DBS on c band mesh dish?

[jackeee]

I picked up a 7 foot mesh dish for free and was wondering if dish network or DTV signals would reflect back to the dish/direct lnbs for a good signal.I tried it on my old solid dish for fun and it worked well (wired the lnb's on),I was just wondering if anybody has tried it on a mesh dish? Or knows if it would work with a mesh. :confused:

[Chris Blount]

Shouldn't be a problem. In theory, mesh size of 1/16 of a wavelength or smaller will make the dish look like a solid dish to the signal.

In practice, if a standard #2 pencil will not fit through the mesh, then
the mesh is fine for C or Ku band.

[jackeee]

Thanks,I will make the change and let you know how it works.

[AntAltMike]

The feedhorn part of the DBS LNBF is engineered for a reflector with an F/D ratio of about .60. Mesh dishes typically have F/D ratios of about .35 to .40. That means that if you install a DBS LNB on a mesh dish, it will tend to block out a lot of the signal coming at it from the outer portion of the dish.

Skyvision sells a DBS LNB that has been modified to better "illuminate" a Big Ugly C-Band Dish. It even comes with a convenient mounting plate, and it sells for about $60.

[AntAltMike]

Shouldn't be a problem. In theory, mesh size of 1/16 of a wavelength or smaller will make the dish look like a solid dish to the signal.

In practice, if a standard #2 pencil will not fit through the mesh, then
the mesh is fine for C or Ku band.

Make that "#2 pencil lead" for Ku band. As I recall, the wavelength of Ku band is around 3/4"

[boba]

The surface of the mesh will also affect how well it reflects the Ku signal. Your solid dish probably has a better reflective surface than the mesh dish. Dbs is 1 frequency band higher than the Ku used on the "C" band dishes so the wave length is higher the actual wave is shorter and mesh dishes are more susceptable to denting. Hail damage that dosen't seem to affect "C" band reception might destroy Dbs reception. That little 18" dish might give you more signal than a poor 7' dish. The other factor might be the narrower focus of the 7' dish might give problems with colocated satellites some transponders might be strong and the dish might have to be bumped slightly to get other transponders. If you have the time play with it and report back you results or lack of results. Personally I had a lack of results but found a Primestar Dish with a Directv LNBF gained me signal strength and less rain fade.

[ericha]

Ku band starts at 26.5 GHz and goes to 40 GHz (I'm sure of the bottom, and I think the top is right). The wavelength at 30 GHz is almost exactly 1 cm--above this frequency is called "millimeter waves", since the wavelength is shorter than 1 cm.

[xgrep]

The other factor might be the narrower focus of the 7' dish might give problems with colocated satellites some transponders might be strong and the dish might have to be bumped slightly to get other transponders.Interesting point, if true. What's the actual angular difference on some of these? Is it actually enough to make a difference? Geosynchronous orbit is pretty darn far away! Those "colocated" sats would have to be pretty far apart for this to be noticeable, wouldn't they?

x

[oljim]

I have used 6 and 6 1/2 ft solid C/KU dishes, and found a P star dish is better. I think it is the f/d problem . If you can find a CM feed with 3 1/4 bolts it is easy to slide c band feed out and put a D LNB in its place, just use longer 1/4 in bolts.
The Primestar dish is better.

[jackeee]

I got the old solid beta 9 ft off and the mesh on yesterday and will play with the lnbs this evening or tomorrow.The solid just moved to much in the wind for good signal to stay on.

[boba]

Jackeee how many hernias did you get removing a LAUX Beta 9 by your self
even a perf was a heavy piece of steel. Great "C" band dish but weighs a ton.
It was one of my first dishes back in 1985, seems like a .29 or .3 f/d ratio
great where TI was present.

[jackeee]

Well I backed up the pickup let down the tailgate got out the hydraulic jack and with 2x4's for spacers and lifted it up the pole ~5", bolted it down and left it there till 2 of my buddies who were coming over for the DeLahoya fight could help me lift it the rest of the way onto the truck bed,I figure if the mesh doesnt work well I will get them over again to help me lift it back on the pole or get rid of it.
If the mesh doesnt work I could put the beta 9 back on and use guy? guide wires to hold it in place,or give up on the idea all together,I have a old primestar dish I can play with too!

[jackeee]

I think I got the beta 9 in 1985 too.It is very heavy and seemed to catch the wind and snow pretty well!
I already have had 2 hernias repaired and rotator cuff surgery and more shoulder repair due in Oct. The other guys have had hip replacement and knee surgerys and we havnt hit 50 yrs old yet!But it wasnt that bad getting it up the last 5" off the pole.
The 6 ft wingard mesh is like a dream for handling,I may leave it up and try c band again on it if the DBS doesnt work out.

[dfergie]

Have an 8' mesh and a 10' fiberglass, I am interested in your progress.

[jackeee]

Played with it a little while and coudnt get any signal at all.I am going to have to hook up the old c band rec. and tune it in with that and then give it another shot when I get more time.

[gbranch]

Ku band starts at 26.5 GHz and goes to 40 GHz (I'm sure of the bottom, and I think the top is right). The wavelength at 30 GHz is almost exactly 1 cm--above this frequency is called "millimeter waves", since the wavelength is shorter than 1 cm.

Not quite. The downlink side of Ku-band is in the 10.7 to 12.75 GHz range. Dish and Direct use 12.2 to 12.7 of this band. Loose definitions of the downlink side of the various bands are as follows:

L-band: 950-2000 MHz
S-band: 2.0-2.8 GHz
C-band: 3.4-4.8 GHz
X-band: 7.25-7.75 GHz
Ku-band: 10.7-12.75 GHz
Ka-band: 17.0-22.3 GHz

Later,
---
GSB

[ericha]

Sorry--I made 2 mistakes here:
-I was thinking of the Radar bands, not the communications bands. Curiously, they use the same letter designations as the radar bands, but for different frequencies.

-I also was thinking of Ka, rather than Ku.

I couldn't find a definitive list of bands in about 1/2 hour of searching, but a pretty good one is at: http://www.naval.com/radio-bands.htm

This shows the Ku radar at 12-18 GHz, but the TVRO Ku band from 10.9-12.75 GHz (in 3 sub-bands), which is very similar to gbranch's numbers. Do you have a definitive reference that lists all of both radar & communications band letters?

[ericha]

...So the wavelength at 10 GHz is about 3 cm, or a bit more than 1 inch.

[jackeee]

Success??
I got the c band up and running,theres so many scrambled channels its hard to zoom in on a clear channel! I focused it on G3 took off the feedhorn and put up a dual lnb with wire holding it in place.Nothing at first,moved it west and got signal on 119,zoomed it in and it peaked at 120 signal on 119 sat and 110 signal on 110 sat!
Took my quad out and tried it and couldnt get anything for signal.Put the dual back up and had to fudge with it alot more to get signal and couldnt get 110 sat.
For the best signal on 119 the lnb is pointed to the left of center so my arc is probably off on the c band side.
I had the receiver on the dish 500 quad switch mode when I had sig. on both sats so I would think the quad would work.
I will mess with it more later.I wanna try skipping the arc (free up the az/el) and zoom in the dual lnb to dish center for 119,110 then move the dish to a posistion between the 2 sats to make the quad work.If that doesnt work then 2 duals with sw 21's or get a sw 64.
I have wire holding the lnb on so I need to get some perforated metal straps to run between the 4 arms that hold the feedhorn on to steady the lnb and keep a good focal distance.
So success!! the mesh 7" will reflect dishnet signals!(oh yea 1 petal section is missing,one has a hole in it and 2 others are bent,hey what do you want for free?)

[Chris Blount]

Great news Jackeee! It's fun tinkering with this stuff isn't it? :)

[jackeee]

Now I gotta cut the lawn in the dark!! lol

[dfergie]

what was your signal strength jackee?

[jackeee]

got signal on 119,zoomed it in and it peaked at 120 signal on 119 sat and 110 signal on 110 sat

[boba]

jackeee not to be too much of a spoilsport but I am pulling similar signals off my DISH 500. that's only 20" not 7'. It maybe fun to play but that doesn't seem practical to actually use.

[jackeee]

I was gonna see how it does with my rainfade problem.We seem to of been getting alot of rain more than ever and losing the signals,I was hoping it would cure that,also I was thinking if I got multiple services they could all come off one dish,I am thinking of trying FTA someday too.Plus I like to play with these things!

[dfergie]

I have an old C-band feed horn I cut off and taped a Direct tv single lnb to. Im going to try it to see if it works with both my 10' and my 8'mesh.