36 '' Geosat pro vs typical direct tv or dish network dish for ku

[glover31]

Looking for input here.....
I am not understanding why the wide dishes that are used with dish network "hd" type, or direct tv slimline also very wide would not be suitable for fta. They are as wide as the geosat pro 36" from what I can tell just not as tall. I asked this question before but I am told it isn't reliable. I find that odd.

 

[Titanium]

The surface area of the dish is one of the main factors when determining the signal gain of a reflector. If the reflector has less surface area, less signal is reflected to the LNBF. It may seem to be a similar size, but a 36x24 DTV dish provides a surface area approximately the same as a 29" round dish.

Examples:
DTV Dish - 36 x 24" oval reflector = 678 square inches (approx.)
GEOSATpro - 37 x 33.5 = 973 square inches (approx.)

 

[. Raine]

A dish like a Slimline may be suitable for FTA, depending on what you want to receive with it. I have a Slimline here fixed on 121W and a 18''x20'' Direct dish on 95W, another Slimline on 97W, they all work good for the FTA channels I want on those sats. But, on 87W LPB, 103W, 125W, most any other sat, those dishes can't pull in anything FTA reliable at all. If you're looking to pull in one strong transponder on one sat, something like a Slimline might work for you. If you're looking to motorize the dish or will be aiming for weak transponders, get a 90cm for sure.

Direct TV, Dish, etc, the paid service transponders that those dishes were designed to receive, are more powerful than the FTA ones, so the smaller dishes work fine for the paid services, not so good for the weaker FTA transponders, for the most part.

 

[lamp]

I have a Direct TV Slimline dish aimed at 72 West and it works OK.

 

[danristheman]

I have used the slimelines can't get much with those, only the strong transponders.

 

[glover31]

SO....Its about surface area? Does that explain why solid dishes can pick up more signal compared to mesh. All those holes make less surface area too?
Also the slimline dish has better adjustment ''fine tuning". Something like geosat pro just has alignment marks. Is there a kit for these fta dishes so that fine tuning can be done or maybe a conversion between slimline and fta dish? And lastly are there any bolt on kits for slimline dishes to just remove proprietary reverse polarity lnbf and replace with ku bullet style? Pictures?

 

[bpalone]

As for fine tuning a GeoSat Pro 90cm, here is what I came up with:

http://www.satelliteguys.us/xen/threads/ku-band-setup-tune-up-tool-aide.338738/

Your mileage may vary, or it may lead you to think of a better way. For your other questions, I'll let someone with better experience level answer.

Good luck with whatever you decide.

 

[Titanium]

Surface area was the most appropriate answer for your original question.

Mesh vs solid reflector has no effect on the amount of signal reflected as long as the opening size is appropriate for the frequency. If the mesh openings are too large for the frequency the surface no longer appears to be "rf solid", it is creating a reduced efficiency reflective surface. Surface accuracy is more of an issue with mesh designs as the panels are often not shaped into a parabola with the flat sheets placed side by side in a petal design. Solid dishes are either reflective materials sandwiched in the materials forming the parabola, pressed into shape or the most accurate types are spun or hydro formed.

You will find several threads where members have designed fine-tuning adjustments for their dishes. I posted a GEOSATpro 90cm fine-tuning bracket project several years ago, but no longer have the photos.

Slimline LNBFs are not reversed polarity, but they are circular polarity and receive the DSS/DBS high KU band 12.2-12.75GHz frequencies. The scalar is designed to illuminate the shape of the reflector. Changing the LNBF to an off-the-shelf type will usually not be as efficient as the original feedhorn/scalar as the reflector will be over or under illuminated.

You can often find the rectangular mount linear FSS LNBFs on Ebay that fit into the original arm mounts. If not, most use the generic LNBF clamps with adjustable riser section. This design allows the new LNBF feedhorn/scalar to be placed at the same position as the original LNBF.

 

[glover31]

thanks

 

[rsmithwi]

Most people trying to use the DN WA or EA dishes for FTA is to steal programming, Just a couple of strong satellite transponders can be received with those dishes. For the basic setup, at least go with a 90cm for some decent signals. If you can, get a 1.2 meter much more stuff can be received.

 

[danristheman]

I have used dn dishes for strong transponders on 121w ku and 97w ku even had the dishe upside down.

 

[. Raine]

You're right about the Slimline adjusters, those are really nice, probably wouldn't be very easy to transfer them to a FTA dish though. Some cutting and welding would be needed, I'd think. Nice heavy mount on the Slimlines too.

The LNB holder that Titanium posted a picture of above are the ones that I use on my Slimlines and the 18''x20'', with PLL LNBs. I removed the original LNBs, cut a small board to fit tight into the end of the arm where the old LNB slid into it and then mounted the bracket onto the board.

 

[danristheman]

I had a 1 meter commercial dish on a slimline dish mount worked fine for 2 years.