View Full Version : [TM-TWIN-OE] Best channel for dish tuning?
Based in the West Midlands, I have, until a few hours ago, used an early Sky minidish (maybe Zone 1?), Quad LNB, which is 53cm across the oval plane. Many years since I originally got this dish, so don't remember it's provenance, but it has done a few miles! The quad LNB fitted is one of the earliest that became available, label now unreadable.
Recent heavy rain and resultant loss of signal lock, even on FTA channels, made me do a Menu/Setup/ Service Searching/Signal Finder check. I found I had roughly 78% SNR & AGC on Sky Premiere Movies. Much dish tweaking later, I found that I couldn't improve the SNR, using a satelitte meter and a feed from a receiver tuned to Sky Premiere Movies (which seems to be a fairly low signal strength normally).
So - I put-up a Raven MK? dish (don't know type, but it measures 59cm across the oval), 'peaked' it on both satelitte meter and on Menu/Setup/Service Searching/Signal Finder (Yes! I confirmed I was on the right box and tuner, with the help of my wonderful wife of nearly fifty years!), and - an improvement from 78% to 79-80%! LNB noise level unknown (again, label there but faded to unreadable).
Mmm! Thought I would have had a much more significant gain! Line-of-sight to 28.2E at 23 degrees elevation (ish) is clear - through a break in surrounding trees! LNB skew is also peaked!
New 80cm dish on the way, then I can start messing around with different LNBs!
Thereafter, should nothing improve, it might be a case of doing a bit of chainsaw work! I will have to wait until my wife has gone Christmas shopping, otherwise tree-felling would be a no-no!
So, back to original question - what is a known weak 28.2 E channel to tune a dish to i.e. transponder/frequency/polarity/etc. etc.? I can of course, experiment, but there is almost certan to be those on here who can advise me of the best channel to choose!
For those that have read this so far:
1. Yes! Clean and new co-ax from LMB to receivers!
2. Yes! Re-made F-type connections all ends!
3. Yes! I know how to peak a dish - only been at this game since the late 1980s!
4. No! I do not mind being told I have missed something fundamental - I'm too old to have any pride!
I am proud to be a member of the OpenViX user community and have helped many people to get started in satelitte viewing over the past few years - they are exclusively ViX users too! Unlike many, I do nothing for profit, I just enjoy helping people!
I look forward to any comments, good or bad!
When I had issues with the skew on mine I found that channels like Cartoon Network, Cartoon Network+1 & CNN wouldn't decode with <25% SNR while other channels would be reading 99% SNR and all working fine.
After peaking the skew I get around 67% SNR on those now - I know SNR changes per box due to drivers so your milage may vary depending on what your issue is.
The free to air channels like BBC 1 HD & ITV HD all seemed to have high power when I looked at those
Living where you do yôu should be in the apex of the beam for all 3 of the 28.2E satellites ... so just choose a channel that is less than 90% SNR and play around ... it is better if you can use a mobile thru one of the apps or webif to monitor all your tweaks.
If you are just interested in 28.2, then a 60cm dish would be fine in the West Midlands. The zone 2 sky dish used all over Ireland is only 60cm. My motorised dish, is only 80cm (I took down my 1.1m dish just recently as I figure I'm getting too old for fannying about on the top of a ladder with a large dish and motor!). I find that the Horror Channel +1 and some of the CBS channels are weakest for me. These can be in the high 60's SNR, but the signal is rock solid even in rain. The main BBC channels are 98%.
When I had issues with the skew on mine I found that channels like Cartoon Network, Cartoon Network+1 & CNN wouldn't decode with <25% SNR while other channels would be reading 99% SNR and all working fine.
After peaking the skew I get around 67% SNR on those now - I know SNR changes per box due to drivers so your milage may vary depending on what your issue is.
The free to air channels like BBC 1 HD & ITV HD all seemed to have high power when I looked at those
Forgot to mention that I also peaked the skew and LNB focus, using a satellite meter and viewing the box signal finder on my iPad using WebIF. Obtained a decent balance of signal strength on both V & H polarised signals.
Found another 2-3 % by moving the LNB away from the dish by a couple of millimetres, by which time there was no further adjustment remaining between the LNB and the arm collar.
Thanks for the reminder though!
Living where you do yôu should be in the apex of the beam for all 3 of the 28.2E satellites ... so just choose a channel that is less than 90% SNR and play around ... it is better if you can use a mobile thru one of the apps or webif to monitor all your tweaks.
Have used a satellite meter and viewed box signal finder via WebIF on an iPad. Tweaked as much as I could out of the dish/LNB for alignment, elevation, skew and focus. Did it in the pouring rain of course - it always seems to rain or snow when we mess around with dishes, doesn't it?!
80cm dish on its way, should be putting that up by Thursday at the latest. Even though there are no leaves on the trees now, it is possible that the dish is slightly obscured. My options to mount a dish are very limited without ending-up with long cable runs, which would no doubt introduce further attenuation issues.
Thanks for the advice!
If you are just interested in 28.2, then a 60cm dish would be fine in the West Midlands. The zone 2 sky dish used all over Ireland is only 60cm. My motorised dish, is only 80cm (I took down my 1.1m dish just recently as I figure I'm getting too old for fannying about on the top of a ladder with a large dish and motor!). I find that the Horror Channel +1 and some of the CBS channels are weakest for me. These can be in the high 60's SNR, but the signal is rock solid even in rain. The main BBC channels are 98%.
Thanks, Fat-Tony! I have been motorised many times before, but like you, my days of messing around at the top of ladders are now behind me - did a fair bit of free-fall parachuting in my youth, but now decidedly unhappy up ladders!
Biggest fixed dish I have put up was a 2.5m on the roof of my villa in Oman, where I lived and worked for a few years. During assembly of the dish segments, the wind caught it, it rolled and it almost fully severed two fingers of my left hand! I still put the dish up and calibrated it, with the scene somewhat akin to an abattoir by the time I'd finished! I digress!
I don't bother satellite hunting anymore, not that it would do me any good here anyway, as I am low down in a horseshoe shaped bowl in the Shropshire Hills, with my view of anything but 19.2E and 28.2E obscured by the surrounding hills and big beech trees, which are not on my land!
So, it's just 28.2E I'm watching these days. I know that I will have to get a few of the tress lopped eventually, but that will be easier said than done.
Raining again today, so do not intend getting wet through again for little or no gain!
Just noticed, scrolling up through the transponders while viewing the built-in-image Signal Finder, that Horizontally polarised signals seem to generally be up to 10% better than Vertical, although it isn't totally consistent. Maybe I can tweak a bit more out of the LNB skew!
Thanks for the advice!
I use my motor very little these days as a significant number of transponders on most sats are now encrypted and not worth the bother as I'm not interested in football particularly anyway. RTL on 19.2 is good for those F1 weekends when CH4 are not carrying the event live. Otherwise I just do an occasional bit of feed-hunting or testing new ViX images on the motor.
As regards signal levels and differences between H and V transponders - I've noticed some very inconsistent results with SNR as I nudge the dish east or west on various satellites, almost as if I was getting signals from side lobes of the main beam. I thought it was maybe a warp in my dish but I've noticed the same effect on my 1.1m and now on the 80cm dish. It's probably just the way these cheap tuners in the boxes work, coupled with the AGC. I never noticed it when I was using my old Manhattan receiver which pre-dates all this new open-source stuff.
I had a Manhattan too! In fact, I seem to remember that Manhattan LNBs were also supposed to be the bees-knees back then - I remember paying a fair bit of money for them too!
D2MAC days were fun - burning your own EPROMs and always having a hot soldering iron on the workbench. I know that you could do toast on some of my early receivers! Made my first motorised setup from scratch - it wasn't pretty but it worked brilliantly! Wouldn't know where to start with these new-fangled boxes, other than repairing PSUs etc. However, they are great pieces of kit, even if they appear pretty 'empty' when you get the casing off!
Guess we are just dinosaurs Fat-Tony!
I had a Manhattan too! In fact, I seem to remember that Manhattan LNBs were also supposed to be the bees-knees back then - I remember paying a fair bit of money for them too!
D2MAC days were fun - burning your own EPROMs and always having a hot soldering iron on the workbench. I know that you could do toast on some of my early receivers! Made my first motorised setup from scratch - it wasn't pretty but it worked brilliantly! Wouldn't know where to start with these new-fangled boxes, other than repairing PSUs etc. However, they are great pieces of kit, even if they appear pretty 'empty' when you get the casing off!
Guess we are just dinosaurs Fat-Tony!
Whoa there Piranha! - I try to think of it as life experience :D Actually, I try to continually adapt to new stuff. I built one of the Elektor kit Software Defined Radios (SDR) back almost 10 years ago and am running two Raspberry PI's - one acting as feeder into Planeplotter using input from Beast ADSB receiver which I got in kit form. Recently upgraded my antenna - last foray onto the roof, though, probably! Am also running a Raspberry PI as a microsecond-accurate time server for my LAN, using a cheapo GPS receiver I imported direct from China. Every day is a learning day...
OK! Have today fixed a 80cm, Zone 3 Sky dish with Quad 0,1 dB LNB. Cut-back and remade all 'F' type connectors, both dish and receiver ends.
Net gain - SNR is significantly increased (10-15%) on almost all channels that were less than 89% previously, however, despite much tweaking, I cannot get anything higher than 89% SNR on any channel, even the really strong FTA signals.
The larger dish will no doubt give me better reception in poor weather, but it seems likely that the obscuration from the treetops at roughly 28.2E and (more likely) the ridge in that direction (also covered with growing trees) is going to be an increasing problem.
I have used various iPad and iPhone apps that use the device camera to show the satellite chain and 19.2E & 28.2 E both show as well above the horizon, but the reality seems to be somewhat different!
Living in a large, single-level wooden lodge, my options to mount a dish higher are very limited, although I fully appreciate that a few metres higher here on planet Earth would make a lot of difference in receiving the Astra group @23degrees elevation (ish) for my location.
Lopping the tops off some trees might be possible, but removing a few million tons of the Shropshire Hills is a bit more of a challenge!
Ho hum!
I am surprised that the elevation is an issue - I have an 80cm dish for 19.2. E which with my location I would expect 99% but its more like your signal reception ..... and its well setup so ...:)
I also have a bunch of fir trees (how my neighbours love their fir trees, forgetting how tall they grow,here!) directly in front of the dishes (probably 20 metres away) and signal is fine .... but the dishes are on top of the garage:) ... however, we shall be requesting the presence of a chain saw for the New Year!
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