How many channels FTA on 58W - CBand?

[chapelrun]

I fine tuned my C-Band dish fixed on 58W and now get 34 channels FTA. I still think I can get it better. For example, 4120 V 27500 has a Q of 71 on microHD with cloudy skies and a slight mist falling.

I have several questions - How can you know precisely when the skew is set exactly correctly? This is a Chapparal Dual with two Norsat LNB's.

Second, is there any way to avoid conflicting signals that are very close to the same Freq and SR but are opposite polarity?

Third, when measuring the focal length of the dish, where do you measure to on the LNB?

Last, how many channels are others getting on 58W, FTA?

 

[Babadem]

I fine tuned my C-Band dish fixed on 58W and now get 34 channels FTA. I still think I can get it better. For example, 4120 V 27500 has a Q of 71 on microHD with cloudy skies and a slight mist falling.

I have several questions - How can you know precisely when the skew is set exactly correctly? This is a Chapparal Dual with two Norsat LNB's.

Second, is there any way to avoid conflicting signals that are very close to the same Freq and SR but are opposite polarity?

Third, when measuring the focal length of the dish, where do you measure to on the LNB?

Last, how many channels are others getting on 58W, FTA?

I get about 36 channels when I scan with my Micro HD using the "Normal Mode" and on 4120V 27500 SR, I get 74% quality. If are you getting 3960V 30000SR and 3880 H 27689 SR without issues then you're well tuned. You should also try the "detailed Scan" to pull in the channels that the "Normal Scan" missed. What size dish are you using?

 

[chapelrun]

10' Channel Master Fiberglass.

3880 H 27689 - Q 72%
3960 V 30000 - Q 10%

I want to adjust one thing at a time. Either Focal Length or Skew in very small increments - until the signal improves.

i played with Elevation and left, right already and these are very close to being correct.

 

[Babadem]

10' Channel Master Fiberglass.

3880 H 27689 - Q 72%
3960 V 30000 - Q 10%

I want to adjust one thing at a time. Either Focal Length or Skew in very small increments - until the signal improves.

i played with Elevation and left, right already and these are very close to being correct.

Get 3960V 30000 peaked and you should be good. Is this motorized or stationary? If motorized you shouldn't be messing with the elevation unless it is your most southern satellite, otherwise adjust (Left, Right) azimuth and actuator movements.

 

[chapelrun]

Currently this dish is fixed on 58W. Next summer I have promised myself to get it motorized, but not before winter.

Which should I adjust first focal length or skew? (Or does it matter?)

 

[Babadem]

Currently this dish is fixed on 58W. Next summer I have promised myself to get it motorized, but not before winter.

Which should I adjust first focal length or skew? (Or does it matter?)

Start with the skew first and note any improvements or lack therefore. Satisfied with the skew you can then move the lnb in or out while maintaining the skew with the best quality position.

 

[Lone Gunman]

I've got 43 channels on my Winegard system. Haven't done a rescan in a month or two though so that info isn't what I'd call "current".

 

[turbosat]

testing! Hey - I can post again, thank you Scott, or whoever unborked me!
Chapelrun how can you change skew on a dual-lnb feedhorn? Does it even have a polarity motor, or are you just speaking of 'twisting' the feedhorn body a little in the scalar?
And yes the focal distance does matter, there is a formula for calculating it someplace here, 12Xdepth of dish divided by something...dang it. Post back for you when I find it.
You'll have to measure the depth of your dish by putting a straight edge across the face of it, and measuring down from that to the dish center.

 

[primestar31]

testing! Hey - I can post again, thank you Scott, or whoever unborked me!
Chapelrun how can you change skew on a dual-lnb feedhorn? Does it even have a polarity motor, or are you just speaking of 'twisting' the feedhorn body a little in the scalar?
And yes the focal distance does matter, there is a formula for calculating it someplace here, 12Xdepth of dish divided by something...dang it. Post back for you when I find it.
You'll have to measure the depth of your dish by putting a straight edge across the face of it, and measuring down from that to the dish center.

If you are talking a orthomode feed (no servo), then you motor your dish to dead south, top of arc. Whether there's a satellite to point at there or not for your location. Once it's there, you'll notice that ONE lnb should be parallel with the ground (loosen the screw holding it to the scalar, and level it with a inclinometer to 0 (zero)) and the other lnb should be set for 90 degrees with an inclinometer. (straight UP and DOWN). Now it's set perfectly, and will properly skew when it's aimed at the different sats.

 

[beavs2112]

10' Channel Master Fiberglass.

3880 H 27689 - Q 72%
3960 V 30000 - Q 10%

Hi Chapelrun. I have a 10 foot Channel Master fiberglass on a polar mount. Your last reading of Q 10% concens me. Is it a typo? Did you mean 70%. I get Q 68% on that TP. Most of your other readings are close to mine. My results below(don't forget my rcvr is different) :
3880 H 27689 - Q 72%
3960 V 30000 - Q 68%

I get 36 TV channels & 64 radio chanels FTA.
Hope this helps,

Kevin

 

[chapelrun]

OK, guys - I worked on it for about an hour today. With some positive results. But . . .

This is a dual ortho with two Norsat 8700 LNB's (not the best but they work pretty well)

3960 V 30000 still very low at about Q of 22. The skew was just slightly off (I turn the entire assembly to set skew). Again this dish is fixed on 58W.

i did find that the LNB had to be moved slightly away from the dish to get better signal - but still having issues with 3960 V 30000. But even this one come in early morning or late at night.

Is there such a thing as a larger Scaler with one extra ring? Does anyone carry an oversized scaler?

some more readings

3840 V 27689 - Q 75
3840 H 27690 - Q 72
3880 H 27690 - Q 72
4040 H 26590 - Q 71
4120 V 27504 - Q 72
3960 V 30000 - Q 22

 

[Lone Gunman]

I'm near the center of Virginia and I've got that 3960 TP at 80% on my 10ft Winegard system using the Openbox S9 receiver. I expect that the AZBox would have it at close to 100%. Most of the other TPs on that satellite are in the mid 70s% range.

Just did an FTA only rescan of that satellite and got 29 TPs and 38 channels ITC,

 

[beavs2112]

Is there such a thing as a larger Scaler with one extra ring?

The original scalar that came with my Channel Master dish IS larger than any of my other scalars. It is 8 inches diameter and my Chaparral scalars are 6.5 inches. My original Channel Master scalar has 5 rings whereas my Chaparrals only have 3. Did your dish come with the original scalar ring?

 

[chapelrun]

I have the original but it is not on the dish right now. I'm using the scaler that came with the dual ortho.

I guess I need to change it back!

 

[beavs2112]

I guess I need to change it back!

Good idea! My brand new Chaparral bullseye feed tube fit perfectly inside the Channel Master scalar.

 

[Anole]

It is very difficult to move the focus in & out without changing the F/D.
Or vice versa.
Moving the feed in/out within the fixed scalar, changes both.
.
If you don't have some good calculations or data to use for set up, the ideal is a button hook which clamps onto the feed directly.
You tune that with no scalar as the first step.
Then, you put the scalar onto the pre adjusted feed, and tune it for best performance.
Not a fun nor easy job
.
Understanding the interaction, is half the battle, in the real world.
?.
.

 

[chapelrun]

OK, I just checked all the scalars that I have (at least 6 that I could find in the hayloft).

The original is a normal 6.5" three ring that came on the original dish. Anybody know where I might find the 8" scaler thar beavs2112 mentions above?

i know where I can check locally and I will do that tomorrow. But this is obviously my issue, wrong scaler for the dish I have.

 

[FaT Air]

I want to adjust one thing at a time. Either Focal Length or Skew in very small increments - until the signal improves.

Start with SKEW. Being the 'peak' may be quite broad, it may work better to find an equally low value of Q, one being CCW and the other CW of an apparent maximum reading. Marking the throat with each, then make a mark half way between for the 'center'. Setting the feed to the center mark assures you that you're 'dead center' with the skew.
Measuring and Calculating focal length will usually only get you in the 'ball park'. Ultimately, fine tuning the focal length will almost always be required.

More rings on the scalar will 'cut off' illumination towards the outer edge of the dish at a faster rate then one with fewer rings. Could set it to a lower F/D ratio, than calculated, for increased dish illumination.

Expounding on: Moving the feed in/out within the fixed scalar, changes both. (F/D and focal length) My personal belief is if you only change the focal length slightly there's inconsequential effect on the F/D. Do the math if you must. (example: calculated F'D = .4 . Change the focal length a 1/4 or 1/2 inch= minimal change if F/D)

 

[mmewrench]

The original scalar that came with my Channel Master dish IS larger than any of my other scalars. It is 8 inches diameter and my Chaparral scalars are 6.5 inches. My original Channel Master scalar has 5 rings whereas my Chaparrals only have 3. Did your dish come with the original scalar ring?

I'm pretty sure you will get best results using the chaparral scaler. They also recommend that you set the f/d ratio and leave it alone. So to really get your focal distance right you may have to use shims where the scaler mounts to the lnb arms (or shorten the arms). Its just as important to get that feedhorn pointing at the center of the dish. When I set mine up I used a laser pointer mounted in the center of the feedhorn. Made a wooden plug to fit inside the feed and drilled a hole in the center of it for the laser pointer. It wasn't very precision but by rotating that plug I could estimate my true center and get it pretty close.
As far as the skew goes that should be adjusted at true south and the horizontal lnb should be perfectly horizontal as measured with an inclinometer.

 

[beavs2112]

I'm pretty sure you will get best results using the chaparral scalar.

I disagree. I think the Channel Master scalar was made for THAT dish. The newer Chap scalar wasn't. Also the bolts didn't line up properly with the stock feed legs and the Chap scalar and the focal distance was wrong with the chap scalar. I would have to bend the feed legs to mate the chap scalar. That's a BIG no-no.