Testing out a 1 Meter “C” band dish.

[Terryl]

OK all you “C” band guys it’s summer time and it’s time to do some experimenting and testing, I found an old “C” band LNB in the junk drawer, it is an old Channel Master with a 40 degree LNBA on it, it has a polar rotor on it but I have no way (yet) to control this and I will be only testing the “H” polarity channels for now.

I have made a test mount for this assembly for my 1 meter dish, I will be testing it on 91 west as this location has both “C” and “Ku” band satellites, I can find Galaxy 17 easier this way.

The only thing missing from the LNB assembly is the scalar ring, I have no idea were that went to or what I may have used it for, who knows, it could be the center part of the dome I built back in the 90’s.

So it’s “Hair pulling time” I hope the LNB still works, I get an “S” reading on the CoolSat 5000 so there may be hope yet, but have yet to mount the LNB and tweak it in, if it works that is….

Anyone else tried this?

[Costactc]

Sounds awesome Terry. However that lnbf you have is rustic. I could make a couple of suggestions on a new lnbf or if you like I can send you my geosatpro c 2 lnbf- I just changed feeds last week.

[Terryl]

Yah after several hot hours out in the sun (87 degrees F in the shade, 130 in the direct sunlight) I'm beginning to think that the LNB may be toastier then I am right now, after all that nice work making a nice 3 way adjustable bracket I think it's time for a dip in the pond........Oh wait.......That dried up last week......Darn........Then its beer 30 time.

Hummmmm...... Geosatpro......Hummmmm I would have to redesign the mount....But I might take you up on that, I'd pay for shipping......If I can find a way.......Thanks for the offer Cos...


I'm going to have to do this at night, its going to be even hotter tomorrow...

[jvvh5897]

May not be the LNB--lyngsat shows that 91 is a little weaker than 99, and I've never gotten anything on 91 even though I should be in good spot in the footprint with my 1M dish. Have been able to get 99 (world harvest/lesea is the easiest TP to get) and 107.3 MeteoMedia came in pretty well--but you are fighting both the low gain of the dish and its wide beamwidth (about 4.5 degrees so you get lots of signal from other sats)--you will find that some TP come in and some don't on the same sat.

Oh, and without the scaler, I'm not sure you will get anything. With a flat scaler I don't get anything, had to use a conical scaler. That is with an offset feed dish-maybe flat scaler OK with prime focus dish.

[Terryl]

What about 89 or 87?

What I'm eventually trying for is the NASA channels in HD, this (if I get it to work) will tie into my CS8K for HD, this is why I'm aiming at 91W, I can strap the circular LNB on this rig and get the signals from Nimiq 1,(tells me I'm on the arc) then I plan on jogging it over to 87W, this thing doesn't have a motor on it, just me, with an old 9" TV and the CS5K on a card table out in the back, (this is old fashion testing with the dish mounted on my test pipe) saves me from running back into the house to look at the main TV all the time.


And after further testing with that old LNB I'm beginning to think that the old LNB is junk in the trunk, and no where in any boxes or on any shelf can I fint the scalar ring, so this may be fruitless, but it's keeping me sane and out of trouble. (maybe I can use that old funnel for filling the tractor?)

Oh and I have to wear my side arm, the snakes are getting restless, already got a 4 footer, a 9mm with snake shot works wonders on rattle snakes.

[Costactc]

Yah after sever hot hours out in the sun (87 degrees F in the shade, 130 in the direct sunlight) I'm beginning to think that the LNB may be toastier then I am right now, after all that nice work making a nice 3 way adjustable bracket I think it's time for a dip in the pond........Oh wait.......That dried up last week......Darn........Then its beer 30 time.

Hummmmm...... Geosatpro......Hummmmm I would have to redesign the mount....But I might take you up on that, I'd pay for shipping......If I can find a way.......Thanks for the offer Cos...


I'm going to have to do this at night, its going to be even hotter tomorrow...

No problemo bud, better on your dish then collecting dust in my garage.

[satchick]

Why not try for 121w first? That seems to be a strong one and a starting point for people running mini-BUD setups.

[jvvh5897]

I'm going to have to take back some of my previous comments. I had an hour to play around and nothing better to do so I took off the conical scaler and tried the flat Chaparal style scaler and I got OK results on a number of the 99 degree TPs (LNB was just even with bottom of the scaler and no change in LNB position forward or back improved things so focal positioning much be the same with this scaler as with conical). So I took off that scaler and still got the GDMix (strong but think the video is 4-2-2, audio is OK though--Q reading 50) and Lesea TPs (not usable but got a lock) with nothing on the LNB at all. Then thinking of the info Paul Wade has about scalers, I cut out a ring from cardboard and used spray adhesive to attach heavy AL foil to it and found that if 1-1/4 to 1-1/2 inch back on the LNB GDMix peaked up at Q of 55 (reading was about 65 with conical scaler and about 60 with Chaparal scaler). Did try to fake a simple cone with another peice of cardboard with AL and seemed to get a peak if the cone flaired at an angle that had the edges of the cone pointing at the edges of the dish and the cone started about that same 1-1/2 inch back on the LNB as the ring maxed at--had to hold the cardboard in place so no reading taken.
Did try for Nasa--could not get it.

[Terryl]

OK the hardware is wayyyyyyyyy too hot to handle, (93 in the shade) this is now an after 9PM projo......

[jvvh5897]

I built a couple more cardboard and aluminum foil scalers to try them out.

http://www.w1ghz.org/antbook/chap6-3.pdf describes a VE4MA feed--a ring with a lip--didn't work all that well, but about as well as the simple ring "choke".

Better was a true cone shape--I tried a 60 degree cone to fit on the LNB and it did not quite see the whole dish. Calcs say that I need an 79 degree angle of acceptance (2*arctan(D/2/f)). Still it peeked up the strongest signal about as well as anything else I tried, but not well on ALL the TP (and the strongest is not the one I like to watch).

I ended up putting the Chaparral feed back on. Might have to try to move the dish to see if I do better on other sats with this.

[jvvh5897]

Seems not all Chaparral scalers are equal--had a backup C band LNB and the scaler with it does not work. The lips on the rings are only 0.5 inches high and they should be at least 0.7 to be 1/4 wavelength at the highest C band frequency (so it is better if they are at 0.8 inches for the lowest freqs).

Found that an 80 degree conical horn is pretty easy to use and almost as effective as anything else--positioning is not critical so if you don't know exactly where the focal point is or where to put the scaler and you haven't get a good idea of dish positioning yet, it might be the best to start with. I used two concentric circles: inner radius 2.05 inch, outer radius 5 inch for a cone that fits on 60mm LNB and for 6.4 diameter outer radius of the horn--you only need 230 degrees of the circle but I left another 10 degrees of arc for joining the two ends and left two 10 degree tabs to center of circle to attach to a ring to hold it on the LNB (picture the capital C with some odd lines to center).

[Terryl]

I might just try this out, I have some very thin aluminum flashing that will be just the right size, now to go find my protractors...

[Terryl]

OK this is what I whipped up out in the shop, does this look right?

10639

[Terryl]

Here is another shot, for size comparison its sitting on top of my stack of old Dish 311 receivers.

10640

[jvvh5897]

Look pretty good to me! I might add a cylindrical band to the LNB transition, the cone has to feed directly into the waveguide and if you can't press the rim directly to the LNB, a cylinder could help mate the two--I found that I could mount the LNB where it was convinent and then slide the funnel about till I could eyeball the edge of the dish past it (and maybe squash it one way or the other) and the cylinder would make the transition electrically.

I suspect that the guy that reports using a metal salad bowl for a feed on a mini-bud was getting pretty much the same funnel like effect with a curved surface.

My test showed that the outer rim of the funnel was not that critical in size (I tried one much smaller with a stiffening ring of diameter 6.4 inch and it was OK)--max readings for Chaparral was about 62 on GDMX TP and with cone I got 60, and on Virgin Is TP also drop of about 2 Q points. There is some loss due to the thin AL foil too I think--might be better with thicker material. Also recall ham info on microwave gear saying that there can be some odd effects from rivits and seams--they would likely use brass shim stock and silver solder. Think the biggest effect would be matching the required angle for given size dish and focal length--much more critical than materials and construction method.

I have an old primestar LNB that uses a 60 degree horn and a 20 degree horn--I get slightly better results with that old thing than some of the rest of the LNBs I've tried on KU band--but lots of metal required for something like that, I bet the current designs are to save a little on materials.

[Terryl]

It slides onto the LNB real nice, I used electrical tape to hold it in place till I can tweak it in, but it looks like the "C" band LNB I have is FUBAR, I guess this will have to wait till my Xmas present gets here.

We use to use silver plated brass sheets to make up wave guides, RF shields and other stuff for the 2 GHz stuff on up, some of the wave guides had to be silver soldered by a certified welder (military stuff) to pass some of the codes and regulations, when we got to the 60 GHz band we had square tubing about 5 millimeters in size to work with, that was fun.

I wish I still had some of the stuff from the junk trunk at work, this test would have been over and done with, but then what the heck would I do?

Funny about the salad bowl, I once used a Marie Calender pie tin for a secondary reflector on a 7 GHz setup, (all I had at the time) it worked great, and as far as I know it's still there.

[jvvh5897]

I hate to even think of what stuff like that costs now--silver 10x what it once was and even copper is pricey. I was just thinking of using AL foil on plastic PETE from one source or another for something that could take being outside, or maybe go to dollar store and try to find heavy foil baking tray of AL. Last cone I tried was only 4.4 inch diameter at open end and that takes 4.4/2/sin(80/2)=3.4 inch diameter outer radius and should be about the minimum fraction of wavelength needed at the open end of the cone according to Wade. Something that size should be creatively created out of pie tin, or plastic disposable dinner plate and AL foil.

[Terryl]

You can get nickle silver sheets here.


http://www.onlinemetals.com/merchant.cfm?pid=12533&step=4&showunits=inches&id=904&top_cat=0

And it's not that expensive, the nickle silver does tarnish a bit, but you can spray it with a clear lacquer and that stops it, or if its the back side you can paint it to match the dish color.

[Terryl]

Well it looks like that "C" band LNB I found in the junk trunk is FUBAR, I tried it on a friends BUD and got nothing out of it.

So project 2011613-1A is on hold.

[xilbus]

fridge has the 421 lnb on special like 14$ its a really good one. Im using it at the moment with great results

[Terryl]

OK this projo is back up and running* (but not receiving) now I need info from those that have it working, what I need is the focal point distance used on the 1 meter dish to the front of the "C" band LNB, I have tried several spots, one was where the linear "Ku" worked on 87W, I get zip on the "C" band TP's on 87W. Trying on TP 4000 the NASA channels.

So some type of spacing info is needed to start off with.


*Thanks big time to our illustrious Costactc, thanks bud I owe you a couple drinks.

[Terryl]

Bump bump.......No one???????

[Costactc]

Wish I could help you out bud but the smallest dish I've ever used for c band was my 6' solid and it's 22" on that dish.

[Terryl]

Yah I need to know as I tried it at the "Ku" focal point and got zip..

Hey can you look at 87W and give me an idea of a good and strong "C" band TP on that bird, that may help a bit.

[Costactc]

Yah I need to know as I tried it at the "Ku" focal point and got zip..

Hey can you look at 87W and give me an idea of a good and strong "C" band TP on that bird, that may help a bit.

Try the Nasa tp, always comes in with great signal quality:

4000 H 28111
fec: 3/4

[jvvh5897]

I"ve never been able to get 87 on my 1 M dish. I would try 99 4000H and 3820V (strongest for me on 99), or 107.2 4060V first. I know they are doable, but don't think 87 is--lyngsat shows it as at least 1dB down from 99 and that is too much lower signal.

On my 1M dish the C band LNB ends up pretty much where the Ku band LNB does (24 inch f on 40 by 43 inch Primestar 22.5 degree offset--pretty much a scaled up 18 inch prov offset dish)--maybe a little closer to the dish to get to the right place in the entrance of the waveguide. The same spot works for flat scaler as for the conical scaler. I did have to do lots of playing with the dish and LNB position and scaler before what I have sort of works, but there are TPs that I simply can not get signal on, some that seem to give signal but get nothing on a scan, and some that work part of the time but if I leave the dish alone come back (I figure a TP goes active on another sat and my bit error rate goes up too high until that signal goes away). I have a Ku band LNB next to the C band one so that I can point the dish where I need it for C band--I use 89 degrees and the ABC Now mux for 99 degrees on the C band. I did try pointing the dish to 97 degrees with Ku band at standard spot to get me close to the 99 degree point first. You might want to use another sat at Ku for you dish depending on what you want to do--109 DN circular is a good one to use, nice and strong even with angled shot.

[Terryl]

Hummmm maybe that is my problem, 87 being a bit too low in power for me to pick up, I will try for 91W as a proof of concept as it showes at 40 to 43 at my location, I can also sight in on Nimiq 1.

[Terryl]

Try the Nasa tp, always comes in with great signal quality:

4000 H 28111
fec: 3/4

Thats what I've been looking for, and the channel I want.

[Costactc]

Galaxy 17 would be a good bet Terryl, I've heard others having minimal success with a 1m dish. Maybe try Spotsnet California tp:

3840 H 29270

[Terryl]

SUCCESS!!!!!

On 91W TP 4014H, the only one I can get, I tried all the others and get zip, but now its too hot outside to work on this, I will move the small 9" TV and the CS5000 out to the workbench and try the others when it gets dark and cooler, this way I can tweak the LNB and dish without running back into the shade to look at the signals.

http://www.satfix.net/attachment.php?attachmentid=11192&d=1313527192

11192

As you can see the "Q" is very low, I will have to play later tonight with the LNB.

And one little secret that I will tell you all later if I get it tweaked in any better.

[Costactc]

Great to hear Terryl, I know you'll pull in more channels on G17, very strong sat.

[xilbus]

Sorry Terry, havent been browsing the site for a while. Im happy you got the word network on 91. If you want to test out you have to try 91 and 99w
now remember that if you have a motor, bump your dish EST and your c-band signals should come in stronger. ill try and find a list of channels that i got with my old 1m dish. I have a 1.2m geosat now. also push your lnb as close to the dish as possible and get your connical scalar on the edge of falling off the lnb.

[Terryl]

MMMmm I don't have a conical scalar ring, maybe it's my next investment, I did make a cone about the same size out of aluminum, but dont see any difference in "Q" on the channels.

Dont have a motor but this is setup on a workbench with a small TV right next to the dish, I have tried other satellites with no luck, I only get the one channel on 91W.

I have tried both the CoolSat 5000 and 8000, and both get just the one channel, the 8000 has a lower "Q" then the 5000, I was hoping to get 87W as that has the NASA HD channel on it, I may have to try a bigger dish.

[chifut]

Terry,but for HD chns , need higher Q level ,then SD chns ,Don't waste time for NASA HD .JMO.Good luck

[jvvh5897]

A 1 meter dish at C band is too small, pointing and other adjustments get very critical. Beamwidth is above 4 degrees and gain is very low. 1.2 is lots better with beamwidth below 4 degrees--so nearby sats inferfer less. Bigger is better--7.5 feet gives you the beamwidth below 2 degrees (that really is the lowest that one should have for use in any band) and 3.5 dB more gain than 1 meter (about twice the signal).

----edit--

I seem to have trouble remembering to square the ratio of diameters when I'm on the web computers. Should have had 5 times the signal and 7dB for the gain of 7.5 feet verses 1 meter.

[Terryl]

OK more info, after some good night time work, (too hot here to work in the day time) I have found a few more satellites, these are all the high powered ones.

Now for the little secret I mentioned earlier, the truth is that the dish I'm using is not a 1 meter dish, it is an old WildBlue data dish that is a 28 x 26 elliptical, it works great as a "Ku" band linear dish, and with the help of good old Costac it now works as a "C" band dish on the higher powered "C" band satellites.

So WOW "C" band on a 28" dish, here are some photos.1121011211

[Terryl]

And some more.1121211213

Now to work on a weather cover for the LNB.

[jvvh5897]

I just happen to have been doing some tests on common plastics and found that PETE is ok in signal path, but HDPE seems to be reactive at Ku band, not sure why--maybe it is a really big molecule or has something hanging off that is just right, but you have to assume that anything that changes Ku can change C band too. About the same amount as teflon does too.

Could we get you to do some measurements on that dish--like filling it with water to the level as the top and bottom edge and then finding the horizontal edges at the widest part of the filled area. Think you can do this if you are careful with out water and two straight edges. The idea is to get the vert and horiz sizes to figure offset and then to evaluate how they construct the elliptical dishes. Think you will find that there is an oval area filled with water that you can use the standard offset eq on to find offset and f.

[Terryl]

Well I'm not going to move that dish off the test bed anytime soon, so the water trick will have to wait, standard measuments put it at 28" horizontal by 26" vertical.

As far as the tru focal area, it was found by using my linear tracking system, this clamps onto the dish arm and moves in the X, Y, Z plane, used a small "Ku" band LNB attached to it, then the CS 5000 as a signal indicator, I wish I still had the spectrum analyzer for this but I don't have access to it now.

The arm attached to the dish is right on the beam as far as the offset, I then constructed a set of brackets to mount the "C" band LNB.

A standard Dish 1000 plastic LNB mount works fine to hold the "Ku" band LNBs.

[Pollypurabred]

Please excuse my reply as it has no relevance to this thread.

I am a perfectionists but maybe filling a container with water and measuring the distances needed is beyond my comprehension. While I very much respect Terryl, why would you, jvvh5897, allow theses measurements without a video representation....do you trust Terryl? ......LOL :hide:

Actually I have learned a tremendous amount (via net) following your different post and appreciate with all you peeps put forth....tks.

[jvvh5897]

Do I trust a member of a forum? I tend to. The point of forums is that people share info. I don't own that dish and don't have access to one beyond taking a pic if one is close to sidewalk, but I am interested in how they are made. The water trick is one described in the n1bwt / Paul Wade info on parabolas.

[chifut]

Hey Polly, Do you know who made modyfied BINs for fortec and pansat, durring N2 days??
p.s .My respect is for both of them .Don't get me wrong .

[Costactc]

I would suggest that we all take a deep breathe and relax. There is no room for hostilities in this extremely informative thread.

[Terryl]

I should change the title of this thread to "Testing a micro-mini-bud" and I have found a few more channels on 121W Galaxy 23.

The dish I'm using is a bit too small for anything but the strong "C" band satellites, but it works.

[Terryl]

No new things to report on the micro-mini, things are still too hot on that side of the barn right now to work on anything, looks like a mid October job as I see it. (unless we get a hot Indian summer)