[CNX] Noob with a Duo, 32"w oval DirecTV dish, MK1-PLL, RG6 (1 Viewer)

N6ATF

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Sep 14, 2017
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20170914_015628.jpg 20170914_004919.jpg

Is there absolutely anything FTA I can receive on the Duo pointing out my fiberglass screened (RF transparent?) south-facing open window, or...?

For days I've been working on cleaning the bird poop, cobwebs, leaves out of the (free) dish, and trying to figure out how to set the remoteless Duo with Peel Remote on my tablet (which limits the amount of custom buttons I can set - I have 0 through 9 & the select button, using the dropdown+test to send other Duo-specific IR codes), and using the Duo's front panel for Menu, OK, up down left right). I just found the manual today despite it being paywalled or fake posted everywhere but here, but it isn't much help, still.

All I see on the ~11760-12900 blind scan (2 mhz step, all polarizations, all symbol rates) is the S going from 80-95% & the Q consistently showing 0. Would the signal go to 100% & the Q go anywhere but 0 if I took the screen off & let the bugs in, or is the Duo incapable of scanning for anything modern near where the dish is pointed? Someone had suggested laying the dish on its back pointed skyward, and getting signal, but so much of the FTA discussions are years old.
 

Titanium

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Welcome to Satellite Guys! The Duo can receive FTA DVBS MPEG2. Most channels on 97w are still transmitted in this format. Even though many threads are several years old, the aiming and scanning process remains the same.

The dish aiming is highly critical along with the correct LNBF skew (rotation) and the receiver must be set to an active transponder for the satellite that you are trying to find. It is very important to mount the dish on a solid pole that is plumb and level. This will simplify the aiming procedure!

Use a dish aiming program like Dishpointer to find the compass reading, elevation and LNBF skew for 97w - Galaxy 19. Aim the dish in this direction and set the LNBF skew and elevation angle. This is assuming that the new LNBF has been mounted so the feedhorn is in the exact position (height, distance from the reflector and angle) matching the removed Directv feedhorn. Remember that the Slimline dish is an offset type design and is actually looking at a point in the sky that is approximately 26 degrees higher than the face of the dish is aimed. Make sure there is nothing blocking this (roof overhang, branches, etc.).

Look at Sathint.com and find an active transponder for 97w -G19 KU band. I suggest using TP frequency 12152 Horizontal, SR 20000. On the DUO Install menu, select the KU band satellite located at 97w (the name is not important as it likely has changed). Set the transponder to the above suggestion, select LNB type to 10750, LNB Power to ON.

With the TV screen next to the dish, SLOWLY pan the dish 20 degrees on either side of the compass reading for 97w satellite while watching the Signal Quality Meter. Once the signal is found, the Signal Quality reading will increase. The meter reading may momentarily jump as the signal is being located, but if it doesn't stabilize, it is likely a false reading.

If no Signal Quality reading is noted, increase or decrease the dish elevation setting in one degree increments and SLOWLY sweep the section of sky again. Repeat until the satellite Signal Quality reading is locked and optimized.

Once the satellite is found, perform a Blind Scan for ALL channel types. You should scan in over 200 free channels on this satellite.
 

N6ATF

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Sep 14, 2017
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It was given away without the Directv feedhorn present. The feed arm stretches 18.5 inches from the front of the dish. I'm not sure how to find the focal point from scratch. The LNB bracket hasn't been bent from the angle I bought it in, new, so does it need to be bent and/or what degree of up/down on the 10-0-10 slider should it be set to? The bracket is clamped dead center, pushed all the way in.

Haven't even been able to find a diagram of what polarization that is, or if 0 on the bracket in line with 0 on the LNB is horizontal or vertical.
 

KE4EST

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You may have to do it by hand, ie. hold the LNBF in your hand and move it until you hit the signal, then make mental note as close as you can and then move bracket to match.....but this will be very difficult using a receiver instead of a meter and being a beginner at this, especially since the dish is not even right to start with.
I would start with what you have and do as Brian(Titanium) said above.
First of all though you have your LNBF rotated 90º . With the F-Connector pointing down you will be a zero. Then you need to go from there to see how much you need to skew it for 97W for your location. This is where dishpointer.com will come in handy. Remember to move slow as receivers are very slow at locking where a good meter will grab it quicker than you can move your hand.
After panning back and forth and after moving the dish elevation up and down from your starting point and still nothing...then you can try bending the bracket more in or out.
 

N6ATF

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The LNB warms up... do I need to wear a shielded glove when I'm holding it, for RF safety? Also, eventually I'm going to be switching my dish work to a SDR dongle; will that+a laptop & F to SMA adapter with open source software be as good or better than a meter, or will there be too much processing delay even on an i5 proc?
 

Titanium

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Don't have a DirecTV dish to advise the correct LNBF position. Could you borrow one to make a template?

Looking at photos online, the feedhorn opening needs to be higher and the focal length distance appears to be too far way.

It will be very difficult to both find a satellite and set the feedhorn position. The feedhorn position affects the dish elevation angle setting and will have very poor performance if not positioned in the exact convergence point of the reflected signals. Not impossible, but with 30+ years satellite installs under my belt, I wouldn't want to take on the job. If you are going to try KE4EST's suggestion for hand-holding the LNBF, be sure that the dish is set to the correct elevation and azimuth for the target satellite.

The LNBF does not emit any signals and shouldn't be too hot to touch. Warm? Yes. Hot? No.
In my opinion, the learning curve of both the SDR as a aiming tool and this being your first satellite install would add one more complication and make it even more difficult.
 

KE4EST

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In my opinion, the learning curve of both the SDR as a aiming tool and this being your first satellite install would add one more complication and make it even more difficult.
I agree with this statement. I would wait on that until at least you hit your first satellite and have it locked on and know it is working. Then you will have something to go off of to figure out how to make it work with SDR.
BTW i5 is plenty fast enough, if too many other things are not running at the same time.
 

N6ATF

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I guess I can't proceed without spending $100s more. The S meter flutters between 80-85 for Sathint's Galaxy 18 EXRN transponder freq, pol, symbol rate, LNB to 10750, no matter where I hold the LNB, even pointing it directly at the middle of the back of the aimed dish at 1 inch away. The dish is inside on the floor, aimed at G18 out a window, so other satellites shouldn't be splattering through the building? I held the LNB up to my 802.11G router & still fluttered between S80-85. As the LNB lays on the floor pointed directly down, the S mostly holds at 80 with an occasional flutter to 85, and when it's laid on the floor on its side, it flutters 80, 85, 80, with not quite the same interval every time.

Quickly flipping through the other satellites with the wrong LNB set, even getting S80, 85, 90 on each of them, with the dish inverted on the floor, the LNB centered underneath it, as close to total sky blocking as possible without taking the back bracket off and just having the dish lean on it alone. Wonder if I put the LNB in a Faraday box the Duo would still show signal (birdies?)

Maybe this explains why the last owner of the Duo threw it away. It's not beeping when I hit the blue button for Beep either.

P.S. Satellite Director by Zekitez has me pointing at an interior wall to get G19 97W
 
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KE4EST

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As long as the signal meter shows something it is seeing the LNBF. It won't lock solid until there is a quality indication. So for one you need to be looking at quality(yes I know it is confusing).
Also remember that an offset dish is generally looking about 22º higher than it looks like it is, so trying to shoot out a window is really adding more complexity. :)
 

Titanium

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The dish size is a bit too small to receive all KU transponders, but you probably don't need to spend any more money to receive most DVBS2 MPEG2 KU FTA channels.

Signal Quality reading is not the same as Signal Strength. The Signal Strength reading only indicates that the receiver is connected to a working LNB. It does NOT indicate that the LNB is receiving any signal. The signal level shows the RF noise from the LNB amplifier, nothing more.

To display a Signal Quality reading from a satellite you MUST first select a compatible active transponder on the target satellite. If a transponder is selected from the list that does not carry a compatible DVBS MPEG2 signal, the Signal Quality meter will not display a increased reading. Only the increased Signal Quality reading will indicate that the target satellite has been located and the active transponder is locked and ready to scan for services. Many satellites use the same transponder parameters, so false positives can occur if the dish is aimed at a different satellite with a similar transponder.

Go to Dishpointer.com website, select 97w - Galaxy 19 satellite and drag the pointer to the exact dish location on your property. The site will show a line between the dish and satellite. You can determine the exact direction to point the dish and see if any object is blocking reception of the satellite. 97w satellite is only 20 degrees east of true south for your location (not very far east) and still very high in the sky. If you have any DirecTV dishes in the neighborhood, your dish will point very close to the same direction and elevation angle.
 
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N6ATF

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G19=Massive dense leafy tree.

Please don't give yourself carpal tunnel syndrome over my pathos; clearly I've reached the limit of what I can do on a budget in a rented bedroom. If I can trade for a circular DirecTV dish like this (at least 18", I'm told I'll need eventually), will the offset issue go away? I can actually tripod that without staking it down inside & not worrying about tipping, unlike this oval & 4 foot mast I'd probably have to guy wire to everything in my bedroom & put in a heavy umbrella base stand or concrete-filled bucket.
 

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KE4EST

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Please don't give yourself carpal tunnel syndrome over my pathos
Nah, Brian is just helping out. We love helping newbies. It is hard to explain to someone new in a couple of sentences. :)
 

. Raine

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A 18" Directv dish will be worse for reception and is still a offset dish. Titanium was right about the feedhorn opening needing to be higher, you need to raise the Lnbf up an inch or so. I have three Slimlines setup here, I'll try and post a picture tomorrow of one of them so you can get a idea of the lnbf placement.
 
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N6ATF

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So, an inch or so would put it closer to the apex of these shoelaces, either by extending the "universal" bracket past its limit, or? Not moving it up the feed arm by drilling a hole further up it, towards the base of the arm/dish?

P.S. I disassembled the 4 arm bolts, there's no way I can see to adjust where the tip of the arm ends up.

Also, once this focal pointing is figured out, a 21V power inserter is listed as required for the future SDR. Did I need it for FTA too? 13/18V 500mA max is what the Duo supplies.
 

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bpalone

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It has been a while since I did this and would have to start from scratch again myself. But, do a google search for finding the focal point for an offset satellite antenna. There are methods of using string and sometimes water, to get the correct measurements to calculate the focal point. It won't get you dead on, but will get you close enough to get signal when properly aimed at a satellite, then you tweak it to get the best.

If there is any way to get it out of the room and into the great outdoors, you will have a much better chance at success.
 
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N6ATF

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If a 30+ year satellite installer at post #7 wouldn't want to take on the job, a <30 day noob with mathematics his worst subject who already saw some Google results full of equations & had his brain melt down...

Though, since you mentioned water, my latest search results found John Legon's page "Calculation of the Focal Length
of an Offset Satellite Dish Antenna
" & word searched for 'water', finding it at the bottom. I guess after dinner I can make a level birdbath, measure it, and replace his values with mine, then stretch my measuring tape out from the center of the tip of the LNB to the focal length result from that calc.
 

N6ATF

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(20.75 * 20.75 * 20.75) / (16 * 1.4375 * 20)
was converted by DuckDuckGo to
((20.75 * 20.75) * 20.75) / ((16 * 1.4375) * 20)
=19.42211277174 or 19 7/16

Taped 19 7/16 to the center indent of the LNB & 0 on the dish after having to push the universal bracket angle forward a bit to get the tape 0 to touch. There was this little abrasion in the paint (at 11.5 inches out of 22" on vertical axis & 16" out of 32" of horizontal axis, I only just measured now) I had noticed while cleaning the dish days ago, and it turns out that's probably what was previously marked as the focal point (By the DirecTV installer? By the dish manufacturer? By the last person to use a universal LNB clamp?), as it's where my tape 0 ended up, as close as a straight line I could get from the LNB without clamping in a boresighter or laser pointer (mine got ruined by battery leak).

Still wondering: a 21V power inserter is listed as required for the future SDR. Did I need it for FTA too? 13/18V 500mA max is what the Duo supplies.
 

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. Raine

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Here's some pictures of my Slimlines. One you might see the lnbf is lower and crooked, that's because the reflector on that dish is bent, the guy removing it threw it off the roof it was on.

IMG_20170915_180033.jpg IMG_20170915_180023.jpg IMG_20170915_175941.jpg IMG_20170915_175856.jpg IMG_20170915_175828.jpg IMG_20170915_175813.jpg IMG_20170915_175625.jpg

You don't need the 21v inserter for FTA.
 

N6ATF

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After a horizontal flip & rotation, mine looks just about like your last photo (ends in .128216 when you hover pointer over it) but for the difference in equipment. So... does anyone disagree, focal point solved?
 

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