weigel mux, I have to position azimuth, elevation, LNBF placement just so. When successful, I can get SQ 72% and the channels are clear. But to get most other transponders, I must very slightly adjust azimuth or elevation or LNBF placement or a combination. This would be easy if I had an actuator but instead it means running to the dish to tweak manually.

I believe this is likely due to my dish being worn (a couple of mesh tears), and probably a little out of perfect shape. My question is what is a practical remedy for this? On many other satellites, the transponders are so strong that this issue doesn't really matter.

Check and see if your cross pole polarity isolation is peaked so that you get max signal on desired polarity. Switch to other polarity and check for presence of previous signal from desired polarity. Rotate the LNBF for a full null on that signal. There is a greater null when minimizing an unwanted signal, as compared with peaking same signal on proper polarity. Everything else that you are doing is correct...you could check to see that the LNBF is placed dead center with equal spacing length on each support leg, and tweak left/right as well as up/down for centering of feed, followed by peaking the elevation and azimuth. Once you have gone through all of these things, make a list of all transponders on both polarities of 101, and then do the same for 99 as well as 103 West. See if there is any possibility that a weaker TP on 101 is within 10 MHz or so of a working TP on either 99 or 103. If 99 or 103 have a strong signal, it might be smoking your desired TP on 101. Changing the illumination (or focal distance) slightly in or out might bring up your levels on 101, while dropping the strength a bit from undesired satellite(s). Same concept as using a former RP-1 or RP-2 feed from ADL (no longer made), which had better isolation from other signals when compared to the Chaparral CoRotor design or ADL's own adjustable RP-3 feedhorn. Seavey Engineering also had great isolation on their feedhorns back in the day. Since you are using an LNBF already, it is simpler to do the above tests to see where the imbalance may be coming from, and in some cases you might also use tin foil or aluminum mesh on the feedhorn/LNBF or even the perimeter of the scalar plate to keep other sidelobes in check. As you said from the beginning, using an undersized reflector does have its compromises and limitations, but using similar techniques to those that were successful in the past at keeping terrestrial interference out of the feedhorn area or the dish edge itself could also be explored. Enjoy your challenge! Mike

I agree wholly with Mike. Additionally, use your receiver that gives you Carrier-to-Noise in dB.

It's the only way you'll be able to properly assess your signal margin and the associated for a particular mechanical change in your setup. You can track your results with those nebulous percentages, however you will have a much harder (or impossible) time comparing your results and those of others. The percentage is non-transparent on how the value is calculated and it can (will) vary between receivers for a multitude of reasons.

The horizontal transponders on that 101W satellite are all 8PSK 5/6 except for Jewelry TV which is DVB-S 3/4. You are looking at a maximum 4% change in frequency from the bottom to the top of the list of transponders. Any mechanical issues with your dish (e.g. mesh tears, eccentricity, etc.) should affect things equally.

Now if you have some crazy issue that happens to overlap wavelengths with 4180 MHz, then all bets are off. I mention this last point because 22 years ago I had an issue with outdoor 2.4 GHz WiFi working intermittently in a construction trailer that had aluminum sheet cladding where the corrugations were 12.5 cm peak to peak. If you recall, f = C / lambda = 300 / 0.125 = 2400 MHz. Now trying to get IEEE 802.11b WiFi to work through a variation of a Faraday cage is a fool's errand at the best of times, however the signal strength changed markedly depending on the angle of incidence to the aluminum cladding. Conversely, in the past I have had 2.2 GHz licensed microwave running into an extremely beat-up 12-foot GridPak antenna (like it broke off the tower and dropped 150 feet and was subsequently reinstalled with deformed ribs that also broke away from the perimeter steel because there was no spare) with less than a single dB difference against baseline. Undoubtedly the radiation pattern would have been altered because the mechanical setup was altered.

Even if you are peaked for everything else on 101W, your antenna may not be 2-degree compliant and if you also have a cross-polarization issue, something like 4180V from a newer, hotter SES18 at 102.9W might be contributing to the beating-up of your noise floor and you are encountering threshold degradation and you don't have sufficient natural gain from the 7.5 feet to overcome this.

I'm interested to see what results you get.

Everyone else's mileage may vary.

 

[cyberham]

Thanks for all the feedback. I certainly enjoy the challenge. After all, I'm doing this for fun; not to receive TV. It's a good excuse to get me outside on these nice days.

Since I don't have or use a satellite meter, I use the remote monitor ability of the Edision to see the receiver's received level in dB on my phone at the dish. The reading is given to two decimal places. Once transponders are scanned in for the first time, I can quickly check level on each tp and this allows me to choose the best settings for balanced levels. I can't really check for minimum level on the wrong polarity since minimum means no tp lock and no reading. I guess this is one situation where a satellite meter could be useful. Occasionally I use the GT Media remote monitor ability since its reading on my phone is more damped so it's actually easier to know when peaked.

I only quoted an SQ reading since when actually watching TV, the GT Media V9 Prime is able to take a given signal quality and do more with it. When near the C/N minimum lock of 9.4 dB as Weigel is before being fully tuned, the GT Media shows a clear watchable channel whereas the Edision is breaking up. So the GT Media appears more sensitive though I'm not sure this is the correct term. At the moment, I am getting SQ 72% on the GT Media with a completely clear METV picture. On the Edision, I'm seeing from no lock to peaking at 10.2 dB locked and a distorted picture. So at the moment, the Edision is not useable whereas the GT Media is perfect. As a reference, the GT Media V7S5X is showing the same SQ 72% and perfectly clear picture.

Using Lyngsat, which is pretty accurate these days, I checked adjacent satellite frequencies. 103W SES 18 is a powerhouse whereas 99W Galaxy 16 is likely less problematic. In all cases but one, adjacent frequencies that are the same frequency as on 101W are on the opposite polarity. There is one example where there's just 4 MHz difference and on the same polarity. This is the Jewelry channel (101W) and the Victory channel (99W).

I think the actual solution is just to put in the time and effort when on 101W to position the LNBF precisely in all three dimensions plus orient the skew also precisely to balance on all frequencies as much as possible. My complaint is that the way an LNBF is positioned with just three points of contact between three screws makes this task awkward coupled with the fact that you are standing in front of the dish and blocking a significant amount of signal with your body. At least I don't need a ladder and can reach the LNBF assembly while standing on the ground. On weaker tps, my body attenuates the signal enough that I lose lock while standing there so I must adjust, move away, read, then adjust some more. It's not a good way to do precise tuning. Not complaining, just stating facts.

On most satellites, this above process is much simpler since the transponders are stronger. So I don't need to move; I just watch the reading and adjust at the same time.

 

[primestar31]

Here's a challenge for troubleshooting. With my fixed 7.5-foot Perfect dish, I can receive most of the transponders from 101W SES 1. But...not all at the same time. To get the Weigel mux, I have to position azimuth, elevation, LNBF placement just so. When successful, I can get SQ 72% and the channels are clear. But to get most other transponders, I must very slightly adjust azimuth or elevation or LNBF placement or a combination. This would be easy if I had an actuator but instead it means running to the dish to tweak manually.

I believe this is likely due to my dish being worn (a couple of mesh tears), and probably a little out of perfect shape. My question is what is a practical remedy for this? On many other satellites, the transponders are so strong that this issue doesn't really matter.

Stitch metal tears up using metal Picture Hanging wire and working the stitch as flat and tight as you can get.

As for possibly being out of round, use some galvanized guy wire and turnbuckles. One up and down (12pm and 6pm) and one across, IE: 9am and 3pm along the edge. One turnbuckle for each (2 total). Slowly crank the turnbuckle to get the guy wire taut, and measure from various spots from dish edge to feedhorn, get those all equal as best you can. You can do more of them around the edge (1 per petal) if really needed, but hopefully you won't need to.

 

[EnoSat]

Yes, EDISION requires a higher input signal than GT

 

[cyberham]

A brief session so far has been positive since I started from scratch. Some notes:

• Read the instructions!
  • The Perfect manual says F/D for this dish is 0.375. So I started by placing the LNBF at about 0.38 according to the LNBF holder gauge.
• I then visually centred the LNBF in its holder as best I could: horizontally, vertically. I used the skew gauge on the LNBF to set the skew where dishpointer.com says it should be.
• I then adjusted the dish in azimuth and elevation to peak as many tps as I was receiving.

I have to admit this is about as good results as I achieved yesterday. I also notice the dB readings are more stable than I recall from yesterday. And it only took maybe 15 minutes.

After lunch, I will try moving the LNBF just a bit more to meet that 0.375 suggestion in the manual. I should add that yesterday had heavy clouds whereas today the sky is perfectly clear. Not sure if that is a factor.

Having done the above, I'm still finding the Weigel mux reception requires me to move the dish a very little amount to the west to peak it.

 

[cyberham]

Yes, EDISION requires a higher input signal than GT

So you've experienced this too? Why is that? Is it the Edision hardware or the TNAP OS causing this?