Yet Another Thread about using a Tiny Dish for C-band

[cyberham]

During the holiday season, just for fun since I will have free time and because it's convenient (read $0 to do), I plan to install an old rescued C/Ku-band LNB on my experimental fixed 1-metre dish. The goal? To see if I can receive even one C-band transponder from any satellite. My first attempt might be on Anik F1R at 107.3W since that satellite has many interesting C-band channels and I happen to know I have good LOS to this satellite since I can receive it well on Ku band.

My best old LNB from my bones yard has the following specs:
Norsat 5400 Series C Band LNB: Input: 3.7 - 4.2 GHz; Output: 950 - 1450 MHz; L.O.: 5.15 GHz; Gain: 65 dB; Temp: 17 K; Made in USA 01/18/96
Norsat Ku LNB: 0.5dB NF; 58 dB gain; A freq; Made in Taiwan; 710-0307; 94/11/17 (What is the LO frequency for this?)

It has a scalar ring, but it is flat so not appropriate for an offset dish, right? It has a Chaparral co-rotor with polarizer. I assume this uses voltages similar to Ku-band LNBs: 13V for V and 18V for H? What voltage to which wires?

Does anybody want to classify this project? Ratings to use could consist of:

Class A Project: Great idea! Why haven't I tried this?
Class B Project: Better than watching TV.
Class C Project: Too much time on hands. Obviously needs a life and a new hobby.

 

[FaT Air]

Norsat Ku LNB: 0.5dB NF; 58 dB gain; A freq; Made in Taiwan; 710-0307; 94/11/17 (What is the LO frequency for this?)

I'll stick my neck out and say it's probably 10750Mhz

It has a scalar ring, but it is flat so not appropriate for an offset dish, right? It has a Chaparral co-rotor with polarizer. I assume this uses voltages similar to Ku-band LNBs: 13V for V and 18V for H? What voltage to which wires?

If it's this, http://www.chaparral.net/feed-horns/ku-wideband/ or the Chaparral co-rotor it uses pulses to change/adjust polarity. 1ms, plus or minus .5ms, applied to the white wire. With a max voltage of 5Vdc. That's also the steady state voltage applied to the red wire. 0(gnd) on the black. It's also for a prime focus with a flat scalar. Circuits that can be used: 555 servo
Picture of it??
BTW, have never seen or heard of a "C/Ku-band LNB", only a Dual band feed with an lnb for each band.
If its a dual band Chaparral co-rotor with an adjustable scalar, replace the flat scalar with a conical.

 

[Cham]

I would try 10750 for the Ku LNB, especially if it was originally installed on the corotor feed horn.
You can set up the feed horn just like you would an LNBF, but it will only pick up one polarity at a time unless you set up the servo as depicted above. If you pick up vertical Ku then the antenna will be oriented for vertical C-band as well. You can remove the servo to change polarity manually, just move the axis by 1/4 turn, or you can turn the whole feedhorn/LNB assembly in the clamp... either way accomplishes the same.
Also if there is a way to maintain 18v to the LNBs, the vertical will work better. Best bet is to use a horizontal TP to line up the dish and the skew, then switch the skew 90 degrees and check for vertical TPs.
An old analog receiver would have skew output (the three wires). You can use it to control the skew electronically. If the dish is on a diseqc motor or equatorial mount the skew shouldn't change between satellites except for 103 on Ku. Just need to switch between V and H.

 

[cyberham]

I think your neck is safe on that guess of the Ku LNB LO frequency. I have the GI Innovation 650i receiver that came with this item. I also have a Uniden UST-9900 receiver. Maybe between the two of them, I can generate the pulses you describe. "Dual band feed with an lnb for each band" sounds more precisely accurate. I only have a flat scalar since all my C-band junk has come from prime focus dishes. It's flat or nothing. Which is better? Some pics attached.

 

[FaT Air]

If all you have is the flat, I'd move it as far to the front of the feed as possible. Higher than the highest F/D ratio mark on the throat. An offset 'should be' .6 - .7 but the flat is probably only capable of ~.42 or so. And that will, I would think, only affect C band. So Ku should be unaffected. (As the scalar geometry is from c band freq calculations. 1/4 wave 'slots' IIRR) Think I've also seen some experiment with no scalar, and got better performance than a flat or conical on a small offset dish. DIY conical scalar ?
Yes, the GI Innovation 650i or the Uniden will operate the servo. DOn't know which would be more convenient. When mounted at '0' skew, the servo with the 3 wires would normally be at the 10:30 to 11:00 position. (when facing the dish face)

 

[turbosat]

cyber I have both those c-band analog boxes, still using the 650 to move my c-band sami dish, works great. And it will store skew info for each transponder on a satellite, but it probably has to be able to receive analog video in order to do that. Regardless-you can still use it to switch polarity, if you get that deep into the project. You should be able to pick up something, might not be all the tps on whatever satellite you pick, but will be educational.

 

[primestar31]

Actually, on an off-set dish used as a c-band mini-bud NO scalar is preferable to a flat scalar.

However, it being a small dish, with or without the flat scalar, you are unlikely to get anything except from the very strongest sats such as 99w. A conical scalar however, might be all you need for the difference between just quite CAN'T receive, and "I can't believe I get a picture with that low of a signal!.

 

[jorgek]

Does anybody want to classify this project? Ratings to use could consist of:

Class A Project: Great idea! Why haven't I tried this?
Class B Project: Better than watching TV.
Class C Project: Too much time on hands. Obviously needs a life and a new hobby.

I would rate this venture a combination Class A + B.
Looking forward to a report of successful reception of C band!

Good luck and have fun......

 

[cyberham]

...A conical scalar however, might be all you need for the difference between just quite CAN'T receive, and "I can't believe I get a picture with that low of a signal!

Walking about the house looking at each lamp shade...but most are plastic. Thinking about a gasoline / oil funnel. Or those dog collars to stop dogs from biting a wound. It's amazing how almost everything is made out of plastic now. I will be reviewing all of above suggestions as I proceed and learn more about this.

 

[Titanium]

99w has the strongest transponders for your project, if you have line of sight. You will be able to receive the LeSEA mux without any scalar and bring in a few more channels by adding a flat scalar. The conical scalar will make an incredible difference on transponders that are near the noise threshold.

To play around with plastics in your home, line any cone shape with foil.... The results will vary.

 

[OkiMarine]

I tried a project like this several months ago and had no luck at all with a 1.2m channelmaster on 99w (the only one I tried). There were probably many issues that existed in my setup that someone with more experience could have resolved but I just couldn't get it. Please keep us updated, I'm very curious to see your results. I may have to dig the CM back out of the garage if you have success.

 

[cyberham]

...line any cone shape with foil...

...then put it on my head!?

 

[toucan-man]

...then put it on my head!?

A tinfoil tuque for the Canuck said the Yank.

 

[cyberham]

99w has the strongest transponders for your project, if you have line of sight.

From this fixed dish, 99W and east is iffy due to a large (now) naked tree. But I can start with 99W. 107W to at least 127W is proven clear LOS. I can orient the dish using current Ku LNB first. This would eliminate a couple of variables. Though 107W C has a lot of DVB-S2, I notice 121W has several DVB-S and FEC 3/4 or 2/3. 99W too. 121W is usually easy to find on Ku due to Dish. 125W also.

 

[primestar31]

Don't forget that due to the size of the c-band style lnb, they tend to sit much higher on the mount, and aren't in the 'true' sweet-spot. So, you might have to re-engineer the side arms to allow it to sit lower. I did this with a Channel Master 1m dish, and that was my biggest problem. Also, the side arms on that particular dish are so close, it makes it hard to get the conical scalar in there.

 

[cyberham]

...So, you might have to re-engineer the side arms...

I have a hammer.

 

[toucan-man]

I have a hammer.

I have a BFH.

 

[rsa2000]

On my 1m CM i had to totally remove the ku lnb mount to get it low enough to work. I had tried and gave up so many times till i figured that out.. Currently zipties are holding it all together. Been watching it everyday for a week. 99w is best sat for me I can get most of whats there, but quite a few were unwatchable without the conical scalar. Crosstalk is insane i can get lots of channels from adjacent sats and it's annoying. It was quite the feeling when I got signal for the first time! Keep at it. You will get it there.

 

[cyberham]

Encouraging to hear. I have cold weather cable ties and lots of duct tape. I will resolve before I start if 99W is possible. Biggest hurdle may be weather. Ice storm coming tomorrow.

 

[cyberham]

I have a BFH.

Had to research BFH. Mine is small.