[Danster]

Does anybody here have one of these boxes? I want to take my 4 foot dish with actuator arm to replace my faulting STAG120 motor and 1 meter dish. I want to be able to pick up DBS2 better than I do right now.

The only draw back is that the converting box will be away from my setup. I will mount the dish on my woodshop and put the G/VBox inside. Does it need to be constantly adjusted or can I just program it and then use it as if nothing was there?

I can't run new wires from the room where my sat receiver is to the actuator arm.

 

[trckr]

I noticed fridgefta is selling the vbox 7. According to the website, as long as your sat receiver is diseqc 1.2 compatible, you can use the receiver to automatically control the positioner and do not need to use the VBOX remote itself.
So you could have you receiver in your house, RG6 to the VBOX in your woodshop, and then the RG6 and the actuator wires running from the VBOX to your dish.

 

[Danster]

That's what I want to do. Use it as if the receiver was directly connected to the dish and forget about dragging new hardware anywhere. Simple install is alright with me.

 

[majortom]

Wouldn't do me any good, would still need to use the old analog rcvr to switch polarity. Would require a new feed/electronics on the dish. Not about to spend money on the antenna, unless something breaks.

 

[Danster]

I have C/Ku LNB that would go from my existing small dish to 4 footer. I only need to buy a new actuator.

 

[bigredneck]

Thanks for the post, this is how I've learned what little I know. Got any more good questions? I need to know more!

 

[Danster]

That's why DHC exists! People asking questions and others answer. Amazing how it works, doesn't it?

 

[Danster]

Might be long to read!!

Ok, so I finally got my stuff together. I have the Vbox, the new actuator arm and my 6 food dish who I thought was much smaller.

I wanted to do the best install as possible in order to prevent any problems later. Well that didn't go far. There were so many meaurements and degrees that I lost patience. Maybe it's due to the cold weather we are in right now.

anyways, here are a few numbers. My dish is 6 foot, the depth is 1 foot. According to the F/D calculator I found on the net, I get a number of 28.something. What is that? Foot, inches, number of elections we'll have in the next 5 years? Please help me someone.

Next, I was trying to find my true south. At 66.5 or something, I figured that was it. Trying to use my damn compass good for finding nothing, I think I hit that general area.

Then, I wanted to adjust the inclination. With the closest sat at 66.5, the elevation for my polar mount is 37.2 degrees. Take away the declination of 6.81 for my latitude of 45 and I should get a result of 30.39 incline on the front/rear of the dish. Am I right?

After connecting the vbox, I tried to set it with my PANSAT so that I could scan the skies. Didn't pick up anything. I did see some signal go up and down while the dish moved but no quality. I can't be too far.

In regards with the vbox using disecq 1.2, with my receiver, how does it know which sat to go after I find a satellite? Do I store it using the numbers provided by my receiver or what?

Anyway, right now, I won't be going back out until we hit at least 15 degrees and no wind. That's another thing. When I started this morning, it wasn't windy at all. As soon as I had all my equipment all setup ready to scan, as soon as I got on the roof, breezy galore. It was only 2 degrees out but factor in the wind and it was -10. Today was not a good scanning day. As I type this, I still am cold. Might have to jump in the hot tub to warm up me bones!!!!

Thanks for the info anyone might have.

 

[bigredneck]

Wow! It was 80f plus, here today. Too hot to play with the dish. But i do understand the frustration. Majortom has been a big help to me.

 

[majortom]

danster,

My dish is 6 foot, the depth is 1 foot. According to the F/D calculator I found on the net, I get a number of 28.something.

F/D Ratio is generally used by some feeds, to set the Focal Length properly.
The antenna manufacturer generally will specify that for the optimum Focal Length setting of their antenna.
But more often than not we don't have the original documentation for our antennas so we have to calculate it.

I get .375 for F/D Ratio with the measurements u gave there. Should be a good starting point if your measurements are accurate.
You'll still have to peak it though for best SNR on a given transponder.

F = D^2/16d

F=Focal Length
D=Diameter
d=depth

F/D = Focal Length / Diameter
If ya used cm for dish diameter, use cm for depth, If ya use inches for diameter, use inches for depth.
plug in to that formula, ya should be able to get the same as I did.

read thru the below theory/instructions on setting up ur own dish at this link. There's a wealth of information there. Everytime I read it
I learn something new.
http://www.geo-orbit.org/sizepgs/tuningp2.html#anchor469886

For your compass, what I always try an remember is:
When aiming for a given true azimuth add your local magnetic deviation to get what ur compass should read.
When measuring an azimuth setting, subtract your local mag deviation from the compass reading to get the true azimuth.
someone on the west side of the zero mag. deviation line would do the opposite...
I think you are on the opposite side of the zero mag deviation line than I am, so should be opposite for you.
If ya still have some questions or issues the next time ya get in to alignment mode, will try and help...
(My dish is on the ground on a 15 foot pole)

 

[Danster]

Majortom,
That number that you got, .375, is that the number I see on the LNB tube inserted in the scalar ring? If so, does the line have to be in the front of the scalar ring or on the backside?

Also, am I right to assume that the o degrees on my LNB has to be in line with my polar mount? I have installed my 10 footer too long ago to remember what I did.

As for the elevation and declination, as per my message #8, do I calculate it right?

 

[majortom]

Danster, yeah the .375 F/D should be close to a number u see on the side of the feed. Should be a set screw nearby to allow adjusting it. I had set mine initially so I could see the mark still. Then like I said, fine tuned ever so slightly in & out from there while monitoring real time to get best quality on a given transponder. Last time I did any adjustment here, I used my Blackberry (iphone works too) and an SSH terminal session to my linux pc see the measurement reports from my tuner. A lot easier than dragging a tuner and a TV out to the dish. I posted about that here someplace on DHC.

What satellite are you using as your "true south" satellite? If ya can send me a pm with ur location's Lat / Lon
I can try and help some more.
It's early in the AM here, and have a busy day, but try and get back to ya on ur other questions later on.

 

[majortom]

Danster,
I musta been thinkin u were in Lincoln Nebraska, (what was I thinkin, LOL).

So your magnetic deviation should be 18 degrees. So adding 18 degrees to
180 degrees, when ur compass is pointed to 198 degrees magnetic,
it's aimed at true south. That should be the highest point in your dish's arc.

Here's a modified polar mount diagram

and here's the modified polar mount angles to use for reference when setting the elevation and declination while at the highest point in the arc (true south apex).
these are just screen captures from the satmaster program. Your declination looks like 6.23 degrees. So at your highest point in the arc (true south),
your mount's polar elevation should be 43.46 degrees, and ur dish's elevation (as measured at the face of the dish) should 6.23 degrees lower than that (declination), or 37.23 degrees. In other words, your lowering the face of the dish an additional 6.23 degrees to compensate for the fact the earth is round.

Since there is no satellite covering N.A. at 66 degrees Lon, what I would probably do is aim for True South using compass,
set the elevation and declination there. Then move over to AMC6 72W, Ku band, look for the NBC Mux
at 12053 V 6890. There's always a signal there and it's only DVB-S QPSK. Try peaking your feedhorn there. Once the feed is peaked, try peaking the elevation some more again, but leave the declination alone, since it was already set at the true south position.

Once that far, move to your lowest Western sat and ever so slightly rotate the mount on the pipe, to peak that sat.
Might have to go thru a few iterations, as described on the alignment link, to get a feel for it. Most importantly don't get discouraged, 'cause like I said, every time I read that thing, I learn something new.
Once ya have it down pat, once or twice thru the procedure ya should be tracking pretty well.

 

[Danster]

Thanks for the info. I was going to try and tweak today but it was way too windy for that.
I bought myself a digital finder, the DSF120+. I used to have an analog for my c band but thought this might be better.
On the first day without too much wind, I will try getting better signal and will reply back on here.

The only thing that I can't fully understand is diseq 1.2. With usals, it is easier to find the birds. Find one and then the receiver will bring your dish where you are supposed to get another bird. With diseqc 1.2, how do you find it? Manually then what? So confusing...

One last thing. The top of my LNB where it says 0 degrees, that should be straight vertically matching the polar angle, right? That way when the dish goes down, it will look rotated to match the degrees that a specific bird requires

 

[majortom]

One last thing. The top of my LNB where it says 0 degrees, that should be straight vertically matching the polar angle, right?

can't be sure cause ya haven't said what the feedhorn, LNB manufacturer make & model is.
But on the Chapparal Polarotor type Dual Band Feed that I have, there is a template that they provide (or download off their webpage) and ur supposed to line it up with the North Star.

 

[Danster]

I think it's a DSM 741 or something. It's the one that has c band as well as Ku on it.

 

[trckr]

I believe you could be referring to the skew adjustment. When your dish is pointed to true south of your location, the 0 mark should be it the vertical most position (straight up). So if your longitude is 97w, then the LNB should be set to 0 skew when pointed at the sat located at 97w.

As your dish tracks the arc from east to west, the LNB will be skewed accordingly (assuming the dish is setup right). The further east or west the sat from your position, the more the polarized signal is skewed from a perfect horizontal or vertical plane. The LNB needs to be skewed to match so that you get peak signal strength.

Usually you would adjust this off from 0 when you are using a stationary dish that does not have a skew adjustment.

 

[majortom]

The only thing that I can't fully understand is diseq 1.2. With usals, it is easier to find the birds. Find one and then the receiver will bring your dish where you are supposed to get another bird. With diseqc 1.2, how do you find it? Manually then what? So confusing...

I don't use either, but from what I hear USALS has it's drawbacks. Namely in accuracy, as it depends on how various receiver / tuner software developers interpret / implement the USALS standard. Inaccuracy reportedly more noticable with DVB-S2 signals, and /or Ku band. USALS can work well, if and only if the receiver manufacturer worked closely with the specific USALS motor manufacturer your using, during product development.
IMO, that's not likely in most circumstances, YMMV, depends on the specific equipment u have.

With diseqc, u the end user set the position of satellites X, Y and Z manually once, and ur motor will remember. Much more likely to stop on a dime so to speak. At least until something bad happens to ur motor (i.e. - wear & tear induced slop).

 

[trckr]

^^^^^ Pretty much sums it up.

Usuals is a little easier to setup.
Diseqc takes a bit of time but is typically more accurate because you can adjust each stored dish position by 1 step at a time. I have found with the various receivers and PC software I have used, that 1 step equates to about .01 of a degree.

 

[stephan.b2hv]

The VBox X is affordable (About $30 shipped) and the GBox is more expensive and it seems nearly impossible to find! Is the VBox X much better than its predecessors???