semi sucess with minibud

[outbackjack]

i went out and really tightened everything but not to the point of over tightening the dish or motor. i put the dmx741 (not universal) and scanned 91. i was able to get spanish channels in c band but no cw despite putting in the symbol rates. it was neat being able to get anything but nothing on ku. what i would like to do is scrap the dmx and use the spitfire for ku and the best cband to put next to it. how far off would the cband need to be if i use a bracket or one supplied by a vendor to continue this experiment. what cband is the best (hopefully not the heaviest to avoid pulling down on the dish)? and what bracket or degree offset do i need to make. thanks guys for the info.

 

[Lak7]

i was able to get spanish channels in c band but no cw despite putting in the symbol rates.

For the CW channels, they must be entered Manually / PID Entry.
And in the case with some Coolsats, there is a trick.

 

[1ADAM12]

C Band on 1 meter dish

i went out and really tightened everything but not to the point of over tightening the dish or motor. i put the dmx741 (not universal) and scanned 91. i was able to get spanish channels in c band but no cw despite putting in the symbol rates. it was neat being able to get anything but nothing on ku. what i would like to do is scrap the dmx and use the spitfire for ku and the best cband to put next to it. how far off would the cband need to be if i use a bracket or one supplied by a vendor to continue this experiment. what cband is the best (hopefully not the heaviest to avoid pulling down on the dish)? and what bracket or degree offset do i need to make. thanks guys for the info.

If you are using the 39" dish as a minibud then you will get poor results unless you use the Walrus1957 stacked cone Scalar. I've good results on a 90cm dish with this Scalar. DMX741 will give you good results on your dish with this Scalar.

If you want more info. Google Walrus1957

 

[outbackjack]

thanks 1ADAM12 i looked it up and copied the specs. i am going to build one this weekend and try it out and post any performance gains.

 

[1ADAM12]

Stacked Cone Scalar

thanks 1ADAM12 i looked it up and copied the specs. i am going to build one this weekend and try it out and post any performance gains.

What I found is that it can be very selective about transponders on a given satellite. So you might want to tune the Scalar for your most desired TP. ie; 99W virgin islands strong WHT falls away.

Adam

 

[outbackjack]

1ADAM12 man i messed the first try up severely. i bought the flashing but for the life of me i can not make it cone shaped. i made the cuts and it still wouldnt flex enough to a circular shape. i tried the lamp reflector and that worked the same as the conical scaler i had. i am going to try the metal bolt on the side of the original scaler as i try to figure how to make these bends with the flashing.

 

[1ADAM12]

There are no bends. Just bring the two ends of the C shaped sheet together and the cone forms itself. Tape it with the foil tape on both sides of the sheet.

 

[outbackjack]

it was me looking crosseyed at the pics. i was actually trying to flatten the rolled flashing into cone shaped no wonder i was having such a hard time.

 

[Panavision]

I've gotten away with placing an Invacom Ku-LNB at the dish's main focal point and offsetting the C-band LNB next to it on a bracket. I found that I get about the same signal level and quality having the C-band LNB offset versus dead on in the main focal point. But the Ku-band LNB drops off too much with the roles reversed.

I am interested in Walrus' scalar. I'm only getting a few C-band channels (like CTV on AnikF1R 4060 V 28346).

 

[outbackjack]

Panavision nice idea for the bracket. how far is the distance?

 

[Panavision]

From the center of the Ku-LNB to the center of the C-band, it's 5 3/4 inches. To compensate for the C-band LNB being off center of the dish's usual focal point, I have to steer my motor a little over six degrees to the east (west if the LNB was on the other side of the bracket). This value probably would be different for you in Maine. I'm in Minneapolis.

 

[1ADAM12]

Great to see that you both are experimenting. Search here for Dreamfox posts or Dreamfox1.
I found the offset C lnbf works just as good as centered. I moved on from that to the Dmx741 with 1/2" spacer on my 90 cm dish. It works good enough for MiniBud.
I like the 90cm better then the 1.2 m for MiniBud and with stacked cone Scalar.

 

[Panavision]

I wonder if Walrus' scalar would help me get more than a half-dozen c-band channels. I'm in Saint Louis Park just outisde of Minneapolis, MN. Maybe I'm falling off the footprint. On CTV AnikF1R 4060 V 28346, I get 55% signal level and my quality is on the edge of the cliff (sorry, no number, it's aQuali). Are there members out there in my area that could post results from this transponder on a 1.2m? Any reports are greatly appreciated!

 

[Mr Tony]

The issue with that CTV station (formerly ASN) is the FEC is 7/8 so you need a fair amount of quality. I'm just down the road on 169 and had a 4 footer for some stuff (99W, 121W) but ended up scrapping that idea and using the dish as a killer KU dish

 

[Panavision]

Thanks for the response, Ice! Yep, that FEC makes it really difficult. On the other side of the spectrum, I can watch NHK World on 58 degrees with, get this, a signal level of 30%. I guess it's all in the error correction (7/8 versus 1/2).

 

[Mr Tony]

yep 1/2 has the most correction so you can have very little signal and it works

White Springs (remember them) ? you could get stable signal on a Pansat with a 15 quality..

 

[ynnedibanez]

that is an interesting concept, never thought about it, but it makes perfect sense that more error correction with less sig quality would work as well as less error correction with higher sig quality
i would assume it must require more bandwidth for more fec
maybe that is why lots of channels use less fec, so they don't have to purchase more bandwidth?

 

[Cletus2k]

...it makes perfect sense that more error correction with less sig quality would work as well as less error correction with higher sig quality
i would assume it must require more bandwidth for more fec
maybe that is why lots of channels use less fec

Yes the better the FEC the more bits it takes up total of the downlink.. FEC has to do with how many bits are used for data redundancy (I.E. they can be corrected when received incorrectly the first time) vs. how many bits are used for the content (video/audio)..

More bits for FEC allows for more receiving errors to be corrected.. This means more bandwidth but you can get the data (video/audio) with a crappier signal .. Less bits dedicated to FEC means you have less chances to get the data right if you receive it wrong the first time, so you in turn need a better signal level..

It's been about 10 years since I took Communications Engineering but that should be clear enough to answer in a vague sense..

 

[outbackjack]

well its been a bit but i finally made the walrus1957 scaler. i will be testing it tomorrow. 1ADAM12 i taped the regular scaler to the back to make up for the difference in the throat to attach to the dmsx741. if it wasnt so late i would try it now but the glue took forever to set.

 

[outbackjack]

well i made and put on the walrus scaler but nothing. i am sure it is either my location but most likely my design of it. i put back on the conical scaler not the flat one and also added the socket to the inside. for some reason it did jump the signal bout 5-10 percent so i was able to get signals from 58-101w. not all that i could get from the list but it was sure delightful to get something. now i just have to readjust my ku to get signals less than 72w. i am peaking from 74-103 at 97 percent. thanks for all the info guys it has been really fun to mess with.