Old 30K Chaparral LNB Specifications

[mark_calgary]

I was just given an old, but never used, Chaparral Polarotor feedhorn with attached LNB. This is the first piece of the C-band system that I am trying to put together to complement my Ku system. My question is in regards to the specifications of the LNB that is attached. There is no part number on it but the label says:

Chaparral Communications

C-band P-HEMT Low Noise Block Downconverter
Gain 62dB
Input 3.7 -4.2 GHz
Output 950-1450MHz
DC +14 to +24V

The noise temperature is specified by punching a hole in the label below a row of numbers (25 30 35 40) - hole is below 30.

I would post a picture but I have no camera available and am not sure I've had enough posts to do it anyway.

I know this LNB is old and has certainly been superseded by many better units but does anyone have any info on what the LO stability might be or even the LO phase noise specification?

The real question is whether or not it will be good enough to receive C-band DVB. Perhaps someone is using one in this manner already? I have no issues with replacing it although it is always nice to be able to use something you picked up for free.

Now to track down a good dish and mount........ I've managed to find someone with six 12 foot Paraclipse (I think?) dishes locally in various states of repair but my wife would kill me if I put up one of those. A "discreet" 10ft or 8ft may be all I can get away with.

 

[drhydro]

i would give it a try anyways, my first lnb that i used was a cal amp 65 degree that was at least 10 years old and it worked very well.

 

[mark_calgary]

i would give it a try anyways, my first lnb that i used was a cal amp 65 degree that was at least 10 years old and it worked very well.

Thanks, that's good to know. I've been informed that this one has been sitting on a shelf for at least 5 years. I can confirm it hasn't been used because the servo wires are pristine and the whole thing is clean but it is missing the throat cover.

I'll certainly be giving it a try once I obtain a dish, hopefully before our short summer is over.

 

[mark_calgary]

I thought I might add my results to complete the thread.

I'm happy to say I got my C-band dish (10ft mesh) and installed it before the end of summer. I'm getting 60-70% quality on a Pansat 2500a on the strongest transponders on Pas-9 (my desired satellite). The news is that the LNB is not stable enough for lower symbol rate transponders. I can see the quality level drop out regularly (60+% to 0% and back again). High symbol rates are rock steady.

So I'm in the market for a new LNB. My debate is now whether I should get a voltage switched polarity LNB with feedhorn such as the ASC 421 or just get a single polarity LNB and continue to use my Polarotor......

 

[Shawn95GT]

I thought I might add my results to complete the thread.

I'm happy to say I got my C-band dish (10ft mesh) and installed it before the end of summer. I'm getting 60-70% quality on a Pansat 2500a on the strongest transponders on Pas-9 (my desired satellite). The news is that the LNB is not stable enough for lower symbol rate transponders. I can see the quality level drop out regularly (60+% to 0% and back again). High symbol rates are rock steady.

So I'm in the market for a new LNB. My debate is now whether I should get a voltage switched polarity LNB with feedhorn such as the ASC 421 or just get a single polarity LNB and continue to use my Polarotor......

I have an ASC421. The frequency stability probably isn't much better than what you have. It's rated at ± 1.5 MHz (-40 to +70°C). All you are really gaining is the voltage switched polarity. I have this LNBF on my 5' mesh right now.

I just broke down and ordered C and Ku Norsats for my little mesh .

 

[drhydro]

The news is that the LNB is not stable enough for lower symbol rate transponders. I can see the quality level drop out regularly (60+% to 0% and back again). High symbol rates are rock steady

Sorry to hear its not stable enough to lock on, i didnt have any problems with my cal amp LNB locking onto low signal rates.

So I'm in the market for a new LNB. My debate is now whether I should get a voltage switched polarity LNB with feedhorn such as the ASC 421 or just get a single polarity LNB and continue to use my Polarotor......

If you are using this dish just for c band, i think i would use a voltage switched lnb and get rid of the polarotor, one less part to break/ have to replace in the middle of a blizzard. I use my BUD for c and ku, so i am kind of stuck with using a polarotor :-(