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Thread: Small Dish FTA
11-26-2008 10:49 PM #1
Small Dish FTA
I got my start with FTA a couple of months ago using a Coolsat 5000, a Techsat Tracker II+ lnb on an eBay lnb bracket, and a DTV AT-9 dish (~24x29" rounded rectangle). I was very happy to get all of the available signals at 97W. I've since added another Tracker II+ to get the Pentagon Channel and MS91 on 103W (after a lot of fine adjustment to the lnb, for which the mount is still in the prototype phase).
For my next project, I'm planning to set up another dish to receive 123W with an additional lnb to get 129W. Before I start, I was hoping to get some advice and opinions.
I have another AT-9 as well as a Slimline dish available. Any thoughts on which might provide the strongest signal?
I'm assuming that I should aim at 123 and then add a sidearm to get 129, but is that the best approach?
Which of these two dishes would be easier to add a second (or third) lnb? (I haven't come up with anything better than a "hunt and peck" alignment approach with the AT-9 for the second lnb).
How much better is the Tracker II+ lnb at 0.2 dB versus a 0.3 dB lnb, especially with a small dish?
Just for background on my existing setup, I've attached some pictures. The photos show the initial set up for 97 only and also for the extra lnb. For the second lnb, I used a homemade bracket mounted on a tie-strap that is completely separate from the main lnb mount. Until I install a permanent mount, this allows me to swivel, rotate, etc without moving the main lnb.
For the 97W mount, I simply removed the old lnb and installed the Techsat linear lnb with its face at the same location as the existing center lnb that was on the AT-9 and then aimed at 97W. The dish had an Eagle DTVP3 triple-head lnb (which may not be standard, but it had apparently been used for a 101,110,119 setup). I used the nice little eBay bracket that is made for 30-40mm lnb's and attaches by a single nut and bolt through a hole I drilled in the existing arm.
On 97W, I'm getting either 66-70 or 88-90 signal quality depending on the transponder. I think I need a minimum of about 63 to lock. So far it's been good through light snow and fog, but we haven't had a big snowstorm yet. I'm getting about 69 SQ on the Pentagon channel on 103W with the adjacent lnb. Before settling on 103, I got strong signals on 105W (it was hard not to get 105) and also tweaked enough to get 101W. On the other side, I'm hoping to get 87W, but that's probably a longshot. All I've gotten so far is a feed that I think is 91W.
I hope to someday get a motorized C/Ku system, but for now I'm trying to get the most bang for the buck while learning the ropes.
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11-27-2008 01:59 AM #2
good work - thanks for the pix
Looks like you did everything very well.
The only criticism is in using a dish that's borderline too small.
That's not so much a criticism as an "if you don't like your signal levels, you know why". -
As you noticed, you are very close to the cutoff signal quality for the Coolsat.
A larger dish would give you more operating margin, into the bad weather, the rain, and the snow.
As for your bracketry, it all looks fine 'n dandy.
Putting the new LNB at the exact same altitude and angle as an original is all one could ask for.
I've done the same thing on an even smaller dish, but for an easier-to-get Whitesprings signal. -
And at least where I live, the 129°/Whitesprings signal is definitely the one you put on the secondary LNB! -
Or the marginal dish.
If you want to have a better clue where to put your secondary LNB, or if you can even get a second bird that may be too close to your primary, take a look at some calculations I posted in page 4 & 5 of the AMC-21 thread, a while back.
You'll see practical examples, discussing LNB size, spacing, and dish focal length.
In it, there is a link to the original math by MJflash.
It's not at all difficult, once you get the hang of it.
As for the Tracker LNBs being better than others, that has not been shown.
Now that they're available for a low cost, I see no reason not to give 'em a try.
If they work for you, then they're fine.
But, if I wanted two-output models for some reason, or bandstacked LNBs for some reason, there are certainly other competitive choices available.
Not sure if you know, but the Dish Network SuperDish (originally deployed for 121° or 105° birds) has a suitable FSS LNB on it, and at the focal point.
Those dishes are also a little small to -recommend- so don't buy any, but if you run across one, give it a shot!
And for info on connecting a gaggle of cheap little dishes, we have a Switches Simplified FAQ, with many interesting designs.
You might like post #6, if one receiver and lots of dishes are in your future.
11-27-2008 07:46 AM #3
I'm pleased with those little red lnb's, have 4 of them working. Ice did a review on them a while back. Anole is right about the superdish (have 4 up, modified), and building an array of smaller dishes works fine until the opportunity to score larger ones comes along. From your pix, you have plenty of room for an array, congrats!
123 and 125 may be a problem with a smaller dish, I was getting interference from one to the other, untill I went to 4' DTN dishes for those two.
11-27-2008 07:43 PM #4
Very cool picsDirectv Slimline SWM 5 LNB and DirectvWorld dish on the roof of the apartment building...Directv HR34 AKA Genie
All FTA stuff in storage right now
11-27-2008 11:12 PM #5
Thanks for the input
I'm going to study the offset lnb placement calculations some more. A calculation seems better than an eyeball adjustment for the placement and angle of an lnb. I've never been good at judging a bankshot at pool, and lnb placement seems kind of like that.
I will check for the potential for interference on 125 if I set up for 123 - I did notice that if I tweak things just right, I can get both 101 and 103 on the secondary lnb I currently have, so adjacent satellite interference seems like a possibility if the transponders are the same.
I'll keep an eye out for a discarded Superdish - I didn't realize that the lnb could be used for FTA.
Finally, I will pay attention to any future posted pics. I was trying to minimize file size, but I see that I also need to adjust pixel dimensions for convenient viewing .
11-29-2008 04:34 AM #6
Current systems: 3X GEOSATpro microHD PVRs; Digitrans DTE-7150 DVB/Digicipher II; SiliconDust HDHomeRun ATSC/QAM networked tuners; fixed 1 meter Channel Master dish with Eagle Aspen P870 FSS stacked Ku LNB; 2X 3ABN 36" dishes with Sadoun KBSL1 stacked Ku LNBFs on Powermax SG-9120B H-H motors; fixed Sadoun SD180G 1.8 meter dish with Eagle Aspen B1SAT stacked C LNBF; Winegard Square Shooter OTA DTV antenna