Which combo feed LNB configurations or LNBF's works well or use 1 mtr dish for Ku?

[wen]

My main dish is a 12 ft Paraclipse Classic Polar T. I have a BSC-621-2D which came with no directions and almost no specifications and some web sites say it is for experimental use. It does not work as well as the BSC-421 (which at least has markings for f/d) location on the feedhorn and seems to work with my old Chaparral feedhorn or with the one that came with it if you can shim it to fit. The body is tapered so the fit varies from poor to worse. Comparing these two, the BSC421 works better. The ku on the BSC-621-2D varies from pretty good to not so good and the sweet spot is several actuator movements from the sweet spot for the c-band lnb.

I also have a Chaparral co-rotor II+ (not wideband) and 1992 vintage good lnbs for C & Ku band.

I also have a Chaparral feed that has both a C-band feedhorn with a Ku band feedhorn slightly offset in the polar axis direction, but in the same plane as the C-band LNB. It uses two polarators (one for each lnb). (I have not found this configuration listed on the Chaparral website)

Since I don't have anyway to control the polarator, If I simply remove the polarators, will the polarity be the same as the LNB or is there any easy way to block it to one polarity? That would at least let me check how well these four configurations compare without spending more on a polarity controller!

Does anyone know how well these configurations compare to save me a little time in narrowing down what to test? I also have two 1 meter motorized dishes that I will be comparing the ku band feeds against with a single Titanium Satellite Ku Band PLL LNBF and a dual Avenger Ku Band PLL322-2S LNBF on the other dish!

 

[mmewrench]

I have a corotor II on my dish (also a paraclipse) and once you dial it in the Ku is awesome. On my old unimesh 10ft, I started out with a BSC621 and later upgraded to a used corotor II, with ancient lnbs (the C band lnb was an old Macom that weighs at least 2 lbs). It was a definite improvement. Ive since updated both lnbs to PLL and its better yet.

As far as removing the polarotors goes, I would not. You can use a 6 volt lantern battery to change the polarity (a pain in the arse but for testing purposes it should be fine).



This pic shows the waveguide in the verticle position as it looks when the dish is at its zenith. You cant see it in the pic but the ku probe is straight up further back in the feedhorn. I don't have any experience with the dual polarotor type feedhorn.

I also have a 36 inch offset for Ku and the performance is similar to the bud, but drops off miserably on rainy days. Overall the bud picks up signals that the small dish cant once it is tuned to the arc. Right now I have t 12180 on 125 w at 83% quality with a tree partially blocking my line of sight. 70% on the Ku dish with clear line of sight.

 

[wen]

Thanks very much for posting the information on the corotor II. What lnb's are you using on it now and how are you controlling the polarity?

 

[mmewrench]

I am controlling the polarity and powering the lnbs with a 4dtv receiver. I have an azbox HD elite and a nano HD slaved off of the 4dtv. When I originally upgraded to the corotor, I used an old macom lnb for Cband and an equally old gardiner lnb for Ku. Since then I have upgraded the lnbs twice, first to norsat dro's (8530 Cband, 4106 for Ku and lastly to a norsat 3220 pll for Cband and a NJR pll for Ku. The major difference in the three stages of upgrade was an improvement in stability. Each step gave me a bit more stability. The plls will lock a signal with a quality level of 25% and make it watchable.

 

[mmewrench]

My main dish is a 12 ft Paraclipse Classic Polar T. I have a BSC-621-2D which came with no directions and almost no specifications and some web sites say it is for experimental use. It does not work as well as the BSC-421 (which at least has markings for f/d) location on the feedhorn and seems to work with my old Chaparral feedhorn or with the one that came with it if you can shim it to fit. The body is tapered so the fit varies from poor to worse. Comparing these two, the BSC421 works better. The ku on the BSC-621-2D varies from pretty good to not so good and the sweet spot is several actuator movements from the sweet spot for the c-band lnb.

While setting up my paraclipse dish I found that if you adjust the dish for better ku reception, the C band sweet spot will move closer to the Ku sweet spot. The same held true for my old ten footer but its more noticeable on the paraclipse. You may find that your lnbf is better than you thought just by dialing the dish in a bit closer. The Cband signals are a lot more forgiving than the Ku. That lnbf is not the best but it is adequate to receive most Ku especially with the high gain of the paraclipse.

 

[wen]

Thanks again mmewrench for the information. If you have a picture of your feed and lnb's, you might post it. I had several setbacks in this installation that made it take much longer than necessary. I bought one of the 1 5/8 diameter actuators (advertised as heavy duty monster) which lasted about a week before a small wind gust took it out. See attached photo.

Then I tied it down in an ice storm, and the electricity went out and came back on and the receiver/vbox tried to reposition it blowing an internal fuse. Then the BSC621-2D arrived and EVERYTHING is by trial and error. No marking or specs leave you guessing on f/d, ku focal distance measurement distance and that sloped barrel. I may try it again, but the co-rotor worked well at one time and I wonder if the combo lnbf will ever work as well?

This is the co-rotor that I was using just before I left San Diego 19 years ago. The mounting orientation can be seen from the black line on the polarator. With no signal applied would I get vertical or horizontal. I guess I need to set it up for horizontal since the receiver voltage is higher.

I went ahead and ordered the Titanium Satellite ASV-1 motor controller which has polarator control, but it will not ship until mid December. I really hate to get the first run of a new product, so hope I don't regret this decision.

 

[mmewrench]

View attachment polar axis template.jpgView attachment polar axis template.jpgView attachment polar axis template.jpgHere is my feed (pictures are not very good).I had to use a spare scaler as a spacer, because the previous owner cut the nylon thumbscrews flush with the feed plate. I am also posting a pic of the template that chaparral included with the corotorII. The smaller notch on the template goes on the Ku elbow, with the text facing away from the dish. The arrow faces up when the dish is at its zenith.

I know what you mean about the lack of specs on that lnbf,makes for a much harder install. If memory serves me right , I think I just matched the f/d ratio to and old Cband only polorotor that came with the unimesh dish.

Either polarity should give you enough voltage to run the lnbs, you will actually determine signal polarity with the polorotor.

 

[martin-f]

I have a corotor II on my dish (also a paraclipse) and once you dial it in the Ku is awesome

Hi, old thread is the corotor still in use please, have you found anything that works better ?, ive just acquired the same dish and looking ahead on the install,

I bought one recently for another install but going to use it on the paraclipse, mines the wide banded type with a extra KU band lnb its a matched FD for my dish.

 

[wvman]

I have a corotor II on my dish (also a paraclipse) and once you dial it in the Ku is awesome. On my old unimesh 10ft, I started out with a BSC621 and later upgraded to a used corotor II, with ancient lnbs (the C band lnb was an old Macom that weighs at least 2 lbs). It was a definite improvement. Ive since updated both lnbs to PLL and its better yet.

As far as removing the polarotors goes, I would not. You can use a 6 volt lantern battery to change the polarity (a pain in the arse but for testing purposes it should be fine).

View attachment 93104

This pic shows the waveguide in the verticle position as it looks when the dish is at its zenith. You cant see it in the pic but the ku probe is straight up further back in the feedhorn. I don't have any experience with the dual polarotor type feedhorn.

I also have a 36 inch offset for Ku and the performance is similar to the bud, but drops off miserably on rainy days. Overall the bud picks up signals that the small dish cant once it is tuned to the arc. Right now I have t 12180 on 125 w at 83% quality with a tree partially blocking my line of sight. 70% on the Ku dish with clear line of sight.

You can minimize the pain in the arse by using a double pole, double throw, spring loaded rocker switch that returns to the off position when you let go. It should have 8 terminals, with the 4 in the middle wired in an X so both sides of the switch will be the reverse of the other. That will leave 2 terminals on each end, with 2 hooking to the servo, and the other 2 to the battery.

One end of the switch will move the servo one way, the other end will move the opposite direction. You can bump the switch for fine adjustments. Sounds more complicated that it is. It worked well with the old PR 1 also.

 

[mmewrench]

Hi, old thread is the corotor still in use please, have you found anything that works better ?, ive just acquired the same dish and looking ahead on the install,

I bought one recently for another install but going to use it on the paraclipse, mines the wide banded type with a extra KU band lnb its a matched FD for my dish.
View attachment 128779

Still using the corotor and it works great

 

[martin-f]

Still using the corotor and it works great

Many thanks.