Think this Chapparral lnb is still good?

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slider

SatelliteGuys Family
Original poster
Sep 11, 2012
42
1
Colorado
Along with my dish came a C-band Chapparral lnb with a blue box (servo?) attached to the back. It looks like high quality stuff but I took it off as there was part of a paper wasp nest hanging inside of it. Also I wanted both C and KU. Now I'm thinking of a separate dish for KU so I'm wondering if this lnb might be worth trying. Any suggestions about cleaning out the inside? The nest is out of it but it's still a little gunky. I'll hook the meter up & see if it shows a signal.
 
How would I find out how to fiddle with the servo? I just hooked it to the meter and the red power light comes on and it registers a 65% signal in the living room.
 
I don't know of any way to test a servo without an old analog receiver, some sort of homebrewed device, or a couple of the Pansat DVB receivers have servo control capability.

I don't think there is any way to test one with a voltmeter or a standard power supply, I believe they require a pulsing voltage to operate properly.
 
Ok so this is old tech not really used anymore? I wondered why my BSC 621 had no servo on it. So the three servo wires went directly to the old analog receiver and would not do anything with a V-Box and Micro HD I gather. If that's the case I'll buy an updated Chaparral C-Band lnb. Are there any other high quality favorites I should look at? I know almost nothing.
 
There are still a lot of servo-controlled feeds still in use but yeh, "old tech" is probably a good description. I am still using one on my present main scanning BUD, and I use an old Toshiba analog receiver to operate the servo (and to move the dish).

Yes, the servo wires can not be used with a V-Box/MicroHD setup.

The alternative to a servo-type feed is a voltage-controlled LNBF. With this style, voltage does the polarity switching instead of a servo motor. "LNBF" just means the LNB is integrated into the "F"eedhorn, the LNB is not removable like it is on your Chap servo-controlled feedhorn.

The only C-band-only LNBF that I am familiar with is the C2 from Brian at SatAv, but I don't think they are available from him anymore. Maybe some of his dealer network may still have some in stock? The C2 is also a dual output unit, and you need that if you ever want to hook 2 (or more) receivers up and be able to receive both polarities at the same time on multiple receivers.

I'm sure there are other C-band LNBFs though, maybe someone can recommend one they have had good experiences with.
 
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Thanks phlatwound! A little explanation saves me a lot of time & trouble. I think I've read all this but not retained it all in a short time. For the meantime I'll give that BSC621 another whirl.
 
Glad to help!

I meant to mention above, and I think you have already figured it out, but your BSC-621 is a voltage-controlled LNBF.

I haven't heard a lot of good reports on the BSC-621s, but IIRC most of the bad stuff was from people that were trying to get C & Ku band both, when they would get C working good, they would lose Ku...or vice versa.

Your idea of going with a separate dish for Ku is a good one.

If everything is setup correctly and functional you should be able to get C-band working with the equipment you have.

Another option, if you can't get anything with the 621 would be to install the Chap feedhorn and just manually set the probe to be either horiz or vertical when your dish is at apex, and then just scan for the polarity you set the probe to.

With that setup you won't be able to switch polarity from your receiver, but you will be able to get either H or V from any satellite once you are tracking the arc.

That method assumes that your LNB (the removable part with the specs printed on it) is still functional, they are occasionally cooked by lightning.

And as always, for initial testing and tuning, it is best to take a small tv and receiver out to the dish, remove all switches (if applicable), and use short pieces of RG6 cable that you know are good.
 
@slider
Calculate your actual focal length and f/d ratio or tell us the depth and diameter of the dish and someone can do it for you. Also do the "string test". Lot of adjustments were needed to get my 7.5ft hydro performing well on C band(do not be surprised if your hydro is 7.5ft also). Example "performing well" it can get the CBS distro feed on 89w and ABC on 95W and 99W with 9/10 fec. As far as Ku is concerned, this dish should pull in anything you throw it.

At first I used a bsc621 also, but have since changed it to a C/Ku corotor. I will spare you my opinion on lnbf that do both C and Ku bands.

Ask yourself two questions. How many simultaneous receivers do you plan to use? Will you use C and KU on seperate dishes? This will determine what type of feed you will want/need.

For reference my hydro has a diameter of 90" and depth of 18".
 
sticking to the basics

Okay, I read your original question, and want to offer my opinion.
Do NOT try to clean and reuse the original feedhorn nor LNB.

I'd give you two options, instead. (C-band only, use another dish for Ku)
- the dual output C2 LNBF from SatelliteAV.
- an Ortho feedhorn, two C-band LNBs, & modified self-powered multiswitch.
The latter is what the OP of this other thread is seeking:
http://www.satelliteguys.us/threads/293335-Where-to-Buy-New-C-Band-Dishes

Diddling around making a corotor work, is just a distraction.
Get on with the good stuff, and watch some TV! :)


Also, pay attention to the terminology and don't let it confuse:
(hope I get this right :) )

The corotors are Feedhorns with a servo to mechanically choose polarity.
They may be designed to carry only a C-band LNB, or both C & Ku.

An LNBF is a feedhorn with a built-in voltage-controlled LNB.
You select V/H polarity by powering it with 13 or 18 volts.
These come in:
- C band only, one output
- C band, two output (like the C2)
- C band & Ku, one output each
- and of course, Ku only, one or more outputs
Yes, there are other varieties, but the above covers what we are talking about, here.



iPhone4
 
Yes Anole, mine is 7.5' too. I guess I think 8' because of the lip around the outer edge. Thanks for the help everyone. I think that 621 will bring in more quality tomorrow. Like I may have mentioned in an earlier post I live on a hillside in an aspen jungle. I stood several yards uphill from the dish this afternoon and believe I see the culprit. It looked before like I was shooting through a wide open space with some closer trees off to the side but I see they are obstructing. Four or five (one at a time) may come down tomorrow. There are hundreds of them & they grow like weeds. When I'm all set I won't be expecting to get everything here unless I move it down to the road. It looks like I should get some tv though. I'd better after cutting down those trees (says the wife).
 
One thing I'll mention here that I haven't seen much of before is that the little antenna wires inside those C/Ku LNBFs are usually NOT 90* to each other. Every DMX 741 (BSC 621s look exactly the same) I've had was like that and I've had to "bend" them some to get the alignment right. You also need to make sure that the Ku and C antenna are aligned as well as both are going to be using the same setting when the LNBF is clamped into the scaler ring. You can "tweak" those antenna using a long screw driver but be careful on the Ku ones as they are small and it doesn't take much to move them.

As far as performance goes, on my 10ft Winegard dish I switched from a Chaparral corotor with Norsat LNBs to a DMX 741 and saw little to NO difference in Q readings on sat locations that I had written down to verify what the difference was. I picked sats/TPs at both ends of my arc and also in the middle and did this A/B test on the same day so weather wouldn't be a variable.

When setting up I use a Cband sat to get "close" then switch over to Ku and do the final tweak as the Ku side is much more sensitive than Cband, which can be off a few clicks and still lock and give you good Q numbers.

And a final note. DMX 741 LNBFs will be no more as DMS sued WSI and they can't use that term any more. The 741 WILL be available probably by December though and will have a new name, ie, I've been told they will be ESX 741s and will have the capability of doing both Standard and Universal LO settings on the Ku side or at least that's the rumor that's going around. Until then you can play around with what you've got and or look for an Ortho feedhorn like Anole mentioned.
 
I'm pretty much sold on the idea of the c2 but don't see it anywhere on SatAv's site. I'd like to do a separate ku dish later. Tomorrow though I'll check things out once again to see if I can find anything else (lnbf not centered etc.). I did bring down a couple of trees this morning and knocked the Q up a couple of % to 52. I'll post tomorrow how I've got the meter set in case I'm doing something wrong there. Hope to get this going this week because I'll be hitting the road until January & it would be swell to have tv when we get back. It might be too cold then to mess with it.
 
Good luck finding the C2, as when Satav obsoleted them, any remaining all apparently got pulled from the market. Unless you can find another hobbyist to sell you one, you have next to no chance of getting one from any dealer, even if they have them.
 
It was my understanding from SatAVs posts, that some of his dealers -might- have a few.
He certainly didn't say they were pulled nor recalled ( so far as I know).
 
I just replaced a Chapparral dual (K/C) LNB with a cheap Eaglestar... After 3 days of fiddling,it was the LNB was found to be the issue on why I could not receive TP 3941 on Galaxy 17.

I could receive most of the other TPs with very good signal but that one..

It does look well built though and I will probably not throw it out.
 
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