Prime focus Ku ONLY LNB
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Prime focus Ku ONLY LNB
Can anyone recommend a Ku ONLY LNB for a prime focus dish? I would like to run some Ku tests comparing the signal strength differences of a 6ft mesh prime focus vs a .96m offset Ku dish.
Im curious if some frequencys will do better on one dish or another.
Also curious if one dish will respond better than the other in hot signal areas. Also curious if one dish will respond better than the other in fringe signal areas.
Im curious if some frequencys will do better on one dish or another.
Also curious if one dish will respond better than the other in hot signal areas. Also curious if one dish will respond better than the other in fringe signal areas.
Re: Prime focus Ku ONLY LNB
I would supect that the mesh would degrade you signal so that you wouldn't see any improvement at all........Just a guess
10.5 cband western arc 75deg to 139deg. 4ft ku with motor, full western arc.
Re: Prime focus Ku ONLY LNB
You could try a INVERTO ULTRA SINGLE BLACK, the dia. is only 40mm, you may have to mod your dish for this LNB to fit.
DEN
DEN
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Re: Prime focus Ku ONLY LNB
What is the f/d of your prime focus dish? Most offset lnbs are usually made to illuminate an offset with a f/d ratio of .6.
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Re: Prime focus Ku ONLY LNB
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http://www.linkboxusa.com/pf7900u.htm
Re: Prime focus Ku ONLY LNB
My prime focus is 71" wide x 24" deep
Ill see if I can get my hands on a linkbox LNB
Ill see if I can get my hands on a linkbox LNB
Re: Prime focus Ku ONLY LNB
have you come to any conclusions yet?? I have ran similar tests on a c/ku setup on a 10' big dish vs an offset small dish and a prime focus small dishhotsat9 wrote:My prime focus is 71" wide x 24" deep
Ill see if I can get my hands on a linkbox LNB
Re: Prime focus Ku ONLY LNB
If you need a standard ku lnbf for prime focus you can buy the GEOSATpro SL1P SINGLE STANDARD 10750 with 60db gain and 0.6 noise figure, if you need a universal ku lnbf for prime focus recommended the Golden Interstar GI-209P with 60db gain and 0.2 noise figure or the MTI AP8-TFT with conversion gain: 65dB and noise figure: 0.1 , all three you can buy in ebay.
Regards
Regards
Re: Prime focus Ku ONLY LNB
can you line the back of a big mesh dish with aluminum foil will that help bounce a better ku into lnb?
V8 Golden / V8 Novas / V8X/ GTC / V8 UHD
Re: Prime focus Ku ONLY LNB
You can take out the mesh and replace it with sheet metal, I have done it and it works great, remember to paint it with flat black or flat gray paint before you put your LNB on it, if you don't paint it you will kill your LNB just as soon as the sun hits it.mos wrote:can you line the back of a big mesh dish with aluminum foil will that help bounce a better ku into lnb?
Re: Prime focus Ku ONLY LNB
yes thanks i have an idea now i will try it also is there a difference with the focal point distance of ku lnb compared to c lnb? i have 8 feet dish.
V8 Golden / V8 Novas / V8X/ GTC / V8 UHD
Re: Prime focus Ku ONLY LNB
I have a mesh dish and it works great with both c band and ku. I use the same focal distance. If your dish is well aligned you should be able to scan ku.
Re: Prime focus Ku ONLY LNB
The focal point for your particular dish is the focal point no matter if it's C or Ku. I have a 10' Mesh dish that gets excellent C/Ku. The distance is calculatedmos wrote:yes thanks i have an idea now i will try it also is there a difference with the focal point distance of ku lnb compared to c lnb? i have 8 feet dish.
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http://www.satsig.net/focal-length-parabolic-dish.htm
Re: Prime focus Ku ONLY LNB
Jim wrote:The focal point for your particular dish is the focal point no matter if it's C or Ku. I have a 10' Mesh dish that gets excellent C/Ku. The distance is calculatedmos wrote:yes thanks i have an idea now i will try it also is there a difference with the focal point distance of ku lnb compared to c lnb? i have 8 feet dish./quote] . If you know th the brand of your dish this chart will help too!Code: Select all
http://www.satsig.net/focal-length-parabolic-dish.htm[
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http://www.bigdish.info/mainten/lfocal.html
Re: Prime focus Ku ONLY LNB
Please let us know if that worked?
Re: Prime focus Ku ONLY LNB
Completamente de acuerdo contigo,el ancho de banda de la frecuencia en KU requiere que el plato sea de lamina y no de malla para que funcione en esa banda,si es malla pierde ganacia cuanto mayor sea el diametro de las perforaciones de dicha malla,saludosowhite47 wrote:I would supect that the mesh would degrade you signal so that you wouldn't see any improvement at all........Just a guess
10 foot prime focus c band dish w/36 actuator pansat ap-3000 positioner at full arc & freesat V7,V7S2X & sg2100 motor W/ 90cms offset antenna and lnb universal KU 45º at 131º
Re: Prime focus Ku ONLY LNB
Some mesh dishes with flat sheet that is punched with small holes is spec'ed or said to be Ku / c band.
This sheet has a smooth surface. As I went to photo my dish I find my turkeys on my highest dish.
One jumped off before I took the pic. Owen
This sheet has a smooth surface. As I went to photo my dish I find my turkeys on my highest dish.
One jumped off before I took the pic. Owen
Dishes; 3x3m, 2.4m and 4.1m, 10+ ku, 2 movers, USARLS. V8 Combo, Pro, V8 Golden, Nova V8Pro2, GTC, Super.V7HDs, Combo and V7s V7Plus Finder, Finder-Meter V8X / UHD V7Pro GT/XCombo. Sats 100.5E to 177W. I'm a Sat hobbyist who helps out.
Re: Prime focus Ku ONLY LNB
Nice "bird" what transponders does it have? My wild turkeys never get on the dish, thank goodness.
Re: Prime focus Ku ONLY LNB
lolFeralkiwi wrote:Some mesh dishes with flat sheet that is punched with small holes is spec'ed or said to be Ku / c band.
This sheet has a smooth surface.
IMG_6813.JPG
As I went to photo my dish I find my turkeys on my highest dish.
One jumped off before I took the pic.
IMG_6812.JPG
Owen
Re: Prime focus Ku ONLY LNB
I do have installed a Universal LNB in a 2.4m along with 2 for C band
It does work however I do not see much of signal improvement due the signal here mostly is over 85%. BUt..... I do see the difference when it rains
On 76cm I lost the satellite.
1.2 m almost lost
2,4 some flickering
I havent tried one for Prime Focus, still. I like to hear about those PLL LNB Downconverters though
It does work however I do not see much of signal improvement due the signal here mostly is over 85%. BUt..... I do see the difference when it rains
On 76cm I lost the satellite.
1.2 m almost lost
2,4 some flickering
I havent tried one for Prime Focus, still. I like to hear about those PLL LNB Downconverters though
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Re: Prime focus Ku ONLY LNB
thanks for the info
i bought a c/ku lnb and i was never able to get ku to work properly maybe 2 or 3 channels on 87w but that was about it
i bought a c/ku lnb and i was never able to get ku to work properly maybe 2 or 3 channels on 87w but that was about it
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- Joined: Tue Apr 23, 2019 1:48 am
Re: Prime focus Ku ONLY LNB
Ku is not forgiving like c-band, the dish must be almost perfectly focused on the feedhorn.zoricua1981 wrote: ↑Sun Jul 08, 2018 12:23 amthanks for the info
i bought a c/ku lnb and i was never able to get ku to work properly maybe 2 or 3 channels on 87w but that was about it
Re: Prime focus Ku ONLY LNB
Fully 100% agreed. Tracking Ku signal can sometimes caused pain in the ....Pionex2020 wrote: ↑Tue Apr 30, 2019 2:50 amKu is not forgiving like c-band, the dish must be almost perfectly focused on the feedhorn.zoricua1981 wrote: ↑Sun Jul 08, 2018 12:23 amthanks for the info
i bought a c/ku lnb and i was never able to get ku to work properly maybe 2 or 3 channels on 87w but that was about it
Re: Prime focus Ku ONLY LNB
The mesh dish is done to reduce wind resistance for 6' and up. The frequency wavelength for C-Band and especially Ku sees a mesh dish as a "solid" reflector.
The definition of a parabolic is any line crossing the focal plane to the reflector and back to the focal point will be the same length. The focal point is where the feedhorn resides. All signal energy captured by the dish reflector is sent to the focal point.
To say it doesn't matter what frequency band you're in, it matters the wave length of the antenna in the feedhorn (i.e. if you have a feedhorn that is tuned to capture C-Band and Ka-Band you will receive both.
However for a 6' dish C-band will be harder to get a signal (it depends on the Satellite's footprint), Ka-band works great with a 6' dish.
The definition of a parabolic is any line crossing the focal plane to the reflector and back to the focal point will be the same length. The focal point is where the feedhorn resides. All signal energy captured by the dish reflector is sent to the focal point.
To say it doesn't matter what frequency band you're in, it matters the wave length of the antenna in the feedhorn (i.e. if you have a feedhorn that is tuned to capture C-Band and Ka-Band you will receive both.
However for a 6' dish C-band will be harder to get a signal (it depends on the Satellite's footprint), Ka-band works great with a 6' dish.
Re: Prime focus Ku ONLY LNB
if the holes on dish are too big in diameter you could have trouble.
The 4 ghz longer wavelength c band signals will be reflected back to the focal point/ feedhorn but the KU band signals at 12 ghz have a smaller wavelength , if the holes are too big , some of those 12 ghz signals may pass through the holes and all will not be reflected back to the feedhorn , as if there was no dish at all and KU will suffer losses
this was a big problem in the late 80s and early 90s went people started to try and capture ku band signals on their c band designed/optimized dishes ,i seem to remember if a 1/8 drill will pass through the hole , the holes are too big for optimum refection of 12 ghz signals .
you will have to do a little digging around and searching web sites but there is a definite hole size upon which KU band signals will suffer
The 4 ghz longer wavelength c band signals will be reflected back to the focal point/ feedhorn but the KU band signals at 12 ghz have a smaller wavelength , if the holes are too big , some of those 12 ghz signals may pass through the holes and all will not be reflected back to the feedhorn , as if there was no dish at all and KU will suffer losses
this was a big problem in the late 80s and early 90s went people started to try and capture ku band signals on their c band designed/optimized dishes ,i seem to remember if a 1/8 drill will pass through the hole , the holes are too big for optimum refection of 12 ghz signals .
you will have to do a little digging around and searching web sites but there is a definite hole size upon which KU band signals will suffer