DiSEqC vs 22Khz switching with a dual KU/C band LNBF

[redwudz]

I have ordered a BSC621-2D C/Ku LNBF and I'm wondering about switching between the C and Ku LNBFs. I have both a DiSEqC 2x1 switch and a 22Khz 2x1 switch available. I'm presently using USALS for dish positioning and it works well.

This is with a Traxis 6100HD reciever. After setup will the receiver output the correct DiSEqC signal to my switch or do I need to use the 22Khz option and switch? My dish is a 120mm offset with a DMS 6100 motor. I've had it working on Ku and on C band with no problems, but I have to change out the LNBFs each time I switch bands.

 

[Magic Static]

The unit you have uses a universal ku LNB. That has a 22khz tone switch in it to switch between your dual ku lo, 9750-10600. So you will need a DiSEqC switch to combine the C and Ku portions of that unit.

 

[Magic Static]

Oh and excuse my manners to the forum redwudz

 

[KE4EST]

Welcome to SatelliteGuys!!

DiSEqC Since you have a universal LNBF.

 

[redwudz]

Thanks for the welcome. And the information.

I have a Titanium C1-PLL LNBF set up on the 120 CM dish at present, trying to sort out my satellite aim. Probably in the next couple of days I'll do some fine tuning. Then I may change it out and install the BSC621-2D C/Ku LNBF. I would really like to get C and Ku band on the same dish.

As an alternative, I still have a 90 CM GeoSat Pro dish. I may just set that up and use the switch to choose between the C and Ku dishes. Then I could keep using the Titanium C1-PLL LNBF as it gets great reception. Putting up an extra dish may strain my subdivision agreement, but they haven't noticed the 120 CM dish yet.

I made a C band LNBF adapter for my offset 120 CM dish out of flat aluminum stock that duplicated the height and angle of my plastic Ku LNBF holder.
The C band LNBF holder I got with the conical scalar wasn't tall enough to match the Ku band LNBF holder.

The adapter is rigid enough. It also doesn't destroy the original Ku LNBF holder mounts. But I still couldn't get a decent C band signal, even on G17.

Then I noticed the C LNBF didn't seem to be pointed to the same place on the dish as the Ku LNBF.

I took the Ku LNBF off and used a laser level pointer on both sides of the center of the LNBF bracket and marked where they pointed on the dish.
Then I installed my C Band LNBF adapter. I did the same marks and noticed that they were about eight inches higher than the Ku marks.
Red is the C LNBF aim point and the yellow is the LNBF Ku. Blue is the dish centerline.
Then I re-bent my aluminum adapter to achieve the same aim point as the Ku LNBF, adjusted my conical scaler and immediately got a stable signal.

So next is fine tuning the C band LNBF for aim and deciding if I want to use a second dish for Ku band.
I would probably get better signal strength for both bands that way.

 

[Titanium]

Nice fabrication and great informative post! A photo is indeed worth a thousand words!

Yes, as you found out, the center of the C-band feedhorn must be at the exact same height as the KU band feedhorn and the angle of the feedhorn and scalar are highly critical!

 

[. Raine]

Welcome to SatGuys, Redwudz!

I like how you did that mount!

 

[redwudz]

I'm thinking to just go ahead and use my 90 CM dish for Ku band with my Titanium Ku Band PLL LNBF and forget about the dual Ku/C LNBF. I already have a steel fence post and 180 LBS of concrete mix for a stable mount for the 90 CM dish. I just need to dig the hole. The Ku dish combo got most everything I wanted when I used it before. The 120 CM dish didn't do that much better on Ku band.

My spare DMS 2100 motor is apparently dead, so I'm on Ebay and other places looking for another motor for the Ku dish.

The nice part of this next install is the unused cable input for my place is about 30 feet from my new 90 CM dish location, and it connects to my AV junction box indoors, same as where my 120 CM dish enters. I can put a switch there to select between the two dishes. There wasn't enough room for the C band dish there.

The new Ku dish location is also mostly out of sight of the street, so somewhat low profile. Fortunately, I have just enough clearance with a offset dish that I can see the Clarke belt just above my neighbors roof. We get extreme winds around here at times and I have a tile roof, so not a great place to mount a dish. The roof edges aren't much better. OK for a little Direct TV dish, but not a 90 CM or larger dish. Ground mount seems the only way to go. I'll add a photo when I get it all installed.

Thanks to everyone for the help and advice.

A Raine, I've done a bit of metal bending in one of my former jobs. Aluminum is easy enough to work with using just a good vise, a rubber mallet and a plan. The part of the bracket with two sheet metal screws showing is to keep the plastic C LNBF mount from rotating. I would have liked to make the whole mount out of aluminum, but that would take a lot more bending.

 

[redwudz]

I gave up on the dual Ku/C LNB. It never worked that well and I had my original 90 CM dish in the garage gathering dust anyway. I found a good location for my Ku dish and it was easy to integrate into my system.

A couple of photos of my finished dish projects. The first is the C band 120 CM dish. I mounted it low and behind a tree so the subdivision people wouldn't
notice it. Seems to work so far as it been up at least a month with no complaints. It's using a DMS 6100 Monster Motor and a Titanium C1-PLL LNBF. Good picture on most of the higher powered transponders.

My 90 CM dish is using a DMS 2100 motor and a Titanium Ku Band PLL LNBF. The cable ties into my non-used existing cable TV cable, then runs to my media distribution box in a laundry. I have a 22 KHz switch there to switch between the dishes. Works very well. I also have a HD Homerun tuner that feeds the local OTA TV signals from a antenna in the attic to my LAN system, so that OTA TV is available on any of my PCs.

 

[Jason S]

Very nice setup, Redwudz.

I too like the way you mounted the C-band LNBF.

 

[Mr Tony]

very nice setup. Love the pics

 

[redwudz]

Thanks. The setup for the two dishes is working very well. I should mention the 120 CM C band dish isn't as close to the ground as it looks in the photos, it's about 9 inches above the ground. I thought that should protect it a bit from our occasional high winds, besides keeping a low visible profile. Both dishes also have their coax well grounded as we do get some major thunderstorms here, though as the dishes are ground mounted, fairly safe.