INFO ON TESTING C BAND LNB

[Blue Crystal]

I have my 10ft dish mounted but not set on a satellite yet. The LNB on the dish is and old C Band. However my receiver I bought is a Pansat 2500A digital.
Trying to decide on which LNB/LNBF to buy.
In the meantime I"m wondering, for test purposes, can I hook up the old lnb to my digital receiver and get a signal.
I looks like the ribbon wire I have has a lot more places to connect to an older receiver than my Pansat 2500.
I was wondering if it is possible to connect the coax from the LNB to the IF input on the Pansat. However, if thats possible does the single coax power the lnb, or can this be done only from an older receiver with more connections, or does the lnb get powered at all? I haven't got a V box I am trying to do it by hand, at this point.

As you can see I'm new at this, but willing to learn. (a little at a time, that is!)

Thanks

 

[Mr Tony]

In the meantime I"m wondering, for test purposes, can I hook up the old lnb to my digital receiver and get a signal.
I looks like the ribbon wire I have has a lot more places to connect to an older receiver than my Pansat 2500.
I was wondering if it is possible to connect the coax from the LNB to the IF input on the Pansat. However, if thats possible does the single coax power the lnb, or can this be done only from an older receiver with more connections, or does the lnb get powered at all? I haven't got a V box I am trying to do it by hand, at this point.

If you are aimed at a satellite then you should get 1/2 the channels. The old LNB's had a polarity notch in them that picked up one polarity. The 3 wires coming off the blue box on the LNB normally goes to the analog box to control polarity. Since those are not hooked up its only one polarity...you can manually skew the LNB 90 degrees for the other polarity

So hook the cable from the LNB to the 2500 and do a blind scan...just scan one polarity and see what ya get. Doesnt matter what polarity as it will scan the frequencies that are on whatever polarity the LNB is set to

Do you know what satellite its aimed at?

 

[Mr Tony]

addition...here is an old setup I had

The left LNB was at 99W and is voltage controlled so it got both polarities.

The right one (Channel Master) is an old LNB that got one polarity. The polorotor (blue box) broke off so the electrical tape is to keep the notch (polarity notch) from moving. It was aimed at 103W and got the Horizontal ONLY stuff.

I stuck a screwdriver down the throat of that LNB to skew it to optimize signal

 

[Blue Crystal]

I haven't picked a satellite, yet. probably will try a satmex or I'll try the 103W just to see.
The skew has had me a little confused since I am testing the set-up with out the assistance of the motor. You cleared that up for me with the statement about the screwdriver. I guess I was thinking you manually turned the LNB to adjust the skew. I remember seeing that stem in the bottom of the LNB throat. I'll cross that bridge when I get to it.
Thanks

 

[Cadsulfide]

An old lawnmower or car battery will work for moving the dish to a fixed position untill you get a chance to run the cables

 

[SatPhreak]

The pansat 2500A can control the skew to select the polarity. It can not move the dish though. The skew wires are usually white, black and red. Black to GND, red to +5V, white to hat symbol (pulse).

 

[Mr Tony]

didnt know that the 2500 did control polarity. I have the 1500 which doesnt and just thought the 2500 added AC-3 and S-video

guess I was wrong

 

[SatPhreak]

Yea, it is the same as the 1500 but added AC-3, s-video and polarotor control. I remembered that it was an enhanced 1500A from a few years ago when I was looking for my first FTA box. I got the 2500 for the ac-3 and S-video so I could get any ac-3 with my stereo. I then sold it and got an Ultra, and recently was given another 2500 a few months ago without a remote. The guy I got it from even ended up finding the remote a couple weeks later and gave it to me too.

 

[bubby-joe50]

The hardest part of the 2500a is that the current and factory binary files have been modified to exclude most of the c-band satellites and the transponders are all out of date so getting signal quality to lock onto a satellite is harder, find your true south and manually adjust the linear lnb skew for best signal quality and lock down. Then move the dish with a battery, either set on a specific satellite that you've updated the transponder information on or watch your meter as you move the dish, a high signal without a quality reading usually has you on a satellite then a blind scan will see where your at. Current total 2500's is 3 my original and 2 free ones.

 

[SatPhreak]

You can always use channelmaster to add the sats and new transponders back in. Or the remote if you feel like taking your time. Once the skew is set for one sat, the other sats would just have to be set to the same numbers. The rotation of the dish as it tracks the arc should keep the numbers the same.

I don't have c band capability and have only played with the skew settings with a non mounted c band feedhorn. I was going to try it on my 90cm dish but it has a fixed scaler ring that would need to be hacked up to clear the dish arm and the lnb is a 35K model so chances of getting any c band would be slim to none.

 

[Blue Crystal]

I appreciate all of the ideas. I will try all of them until I get a signal. Raining here today, I'll try again tomorrow.

Thanks everyone

 

[esteveW]

LNB Skew control

I have been reading this topic with considerable interest since I have a 10' Kual-Tronic mesh dish with a Chaparral feed horn. Just aquired it and still exploring the components. Until yesterday, I didn't know what the blue box did.
Now I have to find a way to control or switch the skew 90 deg. for Hor or Ver .

My present STB is a ViewSat PVR7000 and will provide the DiSEqC signal for the rotor. However, I don't see anyway to get a signal for LNB polarity control.
(Right now I'm looking the V-BoxII for rotor control as I understand, that will only control the rotor/dish motion. Please comment on the V-BoxII if there is something better.)

I have been considering a second STB and was looking at the ViewSat Ultra spec. which mentions "Various LNB Polarity Control". But they don't indicate if that feature is something available externally. I have my doubts.

Maybe, if all else fails, I could resort to a toggle switch from a "wall wart" power supply.

Anyway LNB polarity switching is still a few months away, as is the second STB.
Rigth now, I have to find a clear location to the South. I'd hate to cut down any trees. I really need to do a satellite search and see which ones might be blocked from my prime location choice in my yard. I have one acre but many trees in my back yard and only one tall fir tree in my front yard. It is in my east quadrant. (really need to get out the old compass and see where true south really is and work from there. )

Thanks,

Steve

 

[esteveW]

LNB polarity control

I have just been reading the ViewSat 7000 manual for info on how this skew control servo might be activated via the normal ViewSat Antenna Configuration setup.
I find that the polarity control signal: "In the case of Horizontal , 18V and in the case of vertical, 13V are output through LNB line."
It seems that if this voltage presents or difference could be detected in the LNB line, it could be used to control a simple servo controller/the Little Blue Box.
Maybe I'm over simplifying this and I'm not knowledgeable enough to proceed beyond the "idea" stage.
I'm just wondering if this has been tired or if there is a simple servo controller available that would perform this function. Similar to the V-Box, etc.

Additionally I notice that the ViewSat 7000 has both DiSEqC 1.0 and 1.3 (USALS) motor control. Is it possible to utilize the 1.3 directly, via relay, etc.?? Or do I still need the V-Box (type) interface?

Thanks,

Steve

 

[14karat]

Steve, most folks use an old analog box to handle the mover and polarity control.
You can usually pick these up for next to nothing. I recently acquired one from a thrift store for a grand total of $5.

 

[14karat]

Oh, also, if you haven't already, you should go here and put in your vote on a new controller...
http://www.satelliteguys.us/free-air-fta-discussion/151332-gbox-v4000-polarator-control.html

 

[SatPhreak]

Steve, the viewsats won't control a corotor skew system. The only DVB boxes that I know will do it are the Pansat 2500A, 2700A, and 3500. Best bet is to follow 14karat's advise and get an old analog receiver to control dish motor and skew, or wait till the new Gbox with skew control comes out (from link in above post).

The 13V/18V switching won't control a manual skew system either, only a voltage controlled lnb like the bsc-621.