I've seen calculations showing that a small 18" dish may suffer from ASI, so moving from 18" to 24", 33" or 39" will definitely help, depending on your location and the relative signal strengths of the two interfering satellites. IIRC, the idea is that the extra signal from the edge of the much larger dish (the edge is the part of the dish that isn't pointed at the interfering transponder) will help reduce interference.

But moving from a 33" to a 39" dish, the extra signal from the very slightly larger outer ring of the 39" dish would only contribute a few extra db of signal.

Interference is occurring because the signal levels from two adjacent satellites are too close to each other. The question is, will the extra signal level from the extra 6" band of parabola of the 39" dish provide enough signal compared to the 33" dish to reduce interference?

I don't know the answer. Does anyone know of a reference chart showing how much extra dish diameter you need to overcome ASI for the satellites in question? That chart should exist.

Just assuming that more is better can be a risky strategy. You might think that 39" is enough (and it might be) but maybe the real answer is that you need a 1.2M or larger dish. It would seem to depend on the relative signal strengths of the two adjacent satellites and how much extra signal you need to overcome the interference.

But in any case, it's possible that the quality of the 39" dish might be the larger factor here. As usual with RF, many factors can be in play.

I do agree with you , the manufacturing quality plays an important factor. check www.satelliteguuys.us , they mention some data on the 2 degree spacing for several dish sizes. I do not remember if it was empiric though. I have a Fortec 90 cm dish and no problem with either bird , 123W and 125W. It was raining today I could not play with it. tomorrow i will try and give some results.

taken from wikipedia.com

As a receiver, antenna aperture can be visualised as the area of a circle constructed broadside to incoming radiation where all radiation passing within the circle is delivered by the antenna to a matched load. (Note that transmitting and receiving are reciprocal, so the aperture is the same for both.) Thus incoming power density (watts per square metre) x aperture (square metres)= available power from antenna (watts). Antenna gain is directly proportional to aperture. An isotropic antenna has an aperture of

lambda^2 / 4 * pi

where λ is the wavelength. An antenna with a gain of G has an aperture of

G * the previous formula

Generally, antenna gain is increased by directing radiation in a single direction, while necessarily reducing it in all other directions since power cannot be created by the antenna. Thus a larger aperture produces a higher gain and narrower beamwidth.

Large dish antennas, many wavelengths across, have an aperture nearly equal to their physical area.

donnyjaguar , with all due respect , but I just had to replace the coolsat 6000 box with another one and therefore I had to scan everything again and realing the dish (apparently strong winds misalinged it) and no major problems with 123W or 125W or any other birds only 2 degrees apart. you must be doing something wrong or the new 39" dish is not ok?. for 123W I had to use DiseqC 1.2 instead of USALS to improve reception of the reasearch and UWTV channels because they were cutting out by FINE MOVE 1 time West and for TP 12104 the same but 2 times East to avoid Montana PBS on 125W. For Montana PBS I had to do the same moving away from 123W. other than that everything else is working fine using USALS. well still no success on 30W , eventhough the trees have no leaves still no signal due to lots of naked branches. what to do , no spanish tv for me then lol lol lol.

good luck!!!!

Granted, I work in terrestrial microwave myself and although a larger antenna can resolve interference issues, as a general rule its not the best strategy.

As long

this is true. If the Signal vs ASI is better the net result will be improvement. I would say that I have not netted this improvement with my new 39" wok.


I think you're correct. The dish was marked down to 39$, maybe that should've been my first clue. It was a fair test though as I used my older linear LNB which has the same focal point as the new (replacement) unit. Which works identically I might add.
I suspect the geometry of the dish just isn't optimum. This is unfortunate. The branding on it is EagleSat. No easy way to test this thing unfortunately! :(


I welcome your suggestions on a different dish to try. :)


I tried moving the focal length and it didn't have much if any effect.

Interesting! It sounds like I need to get my hands on a Fortec brand dish. I'm not yet using the dish motor so all adjustments are manual. I know the dish I have is available with a multi-LNB attachment so I'm wondering if its more circular in construction than parabolic.


Luck is for the ill-prepared, I require one miracle! ;)

I don't like the cheap Ku dishes I have seen, too flimsy. I have not bought anything from this place but they do have high quality Ku dishes for sale. Look under medium sized dishes. The better dishes cost quite a bit more money.
[Link: satellitedish.com]

Fortec is a good brand, as long as the dish you're buying isn't counterfeit. I don't know the situation with satellite dishes but I've seen counterfeit set top boxes, motors and LNBs.

I think most satellite motors have a tenth of a degree pointing accuracy, there's a chance you might be able to slightly offset the dish just enough to reduce the signal of the interfering transponder. The motor pointing accuracy is much higher than what a person can achieve, especially when you're standing on top of a ladder in the cold. ;->

IIRC, a 39" dish should have a beamwidth of just under 2 degrees, the 33" dish has a beamwidth (I think) of about 2.4 degrees. So a few ticks of the motor away from the interfering transponder might work, if you have a good quality LNB. However, if your LNB isn't very sensitive or has high noise, moving the dish probably won't work because the LNB might not be able to pick up the slightly lower signal.

For whatever reason my reception on Galaxy18 has improved markedly. I'd basically given up on it last month but tried it on Sunday night and all was working fine.

I just got an old Star Choice receiver DSR 305 in good working condition. Hooked it as slave to my Coolsat 6000 motorised 90 cm Ku Universal LNB. Locked to signal from ANIK F1. So far the Guide has populated for 2 days but the open or free channels do not show picture nor sound. Promo , Knowledge , BC legislature and so on are listed as unscrambled in the lyngsat website yet nothing. The receiver had a subscription a year ago. I just power down the receiver hoping that maybe a firmware update will help as I ran out of ideas. The LED in the front is solid green for the channels on the ANIK F1 bird and the signal quality is 50 (yellow bar). subscription channels show a text indicating to call SC but the free ones say please wait etc ..... and stays like that for long.

Any one have any idea what might be the problem?. I am hoping I might be able to use it to watch the free DigiCipher I or II channels on other birds like AMC 3(although the menu does not allow me to blind scan nor to add any TP or Sat info). Of course slaved to the FTA receiver which will move the Dish. Will see?.

Finally!. I found what the problem was. I was actually locked to the other Sat signal , ANIF F2 @ 111.1. I conected the SC receiver straight to the Motor/Dish and after changing channels for a while I realized that it only locked (front LED solid green) to French channels instead of the free ones on F1. Looking in Lyngsat noticed that those belong to F2 not ANIK F1. In other words it was locking to the same TP's that belong to the free ones on F1 but it was actually on F2!. No wonder it was trying to decode the stream and could not.

Now is when the fun part starts, off to the other birds!. There is a way to change the provider ID on the menu and apparently the software will probably be able to load the other providers channel maps. But this is all probably , as usual, will see? Most people say the DSR 305 wont , but stubborn me , I am always swimming agaist the stream.

Do not slave the SC receiver to the FTA receiver as the SC will move the motor away from the position. No wonder I was having a hard time locking to the ANIK F1 signal!. The best way is to move the Dish into position with the FTA receiver and then power down and dont be lazy like me and go outside and bypass the motor. Then reconnect the cable to the LNB IN on the SC receiver. Thankfully nothing happened to my setup but in one trip to outside I saw the Dish moving for no reason at all. Apparently SC Oval Dish/2 LNB combination has a built-in switch that uses DiseqC commands for control therefore the motor will understand some of those commands as control commands to move the Dish.

Unfortunaelly , the SC receivers , only scan signals with 2 kind of SR (19510 and 20500) therefore you can only tune in to DC II signals using this Symbol Rates. OETA (PBS Oaklahoma) uses 4880 so no go. GPB (Georgia PBS) uses 19510 but as reported on other forums , they shutdown the service just recently although Lyngsat still has it listed. These are the only two In The Clear (ITC) DigiCipher II services on Ku Band which you a tleast need a previously activated DC II receiver. The other one, MTV, although 19510 SR is a subscription based service and for that you need a 4DTV receiver (aprox 500 US) with a subscription. Most of the 4DTV programming is on C-Band. More likely DVB will replace those 4DTV services in the mid to far future. Motorola is no longer manufacturing those 4DTV receivers but you can get them off E-Bay.

Was it Valentines yesterday? lol.

Yes. Unfortunatly, the Free To Air industry has taken a bad rap with all the hackers out there. We have been around since before the hacking started and have never turned to sell any satellite receivers that can be hacked. We simply don't support that market and our customers show us their appreciation.



It's a shame because many of these hackers or websites you see that operate from home and are selling and drop-shipping hack products don't have a clue about the true Free To Air, so it does not suprise me when you say the dealers had no idea what SatCoDX was.



If you need any products, be sure to purchase from an experienced and true Free To Air dealer. We warehouse and ship everything we sell and service all warranty repairs at our location as well.

Please let us know if you have any need for any equipment. Our website address is www.galaxy-marketing.com

Thanks,
Robby

I need to buy a C-Ku Band LNBF but have not been able to find any locally in the GTA area. Actually the whole set-up but at least small dishes @1.2 m I have found so far. If someone has any info please help me. All dealers I know only carry Ku stuff no C-band at all.

Check out the DMX741 or the DMX741U. It's a C/Ku band LNBF. If you want only C band, check out the DMX241.

DMX741 C Ku LNBF - With Standard Ku
DMX741U C Ku LNBF - With Universal Ku
DMX241 - C band LNBF

I was hoping to show the Damaged to a 90 cm Fortec Star fixed Dish after the very strong wind storm last Saturday around 5 pm here in the Toronto/Etobicoke area. The dish did not misalingned but rather it deformed the surface around 25 cm diameter from the center upwards. It looked like a balloon or when the skin swells in your arm after a not properly done injection. Like a car shop mechanic I pushed the surface back into position and eventhough it is not 100% perfect but fairly close it still gets quality levels at 91 on a CS 6000 receiver located on the 2nd floor apartm. Before, I had it on a compromise aiming getting signals from 2 birds , 123W and 125W with only one LNB with 88 quality at 11800 on 123W. 

The Dish is rated at 90 km/h operational and 180 km/h survival winds. This past windstorm as per some reports had 85-90 km/h sustained winds. As usual wind gusts are stronger eventhough for a few seconds. I guess the manufacturer claims are accurate them. It was not operational but it survived after the storm.

Some other same Dishes I have installed for friends recently in the area also did not suffered any damage at all but they were not located on the rooftop of an 8 story building in front of the lake like this one.  Usually there are high winds there almost anytime. The elevator shaft also creates turbulance specially close to the corners of it , exactly were the dish is located. Some other small DBS dishes share the same wall so there is no space to move away from the corners.

Daniel I emailed you the pictures just in case if you could somehow show them here. I could not find a way and I beleive it involves uploading them to some site on the internet I guess. Thanks and sorry for the inconvenience.