C Band Interference!
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If money is no object (yeah, some people have that issue) Microwave Filter Company has filters that will fix your problem. They design filters that install between your feed and your LNB.
Like at restaurants, when they don't list the price, you know it's not cheap. I read they're expensive relative to our hobby expenses of cheap to free. I don't know how expensive expensive is in this case. Everything is expensive to me these days. Specs here: http://www.microwavefilter.com/c-band_radar_elimination.htm
Edit: Just found the price. You can see it if you hit "Buy Now". $395 per LNB.
Norsat has a model BPF-C-2 that I see one site selling for $295.
Since it appears that a filter like this is a bandpass filter I would imagine it prevents frequencies higher and lower than C-Band from overloading your receiver. If that was the case bandpass filters are available for L-band that you would install inline between the LNB and your receiver. Norsat has a BPF-L-CF-1219 inline filter. I can't find a price. Specs here: http://www.norsat.com/wp-content/uploads/bpf_l_mc1.pdf
Like at restaurants, when they don't list the price, you know it's not cheap. I read they're expensive relative to our hobby expenses of cheap to free. I don't know how expensive expensive is in this case. Everything is expensive to me these days. Specs here: http://www.microwavefilter.com/c-band_radar_elimination.htm
Edit: Just found the price. You can see it if you hit "Buy Now". $395 per LNB.
Norsat has a model BPF-C-2 that I see one site selling for $295.
Since it appears that a filter like this is a bandpass filter I would imagine it prevents frequencies higher and lower than C-Band from overloading your receiver. If that was the case bandpass filters are available for L-band that you would install inline between the LNB and your receiver. Norsat has a BPF-L-CF-1219 inline filter. I can't find a price. Specs here: http://www.norsat.com/wp-content/uploads/bpf_l_mc1.pdf
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Crotch - Thanks for the info! I've sent an email to Norsat Sales asking for a price and availability quote on the L Band Bandpass Filter. I expect it to be expensive but it shouldn't be as expensive as one of the waveguide filters. I'll let you know when they get back to me with a price. I'm sitting here right now watching the interference. It has a very repeatable pattern. Most of the time every 3 minutes or every 3 minutes 30 seconds. Sometimes, it will happen at 30 seconds, 1 minute 30 seconds, then 3 minutes. It only happens on a single transponder 3815, horizontal only, and wipes out every channel on that TP (SatMex 8 116.8W)(3815/H/3600)(V258/A257/P259)(FEC 3/4)(Mod: DVB-S2 8PSK). Like you, I also think that it's receiver overload. As you suggested, if that is the case, most likely the L Band Bandpass Filter should take care of it. If I install my Chaparral Horn with my Cali-Amp LNB's, the interference is still there but it's allot less. As suggested by another board member, it could be because the Cali-Amp LNB's have a much better "out of band" rejection than my inexpensive LNBF. Why wouldn't I just use the Chaparral Horn then? Well, because I have no way to control the polarity servo. Regarding your Avitar, being an RF guy, it looks to me like a shorted Grid Drive Waveform on a 225Kv High Voltage Power Supply
. I'm sure that's not the case but that's what it looks like in my world (Industrial X-Ray Equipment, S-Band, X-Band Linear Accelerators). Your expert advice and suggestions are appreciated !
When I put my Pinnacle up I didn't even attempt to adjust the button hook,just ass umed that after 20? years out in the weather it wasn't gonna move anyway.Just threw the lnbf (bsc621) in,gave it a quicky peek job on c band and went about watching tv.The ku side doesn't work as good as it could but I'm more interested in the C on that dish.
Thanks for your post. Yeah, I tried to run Ku on my Pinnacle too but it just didn't work. Signal strengths were good but it was just too rickety for Ku Band. After I got tired of suffering with the problem, I put my GeosatPro 90cm dish with HH motor back up. That took care of the problem once and for all
!
Crotch - Norsat says that the L Band Bandpass Filters are all custom made. The default Center Frequency is 1176 - 1219 Mhz (Bandwidth 16Mhz). The input range of the MicroHD is 950 - 2150 Mhz. What would be the correct parameters for Center Frequency and Bandwidth?
950 to 1450 normally. BW=500Mhz, Above 1450 is used for OCS(One Cable Solution, I.E. Bandstacked LNBF's)
Not a brand recommendation, just something located 'on the web" Satellite-IF Band Pass Filter
How about a hombrew tuneable notch filter? Maybe an aluminum box, bit 'o stripline, a varactor, cap and a choke, and a potentiometer?
Maybe a 1/2 wave stub? (It's half wave for a 'short"? I think, or is it quarter? Know it's got to be DC 'open".)
Not a brand recommendation, just something located 'on the web" Satellite-IF Band Pass Filter
How about a hombrew tuneable notch filter? Maybe an aluminum box, bit 'o stripline, a varactor, cap and a choke, and a potentiometer?
Maybe a 1/2 wave stub? (It's half wave for a 'short"? I think, or is it quarter? Know it's got to be DC 'open".)
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KJ6EO,
If it is terrestrial interference you will want to nail it at the input to your LNB before it has a chance to create spurs all over the band on the down converted link. I have a commercial filter similar to the Microwave Filter brand http://www.microwavefilter.com/pdffiles/13961WE.pdf, bought it several years ago to fix a TI problem at our radio station, worked fine. But we no longer use that service, the filter cost $600 new. We could sell it for $100 + ship. You can test it first and return if it doesn't help, only cost you about $10 each way.
If it is terrestrial interference you will want to nail it at the input to your LNB before it has a chance to create spurs all over the band on the down converted link. I have a commercial filter similar to the Microwave Filter brand http://www.microwavefilter.com/pdffiles/13961WE.pdf, bought it several years ago to fix a TI problem at our radio station, worked fine. But we no longer use that service, the filter cost $600 new. We could sell it for $100 + ship. You can test it first and return if it doesn't help, only cost you about $10 each way.
PixL - An excellent offer. I'll PM you as soon as I get back home. BTW, I'm applying for an LPFM license (LP-100). My engineering studies are complete and I'm ready to file. All I need to buy is a transmitter, feedline, and antenna. For audio processing I'll use a Compellor in front of an Omnia 3FM (which I already have). My automation server (3U rack mounted), is already to go!
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Posted via Topify using Android
Your expert advice and suggestions are appreciated
Don't be fooled. If I have come off as an expert, I apologize. It's totally accidental.
Pixl is absolutely right. You need to knock out that interference as early in your system as possible. If you can get a filter that installs between the LNB and the feed and for cheap do it.
I ran into a head scratcher a few years back. I installed a Dish Network for a couple, and about the same time every evening, they lost their signal. The next morning, everything was working fine. I just happened to be there working when her husband pulled in. She lost signal again. I walked over to his car, looked inside, and saw a radar detector in his truck. Reached in, unplugged it, and she shot out the door and told me everything was back on.
After she went back in the house, I plugged it back in. She came out and said everything was off again. I had her stay at the door where she could see the TV, unplugged the radar detector, and it was back on. I showed her what was going on and her husband started unplugging it when he hit the driveway.
Sounds similar to my mother's c-band system going out every afternoon at about the same time and duration.
Turned out to be a neighbor's dairy farm milking parlor equipment loaded a failing power transformer a few blocks up the road and it emitted interference, which knocked out satellite reception. When the milking was over, the load was reduced on the transformer and the transformer operated normally till the next milking. She never watched TV in the morning, so didn't see the effects from the AM milking.
The electric company replaced the transformer and all was good!
Turned out to be a neighbor's dairy farm milking parlor equipment loaded a failing power transformer a few blocks up the road and it emitted interference, which knocked out satellite reception. When the milking was over, the load was reduced on the transformer and the transformer operated normally till the next milking. She never watched TV in the morning, so didn't see the effects from the AM milking.
The electric company replaced the transformer and all was good!
I just found this 12 foot monster and I'm planning on using it for the satellite channels I'm having trouble with. As you can see, this dish is very deep and should narrow the beam width considerably. Measuring from a string stretched across the dish, it's over 36 inches from the string to the center of the dish. I'm hoping it's deep enough to reject any TI coming in from the side of the dish. I have no idea what brand of dish it is, but it looks like a commercial application dish. As you can see, it's very well made and rolls on pillar block bearings instead of bolts. What's your thoughts on it?
Deep dish is always better.. in pizzas and BUDs! 
Is the interference polarity specific? The channels I'm having trouble with on Galaxy 16 are nearly all horizontal polarity. Only three of the ABC's are opposite polarity, but they're breaking up as well. As of right now, all of the problem channels either have no signal at all, or it bounces up and down. Movies and MeTV Ozark is completely wiped out. No signal at all. I still get MeTV HD and Movies on SES-1.
was being the keyword here.This was a 4 year old thread...
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