ku levels on 10 foot mesh

[truckracer]

I have a new sami mesh 10 foot dish. Some of you may have read some of my posts setting it up. I am using a bsc-621 lnbf.

I am wondering what my KU signal quality should be.
I know that everyone gets different numbers because of variations in receiver signal meters and geographical area in relationship to satellite footprints.

My question is - My 7.5' mesh dish has super strong ku signals
My 10 footer really does not have any better signals on ku.

Should my 10 footer be blowing the 7.5' away on ku since it is bigger and collecting more signal?

I am using a pansat 9200 HD.

Another thing that is odd - when I peaked the lnbf last night, on my 4dtv (dsr-905 sidecar) My Hbo signals were 70% for channels 100-111 and 72% for 112-up.

Now I after the tune up my 100-111 is 60% and 112-up is 70%.

I wonder if my skew is off a little. It also seems on fta c-band that all the Horizionta is stronger than vertical.

 

[Stefan]

bsc-621 lnbf

Well, there's at least part of your problem there. The bsc-621 just kinda sucks on Ku band. It's not properly designed. The idea of putting a little ku feed in back of the C band waveguide just doesn't seem to work. I tried one on 8.5' Birdview and was greatly dissapointed with the Ku performance and went back to my previous feedhorn which performed at least 4 times better. My advice is to get either a corotor or a bullseye type feedhorn and chunk the bsc-621 in the trash can.

In theory your 10 footer should perform better since it's larger but that assumes the alignment of your dish, feedhorn and scaler are all correct and that the surface accuracy of the dish is true.

 

[gabshere]

i can only interject thoughts here cause my bsc621 doesn't get the best of signals on ku on some satellites but on others it booms.... with my problem and i suspect it is a error on my behalf ( off arc in center)

I'm using a 7 1/2 ft mesh on my east side of the arc i get great c-band and great ku signals both boom in the 90's on my Coolsat 5000 but my center of the arc the cband is still in the 90's but the ku drops to 60's to high 60's ( the coolsat threshold is 63 so anything below that is lost).

so my satellite signals look like this : all these are SQ on a Coolsat 5000
AMC 6 c-band 90's + ku 90's +
galaxy 17 / sbs 6 ku 90's +
AMC 3 c-band 70's - 80's ku low to mid 60's ( no PBS reception signal too low)
Galaxy 16 c-band upper 80's ku low 70's
AMC 1 c-band 90's ku low 70's
Galaxy 10r c-band 90's ku upper 80's (11720) (88%)
AMC 7 c-band mid 80's

ok i checked the feedhorm being level in the scaler, checked it to see if it centered in the dish
i need to make a laser sight tool like linuxman has to verify these ....... but other than my dish seemimg to be slightly off arc in the center it performs well with the bsc621 , i do know it takes a lot of fine tuning to get the right position of the lnbf and my skew mark is at 6 pm unlike others with better luck being closer to 9pm

hopefully later this month i will get my 10 ft mesh finished and add the other bsc621 to it ...to compare with.....

I do like the BSC621 and i'm sure i would like SATAV's version also their c-band only version seemed slightly more heavy duty compared to the BSC

 

[truckracer]

I went out today and just started over checking my adjustments. I took a tv outback with a remote control repeater, the v-box remote and pansat 9200 remote. I have an RF channel 5 connection on the back of my storage building for tuning so I can see the receiver that is in the house. This way I don't have to unplug the reveiver and take it outside.

I got my inclinometer and took the dish to the zenith point on the mount. The mount was on 38 degrees and the dish itself is set at 46 degrees. According to the chart that came from superior antenna this is it.

Went to amc-3 ku and locked a couple of tp's (the pbs ones) readings in the 50's quality.
went to amc-3 c-band (booming in) even the 3824H 1808 one was near 90%.

Went to SBS-6 - 11732 6616 72% quality.

Went to G-10R ku 11720V 70% quality
G10R C- outdoor channel 80%

Went to G15 California channel 50% quality or so. bouncing around a little.

Fired up the DSR-905 and checked signal quality on Hbo Ch 111 - 60%
HBO Ch 112 - 76%

I thought the Hbo's were low so I skewed the lnbf clockwise and BOOM!
HBO Ch 112 99%
Ch 111 78%

Go back to amc-3 ku - NO SIGNAL! CRap !@*&^%!

Skew the lnbf back counter clock wise and 57% quality on ku amc-3

Go back to G15 - HBO back down where it was .

Left it alone since I like to receive KU and the dsr-905 will hold stable down to around 38 quality.

There is something to be said for the servo motor type feedhorns that have skew control.
I guess the big dish polar mounts do not skew the lnbf exactly accurately like a H to H motor does the small dishes.

 

[gabshere]

i know when using the 920 and 922 you can set the lnbf to rotate 90 degrees in the menu options...... if the 905 has this option try it.

 

[truckracer]

If I do that it all is lost. If I go with a corotor is there some way to control the servo besides that analog receiver. I would like something more automatic.

Is there a stand alone servo controller , or better yet I could possibly build one.

 

[tvropro]

That's interesting about the skew. I know on G1 on my RP-1 C, ADL feed, on the HBO horiz mux I need to adj the polorotor 5 points more. My G3 vert is 10 points different too. In theory the polarity should be set the same from one end of the arc to the other. That holds true on the rest of my birds. This is where a servo controlled feed has the edge over a fixed skew feed.

One reason I never put a C/Ku feed on my 12 foot dish was I know there is a compromise when you do that and you loose signal. I come from the old OTA antenna school when you used separate antennas for VHF & UHF when looking for maximum performance. I carried this theory into my satellite days.

There used to be servo controllers they sold, it's based on a 555 ic chip.

Here's a simple servo control schematic:

Servo Basics

 

[14karat]

Ok, conclusions (so far) of Truckracer's exercise...
Is it better to have a separate small (1m or so) dish dedicated to Ku?
I was planning to invest in a Corotor (I've already got a 621), but from reading this, I may be better off to use the Cband only feedhorns I have on the 10 & 8 footers and invest the cash into a 1m dish & motor for Ku only...
Geeezz... my configuration is getting more and more complicated as I go...

 

[tdti1]

Or you can grab something like a 3.1 meter Patriot that will be great for c/ku

 

[linuxman]

I haven't jumped in here yet just to see what everyone's else experience has been.

I have an 8 foot 3 inch Birdview perforated dish that I currently have my GeoSat Pro C/Ku LNBf installed on, and my opinion is that the GeoSat Pro does as well as an ordinary Co-Rotor II on that dish. By ordinary, I mean the newer ones without the ADL patent infringing design.

The alignment on that dish has needed some attention for some time, and I hope to have the new mast on the roof Saturday so I can give some more concrete numbers.

I hope to also put up the 8.5' solid Birdview Saturday, and am in the process of ordering another GeoSat Pro C/Ku LNBf for it.

I have never tried a BSC-621, but from all that I have read here with problems getting everything lined up, I probably won't.

I had very little trouble getting the GeoSat Pro tuned in and every indication is that it does C and Ku equally well.

The dish alignment and surface accuracy, along with proper F/D, Focal Length, and dead center on the dish all go into making both bands perform well.

 

[Corrado]

I like the simplicity of the BSC-621, for me it works great. The only thing is for KU operation with my 922 and former 905, is the reverse 90 deg setting on the receiver. I wasn't aware of that at the time of installation and caused a lot of wasted time in addition to figuring out the skew to begin with. But for me that's part of the fun of this hobby.

My complaint was the complete lack of index marking skew details that arrived with the unit. My spare has different marks and is about a year newer. Still without any documentation.

 

[Anole]

I believe the GeoSat dual band LNB is just as simple to use, hook up, or install.
It lacks F/D marks on the barrel, but I've seen a posting somewhere with measurements, and I might use a marker if it seems useful.

As for the correct rotation for zero skew, that is pretty well documented for both 621's and CK1's in this thread:
Linuxman and his GeoSatPro C & Ku band LNB setup.
http://www.satelliteguys.us/c-band-...ck-help-me-think-through-geosat-pro-c-ku.html

I know, too little and too late, but at least it'll help the next person who installs one. -

 

[Cameron12]

try moving the dish where it mounts to pole a very very small amount west and see if it improves. Put marks on the pole so you know how far you have moved it. retighten to pole each time you check. It took me a long while to get it exact.