Home-Brew Satellite Dish

[linuxman]

Fred
did you make any other adjustments besides the two dimes under the cap ?

thats what i mentioned earlier if you adjust the pipe to equal out on all sides it will tilt your scaler & feedhorn just a bit ... so maybe an adjustment is needed there to compensate for the two dimes ? just thinking

I didn't make any adjustments besides the dimes. The scalar is parallel with the end of the pipe, so wherever the pipe goes, the scalar goes too.

I could be that the scalar was parallel with the dish before, and since moving the pipe, the scalar isn't parallel with the dish. May still be parallel with the pipe, but if the pipe was not centered correctly when installed, it could account for the loss.

I'll take the dimes back out in the morning and see if it comes back.

It's 100 degrees in the shade on my front porch.

 

[phlatwound]

I've been following your progress on this one and have a (dumb?) question......does all the signal that is reflected off the dish, pass through the PVC pipe that holds the feed, with no loss?

a little off-topic btw, we are vacationing in Col. Springs, we came here via OKC, then across the panhandle of OK, there's not many houses out in that country but there are a lot of old BUDs at what houses are there...and EVERYONE has pizza dishes.

good luck with your project!

 

[linuxman]

I've been following your progress on this one and have a (dumb?) question......does all the signal that is reflected off the dish, pass through the PVC pipe that holds the feed, with no loss?

Just like the plastic cover on the mouth of the feed-horn. The signal passes right through.

a little off-topic btw, we are vacationing in Col. Springs, we came here via OKC, then across the panhandle of OK, there's not many houses out in that country but there are a lot of old BUDs at what houses are there...and EVERYONE has pizza dishes.

good luck with your project!

I'm sure you could pick up a truck load on your way back.

Have a good vacation.

 

[phlatwound]

Just like the plastic cover on the mouth of the feed-horn. The signal passes right through.


I'm sure you could pick up a truck load on your way back.

Have a good vacation.

Well duh, that makes a lot of sense, thanks.



Hey...if anyone has a question that they think it WAY too dumb to ask, just PM them to me and I'll do it for you, everyone is used to me doing it anyway and I always get great answers!




Looking forward to you getting this one dialed in, that's one of a kind.

 

[gabshere]

Well duh, that makes a lot of sense, thanks.



Hey...if anyone has a question that they think it WAY too dumb to ask, just PM them to me and I'll do it for you, everyone is used to me doing it anyway and I always get great answers!

actually i didn't think it was a dumb question .... very reasonable in fact as they are two different types of plastics plus one is very thin & blue and usually has a bunch of small holes and the other is heavy white with no holes.(except at the end)

but again i don't consider any questions or any theories dumb , especially when they might be a better way to fix repair a dish or gain on a satellite signal

 

[Anole]

PhlatWound -
Not sure if the family would appreciate it, but maybe you can rent a trailer, to haul your booty home. -

Regarding the signal going through the sewer pipe . . .
When electromagnetic waves go through an object, they are bent slightly.
Light through a lens, for instance.
But, light through a flat piece of glass works, too.
Or light entering a pool of water.

And it's the dielectric constant of the medium (what sort of plastic you used) that determines how much bending of the wave.
So, maybe the sewer pipe is insignificant on the focus, or maybe it plays a part.
The old HAM technique of tuning for maximum smoke applies here.
Adjust it 'till it works best.

But, if I could get hold of a friend* who builds phased array radar antenna, I'm sure he could answer the question of how much that tube influences the focus.
And of course, the old adage, "If it works, don't fix it", also applies!

I doubt that it particularly improves performance.
But it may or may not throw off the focal length.


* edit: I sent Jeff an email. Who knows if he'll respond.

 

[linuxman]

I got the Ku back to at least where I was finally.

I took the dimes back and put the pipe back in where it was originally. The scaler is not at the center of the dish now, but back where it was. It is off by about 1/2 inch where two of the adjustment bolts meet the scaler from the edge of the dish to the scaler.

I devised a way to at least get the scaler and the feed-horn pointing at the center of the dish. I cut some slots in the pipe and re-did my laser pointer so that I could put the straight edge through the pipe and get it settled on the mouth of the feed-horn, the laser will point to the dish a distance from the pipe and I can then adjust so that the distance is equal from the pipe on the N/S and E/W axis.

Now I need to learn how to use my Sat Buddy tuner to set the polarity properly. I have had the thing a couple of months now and never learned how to use it.

Once that is done, I can resume the Focal Length perfection distance.

I am already very happy with the C-Band signal considering it is a 6 foot dish. Have C-Band all the way from 137W to 58W and Ku from 129W to 72W. If I can get the Ku equal or better than the C-Band which should be do-able, this will be a great dish, even if it is only 6 foot.

It was 80 degrees when I started at 6:00 AM, and is now 90 out. I have things to do tomorrow and Wednesday mornings so probably won't do much else until Friday morning except maybe learn how to use the Sat Buddy. Anyone with experience on that thing, PM me you phone number and I will call you and we can talk. I'll pay for the phone call.

Here are some pics of the mod on the pipe and laser pointer.

 

[linuxman]

I think I used this Sat Buddy 2 once before, so I had to find it in one of the moving boxes, got it out, and hooked it up to my handy-dandy tuning assembly.

I wasn't hooked to the dish, but put an LNBF on the end of the coax just to have something to play with.

With it hooked to the receiver, it outputs whatever voltage you send to the receiver, it will also use the transponder you select in the receiver. So if it cools off at all this evening, or early in the morning before I have to leave, I will tune Ku for the best skew on my TS satellite and let the C-Band fall wherever it will. Maybe at least I can get that much accomplished.

 

[phlatwound]

Thanks for the thoughts and explanations, gabshere and Anole. That feed support is so different than anything in my limited experience, it really threw me trying to figure out how the signal was going to get through that pipe and find the sweet spot.

As far as hauling some booty home goes, my bunch would be fine with it......if we were in the truck it would be expected.

 

[osu1991]

There are BUD's all over that area because what tv stations you could get back in the good old days were on and still are on repeaters and not very reliable. The last time I went to Denver and Colorado Springs, we took the scenic route back through Pueblo and down to Amarillo before coming back up to OKC and onto Tulsa and what houses you see usually have a bud on the property somewhere. I have a small map of where dishes are all around the Tulsa metro area and down south to the Ada/Tishimingo area, but I am being picky with my limited time right now and holding out for a Birdview, unless something happens to my Unimesh.

 

[linuxman]

Well lest you think that I am sloughing off like Stogie, I am not.

We had a bad storm blow through late yesterday afternoon. So bad it blew part of the roof off the Primary School up in Winfield. (You remember the place 4 miles away that got flooded so bad). The news said they were 80 mph straight line winds.

Wasn't quite that bad here, but still strong winds. Nothing damaged here or in town. It did cool things down a bit, and it is supposed to be better yet tomorrow through Sunday. High in the mid 80's.

So this evening, I took the center pipe off, and loosened the 4 bolts that hold the center cap to the dish, and slipped a washer between the dish and the end cap on the bottom bolt.

Put everything back together and the pipe is now perfectly centered in the dish. I guess the center of the dish had developed a little sag over the years. Hope it doesn't sag any more.

I put my laser pointer on the mouth of the feed-horn and now have that perfectly centered on the dish. It should all be lined up properly now.

Hopefully tomorrow evening, I can lock back onto the signal and resume tuning this dish in.

As soon as I get locked back on the signal (elevation will be off again), I will adjust the polarity with my Sat Buddy 2, and go from there.

 

[Anole]

echo, echo, ... echo, . . . echo . . .

So this evening, I took the center pipe off, and loosened the 4 bolts that hold the center cap to the dish, and slipped a washer between the dish and the end cap on the bottom bolt.

Uhhhhh.... wasn't this what I suggested with the dime in the first place?
Maybe I should have sent along a marked-up drawing? -
I'll take a Dale Carnegie course in public speaking (more clearly).

Put everything back together and the pipe is now perfectly centered in the dish. I guess the center of the dish had developed a little sag over the years. Hope it doesn't sag any more.

Wouldn't rotating that 6" pipe have counteracted the sag?
Next time, I'm just gonna get you on the phone and brainstorm this stuff with ya. -
I'm not so good at this typing thing.

 

[linuxman]

Uhhhhh.... wasn't this what I suggested with the dime in the first place?
Maybe I should have sent along a marked-up drawing? -
I'll take a Dale Carnegie course in public speaking (more clearly).

You may have been talking about that, but previously I slipped the two dimes between the end cap and the tube at the bottom edge on the inside. It didn't work nearly as well as this single washer between the cap and the dish.

Sorry if I misunderstood. Perhaps a drawing would have been easier.

Wouldn't rotating that 6" pipe have counteracted the sag?
Next time, I'm just gonna get you on the phone and brainstorm this stuff with ya. -
I'm not so good at this typing thing.

The sag wasn't in the pipe and the cap. I don't think rotating the pipe would have made any difference. I stuck my hand down inside just to make sure the tube was touching the end cap all the way around. Any time you think I am not understanding something, feel free to call and we'll hash it out. :yikes:

The sag was in the surface of the dish where the end cap sits. After I got around back and looked, I could see just the slightest bulge. Had to be from the pipe hanging onto such a small surface all these years. It's been up since 1985. If I every have to re-do it, I'll need to put a small steel plate in it.

It should be good to go now though.

 

[linuxman]

I managed to get a hour or so into tuning the dish this evening. Adjusted elevation until I got my signal back in line.

I set the polarity on G11/G17 12060V and 12076H I think if I remember correctly.

Had about 60% SQ on the V and about 30% on the H TP. I then decided to move the LNBF toward the dish. Moved 4 turns on each bolt and no change, moved another 4 turns, and the V dropped down to about 30% SQ and the H moved up to about 45%.

I thought that was very strange that one signal would drop, and another would go up. Moved the feed-horn back out to where I started, and the signal went back up on the V and back down on the H. I am doing my best to keep the feed-horn centered while doing all this, so I don't think it is a change from that.

C-Band signal did not seem phased at all by any or all of these adjustments. I will hit it again tomorrow morning early.

Does anyone have an explanation for the strange behavior described above?

 

[linuxman]

Well I am a little frustrated this morning.

I just can't seem to get the Ku to come in like it should.

Another thing, when I left the dish last night, I had 60% on G11/G17 12060V. Hooked everything up and had 30% this morning. The thing changed overnight by itself. I re-adjusted the elevation which is a joke with the double turn-buckles in the front and the single in the back, and finally got back to 45%.

The spring to off-set the slop in the U-Joint is another joke. I think the spring actually twists the dish frame sometimes.

I can get pretty good C-Band signal when I am not screwing that up trying to get Ku. :yikes:

I realize this is just a toy, and I shouldn't expect a lot out of it, but that's just my nature.

I think I am going to put it aside for a while. Before doing anything serious with it, the elevation adjustment will have to be re-done somehow, and the spring eliminated. I might hook up a co-rotor to it before I put it away for a while just to see if there is a huge difference.

 

[Anole]

Spring this !

It always bothered me that the original design used a garage door spring.
Those are meant to have a lot of tension, over a fairly short range.
Also, when you got the replacement spring , did you consider getting the absolutely lightest one available?

Not sure how much tension you need, but what would sound better to me, would be a screen door spring.
Much less tension, and plenty of range.
Of course, one might not be enough, so maybe use two or three?
At least you could add them one at a time to achieve the correct stress.
Might eliminate any frame-flexing, too.

There are also those pneumatically assisted door closers, too.
I don't have any idea whether one of those would be of any use.
If you haven't gotten rid of the wiggle from the off-center U-joints, maybe this would help?

I can get pretty good C-Band signal when I am not screwing that up trying to get Ku. :yikes:
I realize this is just a toy, and I shouldn't expect a lot out of it, but that's just my nature.

I think the original owner used it for C-band only.
And, by your own words, it seems pretty good on C-band.
So, it meets it's mission goals.

Some Thoughts:
- It's quite possible that plastic LNB-support tube interacts more with the Ku signal than with C-band.
- Didn't you finally give up trying to use the CK-1 on Ku on your Birdview?
- What do you really prefer for Ku? Do you have a spare to try?
- Any chance it's the positioner that is insufficient for Ku aiming? You already mentioned frame-flex.
- How 'bout a quickie test by dropping in a Sky Mexico or other Ku-only LNB for a test run?

 

[linuxman]

It always bothered me that the original design used a garage door spring.
Those are meant to have a lot of tension, over a fairly short range.
Also, when you got the replacement spring , did you consider getting the absolutely lightest one available?

Hey Anole,

I got the lightest one they had available, and I can take it back.

Not sure how much tension you need, but what would sound better to me, would be a screen door spring.
Much less tension, and plenty of range.
Of course, one might not be enough, so maybe use two or three?
At least you could add them one at a time to achieve the correct stress.
Might eliminate any frame-flexing, too.

I thought about that today, and the screen door spring might be better. I know they took a lot of abuse when I was a kid. Running out the door and slamming it all the way open against the front porch wall.

There are also those pneumatically assisted door closers, too.
I don't have any idea whether one of those would be of any use.
If you haven't gotten rid of the wiggle from the off-center U-joints, maybe this would help?

Don't know the reaction time, but it's a thought.

I think the original owner used it for C-band only.
And, by your own words, it seems pretty good on C-band.
So, it meets it's mission goals.

Yes, it does a surprising job on C-Band. More than I expected.

Some Thoughts:
- It's quite possible that plastic LNB-support tube interacts more with the Ku signal than with C-band.

Hadn't even given that a thought, but that may be a contributing factor.

- Didn't you finally give up trying to use the CK-1 on Ku on your Birdview?

Yes I did, just couldn't get C and Ku at the same fantastic levels.

- What do you really prefer for Ku? Do you have a spare to try?

I have the SatAv Bullet, and the Sky Mexico universal. I have a spare Sky Mexico that I can try and duct tape on there.

- Any chance it's the positioner that is insufficient for Ku aiming? You already mentioned frame-flex.

I think the positioner is accurate enough, but that's always a thought.

- How 'bout a quickie test by dropping in a Sky Mexico or other Ku-only LNB for a test run?

I had thought about doing that, maybe before I put the co-rotor on it.

Thanks for the thoughts!!

 

[Anole]

- What do you really prefer for Ku? Do you have a spare to try?

I have the SatAv Bullet, and the Sky Mexico universal. I have a spare Sky Mexico that I can try and duct tape on there.

No, I was thinking about your orthomode hardware or co-rotors which you are so fond of.
Once I thought of the Sky Mexico, I listed it separately, further down.

And while it's not where you want to go, I think SatAV lists a prime-focus Ku-LNB for really cheap.
I'd always thought that would be something I'd try if I ever wanted to go Ku- on a prime focus dish for some reason.

Welll, sorry I don't have the magic bullet for your Ku problems.
Is this the same difficulty you described on the Birdview with the CK-1?
Or is it dish-related?
I wonder if you could use this 6'er as a test bed to debug the CK-1, and maybe solve why it gave you trouble on the birdview??

 

[linuxman]

No, I was thinking about your orthomode hardware or co-rotors which you are so fond of.
Once I thought of the Sky Mexico, I listed it separately, further down.

Ah!!

Yes, I have several other hardware options I could go, co-rotors, a spare Bullseye II, and even a dual Ku-Band feed-horn, though I have never tried working with it.

And while it's not where you want to go, I think SatAV lists a prime-focus Ku-LNB for really cheap.
I'd always thought that would be something I'd try if I ever wanted to go Ku- on a prime focus dish for some reason.

I saw that on their website at one time.

Welll, sorry I don't have the magic bullet for your Ku problems.
Is this the same difficulty you described on the Birdview with the CK-1?
Or is it dish-related?

Yes, I had the same problem on the Birdview, so it may only be a problem with the CK-1.

I wonder if you could use this 6'er as a test bed to debug the CK-1, and maybe solve why it gave you trouble on the birdview??

Maybe at some point, just need a rest from it for a day or so.

It does have three screws that hold the Ku onto the top. I thought about trying a Frankenstien LNBF with the Sky Mexico fit into the top.

 

[Anole]

Hey, that bandstacked C-band Eagle/Aspen has a back door, with just a cover plate over it.
I've thought about sticking a SatAV Mini in there.
But then I'd have a nice bandstacked C-, with a regular Ku-. -
So maybe if I find a suitable horn for an old Dish Network FSS LNB , I might give it a try!
Now, that would be a hoot!


Actually, I have the LNB; has anyone got a 105° feedhorn they'd like to part with?
Perhaps there is another one that would work; all I have are the tall elliptical ones.