NOAAport help
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Thanks B.J.
I could always get GEB no prob.
The dish itself is good, it is not out of shape or badly dented. Feed support is centered.
That's the way all mine are
Again I am WRONG, I have begun to suspect I have an LNB issue.
This has shined more light on that problem.
And I will say to b.glynn disgard my comment to needing a larger antenna.
Hope he can get it up and running.
Hmmm, I am wrong
Interesting, When I looked at it, GEB was the strongest signal on that bird.
I could always get GEB no prob.
The antenna here is old as well, It is a steel TVRO 118" .31 F/D got it through a friend that was taking down his setup.
The dish itself is good, it is not out of shape or badly dented. Feed support is centered.
No the dish isn't motorized, all done by hand use a threaded rod to hold the azimuth. Since I was only after the one antenna didn't need to move.
That's the way all mine are
That's possible, though from what I can get it seems unlikely.
Again I am WRONG, I have begun to suspect I have an LNB issue.
This has shined more light on that problem.
And I will say to b.glynn disgard my comment to needing a larger antenna.
Hope he can get it up and running.
I wanted to come on and say, NOAAPORT is working here.
I tried again after reading these posts, And got it working.
Well,What did I do wrong....
I'm not really shure and here's why
I reinstalled the feed and the mounting bracket, coax the same as when I did before. The only change I made was to center the feed a little better.
Remember this antenna had L band brackets on it to hold L band feeds C band is only 1/2 the size of L Band.
The feed was off by about an 1", And yes I am aware for C band that is quite a bit.
It wasn't out of the focus but it was off to the side, Even though it was off to the side it STILL worked with some degration, As I tested it today.
I does work better dead center in the mount.
I tried 3 different LNB's 1 from NORSAT and 2 from Cal. Amp. the results I got were about the same, LNB's came form old TVRO gear used a city's cable system found in these small towns across Iowa.
The receiver cards are a Technisat skystar 2 and Twinhan visionplus, bolth cards worked fine.
Aiming was not too hard, just use gentle slow motions when adjusting. I am used to this due to the work with L band. Dish was set to 75 deg. West and in about 7-10 min had it centered on SES1.
I again apologize about the FALSE information I posted here.
I hope that I have provided some useful info here.
If any have questions a will answer the best I can.
I tried again after reading these posts, And got it working.
Well,What did I do wrong....
I'm not really shure and here's why
I reinstalled the feed and the mounting bracket, coax the same as when I did before. The only change I made was to center the feed a little better.
Remember this antenna had L band brackets on it to hold L band feeds C band is only 1/2 the size of L Band.
The feed was off by about an 1", And yes I am aware for C band that is quite a bit.
It wasn't out of the focus but it was off to the side, Even though it was off to the side it STILL worked with some degration, As I tested it today.
I does work better dead center in the mount.
I tried 3 different LNB's 1 from NORSAT and 2 from Cal. Amp. the results I got were about the same, LNB's came form old TVRO gear used a city's cable system found in these small towns across Iowa.
The receiver cards are a Technisat skystar 2 and Twinhan visionplus, bolth cards worked fine.
Aiming was not too hard, just use gentle slow motions when adjusting. I am used to this due to the work with L band. Dish was set to 75 deg. West and in about 7-10 min had it centered on SES1.
I again apologize about the FALSE information I posted here.
I hope that I have provided some useful info here.
If any have questions a will answer the best I can.
Excellent news on locking Noaaport !
Nothing like tuning a dish and getting a good signal.
That 1 inch would be make all the difference between the L-Band and C-Band.
Enjoy!
Nothing like tuning a dish and getting a good signal.
That 1 inch would be make all the difference between the L-Band and C-Band.
Enjoy!
good to hear you have it working! I hope it's enough signal for the DVB-S2 conversion next year (or you may have to do some more tweaking and even finer installation of the feedhorn/centering, etc. to get it).
btw, you asked about my numbers, I'll give you the info for my "smallest" c-band dish. 8.5' dish, corotor II+ feedhorn with c/ku LNBs, motorized so it's not a fixed type dish, and I get a 99 Quality, 75 signal on my PCI card for NOAAPORT (and a 11.0 CN on my portable signal meter readout).
btw, you asked about my numbers, I'll give you the info for my "smallest" c-band dish. 8.5' dish, corotor II+ feedhorn with c/ku LNBs, motorized so it's not a fixed type dish, and I get a 99 Quality, 75 signal on my PCI card for NOAAPORT (and a 11.0 CN on my portable signal meter readout).
What is the difference from DVB-S and DVB-S2 ?
Thanks for the info.
I have a quality level of 57-58%
And a Sig. Strength of 100%
Exactly what you see on Hector's weather page
using the Technisat skystar card or the Twinhan Vision plus card.
After a few more tweaks.
Thanks for the info.
I have a quality level of 57-58%
And a Sig. Strength of 100%
Exactly what you see on Hector's weather page
using the Technisat skystar card or the Twinhan Vision plus card.
After a few more tweaks.
A few format differences that make a DVB-S only receiver incompatible to get DVB-S2 services. The end result is to try to get more bandwidth into the same amount of satellite spectrum.
NOAAPORT wants to deliver more items in their feed, thus the signal change. Since they haven't released the DVB-S2 signal parameters, I don't know if they are getting the extra bandwidth just from the conversion to DVB-S2 or if it's a combo of the conversion and increasing how many MHz of satellite space they lease from SES World Skies.
This is for anybody looking to get real close to the bird fast.
Got some quick info here for pointing antennas.
I was reading that some were have issues pointing the dish, or were not shure where the satellite (SES1) is at in the sky.
I forgot this one, shame on me.
It started when I was working on my noaaport computer looking over the data 1:30PM CDT and the signal dropped out. Hmmmm I said.
looked over my software and everything was good there. Was just about ready to go out to the antenna and I looked out the window, and said to myself " Isn't the sun real close to the position of the satellite?" shure enough it was, and that is why the signal dropped out because the sun eclipsed the satellite.
You tend to lose the signal when this happens because the noise floor goes up due to the sun being right in the path of the satellite.
But it also helps to aim the dish, Right now this time of the year the feed's shadow will be right dead center (or real close) of the dish.
I forgot this little trick, I have used it on GOES East many times.
Now when you get the feed shadow real close to the center of the dish don't expect for a signal reading, wait about 3 to 7 min and if your system is working properly you should get some kind of a lock, If you don't move the antenna ever so slightly back and forth or up and down.
Hope this helps any newbie's out there.
Got some quick info here for pointing antennas.
I was reading that some were have issues pointing the dish, or were not shure where the satellite (SES1) is at in the sky.
I forgot this one, shame on me.
It started when I was working on my noaaport computer looking over the data 1:30PM CDT and the signal dropped out. Hmmmm I said.
looked over my software and everything was good there. Was just about ready to go out to the antenna and I looked out the window, and said to myself " Isn't the sun real close to the position of the satellite?" shure enough it was, and that is why the signal dropped out because the sun eclipsed the satellite.
You tend to lose the signal when this happens because the noise floor goes up due to the sun being right in the path of the satellite.
But it also helps to aim the dish, Right now this time of the year the feed's shadow will be right dead center (or real close) of the dish.
I forgot this little trick, I have used it on GOES East many times.
Now when you get the feed shadow real close to the center of the dish don't expect for a signal reading, wait about 3 to 7 min and if your system is working properly you should get some kind of a lock, If you don't move the antenna ever so slightly back and forth or up and down.
Hope this helps any newbie's out there.
NOAAPORT reception with low cost devices
Hi
I was searching for information on the Web and saw this forum. I am in California and am able to receive a decent signal from the NOAAPORT satellite at 101 degrees. I wondered if the reference to the person in California who's antenna was deficient for reception of NOAAPORT was "me". I use a 7 foot diameter dish and am able to get a 15 dB signal to noise ratio from the satellite. The dish has been in continuous oporation for over a year. I havent bothered to post images since there is little or no interest in what I am doing.
My antenna receives enough signal to maximize the strength bar on the Twinhan gauge. To me, that is good evidence that big (10 foot diameter) dishes are not alwats required for stable NOAAPORT. I would use the biggest antenna I had access to for any "outer space" signal reception if thats an option. But, big dishes can get difficult to handle. I would have tried using a 6 foot diameter dish but this 7 footer was free
Note, I have less than $100 invested in the entire NOAAPORT system. I got the dish and horn with LNB free for removing it from a neighbor's yard. The Twinhan PCI TV is mounted in my Windows computer where the received signal is decoded.
I want to learn more about the NOAAPORT signal.
Hi
I was searching for information on the Web and saw this forum. I am in California and am able to receive a decent signal from the NOAAPORT satellite at 101 degrees. I wondered if the reference to the person in California who's antenna was deficient for reception of NOAAPORT was "me". I use a 7 foot diameter dish and am able to get a 15 dB signal to noise ratio from the satellite. The dish has been in continuous oporation for over a year. I havent bothered to post images since there is little or no interest in what I am doing.
My antenna receives enough signal to maximize the strength bar on the Twinhan gauge. To me, that is good evidence that big (10 foot diameter) dishes are not alwats required for stable NOAAPORT. I would use the biggest antenna I had access to for any "outer space" signal reception if thats an option. But, big dishes can get difficult to handle. I would have tried using a 6 foot diameter dish but this 7 footer was free
Note, I have less than $100 invested in the entire NOAAPORT system. I got the dish and horn with LNB free for removing it from a neighbor's yard. The Twinhan PCI TV is mounted in my Windows computer where the received signal is decoded.
I want to learn more about the NOAAPORT signal.
Hi,
Ya, you are who I was referring to. I am glad to see that you are posting new satellite imgs.
Again, I was wrong about the NOAAPORT reception issue. SORRY
The issue was here.
I did try to contact you several times via Email and got no response.
That is the easiest way to get a dish, and there is no better price than free.
I should mention here that free for the dish is fine but NOT the pole.
I got my 8' dish from a guy in Omaha, the dish was free but digging it out of his shed I paid for. Ouch
I can understand about the large antenna handling issues, and they can be tough to aim.
Hence the gain you get.
I have here a 12' dish (GVAR a 10' dish (NOAAPORT) and a 8' dish(EMWIN) + several others on a pallet disassembled.
As like you I got them at a (non refusable) price.
Ya, that's sorta sad to see that not a lot of interest in the reception of free WX data.
Thought I have sparked some interest in the local Ham comm.
With the internet and all the TV channels that takes away the attraction of putting up an antenna for it.
However, sometimes (from what I've seen) this information can be tough to find, unless you really involved in weather or
know somebody who uses the service.
The last I knew about NOAAPORT before I tried myself, it was QPSK and not near as easy to receive or affordable.
I got told by a friend that wx data was being broadcast on C band, which after doing some research found out that it was
NOAAPORT in DVBS format.
I am using windows computer here myself OS Win 2000 Pro @ 1 Ghz processor 500MB ram using Wx Node for EMWIN
and WX message for NOAAPORT.
Bolth EMWIN and NOAAPORT are being put on the same machine.
On your site there, The NOAAPORT ear is nice. A have chatted a little with the guy that made the server software.
But have not tried that server yet.
What do you want to learn about NOAAORT?
Ya, you are who I was referring to. I am glad to see that you are posting new satellite imgs.
Again, I was wrong about the NOAAPORT reception issue. SORRY
The issue was here.
I did try to contact you several times via Email and got no response.
That is the easiest way to get a dish, and there is no better price than free.
I should mention here that free for the dish is fine but NOT the pole.
I got my 8' dish from a guy in Omaha, the dish was free but digging it out of his shed I paid for. Ouch
I can understand about the large antenna handling issues, and they can be tough to aim.
Hence the gain you get.
I have here a 12' dish (GVAR a 10' dish (NOAAPORT) and a 8' dish(EMWIN) + several others on a pallet disassembled.
As like you I got them at a (non refusable) price.
Ya, that's sorta sad to see that not a lot of interest in the reception of free WX data.
Thought I have sparked some interest in the local Ham comm.
With the internet and all the TV channels that takes away the attraction of putting up an antenna for it.
However, sometimes (from what I've seen) this information can be tough to find, unless you really involved in weather or
know somebody who uses the service.
The last I knew about NOAAPORT before I tried myself, it was QPSK and not near as easy to receive or affordable.
I got told by a friend that wx data was being broadcast on C band, which after doing some research found out that it was
NOAAPORT in DVBS format.
I am using windows computer here myself OS Win 2000 Pro @ 1 Ghz processor 500MB ram using Wx Node for EMWIN
and WX message for NOAAPORT.
Bolth EMWIN and NOAAPORT are being put on the same machine.
On your site there, The NOAAPORT ear is nice. A have chatted a little with the guy that made the server software.
But have not tried that server yet.
What do you want to learn about NOAAORT?
I'm surprised you are getting stable NOAAPORT - 7 foot dishes are not 2-deg spacing compliant that North American C-band sat use. I'd expect that you get the occasional higher error rate when a feed pops up on a nextdoor satellite transponder.
I think 7' is fine for a hobbyist or amateur. If one was a university researcher or emergency preparedness coordinator, they should want a larger dish to assure 24/7/365 reception with continuous low error rates since any missing data due to loss of signal or increased error rates might cause valuable information to not be processed and made available for emergency or research reasons.
Learning about NOAAPORT
Thanks for the posts about NOAAPORT
I was wrong about the diameter of my dish. It is actually 7.5 feet. When I first set up the dish, the Twinhan showed full green on the Strength bar and near full on the Quality. I wrongly assumed that the 7.5 dish was 'good enough'. Recently, the Quality is near 40% and even though the Strength is 100%, the Twinhan looses Lock.
The main reason for my entering this NOAAPORT forum is to learn something about the "Quality".
When I first mounted my antenna, I made a crude rack to attach the dish to the vertical pole. The rack includes two crude hinges and two linear actuators (WWII surplus). The actuators allow me to "zero in" on the satellite.
Now that I hear that "Quality" can be effected by adjacent satellites, I'll try aiming the beam away from the max signal direction slightly to see if there is a pointing direction where the Quality improves.
Patrik Tast has been doing all the THINKING related to this NOAAPORT in my back yard. Our major interest used to be to get images only. But, Patrik has now become more interested in greater capability, and I am having alot of difficulty learning how to help him.
Patrik helped me set up a SDR (Ettus USRP) here in California so he can control it via the Internet from Finland. With the USRP, I can see the NOAAPORT spectrum display. So, now, maybe, I can use the USRP signal to see how the signal strength varies while monitoring the Twinhan quality bar when I re-aim my dish.
Thanks alot for the help
Jerry
Thanks for the posts about NOAAPORT
I was wrong about the diameter of my dish. It is actually 7.5 feet. When I first set up the dish, the Twinhan showed full green on the Strength bar and near full on the Quality. I wrongly assumed that the 7.5 dish was 'good enough'. Recently, the Quality is near 40% and even though the Strength is 100%, the Twinhan looses Lock.
The main reason for my entering this NOAAPORT forum is to learn something about the "Quality".
When I first mounted my antenna, I made a crude rack to attach the dish to the vertical pole. The rack includes two crude hinges and two linear actuators (WWII surplus). The actuators allow me to "zero in" on the satellite.
Now that I hear that "Quality" can be effected by adjacent satellites, I'll try aiming the beam away from the max signal direction slightly to see if there is a pointing direction where the Quality improves.
Patrik Tast has been doing all the THINKING related to this NOAAPORT in my back yard. Our major interest used to be to get images only. But, Patrik has now become more interested in greater capability, and I am having alot of difficulty learning how to help him.
Patrik helped me set up a SDR (Ettus USRP) here in California so he can control it via the Internet from Finland. With the USRP, I can see the NOAAPORT spectrum display. So, now, maybe, I can use the USRP signal to see how the signal strength varies while monitoring the Twinhan quality bar when I re-aim my dish.
Thanks alot for the help
Jerry
More learning about NOAAPORT
Hi all
I tried swinging the dish slightly above and below "satellite signal max" to see where the "Quality" bar improves. The Quality never improved. After several passes of beam pointing, i realized that I need to learn alot more about 'what I am doing' because no antenna pointing helps improve the Quality bar strength.
Since we are pretty sure a 10 foot dish would give satisfactory "Quality", it seems that the 7.5 foot dish would need to be aimed only about 0.3 degrees above or below the NOAAPORT satellite to get '10 foot equivalent adjacent channel rejection. But, I see no improvement of Quality when the beam is adjusted slightly away from being centered on max Strength.
Note, I have both the Twinhan and the USRP connected so I can monitor the NOAAPORT spectrum while adjusting the antenna.
It is getting clear that I need to learn alot more about modulation and demodulation if I want to understand what I am doing.
I live only a few hundred yards from the Los Alamitos Armed Forces Air Base. There might be some local RFI.
Thanks
Jerry
Hi all
I tried swinging the dish slightly above and below "satellite signal max" to see where the "Quality" bar improves. The Quality never improved. After several passes of beam pointing, i realized that I need to learn alot more about 'what I am doing' because no antenna pointing helps improve the Quality bar strength.
Since we are pretty sure a 10 foot dish would give satisfactory "Quality", it seems that the 7.5 foot dish would need to be aimed only about 0.3 degrees above or below the NOAAPORT satellite to get '10 foot equivalent adjacent channel rejection. But, I see no improvement of Quality when the beam is adjusted slightly away from being centered on max Strength.
Note, I have both the Twinhan and the USRP connected so I can monitor the NOAAPORT spectrum while adjusting the antenna.
It is getting clear that I need to learn alot more about modulation and demodulation if I want to understand what I am doing.
I live only a few hundred yards from the Los Alamitos Armed Forces Air Base. There might be some local RFI.
Thanks
Jerry
7.5' still isn't 2 deg compliant. The 2 deg complaint mark (for a perfectly shaped dish and installed and aimed perfectly) is around 8-8.5'. FYI, your next door sat interference is likely to come from 99W - where there are occasional video transponders that sometimes pop up with soccer, pro and college sports, or syndication feeds. 103W has two full-time services on the transponders likely to cause interference, so if you are getting NOAAPORT fine, you know your dish is aimed good enough that the 103W guys aren't causing you problems. Yes, you might get some interference terrestrially from the AFB. Post Sept-11th stuff has been he** for some dish owners due to the extra training missions or other missions carried out using radar that interferes with C-band. The problem manifests itself as errors -- you'll see tiling in the video of a digital service, white dots rapidly flash through analog video, or you'll see NOAAPORT data receive errors -- about every 9-10 secs apart like clockwork. I've only experienced it twice since 9/11 for about 2-3 hours each incident so it might have been just testing radars in case it needs to be used in a real scenario. No interference on Ku-band since the radar doesn't interfere with those frequencies.
Strength and quality bars
Hi Jerry,
First, The signal strength bar on the sat card (I believe) is sorta an average of signals. Just an indicator of signal present.
The quality bar is the important one, that indicates the quality of the signal present matching your settings.
The lower the quality the harder it is to decode the data, and the harder it is to error correct bits.
There is a big difference between a 10' dish and a 7.5' dish.
NOAAPORT might work on that small of an antenna but everything will have to be at optium.
You might know this but I will explain it anyway.
The larger the dish the higher the gain, And to get higher gain you must concentrate more rf energy in the main lobe which makes the beam narrower.
Hence, a smaller dish will not have the beamwith as a larger dish. So aiming off the bird will not (at least to my knowing) increase co channel rejection.
You could have local RFI , The Universal Software Radio Peripheral should help solve that from what you mentioned
I know I have some kind of interference that pops up on or near 3,955 Mhz in the morning here. It has happend between 8 and 10 AM.
It will cause the receiver to unlock. Though it doesn't happen every day.
I myself am not totally familiar with C band DVBS cards. But the basics are the same, you must have enough signal to decode (even with error correction) to get data out. Being used to GVAR there is no error correction so you have the signal or you don't.
Hope that helps.
Tim
Hi Jerry,
First, The signal strength bar on the sat card (I believe) is sorta an average of signals. Just an indicator of signal present.
The quality bar is the important one, that indicates the quality of the signal present matching your settings.
The lower the quality the harder it is to decode the data, and the harder it is to error correct bits.
I'm not shure what your saying here Jerry.
There is a big difference between a 10' dish and a 7.5' dish.
NOAAPORT might work on that small of an antenna but everything will have to be at optium.
You might know this but I will explain it anyway.
The larger the dish the higher the gain, And to get higher gain you must concentrate more rf energy in the main lobe which makes the beam narrower.
Hence, a smaller dish will not have the beamwith as a larger dish. So aiming off the bird will not (at least to my knowing) increase co channel rejection.
You could have local RFI , The Universal Software Radio Peripheral should help solve that from what you mentioned
I know I have some kind of interference that pops up on or near 3,955 Mhz in the morning here. It has happend between 8 and 10 AM.
It will cause the receiver to unlock. Though it doesn't happen every day.
I myself am not totally familiar with C band DVBS cards. But the basics are the same, you must have enough signal to decode (even with error correction) to get data out. Being used to GVAR there is no error correction so you have the signal or you don't.
Hope that helps.
Tim
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Thanks Skysurfer, I was wondering why the C band sats still needed such large antennas.
It never occurred to me that their spacing would certainly have something to do with that .
That's one of those "why didn't I think of that" moments.
Tim
Hi Tim
My problem is that I dont know what controls the "Quality" We may differ on the importance of big and small antennas, but thats not going to solve anything.
When I aimed my dish above the NOAAPORT satellite, that will lessen the sensitivity to adjacent satellites. And, when the beam is raised a few degrees, the NOAAPORT signal is still producing near max on the Strength bar but, at this aiming angle, the adjacent signal falls far below the relative level provided by a 10 foot dish. The data I accumulated today discounts the probability that adjacent channel interference due to a "too small" dish is my Quality problem.
I may be misunderstanding what I see, but, when I see a near 15 dB signal to noise ratio using a 7.5 foot dish, it is difficult for me to think my Quality problem will 'go away' when I use a 10 foot dish.
A 10 foot dish at 3.9 GHz will have about 40dB directivity and have a beam about 1,75 degrees wide at -3dB. A 7.5 foot dish will have about 37,5 dB and 2.33 degrees. The difference in gain and beamwidth is not monumental.
When I first set up the NOAAPORT system, both the Strength and the Quality were max and near max at all times.
Where can I learn what controls the Quality bar of the Twinhan?
Jerry
My problem is that I dont know what controls the "Quality" We may differ on the importance of big and small antennas, but thats not going to solve anything.
When I aimed my dish above the NOAAPORT satellite, that will lessen the sensitivity to adjacent satellites. And, when the beam is raised a few degrees, the NOAAPORT signal is still producing near max on the Strength bar but, at this aiming angle, the adjacent signal falls far below the relative level provided by a 10 foot dish. The data I accumulated today discounts the probability that adjacent channel interference due to a "too small" dish is my Quality problem.
I may be misunderstanding what I see, but, when I see a near 15 dB signal to noise ratio using a 7.5 foot dish, it is difficult for me to think my Quality problem will 'go away' when I use a 10 foot dish.
A 10 foot dish at 3.9 GHz will have about 40dB directivity and have a beam about 1,75 degrees wide at -3dB. A 7.5 foot dish will have about 37,5 dB and 2.33 degrees. The difference in gain and beamwidth is not monumental.
When I first set up the NOAAPORT system, both the Strength and the Quality were max and near max at all times.
Where can I learn what controls the Quality bar of the Twinhan?
Jerry
The signal strength and quality readings on DVB receivers don't have any absolute meaning. It seems like every receiver manufacturer measures them differently, and they even differ on the same receiver with different firmware versions. So it is futile to try to understand the quality readings. Although in a general sense, the quality seems to be related to the signal to noise ratio and to bit error rates. Relative to being 2 deg compliant, that to is not as absolute as people seem to think. I mean, a 10' dish or even a 20' dish will still receive signal from sats 2 deg away, it's just a question of how much. The 2 deg compliant thing just specifies a somewhat arbitrary amount as being acceptable. Actually, with most dishes, you probably have more likelihood of getting interferrence further than 2 deg away, ie out where the sidelobes are. I know that with my old 10' dish I once locked transponders from 2 different sats that were either 4 or 6 deg apart (can't remember) once without moving the dish, which was due to side lobe reception. I really think that the quality of the dish is a bit more important than the size. A dish that doesn't have a perfect shape either due to design or being warped or dented will receive significant signal from adjacent sats regardless of their size. Any dish will receive some signal from adjacent sats, regardless of size. Relative to S/Q readings not changing much when you move the dish, yeah, that is a symptom of the dish being a bit on the small size compounded with the S/N indicators on the receiver not being too sensitive. Relative to the Twinhan specifically, I have a couple Twinhan 1020a receivers, and they give S/Q readings that are MUCH lower than any of my other receivers. For example, I can get solid locks on transponders that give S/Q readings down below 20, while the same signal might give readings of 50 on another receiver or 80+ on yet another receiver. I'm watching an error free program right now which only gives me 14% quality on the Twinhan. Also, signals that give me >90% S/Q on other receivers will typically only give me S/Q of around 30 on the Twinhan, however occasionally I'll run across specific signals that for some reason give very high S/Q readings on the Twinhan for some unknown reason. So if you are concerned about low S/Q readings on a Twinhan, I really wouldn't be concerned. The fact that you are getting a very high S/N ratio suggests that you're getting a pretty good signal. But if you really want to learn about something related to your issue, I think I'd read up on how the various errors are handled by the receivers. I don't understand this very well myself, but I find it interesting and if I ever get time, I intend to learn more about it. There are all sorts of different kinds of errors encountered in DVB reception. There are CRC errors, TEI errors, continuity errors, Reed Solomon corrected and uncorrected errors, bit errors, and Viterbi Decoded bit errors, and I'm sure others as well, but these are just the ones that my receivers report. The part about all this which is interesting to me, is that even though there are errors, the forward error correction (FEC) will correct most errors. How this is done, I have no idea, despite reading several documents (my aging brain isn't able to comprehend some of this stuff... I guess I need FEC myself). However it's kind of interesting to watch. One of my PC receivers has a control app, which displays Channel bit error rate, Viterbi Decoded bit error rate, Reed Solomon Corrected, and Reed Solomon uncorrected errors, and signal to noise ratio. It's kind of interesting to watch the corrected errors increasing whereas uncorrected errors remain at zero and the Viterbi Decoded BER is at zero, even when the channel BER seems relatively high. Sometimes I even get a relatively high channel BER and zero corrected or uncorrected Reed Solomon errors, which I don't understand at all. Seems like if there are bit errors, that you'd get either correcter or uncorrected errors, but as I said, I really don't understand this stuff very well at all. But anyway, all this has shown to me that there are always errors, but that with the error correction built into these tuners, you can get virtually error free reception even with a relatively sub par signal. But if you have a 15dB S/N, I think your signal is fine. Yes, if you have an application which demands absolutely perfect reception, you will get some errors, but I really can't imagine anyone doing this on a low cost basis with a 7.5' dish having an need for perfection. Actually, I can't imagine even the professional installations needing this perfection either, except that they wouldn't want lengthy outages. Anyway, any installation is going to give some errors, it's just a question of how many or how often.
Hi B.J.
I can see that it will require me to do some studying if I ever expect to learn what NOAA is doing with their NOAAPORT downlink. I am almost completely ignorant of all the modulation systems being used with weather satellites.
I measured the ambient noise at my antenna here and see it is about 25 dB above the receiver noise. When I tune the receiver slightly away from the C-band NOAAPORT signal and record the noise level, the noise increases about 25 dB when I connect the antenna to the receiver.
I now suspect the local RFI is a major problem here.
Jerry
I can see that it will require me to do some studying if I ever expect to learn what NOAA is doing with their NOAAPORT downlink. I am almost completely ignorant of all the modulation systems being used with weather satellites.
I measured the ambient noise at my antenna here and see it is about 25 dB above the receiver noise. When I tune the receiver slightly away from the C-band NOAAPORT signal and record the noise level, the noise increases about 25 dB when I connect the antenna to the receiver.
I now suspect the local RFI is a major problem here.
Jerry
How much of the spectrum display can you see Jerry?
I will agree with B.J., That is well put on the S/Q .
When I aimed my dish I went by the quality info to determine best S/N + using the skystar2 card it beeps faster when your quality get better. Using a pair of old archer space patrol radios I can aim the dish myself.
I seem to be getting a better understanding of what your asking here Jerry.
I can't explain why your quality bar dropped so much.
But I can say that a week ago here my quality shot up to 80% for a hour or two when it normally runs around 60% mabie 65%
I watched your website today and seen perfect data (imgs) on the site but then, it was like something came in and messed up the reception.
QUESTION
When does the twinhan lose lock and is it at certain times or random?
Now some of the errors I saw on your system I also seen on mine, but when it came to losing complete parts of imgs. that problem I didn't see here.
I don't think you have a quality problem from what I've seen, what you have said.
You have a RFI problem.
You have seemed to eliminate the possibility of co channel interference already.
Coming back to the first question.
If you have something interfering (inband) you should be able to see it with the USRP from what you have said. Though I know nothing about USRP's
I do know with my Hp141t Analyzer I saw what was causing my problem, and it stood out like a sore thumb. I have pics if anybody is interested to see.
And it was turned off as fast as it was turned on. It even messed up or wiped out UCTV.
Part of it was right on top of NOAAPORT, and it would cause my twinhan to unlock and my quality to jump around and drop.
As I mentioned before this interference would come and go at certain time periods.
If it is a radar, not much can be done.
I also noticed on your website that you have a picture of your setup. Considering the prox. of those powerlines, have you looked into powerline interference?
Depending on how strong that would be...it can cause issues too.
Tim
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