ordered a dual C and ku feedhorn

[truckracer]

I just ordered a dual C band and dual ku band feedhorn with two Norsat 8000 c-band lnb's and two Norsat Ku lnbs.

This is I guess what you call an "orthomode" feed horn (no servo)

I am planning on running a multi-switch and going "Servo-LESS"

what kind of multi-switch do I need to do this.

I could run two seperate cheap DBS multiswitches (one dedicated to each band) or is their one multiswitch that will perform the whole job?

 

[scottc98]

A 4x4 22mhz switch will be perfect

 

[voomvoom]

I've been wondering about this. Will you need to use a splitter, since the Norsats are not voltage switched, and every other satellite flips polarity from odd is vertical and even is horizontal, then the next bird is odd is horizontal and even is vertical. While the two lnb's sit 90 degrees different from each other and the multi-switch has specific vertical and horizontal connections, I'm getting winded here, but I'm thinking you may have to use a splitter for each lnb and use both sides of a 4x4 multi-switch (regular and 22KHz.) to get it to work on all the satellites? Of course this is my thinking and I usually think too much?

 

[jsattv]

I just ordered a dual C band and dual ku band feedhorn with two Norsat 8000 c-band lnb's and two Norsat Ku lnbs.

This is I guess what you call an "orthomode" feed horn (no servo)

I am planning on running a multi-switch and going "Servo-LESS"

what kind of multi-switch do I need to do this.

I could run two seperate cheap DBS multiswitches (one dedicated to each band) or is their one multiswitch that will perform the whole job?

Hey Truckracer, any idea where one can get a good price on the Bullesye II / Orthomode Feedhorn? I've seen prices varying from $250 - $379 for just the FeedHorn!! Do Maybe our sponsors sell it?

Re How to wire it Up & What Switches are Needed:
Truckracer and Voomvoom, I think Linuxman mentioned on another post that he is is expecting to get a new or reclaimed Bullesye II Feedhorn soon. Sure would be great if someone could Post a Step by Step Drawing on how to actually wire in the Orthomode Feedhorn and what switches would be required.

 

[Anole]

1 vote for: don't care (?)

... every other satellite flips polarity from odd is vertical and even is horizontal, then the next bird is odd is horizontal and even is vertical.
... the multi-switch has specific vertical and horizontal connections,

Ya almost had me trying to solve this problem.
But, I think it's a non-problem... unless you come up with some contradictory facts.

There are no channel numbers. Not on FTA.
So, if you use the ortho (I keep thinking: mattress) with a DVB FTA receiver, not only do the existing transponder tables work, but blind scanning would work regardless.

Now, if you were trying to go othro (-pedic?) with a 4DTV, that's out of my knowledge base...
I'm assuming not, so it wouldn't matter.
Wait! The 4DTV knows how to talk to a voltage controlled LNB like the 621 or Ck-1, so it would sort out the odd/even matter (wow, I just thought of that while typing!) - :up

 

[linuxman]

It works just like a CK1 or a BSC-621 with a 4DTV. The settings in a 4DTV should be a C and Ku LNBF. The satellite setup controls whether it is a "Reverse" or "Normal" polarity satellite.

For a DVB receiver, you need a 3x4 multi-switch for each Band to keep from having to set up more than one satellite for either side. The multi-switch sends the voltage down the correct leg for that polarity. 13V for vertical, and 18V for horizontal.

Then all you need is a diseqc switch with port one going to Ku multi-switch, and port 2 going to C-Band multi-switch.

I am going to use 2 powered multi-switches to insure proper voltage gets to the LNBs because I will be using it with my Twinhan.

EDIT: I may be wrong about the 4DTV, will have to check further.

EDIT Again: After thinking it over, if the 4DTV can control a voltage controlled LNBF, why wouldn't it control the multi-switch? It is just a matter of voltage, and the receiver doesn't know the difference of whether it is hooked directly or through a multi-switch, and the multi-switch doesn't care, so it will work!

 

[voomvoom]

Ya almost had me trying to solve this problem.
But, I think it's a non-problem... unless you come up with some contradictory facts. - :up

Fact: each lnb will be fixed, so it will do only one polarity and not both. If one cable goes to the fixed lnb and that position for that particular satellite is vertical and you have the cable going to the vertical side of the multi-switch, then all should be hunky dorry? But when you go to the next satellite which will have the opposite polarity for the fixed lnb that was previously vertical but is now horizontal and the cable is still going to the vertical side of the multi-switch, then I see it not working? But, what do I know...??? I hope I'm wrong, but that's what my mind is telling me. If I am right, then you will need a splitter and run another cable to the opposite polarity (in other words, a cable for V on one side of the multi-switch and the other cable for H on the 22KHz side of the multi-switch)....???
Hopefully I'm wrong and truckracer will get his new Orthomode hooked up and everything works on every satellite, as per his plans..!!!! And without my idiocrazy.......

 

[voomvoom]

After thinking it over, if the 4DTV can control a voltage controlled LNBF, why wouldn't it control the multi-switch? It is just a matter of voltage, and the receiver doesn't know the difference of whether it is hooked directly or through a multi-switch, and the multi-switch doesn't care, so it will work!

truckracer has a 905, I don't know the 905, but the 922 and the 920 will control voltage lnbf's. These Norsats are not voltage controlled. They are fixed, so you need a servo motor to switch polarity. The Orthomode doesn't have a servo motor so you can't switch them, they remain fixed. The 4dtv has a setting for Dual, so it will be OK with the orthomode feedhorn, as it will internally control them, but a DVB receiver won't (I think?).
Also, a multi-switch is fixed (I think) for V or H? If you have a cable on the V side, you won't get H, and visa-versa (again I think?)? The sooner truckracer gets his new toy, the sooner we can shut me up....????? maybe........

Edit: and I've tried to use a multi-switch on my 4dtv, and had No Success.... I couldn't get it to work....? I could have done something wrong, which I'm good at..!!!

 

[truckracer]

Yes my 905's will do "lnbf mode". I think the normal or reverse polarity does not matter since it would make the entire feed horn work like an lnbf. On an lnbf the receiver always chooses the same probe inside the unit for Vertical and the same other probe for Horizontal. I am pretty sure that the Normal vs Reverse polarity thing is about the channel numbering scheme from the analog
days.

This just makes an old school feedhorn work like an lnbf except you have to have a bunch more stuff to make it work (multi-switch, four lnb's, feed horn).


I can also connect my other receivers to the dish and view seperate ku and C band polarities from the same sat. This will be very handy on G-1 HBO/Max.

 

[Anole]

done 'n documented

Our member, Labgate, did this all last year, and was quite successful.

See also where member Stefan posted some more valuable comments.

Then a little further down, Labgate gives a PDF picture of hookup with multiswitches.

 

[linuxman]

And here is my diagram.



If the 4DTV can control the voltage controlled LNBF on the left just by changing voltage from 13 - 18 Volts, why can't the same thing be done to the multi-switch on the right.

The receiver just passes the correct voltage for horizontal or vertical, and the switch delivers the correct polarity.

Again, if you set the satellite up as G1 (G15) in the 4DTV, the receiver recognizes it as a reversed polarity satellite. The same would be true setting up a normal satellite. That's why the 4DTV rotates the polarity on a voltage controlled LNBF in the setup.

Maybe I am wrong, but I don't think so.

 

[truckracer]

the diagram

on the right, shows how I originally planned on connecting the dual/dual ortho feedhorn.

Using two dbs multiswitches (4x2) and then diseqc swithes for the fta boxes.
The 905 4DTV would just have a "C" and "K" cable going to the proper switch.
the 905 would be set to "c and ku band lnbf's" in the installation menu.

All should work fine. I may have to choose "rotated 90 degrees". Just have to play with that one.:up


As far as the "even vs Odd" polarity scenerio, I always thought that each respective polarity is truely in relationship with polar axis.
Meaning Vertical is Vertical and Horizontal is Horizontal no matter which tp it happens to fall on.

I guess on 4DTV if this a true concern then, one would have to pay close attention this.
On FTA , I don't think it would matter at all since the feedhorn could be rotated to accomodate the proper reading on H or V for a given tp. Everything else should fall into place I think.

 

[Larry1]

The 4DTV works great with voltage switched LNBF's. Just pick LNBF and not LNB in the setup menus. Multiswitches work fine also. My StarChoice (DSR921) is connected to a 4x8 multiswitch. The multiswitch setup you have posted should work fine. The only question would be if the LNB's will run at the different voltages? The vertical LNB will only be receiving 13 volts. Each band has a dedicated LNB for each polarity, so one (of each band, Ku, C) LNB will only be receiving 13 volts and the other LNB will be receiving 16 volts. (unless you use a power inserter to power each LNB). From the Norsat web site, the LNB's require +15 to +24 volts. You can always use a home made power inserter to power the LNB's. I used one for years to power my StarChoice stacked LNBF. I used an old splitter case and removed its internals and built my own power inserter inside it. You would need 4 and a 18 volt power supply if you run into voltage problems. Each of the Norsat LNB's require approx. 200ma, so your power supply should be rated 800ma or more. An old notebook power adapter (19volts) will work fine. The notebook adapters are usually rated for up to 3.95amps, so it will supply 800ma very easily. You only need one adapter and connect it to all 4 of the power inserters, you do not need 4 separate power adapters, but would need four power inserters. The capacitor passes the high frequency signals and blocks the DC power. The diode passes the DC power in one direction.
Attached is a drawing of the power inserter that I made.

 

[Larry1]

I may have to choose "rotated 90 degrees". Just have to play with that one.:up


As far as the "even vs Odd" polarity scenerio, I always thought that each respective polarity is truely in relationship with polar axis.
Meaning Vertical is Vertical and Horizontal is Horizontal no matter which tp it happens to fall on.

I guess on 4DTV if this a true concern then, one would have to pay close attention this.
On FTA , I don't think it would matter at all since the feedhorn could be rotated to accomodate the proper reading on H or V for a given tp. Everything else should fall into place I think.

If this does prove to be a problem, then you will have to reverse the connections to the multiswitch, or as you stated rotate the feedhorn 90 deg. One does it electronically, the other mechanically or physically. This will be for all the satellites and not just one transponder.

 

[Larry1]

This just makes an old school feedhorn work like an lnbf except you have to have a bunch more stuff to make it work (multi-switch, four lnb's, feed horn).

Exactly.

 

[Larry1]

Will you need to use a splitter, since the Norsats are not voltage switched, and every other satellite flips polarity from odd is vertical and even is horizontal, then the next bird is odd is horizontal and even is vertical.

The channel list in the receiver will take care of which channel is horizontal or vertical automatically. Each channel is programmed in the receiver as either horizontal or vertical. Each satellite in the receiver has a separate channel list. Take a look at a FTA channel list with a channel editor program.
The generics on the 4DTV will always have the same parameters for a given generic definition. They do not flip their polarity from one satellite to another. e.g. generic w channel xyz will always be freq: xxxxx, polarity Horizontal and generic x channel xyy freq: yyyyy, polarity Vertical.
Please see
http://www.satellitesurgeon.com/4dgen.pdf

 

[linuxman]

As stated above, Labgate uses his with a powered multi-switch only outputting 13V on the vertical side and he has stated that his has worked fine for over a year.

I am going to try mine without the inserter when it comes in, and if I need one, I will add it.

 

[Larry1]

I am going to try mine without the inserter when it comes in, and if I need one, I will add it.

Certainly worth a try as it will cut down the complexity/devices in the circuit. The power issue may be dependant on the brand/model of LNB's used.

 

[Anole]

power inserter

There should be a coil / inductor / RF-choke between the diode and the signal .
Otherwise, the output transistor (or chip) in the LNB is driving a very low impedance power supply with your IF signal.

Also, the first spec I found on the 1N4148 diode lists its max current as 300 milliamps, much to my surprise.
I remembered it as much less hearty (maybe 50..100ma , if that).

So, I guess you could consider it a sort of a fuse against over current.
I'd have used a 1N4001 , 2, 3, 4 etc as they are rated 1 amp, but it's probably a moot point.

hrmmmm.... though for this particular application, the diode may not be even needed...
I guess if I were making them, I'd put in the diode, so if I wanted to use 'em elsewhere, they'd be ready to go. - :up

 

[ACRadio]

Since I have owned one of these for quite some time and have done some extensive testing with the feed I will share my thoughts.

While the C band vertical LNB's may operate at a reduced voltage, they are usually rated at +15 to +24 VDC. Quite a few KU LNB's are advertised to operate with as low as 12 VDC. My LNB compliment consists of a pair of Cal Amp Extended Professional II's rated at 500 khz stability, and a pair of Japan Radio NJR2535S PLL LNB's rated at 32 khz stability. These are mounted on a Chaparral Bullseye II feed on an 8 ft Channel Master fiberglass dish.

My first thoughts were to do as discussed here and use a single coax and have a DTV 4x4 switch mounted at the dish. I have a pretty long cable run (260 ft) to this dish so Commscope RG11 is used. I had also previously tested this on a much shorter cable run with similar results. I found that one of the C band LNB's wouldn't operate with vertical voltage while the other one would. After some thought I decided the short term answer would be to make sure all the LNB's received 18 volts. That way I could do some signal tests to see if the signal dropped when using vertical voltage. I ran a second coax and placed two 22khz switches at the dish to select between polarities, and a DiSEqC switch at the house to select between bands. I then had to program two satellites per band, one for horizontal and one for vertical. For instance, on Galaxy 11 I had 4 satellites programmed...Galaxy 11 C band H was DiSEqC 1 22khz off, C band V was DiSEqC 1 22khz on, KU H was DiSEqC 2 22khz off, and KU V was DiSEqC 2 22khz on. All frequencies were programmed as horizontal to be sure that 18 volts was always sent to the LNB's.

Testing the signal was then easy...all that was necessary was to change a frequency to vertical so that 13 volts was sent to the LNB and record the result. As I said previously one of the C band LNB's absolutely wouldn't work at vertical voltage while the other would. Both KU LNB's would work with 13 volts. The receiver was a Traxis DBS3500, and taking a quick look at the signal strength while switching between voltages showed a marked decrease in both signal strength and quality on all LNB's when switched to vertical voltage. Putting the meter in line told the story. There was a decrease of anywhere between .75 and 1 db C/N when operating the LNB's at 13 volts.

I saw a marked benefit operating these LNB's closer to the voltage they expect. While all but one would operate with vertical voltage, there was quite a difference in signal level. Personally I will fight for every tenth of a db I can snag. This arrangement operated well for a period of time until I could locate a suitable power inserter. I knew that adding a power inserter on each vertical line not only would simplify the satellite arrangement in the receiver, it would allow me to get rid of a switch and the inherited loss. I decided on the Pico dual power inserter which will power two 18 volt lines with one device. I now power the vertical LNB's with the Pico and power the horizontal LNB's with the receiver using a 4x4 switch. Using the 4x4 also let me get rid of a splitter and gave the home theater PC independent control of this dish without using the Traxis as a slave. Remember that with 22khz switches both LNB's are being simultaneously powered, so current draw might need to be taken into consideration.

Hopefully my experience with the dual orthomode will be of some use here. I also have a 10 foot Channel Master with a single C band orthomode set up similarly. This dish has a left hand drive and is set up for circular polarization Atlantic satellites.