Practical application of receiving Hispasat 30 W through double reflection

[polgyver]

A few months ago I conducted some tests with receiving satellite signals through double reflection, using primary dish of very long focal length and secondary small dish. I described those trials in posts at satelliteguys.us, here, but these trials received less than moderate interest, probably due to their perceived little practicality. I tried my home-built long-focus dish in receiving programs from 97 W and 101 W, and I got it working. However, receiving of these sats proved easier by traditional methods (2 LNB's and a switch). This gave me the following programs: Pentagon, Dutch BVN, and TRWAM (enjoyed mostly by my wife, but also by me) - from 101 W, and Russia Today, AlJazeera, Jewish News 1, Serbian RTS, Padre Pio, Press TV - from 97 W. Recently I upgraded the palette of our programs by adding Hispasat 30 W. This addition would NOT be easily possible without usage of double reflection system. The strength and quality of most of Hispasat transponders is almost the same as S&Q from 101 and 97, however, some channels are weak and pixelating. But let's the photographs speak (recently I learned how to add text to pictures). Cheers, polgyver

 

[rv1pop]

other than making for rather short coax runs from where you have LOS, what is the advantage of the long focal distance? I see you shortened the run by 36 feet (?) and the dish is that far from the house. Does it act as if it were a bigger dish or ? Sorry I did not follow your previous thread if you explained it then.

 

[wanglili]

Ah yes the very right

 

[ynnedibanez]

that is pretty dang sweet!!!
did you use 2 secondary dishes when you had it set up for 97 and 101, or did you use 2 lnbs on 1 secondary dish?

 

[rogerduncan100]

That looks really fun! How is the large dish made?

 

[Cham]

Wonder how it would work with a piece of plywood as the reflector #1 covered with reflective aluminum, and a regular 30-40" dish as the primary? If the plywood was flat (attached to a fence or something) surface might be large enough to compensate for surface irregularities.

For me 30W is only 5-6 degrees off the horizon. Placing a reflector such as yours up on a tower say 40' high would allow a much cleaner view of the horizon; kind of like the old parascope towers used by the telecommunications companies in years gone by. Would be really cool to be able to move the remote reflector (remotely) to tune in other nearby satellites focusing the signals on the prime without moving it.

Have to remember the 90 degree polarity shift (skew) from using an extra reflector.

Cool idea, and certainly applicable in FTA!

 

[polgyver]

other than making for rather short coax runs from where you have LOS, what is the advantage of the long focal distance? I see you shortened the run by 36 feet (?) and the dish is that far from the house. Does it act as if it were a bigger dish or ? Sorry I did not follow your previous thread if you explained it then.

http://www.satelliteguys.us/free-ai...iving-fta-signal-after-double-reflection.html
The link to this previous thread is here. There is some advantage in avoiding running coax through the backyard.No need to dig a groove in the grass and bury the coax.Also some satisfaction from making something from the scratch (not using factory made dish) and seeing it work. Cheers, polgyver

 

[polgyver]

that is pretty dang sweet!!!
did you use 2 secondary dishes when you had it set up for 97 and 101, or did you use 2 lnbs on 1 secondary dish?

I used 2 secondary "dishes" (spherical lids, small), each with own LNB. It was temporary, one-time-use setting.

 

[polgyver]

That looks really fun! How is the large dish made?

I built a frame with aluminum square tubing and used curtain tracks, to which I fastened concentric aluminum rings of various height : outside ring was 3/4" high, and inner rings were gradually lower, the central disc was about 1/4" thick. To such a structure I glued ("no more nails" glue for metal) thin steel plate which took its concave shape with very little pressure. It has 46" dia, and is less than 1/2" deep. Unfortunately, the sheet metal was not pristinely flat, it had some distortion, and because of it the focal point ("sweet spot") is "hazy", big, not well defined. It forced me to use secondary small "dish" to collect the waves more precisely on a LNB.

 

[polgyver]

Wonder how it would work with a piece of plywood as the reflector #1 covered with reflective aluminum, and a regular 30-40" dish as the primary? (quoted from Cham)
I think it would work. I already tried such setting, but instead of plywood with alum foil, I used a piece of styrofoam insulation, which - what a convenience - has one side covered with alum. foil. A full sheet (4' x 8') 3/4" thick is $ 13 in Home Depot, really cheap, and easy to cut. As a secondary dish, I used RCA 18" Directv dish with custom-made LNB holder. Got Quality barely 40%, but with bigger secondary dish, you could get it better.

 

[Babadem]

Original thinking and cool!

 

[xtgold]

at one time I had pics of a c band dish in europe that used a south facing wall with pieces of reflector mounted in spots to add up to a big dish size.
For groove in grass for my first dish ever I took all the blades off a gas powered cultivator except for one and cut a groove that way.

 

[Conky]

where do you get a dish with a focal length of 36 feet! I'm assuming you made it yourself? have you ever posted how you made it?

 

[polgyver]

where do you get a dish with a focal length of 36 feet! I'm assuming you made it yourself? have you ever posted how you made it?

Yes, post #9 in this thread, very brief description

 

[Panavision]

Cool experiment! I find optics in the RF range very interesting.

 

[AcWxRadar]

Polgyver,

That is the most fun experiment and the most interesting challenge that I have witnessed! It is the very epitome of this hobby and really takes it to the top of my list for ingenuity and design! It is very fascinating to me and I just LOVE it!

RADAR

 

[polgyver]

RADAR,
I greatly appreciate your kind and encouraging opinion, especially that you are very knowledgeable and that you have a lot of experience, which you generously share with other members. I like this hobby, even though I did not achieve much: I still can not mobilize myself to make use of Stab Rotor Sat HH90, which sits idle for almost 2 years (my backyard is rather small, with my house on the East and neighbour's house and trees on the West - and I do not want to put the dish on the roof, maybe on an offset pipe attached to the wall). Mostly I like experimenting and tinkering with tech things. However, I am not sure if results of my tinkering would be interesting to majority of members. Cheers, polgyver

 

[Conky]

any idea on your next project? maybe get some ideas here

 

[Cadsulfide]

I have to agree with AcWxRadar; I like mad scientist types who think out of the box...cool project

 

[kodaz]

I have to agree with AcWxRadar; I like mad scientist types who think out of the box...cool project

i second that, the world needs more folks that think outside the box.