That CCTV one I posted above actually has some good stuff on it from time to time.
Hughes Net Dish
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That CCTV one I posted above actually has some good stuff on it from time to time.
I've found no indication that it's anything other than parabolic in shape. It's uniform in depth when measured at 4 points 90 degrees apart. I plan on painting the reflector as soon as the weather permits, and I may measure in 8 inches from the outer edge and score a line completely around the reflector. Once done, I can lay a straight edge across the reflector and measure from the straight edge to the line and see what I come up with. Just looking at it, I'd bet it's the same no matter where you check it.
As you can see in my last picture, I straightened the old feed legs and mounted them to the reflector, and I'll use them as indicated, but it would be interesting to know if I'm correct about its shape.As they say, curiosity killed the cat.
The new Lnb"s are made for round dishes. Using it on a parabolic dish you will ether under or over illuminate the dish because of the shape.
I Tested my hughes dish Moving the LNB closer then 201/2" caused signal loss. 233/4 was the farthest from the dish without loss. A 2 inch sweet spot 31/2 inches from the center arm. I would think moving the lnb to the farthest point would give best performance? to far and you would get background noise.
There are several dishes with a similar shape installed on business roofs all over in this area. Given the fact that multiple LNB's can be installed left or right of center on a standard C-Band dish to receive multiple satellites at the same time, reinforces the idea that this particular dish is in fact a standard parabolic design. As I said earlier, I have a lead on 2 other dishes just like this one.
If I get them, I'm going to remove the offset feed supports and fabricate a set of prime focus feed legs just to see how well, or if it performs at all. My guess is it will. If that's the case, I'll set one up using a prime focus installation just for the hell of it.
Thinking of this, if it is a perfectly round dish with deepest point exactly in the middle, and still an intended offset feed-position.... It might be a spherical dish, not a paraboloid one!
An offset position of the feed on a paraboloid mirror creates abberation: "unsharpness".
An offset position of the feed on a spherical mirror has no abberation due to offset position (feed not on the primary axis of the mirror), only the abberation due to signals that come from infinity (that a paraboloid mirror has not).
With an intended offset feed position, it might well be the the manufacturer chose a spherical dish design.
With a spherical dish, you don't need to be very much concerned with the exact offset angle: if you optimize the aiming angle through changing dish elevation angle or through changing feed location is indifferent: has almost no effect on signal quality.
However, with a spherical dish after setting the elevation and tweaking the feed distance to the dish, you'd have to tweak the elevation again! And then again tweak the distance, and then again the elevation, etc.....
(That is because the needed feed distance towards the spherical dish is not dependant on the direction the feed-holder is aiming, but on the direction of the satellite beam towards the dish.)
Would be interesting, if it really is a spherical dish.
Of course a multifeed dish is circular in one dimension. But I haven't come across a (supposedly) purely spherical satellite dish till now!
Greetz,
A33
Sorry about last evening, I lost my internet and couldn't reply. I can't wait until it warms up so I can play with this dish.
It's a whopping 36 degrees outside right now. I expect it to warm a bit once the sun gets above the trees. If it does, I'll take that dish outside and do the water test to see what it looks like. If that happens, I'll post a picture with the water still in It. I'm curious myself to see how it plays out.
UPDATE: I got the pole in and the dish on the pole. Used my Channel Master meter to locate Galaxy 3C Ku and had a signal when I hooked it to a receiver. I tried several LNB Lo Frequencies and landed on Universal 9750-10750, with the 22Khz off. Tuned in 50 channels, including the CCTV Chinese channels. Also found Africa Live and Telegenic.
Tuned on it for a bit and landed on a 92/74 signal level on CCTV. A few others were lower, but no matter what I done, couldn't get them as high as the Chinese channels. It was raining hard here and had to delay tuning it for a while until it broke. Now, all I have to do is figure out which satellite has the best programming suited for my taste.
All went well and came off without a hitch. I want to thank all the folks that pitched in offering help and advice. Here's a photo of the install. I'm open for suggestions on which satellite offers up programming close to what we have on C-Band. BTW, I did the water test as suggested. The edge of the water measured the same all the way around the dish. Apparently this dish isn't elyptical.
![IMG_20190205_130749[1].jpg](https://www.satelliteguys.us/xen/attachments/img_20190205_130749-1-jpg.137033/ "IMG_20190205_130749[1].jpg")
Tuned on it for a bit and landed on a 92/74 signal level on CCTV. A few others were lower, but no matter what I done, couldn't get them as high as the Chinese channels. It was raining hard here and had to delay tuning it for a while until it broke. Now, all I have to do is figure out which satellite has the best programming suited for my taste.
All went well and came off without a hitch. I want to thank all the folks that pitched in offering help and advice. Here's a photo of the install. I'm open for suggestions on which satellite offers up programming close to what we have on C-Band. BTW, I did the water test as suggested. The edge of the water measured the same all the way around the dish. Apparently this dish isn't elyptical.
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You are right. I changed my post. I had written down wrong.
How much programming is on Ku that's like C-Band? I know there's a lot of stuff that's not listed on SatHint. Tomorrow if the weather's fit I am going to switch satellites. Not really interested in Chinese.
I used the same elevation that was already set when this dish was being used as a WV lottery dish and this is the satellite it landed on.
How much programming is on Ku that's like C-Band? I know there's a lot of stuff that's not listed on SatHint. Tomorrow if the weather's fit I am going to switch satellites. Not really interested in Chinese.
Define YOUR version of "that's like C-Band".
I use all of these, beyond blindscanning at random:
www.sathint.com
Satellite Charts - Search
LyngSat
Cozi is a good one. I may have to play with this thing and pick one that suits me and wife the best.
Given the fact that it is a round dish (and assuming your measures are precise enough):
If it is a parabolic PF dish, focal distance would be 34.13 inch from dish center (along the primary symmetry axis of the dish).
If it is a spherical dish, focal distance would be slightly higher, 34.81 inch from dish center (along the primary symmetry axis of the dish).
The phase center of your LNB should then be placed somewhere perpendicular to the primary symmetry axis/focal point position; if I understand theory rightly.
I don't know if this small difference in LNB-position can also be found in praxis as a noticable different position.
Anyway, maybe these theoretical values are of interest for you.
greetz,
A33
Given the fact that it is a round dish (and assuming your measures are precise enough):
If it is a parabolic PF dish, focal distance would be 34.13 inch from dish center (along the primary symmetry axis of the dish).
If it is a spherical dish, focal distance would be slightly higher, 34.81 inch from dish center (along the primary symmetry axis of the dish).
The phase center of your LNB should then be placed somewhere perpendicular to the primary symmetry axis/focal point position; if I understand theory rightly.
I don't know if this small difference in LNB-position can also be found in praxis as a noticable different position.
Anyway, maybe these theoretical values are of interest for you.
greetz,
A33
Considering the fact that I ended up with a 92/74 signal level using an analog meter, the LNBF must be somewhat aligned with the proverbial "sweet spot." Moving the LNBF in or out, or side to side or up and down causes the signal to drop. My next project is moving the dish to a couple other satellites in order to see what programming suits my wife and I.
I know where there are 2 more of these dishes, but my next project will be swapping out a 7.5 foot dish for a 10 footer. I'll save the info you provided and just for grins and giggles, I may build a quad leg feed for 1 of the 2 other HughesNet dishes I found and see how it works out. Thanks for everything.
Considering the fact that I ended up with a 92/74 signal level using an analog meter, the LNBF must be somewhat aligned with the proverbial "sweet spot." Moving the LNBF in or out, or side to side or up and down causes the signal to drop. My next project is moving the dish to a couple other satellites in order to see what programming suits my wife and I.
I know where there are 2 more of these dishes, but my next project will be swapping out a 7.5 foot dish for a 10 footer. I'll save the info you provided and just for grins and giggles, I may build a quad leg feed for 1 of the 2 other HughesNet dishes I found and see how it works out. Thanks for everything.
1/2" EMT from Lowes or Home Depot are perfect for feed legs. You can flatten one end, and bend it to the angle needed to bolt it to the face of the dish. Or better yet, bolt to the side edge, if there's a large enough edge lip.
I never actually measured it, but the edge lip is over 2 inches. These are a well made dish. It has the webbing on the back of the reflector to keep the dish true to its shape. I actually decided to park it on SES-3 Ku (103W) to get Cozi and the networks. Ended up with a 92/78 signal level. So far, so good. I may plant 1 or 2 more of these just for variety.
