Another 1 meter mini bud experiment

[guapoharry]

Here are some pics of a jury-rigged bracket I made to try out the C band dual I got from Satellite AV on a one meter dish. Cut it out of sheet metal with tin snips, bent it with pliers and banged on it with a hammer until it fit...

At first, I tried to get something on 103º. But after reading some threads, that seemed like too high of a goal to shoot for...

Right now, I can get two TPs on SatMex5 116.8º, the Mexican Gobierno educational mux on 3720. (comes in pretty good) 45-48 SQ on the Merc II. Then there's TP 3990. It was watchable earlier in the morning, but now it's not. 38-40 SQ on the Merc. Like that weather babe...

Somehow, I think the feed is too close to the dish. But the C-band feed mouth is only a half inch closer to the dish than the Ku band feed was... For a test, I pulled it out by hand and held it. Didn't seem to make a difference...

Would anyone have tips on adjusting or tuning this other than, "when it comes in best"? Wondering what I should do about placing the scalar...

 

[walrus1957]

Somehow, I think the feed is too close to the dish. But the C-band feed mouth is only a half inch closer to the dish than the Ku band feed was... For a test, I pulled it out by hand and held it. Didn't seem to make a difference...

Would anyone have tips on adjusting or tuning this other than, "when it comes in best"? Wondering what I should do about placing the scalar...

Quapoharry-

Look at the pics I posted on the thread "My answer to Eqiuty Broadcast problem". One of the photos is of a 1 meter Winegard dish that I initially started my mini bud project with. I was also able to get several C-band channels from several different satellites using a 76cm dish and a home made conical scalar. Also google "W1GHz" a publication authored by Paul Wade and download all that you can, this will give you a lot of useful information for placement of the feedhorn (scalar) and the construction of one.

Please post the f/D ratio for the dish you are testing. Also you can fabricate your own scalar to see if it performs any better than the one you are presently using. "1Adam12" has posted the correct specifications for the demensions of my design for a home made conical scalar on the same thread and believe I have attached the photo of everything you will need to fabricate it. Your out of pocket expense will be under $10 to create your own scalar. A lot of fun to play around with, and isn't difficult to fabricate. In closing two coments here, attach as many photos as you can, we love seeing your experimentation, results and designs, and you are correct about 103W, I can not get reception from this satellite using a 1.2 meter dish in a prime location. The strongest bird for C-band is 99W.

The two satellites I currently have difficulties with are 116W and 103W for some reason. But do not give up the ship, your dish will work for some of the C-band programing.

Good luck,
Walrus

 

[Anole]

shopping list for 1m users:

Here's a shopping list for C-band satellites on a 1 meter dish.
Scroll down a few more posts, and Fred lists additional birds.

 

[guapoharry]

That W1GHz reference is quality stuff. Thank you. I have some reading to do... (That and the mini bud threads too)

Now that night has fallen, 3990 started coming in a lot better. There are longer periods of video that is good. (quite watchable) After scanning, two more TP's are recognized enough that the receiver identifies the channels. With this improvement possibly being due to the lack of sun, I thought maybe that was an indication noise is causing trouble. In haste, I adjusted the scalar forward and lost everything.

Well that was reversible, so the scalar is only closer to the dish by an eighth of an inch now and SQ has improved 3-5 points. That was a real help for 3990

Time will tell if the sun affecting things issue repeats itself.

Not sure about the f/D ratio. From the link pedro posted, it appears my dish is a 1111 series Prodelin. Doesn't say anything about f/D ratio. Guess I'll send them an email.

 

[walrus1957]

I do not have my testing notes handy but thought I would pass along some info that I do recal. Using the 1 meter Winegard dish with a f/D of 0.59, and using the BCS621. I recal the throat of the lnb opening was positioned very close to where the the KU LNB feed horn opening would was positioned, which would be about 1/2 inch further away from the dish from where you have yours placed. Also when using the prefabbed conical scalar as you are using it worked best to move the scalar forward so that the lnb did not extend into the scalar but was flush with the inside step. So if your setup was similiar your scalar would move out 1/2 inch on the lnb and the lnb would have to slide back 1/2 inch.

I also used the string method to find the focal positioning and you should find this information in the W1GHz antenna book.

Of course slight differences in the dish, LNB and scalar can make the comparisions irrelavent. One thing I might suggest is to redesign the lnb bracket to allow for easy adjustments and positioning of the LNB.