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125w tuned down or not?

7K views 34 replies 9 participants last post by  majortom 
#1 ·
a few weeks ago, we had a *ginormous* wind storm in the ottawa-gatineau region, with quite a few trees knocked down in my neighbourhood, house siding ripped off, sat dishes almost blown off a few roofs, power lines damaged (~20 hours power outage in my area), etc.

the dish i have pointed at 125w survived (along with the 91xg on my roof), to my great relief.

but ever since, it seems that i've been having issues getting pbs fta on that sat. either my dish's aim was either thrown off, or pbs has "tuned down" most of the transponders. except, oddly enough, the one used by montana pbs.

so, question: has anyone else been having difficulties getting the various pbs channels on 125w recently? should i peak that dish again or would it be wasted time trying to try to fix something that is not on my end?
 
#2 ·
I would suspect the wind storm may have moved the dish. Having said that, 125W is always up and down like a yo-yo more so with the 33" dish. The problem is also if I peak the dish for Montana then the other TPs are down and vice-versa.
 
#3 ·
well then, i guess i'll try to peak my 85cm dish (the one aimed at 125w) anew, to see if i can get it back to where it used to be. and to think i was sure that dish was low enough to avoid things like this (big wind knocking it off alignment). at least i don't have to climb on my roof.

i'm happy i set up a dish for 87w, then. lpbs is coming in better than what is on 125w, despite the fact that i'm now thinking i've skewed the lnb backwards. if i indeed set my lnb incorrectly and lpbs is still coming in relatively nicely, that bird must be broadcasting very loud!
 
#4 ·
after working on my 125w dish, i still have no better reception than i've been having recently. oklahoma is still "missing" and the rest is not as strong+stable as it used to be. azimuth is as good as i can make it, only elevation was not touched, as i ran out of time.

(working on elevation might be a bag of hurt in itself, because of where that dish is set up -- in the air and off the side of my shed. angles are a b*tch to deal with. definitively not as convenient as my other dish that is reachable from ground level.)

i'm seeing hints that oeta is transmitting, but am not correctly aimed to get it. i still find this puzzling, as i can get other signals from that sat. even after all this time "doing fta", it seems to me that if i can get one, the rest should follow, right? those birds aren't that big, it cannot be that the aim varies from one transponder to another -- i'm considering the tp and the associated antenna as the same for argument's sake.

as for 87w, i had my lnb "backwards" (read: rotated clockwise instead of counter clockwise). rotated "to the right side" and signal quality jumped to 70+! whoa. now, if lpbs just could transmit full time... and add world channel, that would be wonderful.
 
#5 ·
125W comes in fine here. My wife is watching something else or I would check the signal for you.
131W and lower I run in to the neighbor's tree.

Edit: 11.2 dB on 12180 V 30000 and 10.4 dB on 12109 V 8703
given their operating parameters, both signals will fail at ~ 7.9 dB
 
#6 ·
@majortom:

have you noticed if montana pbs has become stronger for you, recently?
that's what i've observed.

and are you getting oeta reliably?
their channels have really disappeared "full time" for me. they were never the strongest, but at least they were there most of the time... before.
 
#7 ·
13 dB on Montana PBS
They all play fine, but Montana can be finicky being a narrow BW signal, so close to a wider OETA.
IMO....125W is a classic example of where having a commercial quality LNB(F) with good LO stability and low phase noise and
not some cheap chinese LNBF should pay off.

I really don't watch it very much to be honest, so can't say much for trends.
 
#8 ·
@majortom:

i am using an avenger PLL322S-2 dual lnb on both dishes, which is the best easily available lnb that i know of. the diseqc switches i've just installed are the "b.e.s.t. germany" 4x1 units, not exactly chinese no-name knock-offs.

are you saying i could replace the avenger lnb units with better ones?
 
#9 ·
I am saying that one should not expect commercial performance / reliability from a residential antenna for under $100 and an lnbf that sells for 20 dollars.
 
#10 ·
tmp31416: I see the same thing here, Montana PBS has been stronger lately. OETA, which has never been a problem before, recently (last week or so?) seems to have had significant signal loss, and now is more AWOL than there. I did check my dish (80cm) yesterday (push/pull method on the dish), and it is locked in at the sweet spot.
 
#11 ·
after re-peaking the dish aimed at 125w and checking the skew of my lnb, i am now wondering if i was right to assume its aim was thrown off by that fierce wind storm. i mean, it didn't really move if i am to believe markers i left on the bracket and the pole holding the dish. now i don't think its azimuth was really affected.

only the elevation was not really worked on this past weekend, but comparing pictures of now vs. before, i cannot easily see any difference.

whatever changed (was it really during/just after big storm?) i am now unsure of what it is. one detail i have just noticed is that reception on 125w seems to vary a fair by time of day & temperature. i am unsure of what to make of it.

at least i am not the only one that sees what i see. (thanks keith)

@majortom: i hear what you say. is there an better lnb you can recommend? would it make a difference before and after i swap the fortec 85cm dish with a hotdish90 next spring?

silly question: would a feed-horn help or hurt reception in my case? or am i better just to swap the dish (85cm ---> 90cm)?
 
#12 ·
If it was me I would keep my eye out for a used commercial 1m or 1.2m offset, like channel master and maybe motorise it. Someone I know put up a commercial 1.2m recently around here with a Norsat Ku LNB (DRO I think) and he gets 15 dB cnr on the NBCs with that. Made a believer outta me... He has enough fade margin for Zero sun outage thus far this fall, where at my house with the Primestar antenna I lose the NBCs for about 5 minutes as the sun passes by. Says something right there.

Now that I think of it, if ya look at the For Sale section, forum member Pinza currently has a couple Channel Master 1m offset antennas for sale in the TO area. I would buy one if I saw them in my area.

http://www.digitalhome.ca/forum/showthread.php?t=220961
 
#14 ·
nezdepain, thanks for the info on First Nations Experience, I was aware (from another forum) that they were going to be on that transponder and be carried by PBS starting November 1st.
 
#15 ·
@majortom: well, i cannot put up a 1.2m dish right now. it will have to wait until spring. though i could replace the lnb -- even though i did just buy a dual avenger pll unit. when you are talking about a norsat lnb, are you talking something like the 4206A?

from what i've found about it, i'm not sure how it would be mounted -- or even if the unit is complete. do you need to buy a feed-horn to add to it, which would then be used to attach the whole lnb to the dish?

on a semi-related note, i've discovered that lpb on 87w went offline some time this afternoon. hadn't returned last time i checked. talk about adding insult to injury! first 125w becomes almost unusable, then its 87w that goes. i wonder what is happening with them, why all three channels disappeared.
 
#17 ·
do you need to buy a feed-horn to add to it, which would then be used to attach the whole lnb to the dish?
yes, an LNB requires a feedhorn. I am not suggesting you find a feedhorn for your pizza pan dishes if that's what your thinkin.
 
#16 ·
Well, I'm using a 1 meter (Winegard DS3100) dish dedicated to AMC21 with dual Avenger PLL LNB and I'm having the same trouble in the last 2-3 weeks. Seems ok in the daytime but really flakey in the evening. Have no signal at all on OETA.
LPB on 87 quite often goes off air because their tp is used by other broadcasters, eg. college football etc.
btw LPB is back now.
 
#18 ·
quick update for those who weren't aware:

* it seems pbs raised the output power for their transponders on 125w during the holidays -- more precisely: all transponders are (still) more powerful than they were last fall, except the oklahoma one (though not at the same levels they were last spring/summer (2014) when even oeta would come in).

* lpb has apparently lowered its power output on 87w in the last few weeks and now feels like the output on 125w last fall.
 
#20 ·
montana was oft-used as an example (? wrong word, here, but i can't think of another) of a weak signal. but since last fall, i've found they can be quite strong, thank you (if i am to believe my geosatpro microhd). doesn't prevent periodic pixelation, though.
 
#22 ·
I know this is old... But just wanted to report my observation this PM regarding Montana PBS. Historically this TP always locked with very good snr margin, 11-12 dB and DVB-S2 8PSK FEC 2/3 shouldn't 'drop out' until ~ 6.6 dB. But this signal was always hindered with a bit of BER, making it unstable.
A few months ago, some kind soul gave me a Norsat 4106A Ku LNB (DRO). I just swapped it in to my system this PM, and so far it's like nite & day. The narrow band Montana PBS signal is now rock solid, at 12.3 dB snr, ZERO BER.

I'm liking it so much I am ordering a new Norsat CBAND LNB to go with it, which I think should help with some of the narrowband CBAND feeds here as well. These things are pricey, as they are normally used in commercial applications, but so far from what I've seen here there's no substitute.
 
#24 ·
yeah, your dish size alone is a significant improvement. What antenna and feed did you settle on?
 
#26 ·
I have two other Ku LNBs' that I have used..
One is Astrotel Gold series that came with an Astrotel feedhorn I bought back in the 90s... The other was a Gardiner F11701220-0.7 that came with a different feedhorn a friend gave to me when he disassembled his antenna system and dropped it off here.
Previously this signal would be all over the road with similar SNR, but with Bit Errors, as I said which would make it somewhat unstable.
Code:
Tuned specs: 
System:     DVB-S2 6 
Frequency:  12105 V 2398 
22khz:      OFF 
Modulation: 8PSK 9 
FEC:        2/3 2 
Inversion:  ON 1 
Rolloff:    25 2 
Pilot:      ON 1 
MIS:        -1 
FRAME_LEN:  LONG 0 
Bandwidth:  2.9975 MHz 
Data Rate:  4.7001 Mbps 
CN Failure: 6.6 dB 

  status Locked | signal -41.0 dBm | snr 13.1 dB | ber 0 | FE_HAS_LOCK  
  status Locked | signal -41.0 dBm | snr 12.6 dB | ber 0 | FE_HAS_LOCK  
  status Locked | signal -41.0 dBm | snr 12.7 dB | ber 0 | FE_HAS_LOCK  
  status Locked | signal -40.0 dBm | snr 13.4 dB | ber 0 | FE_HAS_LOCK  
  status Locked | signal -40.0 dBm | snr 13.9 dB | ber 0 | FE_HAS_LOCK  
  status Locked | signal -40.0 dBm | snr 13.9 dB | ber 0 | FE_HAS_LOCK  
  status Locked | signal -40.0 dBm | snr 13.9 dB | ber 0 | FE_HAS_LOCK  
  status Locked | signal -40.0 dBm | snr 13.5 dB | ber 0 | FE_HAS_LOCK  
Closing frontend ... 
Disconnect from gpsd ...
 
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