Quick - Help me think this through! Geosat Pro C/Ku

[truckracer]

My numbers are added to the list using a bsc-621 and 10 foot mesh SAMI dish. Pansat 9200

G15 - 133W 3745 H C-Band digital 72% SQ-----68% SQ My . sq 72
G27 - 129W 11964 H Ku digital 72% SQ-----68% SQ-----63% SQ my sq ?
G10 - 123W 11718 V Ku digital 75% SQ-----73% SQ-----73%SQ my sq 72-76
G11 - 91W 3720 H C-Band digital 78% SQ-----78% SQ-----80%SQ my sq 80
G11 - 91W 12062 V Ku digital 60 - 65% SQ-----58 - 61 SQ-----17%SQ ?
AMC3 - 87W 12144 H Ku digital 70% SQ-----55% SQ-----17%SQ my sq 55-61
AMC2/16 - 85W 12195 H digital Ku test card 80% SQ-----70% SQ-----23%SQ
AMC2/16 - 85W TP 24 analog had an almost sparkle free picture. Clear with co-rotor.
G17 - 74W 11734 H digital Ku 80% SQ-----75% SQ-----80%SQ my sq 85-90
AMC6 - 72W 12053 V digital Ku 72% SQ-----72% SQ-----67%SQ my sq 72
AMC6 - 72W 4043 V digital C-Band 77% Sq-----75% SQ-----72%SQ my sq 93
IS9 - 58W 4040 H digital C-Band 75% SQ 81% SQ my sq ?

a couple of the sats above I don't have programmed.
Those are my numbers after "my sq".

I have much stronger H polarities than vertical (I need to adjust skew).

On my 4dtv I have to really skew the lnbf to get big number on HBO G15.
I can tune it to get 99% channels 112 and up , 85% on 100-111 hbo's.
Only problem is I can't get much of anything else on the eastern arc without adjusting the skew.

I can also on AMC 3 KU band have a low signal, bump the dish a couple of bumps-losing the signal, bump it again and boom locks in at high 50's. Odd that I can lose the signal between bumps and then get it again. What have I done wrong - Focal point, F/D. ?

 

[linuxman]

I can also on AMC 3 KU band have a low signal, bump the dish a couple of bumps-losing the signal, bump it again and boom locks in at high 50's. Odd that I can lose the signal between bumps and then get it again. What have I done wrong - Focal point, F/D. ?

It looks to me like you have it pretty well tuned in. Maybe still some room for improvement.

I would speculate that it has more to do with the accuracy in the way the 4DTV is interacting with your actuator and the number of counts on the actuator.

There are a couple of good threads along those lines for more information found here and here.

Depending on how much you use the 4DTV, it may be a toss up as to which receiver controls the dish. The DVB receiver combined with a GBox V3000 will give you much more precise control.

 

[truckracer]

I actually use a v-box 4 with my pansat 9200 (diseqc 1.2)

My 4dtv is receivers are both 905 sidecars. So the lnbf coaxes -One for C and one for KU, go into the sidecar first then short jumpers come out into the 2x1 diseqc switch then into the V-box 4. Another short jumper from the v-box 4 to the pansat 9200 HD.

The pansat actually controls the position. I have an automatic A/V switch that switches the inputs as you power on/off each receiver. I have an analog receiver slaved to the pansat loop out with a DC block on it. The pansat chooses the polarity and position.

Kind of sucks that you only have positions 27-49 for diseqc 1.2 positions.
I wish I could so a software tweak to re-claim the 1-27 positions designated
to USALS for 1.2

Now it seems that my Far western sats are too low. G-15 HBO is too low the way the lnbf is skewed for the middle and east arc.

Amc-8 is way low. It is 55 quality when normally it 93 or 99%.

I wonder how the surface accuracy is on my 10 foot sami?
I did the string test in a couple of places. The strings did touch but not pulled hard across each other. My 7.5' dish on KU band (it is a sami mesh too) blows my 10 footer away. It has a homemade feed ( look under :redneck feedhorns).

I will pull up and down and see if my tracking is still accurate on the far west.
At the zenith point I set the angles for my area dead on:

Mount- 38 degrees
Dish back plate 46 degrees

It seems my skew is the problem on western sats.

 

[linuxman]

Find out how many counts are shown in the VBox IV when traveling from you farthest West limit to you East limit, tell us what satellites are closest to your limits, find out how many inches the actuator comes out when going from East to West, and we'll tell you how many counts per inch your actuator is giving you.

Then you can determine if improvement is needed for accuracy.

 

[truckracer]

I will check it out.

 

[truckracer]

Hey George,

I haven't got it yet, but it is close.

After moving to 9:00 position, I found that the polarity was correct, and could get the verticals good, but the horizontals weren't that great.

I moved it to the 10:30 position which may have been the wrong way to go but I had to do something. That pretty much killed the verticals. I moved it little by little back towards the 9:00 position and am almost back and can get the strong horizontals pretty well and the verticals are better, but I think I am going to be back at 9:00 again and still not have the weak horizontals better.

I think this thing has the potential of working out great, but is a bear to dial in. There seems to be a very delicate line on the skew for both horizontal and vertical to work great on Ku.
The analog is working good except I still can't get either the digital or analog test card on AMC2/16 yet.

Should I have moved towards the 7:30 position to try and improve the horizontals?

If I can get at least as good as the co-rotor SQ across the arc I will be very happy. I was so skeptical after everyone has reported problems with the voltage controlled LNBFs that it took a lot of courage to even buy one.

If it works out and the new Fortec I ordered turns out to be pretty good, I think I will have some major switching around of receivers.

I have just the place for this LNBF. It is called the Birdview. That is where all the multi-LNBFs are hooked up now. I will have to wait and see if the Fortec will handle more than 4 LNBs in the setup menu.

I can them move the Traxis to the motorized Primestar, and the Pansat to the Unimesh and share it with the analog, and I can sell my Coolsat 5000.

Thanks for your help guys!

Please let me know if you think I should have moved it the other way.

Fred

There seems to be a very delicate line on the skew for both horizontal and vertical to work great on Ku.

Here is where I am on my BSC 621 Strong H but weak V.

c band is perfect all the way across

 

[linuxman]

There seems to be a very delicate line on the skew for both horizontal and vertical to work great on Ku.

Here is where I am on my BSC 621 Strong H but weak V.

You aren't kidding! It is a fine line, but attainable. At least for me it was.

The GeoSat Pro sets the polarity at the 9:00 position and it seems to be pretty close to equal at that place.

I think George has his BSC-621 at 6:00 for best of H and V.

If you have great C-Band and Great H polarity Ku, you aren't far from the sweet spot. Just a small twist in either direction should bring it in.

 

[truckracer]

I love the satellite hobby but I think this lnbf is getting the best of me.

 

[truckracer]

I don't mean to sound dumb, but when you say "9:00 o'clock" is this referring to the square part of the lnbf that contains the electronics?

 

[Anole]

GeoSatPro CK1 LNBf

There is a little arrow-like symbol on the back end of the Ku body, next to the Ku connector.
That should be aimed at about 9 o'clock
The C-band connector is maybe 5 o'clock.
Both when viewed from the back end.

You can pull off the front cover and look down the throat to see the goodies (probes).
On mine I make the Ku arrow at about 9:30 by that technique.
The cover snaps off and on easily.

edit:
But if you meant the DMSI dual band LNBf....here are pictures on their site.
And from reading this thread, it should be at either your choice of 6 o'clock or 12 o'clock.

 

[truckracer]

OK that's exaclty how I have mine. Like the first pic on my true south,

I did get the most out of tonight. I have c-band HBO 100-111 80% 112-up 99%

Used g10r as a test mule for ku.
11720V ku band best I could get was 55% (pansat 9200)
11800V ku band .................................75%

4180H 29270 .....................................90%

Still get very low quality on amc-3 pbs channels.
No adjustments would bring it in.

 

[Quattr00]

I have a BSC621-2 C/KU LNBF on a 1.2 meter dish and I get the two polarities at 6 or 12...better results at 6. I get a few channels in C band with this setup. Ku band is not good with this LNBF if I adjust for ku I loose C band. My solution was to add a ku lnbf on the side of the BSC621-2 and I get double the signal that the BSC621-2 gives me.

There is a little arrow-like symbol on the back end of the Ku body, next to the Ku connector.
That should be aimed at about 9 o'clock
The C-band connector is maybe 5 o'clock.
Both when viewed from the back end.

You can pull off the front cover and look down the throat to see the goodies (probes).
On mine I make the Ku arrow at about 9:30 by that technique.
The cover snaps off and on easily.

edit:
But if you meant the DMSI dual band LNBf....here are pictures on their site.
And from reading this thread, it should be at either your choice of 6 o'clock or 12 o'clock.

 

[truckracer]

KU band has really sucked on thisbsc-621 lnbf. I have a 10 foot dish and ku is weird. I will have on ku one tp booming in and another at 10% quality.
I have setup and tuned a lot of dishes and the C-band side of this thing works great but ku just is not right. Dish is tracking arc
F/D is at it's best and focal point.


I like voltage switched polarity but the combo lnbf's just don't seem to be great.

Here's my plan:

Buy an orthomode c and ku feedhorn. (dual ku and c lnbs)
4 coaxes down to a weatherproof grey plastic electrical box from home depot

coax 1 KU V
coax 2 KU H
coax 3 C V
coax 4 C H

buy two passive multiswitches: (dedicate one for C-band and one for KU band)

Connect the 13V port to the Vertical lnb
Connect the 18V port to the Horizontal lnb

connect the two cables from my 2x1 diseqc switch (one for C-band and one for KU) through my dsr-905 sidecar and out to the dish to each appropriate multiswitch.

When either receiver sends 13v dc It will switch to the vertical lnb
Same for horizontal.

It would require two passive multiswitches. One for c and one for ku

will lnb's for feedhorns that normally run 18v still operate at 13v?


Here's the horn I am thinking about:High Performance Dual C/Ku Band Feedhorn - PM-C/KU-OR2+2

 

[Anole]

this IS a GeoSat CK1 thread . . .

Here's my plan:
Buy an orthomode c and ku feedhorn. (dual ku and c lnbs)

That's $200 . . . plus four LNBs.
Considering Linuxman found a $50 solution, I would hope you don't give up just yet. - :up

 

[transco]

I wish I had seen this thread before ordering a BSC621 on Ebay... committed now. I've gone through several Polarotors over the years and it getting too expensive to keep replacing them. My first thought was a 4 port feedhorn with dual C and Ku band LNB's, but that's way beyond my limited budget. Anyway, reading this thread has given me an idea of what needs to be done to get the BSC621 optimized. What I don't know is how you set up the 922 to select polarity. I've never used anything but Polarotors with it. How is this done?

 

[Lak7]

In the 922 select the LNBF option, it will then use 13v / 18v to change polatiry. I don't think the 922 can control a 22Khz switch, just run 2 direct lines from LNBs to receiver. Do not use the "jumper" cable that comes with the BSC621. Google how to install. There are no f/d markings, but somebody has a web pages with measurements relating to f/d ratios.

 

[truckracer]

Some people have had them (bsc-621) to work, mine did not do so well. I think there are a wide variety of quality variances in these units.

Your corotor feedhorn type is much better in my opinion. Look around on ebay and othe places. Those dual band dual polarity ortho feedhorns turn up sometimes. I just bought one with four norsat lnb's for 50.00!!!!! DRO type 8000 series lnbs +/- 250 khz drift.

Just keep a couple of servo motors handy for replacement on your standard feedhorn.

 

[transco]

Those dual band dual polarity ortho feedhorns turn up sometimes. I just bought one with four norsat lnb's for 50.00!!!!! DRO type 8000 series lnbs +/- 250 khz drift.

Just keep a couple of servo motors handy for replacement on your standard feedhorn.

Wow! You made quite a deal. I've been watching Ebay and Craigslist, but so far no joy. I'm sure you are right... my best bet now is to stock up on servo motors.