dish alignment

[LocutusOfBorg]

I wish the info on the web could be verified. One site says that I need 11 dB C/N for receiving dvb-s2/8psk-FEC 9/10 feeds while lyngsat doesn't give a figure and tvrosat says I need 7.2 dB (but they list the ABC feeds with a FEC of 1/2). But the tvrosat shows I'm in the hottest area for the 99W beam and that a 2.4 meter dish is adequate for 9/10 feeds (my dish is 3.66 meters). My XR-3 shows the ABC feed bouncing between 0 and 9.8 dB (it's a digital meter so the C/N level is probably higher). The adventure continues.

 

[LocutusOfBorg]

This is weird, 2 websites say the minimum dish size to receive Galaxy 16 where I live is 1.1 meters. No explanation on the website about this. The sites don't mention anything about FEC or modulation considerations. Anyway, I'm still trying to get this alignment done. Don't know what I'm doing differently. I had better performance before "improving" dish condition and alignment. I wish I had left it alone now.

 

[LocutusOfBorg]

I wish the info on the web could be verified. One site says that I need 11 dB C/N for receiving the dvb-s2/8psk/FEC 9/10 feeds while lyngsat doesn't give a figure (for ABC on 99W) and tvrosat says I need 7.2 dB (but they list the ABC feeds with a FEC of 1/2). At any rate, I got the dish aligned much better but some weird things were noted. Before I realized that I was turning the dish mount the wrong way, I found signals on 125W that were 18 dB C/N. After realignment, the signals dropped to 7.2 dB and a lot of services were lost on that satellite! I might have moved the mount just a little too much but I'm going to take a couple days "off". I spent days trying to see if I could get those 18 dB levels again without losing services on 91W but I couldn't. I checked feed centering, parabolic shape (string test), focal distance (56-1/8" +/- 1/8" - I tried using a laser measurement device but it didn't work out too well in sunlight but ended up using a regular tape measure), true south alignment, LNBF orientation (polarity), LNBF f/D alignment (0.4 +/-), and quadruple checked declination angle (5.9 - digital inclinometer accuracy - I had to keep re-zeroing the meter). Fine tuned everything (except declination) as accurately possible. At least I got the 9/10 FEC signals back on 99W (11.6 dB C/N). But I'm disappointed that I couldn't get above 13 dB on any service since I know my dish is capable of producing 18 dB C/N.

 

[LocutusOfBorg]

I forgot to mention that I made sure the pole is still plumb also.

 

[Brct203]

this is a good reference page for required C/N depending on modulation and FEC:

Satbroadcasts.com - no. 1 source for professional work

www.satbroadcasts.com

 

[LocutusOfBorg]

I already know about that. But is there another reference that verifies those figures?

 

[Comptech]

I can verify that if you are only getting 11 Db's on the ABC feeds your alignment is of or your dish is getting adjacent sat interferance. !! ain't going o work very well with a S2 9/10's signal. 10 foot unimesh here and with trees, getting 17.8 Db.

 

[LocutusOfBorg]

I hope it isn't adjacent sat interference considering I'm using a 12 foot dish! I suppose that 4G or 5G may be an issue but how does one determine that without acquiring expensive test equipment or professional services? I suppose the cheap route would be to buy a LNBF with 4G/5G filters to see if that fixes the problem. I guess this might be another one of those issues that I'll just have to live with.

 

[Need2learn]

Peak it to your highest satellite, once you have that done, that find the weakest Transponder on that satellite and peak it from that, once that has been done push down on your dish and see if your signal goes up, next push up or your dish and see if the signal goes up that will tell you if your elevation is adjusted right. But you MUST HAVE Your declination angle set exactly before doing any of these test.

 

[LocutusOfBorg]

Peak it to your highest satellite, once you have that done, that find the weakest Transponder on that satellite and peak it from that, once that has been done push down on your dish and see if your signal goes up, next push up or your dish and see if the signal goes up that will tell you if your elevation is adjusted right. But you MUST HAVE Your declination angle set exactly before doing any of these test.

I set the declination as accurately as possible but both analog and digital inclinometers can't precisely set the declination. My digital inclinometer has an accuracy tolerance of +/- 0.2 and I have to constantly check the zero on it. I do believe that I need to fine tune the declination but that'll be a project for tomorrow. But, I doubt that I'm going to be able to get the 18 dB C/N that others get on the high FEC rates for 8psk. I'm thinking that my LNBF (a Titanium C1WPLL) may not be working as well as it was in the past. Maybe some kind of interference is an issue? Sure is a lot of work aligning and diagnosing problems. Not to mention that the next wind storm will cause an alignment issue. Like I said, a lot of work. Not to mention how hot it has been and the windy conditions have made it a hassle. We have 70% chance for rain tomorrow afternoon also with a forecast high of 95. But, I did get some improved performance today but it should be better than this. Certainly isn't a slam dunk alignment. On top of all this I have received my new TEK 12 footer that's waiting to be assembled, installed and aligned. At least I have a lot of things to keep me busy in retirement but I want some play time also.

 

[LocutusOfBorg]

I ordered the Titanium C1-PLL today - the one with the filters. I couldn't get any better signal levels from alignment so I'll see if this LNBF is helpful.

 

[primestar31]

I ordered the Titanium C1-PLL today - the one with the filters. I couldn't get any better signal levels from alignment so I'll see if this LNBF is helpful.

Are you near any airports, OR obvious microwave link towers?

 

[LocutusOfBorg]

Are you near any airports, OR obvious microwave link towers?

I'm within 5 miles of the airport. There are a few microwave towers including a couple of nearby 4G cell towers. Quite a few cell towers have been installed within the past couple of years.

 

[primestar31]

The C1-PLL with the new filtering should be a good test for you then, I have one myself and it helped. Regardless, it's a low cost test to see what happens.

 

[Titanium]

Without a spectrum analyzer to diagnose the system, component swapping becomes like the games of pin the tail on a donkey or whacka mole.

 

[arlo]

I've been following this thread for a few days. I've been there and feel for you.
The telescope guys with equatorial mounts got it over us.
I know that elevation and rotation on the pole to point right at the north star is step #1
I guess I'm lucky here because my dish mount has been pinned on the pole since the '80's.

Everyone here really knows their stuff. Only thing I can add through the re tweaking process of my 12 footer dish is once you find a satellite is tweak in the lnb to get the best signal. I used 103 after finding a strong sat like 99W to peak the signals.
And stick with your guns. If your lnb points just a little off center of the exact center of the dish and you go working the rest of the settings (elevation, declination, mount rotation ) while going back to peak signal at the lnb. It will have you chasing unicorns.

Getting your mount main axis angle pointing true north is going to be a job. The steel structure will throw a compass off.
That's where a little mental work takes place when thinking wtf is going on when you get a strong signal on one sat but weak on another.
It's true what the guys say. When you get good tracking on a few high in the sky sats. Lock the dish from rotating on the pole.
Declination adjustment along with actuator positioning on lower arc sats makes the biggest aim difference. Elevation and declination on higher arc sats.

Explanation of satellite dish polar mount set-up and alignment

Describes set up and pointing of polar mount satellite dish with setting up examples and pictures for installing a polar mount

www.satsig.net

 

[LocutusOfBorg]

Without a spectrum analyzer to diagnose the system, component swapping becomes like the games of pin the tail on a donkey or whacka mole.

I wish I could afford a $5000 RF spectrum analyzer. If I was running a business I could justify the cost. I balked at spending about $450 for the XR-3 but spent the money anyway. I suppose renting a spec-A is an option but I've heard that's quite pricey also. Anyway, since I've checked and tweaked everything else, I'm left with replacing the LNBF. That's $40 I really didn't want to spend either. The LNBF should be arriving today. If it doesn't fix the problem I guess I'll just have to live with what I can receive.

 

[arlo]

I wish I could afford a $5000 RF spectrum analyzer. If I was running a business I could justify the cost. I balked at spending about $450 for the XR-3 but spent the money anyway. I suppose renting a spec-A is an option but I've heard that's quite pricey also. Anyway, since I've checked and tweaked everything else, I'm left with replacing the LNBF. That's $40 I really didn't want to spend either. The LNBF should be arriving today. If it doesn't fix the problem I guess I'll just have to live with what I can receive.

I have a pretty decent Agilent SA that probably cost around that new I bought from a surplus electronics house.
One of the SDR radios with a tap on the lnb out cable and software does a pretty good job of signal searching and analysis.
I use an SDRPlay RSP2. Works slick. A heck of a lot less than a dedicated SA.

 

[LocutusOfBorg]

I have a pretty decent Agilent SA that probably cost around that new I bought from a surplus electronics house.
One of the SDR radios with a tap on the lnb out cable and software does a pretty good job of signal searching and analysis.
I use an SDRPlay RSP2. Works slick. A heck of a lot less than a dedicated SA.

The RSP2 shows discontinued. Looks like the SDRplay RSPdx replaces it but it's $199 from HRO. I suppose I could find a used one at ebay. The RTL-SDR is a lot cheaper but I guess you get what you pay for. I don't have any experience with SDR so I don't know what would be "best". I'd have to get an SMA to F connector adapter for the RF port also. And if I want to use this at the pad I'd have to either buy a tablet or take a laptop to the pad.

 

[Titanium]

The glass is not half empty...
For a few hundred dollars, the Dr. HD 1000S and 500 combo models have spectrum analyzers that puts the XR-3 to shame. 30fps!

Need to look at a range of the spectrum, not a tiny slice.