Just hooked into my 90cm/36" FTA satellite dish. the snr jumped up to -11, the % vaild packet 99,
the data rate or 17000 to 20000 bps
But I don’t want to be tied to a big dish installation.
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Did you put the Maverick on the 90 cm FTA dish, or are you using the FTA LNB? Ken
Yes the maverick MK1 is installed in the arm on the dish.
This is the kind of comparison I want to do when it stops snowing here. I guess you prove the point that parabolic focus brings in signal. My 80 cm with Invacom LNB FTA system works nearly 100 % over 500 feet of RG6, but when I mount the naked MK1 next to it I get lower performance, and can’t drive over the 500 feet into the house.
It will be interesting, Jim, to see what some of the flat antennas do. By the way, I read somewhere that people built reflecting horns around their LNB to improve reception without resorting to a dish. Have you heard of that? Ken
Is there somewhere a list of files being currently transmitted via Outernet to the “Dreamcatecher 3” in Ku-band?
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Ken,
This guy built one out of cardboard:
Conical Scalar kits certainly help receive C-Band on a little Ku-Band dish.
–Konrad, WA4OSH
I’m most interested in seeing small-reflector hacking, similar to these two videos. The reason I am so opposed to 60cm+ sizes is because they are so difficult for most people to point. Also, a conventional satellite dish provides way more antenna gain than is required for reception–so it’s a bit like lots of pain without much gain.
I’m curious if these three DIY examples are real. Only one way to find out. I’m most curious about the aluminum foil version. I can’t see how it can possibly work, since there is so much wrinkle in the reflector and the 1/4-wave of 12 GHz is around 1-cm, but who knows! I’ve had satellite industry veterans with decades of product development experience tell me what we are doing would never work.
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Metal Cone Test Results
The following test took place here in Annapolis, MD, Long 76.5 W Lat 39 N at 1500 EDT on a clear day viewing SES-2 with no obstructions.
First, I sited the LNB as perfectly as I could using using an Adjustable Sliding bevel to set elevation.
The obtuse angle of 133.5 degrees is my elevation of 43.5 deg plus 90 deg to get a precise site of SES-2.
First test was done with an unshielded LNB.
resulting in SNRs of -13 to -12 dB with Signal Lock:
Second test was done with metal cone loosely fit over the LNB
resulting in SNRs of -8 to -9 dB with Signal Lock:
This is a significant improvement of 3 to 5 dB in SNR. The actual cone is made of card stock with aluminum foil glued to it, then raped around a standard bar size drink mixer so that the foil is on the inside.
Cone size is 7 inches high, with top opening of 4 inches and LNB opening of 2.5 inches. Cone weighs 1 oz. Ken
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I think your ideas are proving the “industry veterans” are way out in left field (or on the moon). I am assembling the 18" dish (it is actually 18" x 21" ) so it fits in-and-out the side door with the tripod pretty easily. The correct lnb (I think… it matches the maverick specs) just arrived this afternoon so by sunday 3/25 I should be ready to receive.
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Let’s try it, Jim. I’m doing great on my 80 cm dish, but we need to figure out the small terminal for the people with no connectivity. Ken
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Very interesting Ken and nicely photographed.
perhaps a piece of pre-cut sheet (metal or plastic with aluminum foil) can work with double sided adhesive. I would try some shorter cone to have less interference with wind outdoor.
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I think the @kenbarbi noise shield is the winner. Some optimization of the of the material selection and what the minimum length should be for the conical attachment (or it could be an open ended box/rectangle if that proves easier to make.) And make it part of the “mounting bracket” assembly
Hi Jim - - I actually got the idea at a discount store where I saw a whole bunch of bar mixer containers on sale. My first though was to cut a hole in the bottom of one, and put the LNB in it. My wife suggested that would be too heavy and I should use it just as a form - - wallah!
The beauty of the 1 oz paper/aluminum design is I can fold it up and carry it with my portable terminal when I travel; and it only took me a couple of minutes to construct.
Yes more testing is needed to optimize diameters and lengths, and the 32 oz soda cups wrapped with aluminum foil is another good idea. I’m looking forward to hearing about Konrad’s experience with a cone. Ken
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I think I wasted a little work… But here is very workable report using
an 18" dish. – not that I am recommending it… I like the no dish system.
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I guess it’s all relative - - your 18 inch dish delivers a better SNR than my cone. My FTA LNB/dish does better than both, but Outernet’s objective is to be small and portable.
I am eager to see some test results from some of the new flat “antennas” being considered. Ken
Hi, @kenbarbi, how do you stabilize the cone in place? Any ideas of how this could be mounted if made of thin aluminum, etc. I agree with @Syed that we should be working towards a portable solution that can be easily moved/stored in order to stick with our original purposes here. My thoughts run toward something like the folding colander bowls or the folding camera flash reflectors from the '50’s…
Hi Jerry - - I didn’t stabilize it. I just stuck it over the LNB. The bottom opening of the cone was just a bit smaller than that of the LNB, so it held on OK. You can use masking tape around the outside of the cone to hold it to the LNB too. My cone was only 1 oz.
Being as long as it is, the cone isn’t wind proof even if taped down. So far, this has been an experiment to assess the merits of a narrow aluminum cone. Again, it’s not waterproof either.
I’m going to try with a shorter cone, then a wider cone. Zoltan is also talking about alternative LNB designs with different horn characteristics that might obviate the aluminum cone approach. Ken