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MMDS Set-up Complete Beginner
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Jimme
Member
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8. November 2008 @ 16:43 |
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Originally posted by Fano:
The Lance 24db grids are very good.
I dont know the exact gain of the Chorus grids ,they vary in size and gain.
Do you have a mesh type grid ?
Ya, I am using an old ch0ru$ mesh type grid. Would a 24db Lance grid be much of an improvement? How would a YAGI compare (if you've any experience of using one)?
Originally posted by Fano:
If you connect the 600T it will tell you alot .
On a dreambox the signal strength should be around 98-99% for a good signal.
BER should ideally be 0 but as long as its <10k it should be stable.
... will give this a go as soon as I can get a loan of a dreambox.
Originally posted by Fano:
I've seen a few faulty downconverters (Panorama) where the snr drops like you describe every 30 secs or so for a few secs .It could be faulty.What make is it ?
I think it could be a "Panorama" but I will need to check.
Originally posted by Fano:
I'm unsure if a booster will make any difference but its prob worth a shot.
The Konig yellow brick booster is supposed to be very good but it might be too strong ,MGB would know better.
Keep at it.
Booster didn't seem to help :(
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mgb17
Senior Member
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9. November 2008 @ 05:00 |
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Originally posted by Jimme:
Originally posted by mgb17:
Your problem could be that the signal strength is near the border between good and bad and a boost could bring the signal into a range your tuner can handle without problems.
Just tried an adjustable amplifier/booster between the power inserter and box. No luck :( The level and quality bars didn't move at all.
What is the maximum recommended length of cable from the downconverter to the power inserter? Maybe thats my problem, but I don't want to go breaking the cable unless it might help. Thanks
Which booster and which downconverter do you use?
The normal boosters for TV have a gap between 230mhz and 470mhz and doesn't help much for ch*rus downconverters which if214 or if222.
This message has been edited since posting. Last time this message was edited on 9. November 2008 @ 05:01
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alec76
Junior Member
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9. November 2008 @ 06:32 |
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Quote:
Would a 24db Lance grid be much of an improvement? How would a YAGI compare (if you've any experience of using one)
i've got both. 24db grid are miles better compare to yagi one
Quote:
I've seen a few faulty downconverters (Panorama) where the snr drops like you describe every 30 secs
i think it is not just faulty downconverter, but some dreambox (driver)issue aswell
had this issue myself (at the same time usb dvb-t stick worked perfectly, while dm600t dropped snr)- so, i had to switch to PLI lolite image( never had a snr drop after that)
i had to change terrestrial.xml aswell: 674000000 to 673800000 and so on ( wasnt able to scan any transponder with normal settings)
This message has been edited since posting. Last time this message was edited on 9. November 2008 @ 07:01
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Jimme
Member
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9. November 2008 @ 12:38 |
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Originally posted by Fano:
If you connect the 600T it will tell you alot .
On a dreambox the signal strength should be around 98-99% for a good signal.
BER should ideally be 0 but as long as its <10k it should be stable.
Just got a loan of a Dreambox 600T. Here are my settings and levels in the manual scan screen:
Frequency: 714000 KhZ
Inv: Not Checked
Constellation: 64-QAM
Guard: 1/32
Bandwidth: 8MHz
Transm Mode: 8k
Coderate LP: 2/3
Coderate HP: 2/3
SNR: Jumps between 97% and 98%
AGC: 53%
BER: Constatly moving between around 150,000 and 400,000
Lock: X
Sync: X
Use ONIT: Not Checked
Use BAT: Not Checked
Only Free: Not Checked
Network Search: Not Checked
The BER keeps changing but is well over 10K. Any idea if this would this indicate a problem with my grid, downconverter or cable?
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satguy99
Junior Member
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9. November 2008 @ 12:59 |
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the ber reading indicates that your received signal is full of errors, sounds like a mis aligned aerial to me , recommend you get some one with a tv meter to point the aerial
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alec76
Junior Member
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9. November 2008 @ 13:11 |
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Originally posted by Jimme:
Frequency: 714000 KhZ
try 713800 or 713900 or 714100 istead, might help, some of those satandcable downconverters arent too accurate
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Jimme
Member
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9. November 2008 @ 13:14 |
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Originally posted by Fano:
I've seen a few faulty downconverters (Panorama) where the snr drops like you describe every 30 secs or so for a few secs .It could be faulty.What make is it ?
The SNR does occasionally drop (by 10 or 20 percent) and then jumps back up again. My downconverter is a panorama. Here is a picture of it:
Also, here is a picture of my mesh, just in case anyone can spot anything I am doing wrong: CLICK HERE TO SEE IMAGE.
Thanks
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Fano
Member
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9. November 2008 @ 13:33 |
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The BER levels you are describing are huge,something fundamental is wrong.
I doubt its your alignment as you have spent alot of time examining the site.
Your grid size looks ok too.
I think I may know the problem.
Are you sure the downconverter is inserted the correct distance into the grid face ?
If this isnt correct,even 1 cm off, then the signal strength will be off.
I suspect this is your problem.
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Jimme
Member
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9. November 2008 @ 13:36 |
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Originally posted by mgb17:
Which booster and which downconverter do you use?
The normal boosters for TV have a gap between 230mhz and 470mhz and doesn't help much for ch*rus downconverters which if214 or if222.
I'm using one of the downconverters from S&C (682mhz, 698mhz, 714mhz etc). The booster I used is an All-for-one amplifier:
Details about the booster can be found here.
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Jimme
Member
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9. November 2008 @ 13:53 |
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Originally posted by satguy99:
the ber reading indicates that your received signal is full of errors, sounds like a mis aligned aerial to me , recommend you get some one with a tv meter to point the aerial
Originally posted by Fano:
The BER levels you are describing are huge,something fundamental is wrong.
I doubt its your alignment as you have spent alot of time examining the site.
Thanks SatGuy & Fano. Yip, I have spent hours tweaking the direction while looking at the signal strength on my TV. The very very best I can get it to work for around 20 seconds without it getting all pixelated. As you say Fano, I don't think this is the problem.
Originally posted by Fano:
Your grid size looks ok too.
I think I may know the problem.
Are you sure the downconverter is inserted the correct distance into the grid face ?
If this isnt correct,even 1 cm off, then the signal strength will be off.
I suspect this is your problem.
This sounds promising. But taking my antenna down and putting it back up is a 2 to 3 hour job minimum. I'm happy to give it a go, but how will I know when I have it the correct distance from the grid face? Trial and error is the obvious answer but that would take days with my set-up :( Is there a set distance or even a rule of thumb to use as guidance? Thanks
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Fano
Member
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9. November 2008 @ 14:11 |
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On second thoughts after comparing that pic to a grid and downconverter I have here the distance into the face looks ok.
It cant go in any further due to the notch in the width of the downconverter .It looks ok.
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Jimme
Member
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9. November 2008 @ 14:23 |
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Originally posted by Fano:
On second thoughts after comparing that pic to a grid and downconverter I have here the distance into the face looks ok.
It cant go in any further due to the notch in the width of the downconverter .It looks ok.
Thats a shame - identifying the problem always seems to be the hardest part. Looking at the pick, have I got the tip (bit furthest from the grid) of the downconverter on the right way round?
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alec76
Junior Member
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9. November 2008 @ 14:28 |
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Quote:
have I got the tip (bit furthest from the grid) of the downconverter on the right way round?
it is fine for V polarization, for H u have to turn it 90 degrees
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glog
Junior Member
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9. November 2008 @ 14:44 |
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Jimme,
I can't access your photo but if you are aiming at the airport in Cork i am nearly sure you should be Horizontal.
This message has been edited since posting. Last time this message was edited on 9. November 2008 @ 14:58
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Fano
Member
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9. November 2008 @ 14:54 |
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Originally posted by alec76:
Quote:
have I got the tip (bit furthest from the grid) of the downconverter on the right way round?
it is fine for V polarization, for H u have to turn it 90 degrees
It looks Horizontal ------- .
Whats your analogue reception like from the aerial ?
This message has been edited since posting. Last time this message was edited on 9. November 2008 @ 14:55
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alec76
Junior Member
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9. November 2008 @ 15:08 |
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Originally posted by Fano:
It looks Horizontal ------- .
he-he i am too lazy at the moment and it is raining . - probably u right, fano. anyhow ,the only opposite polarization i saw in co.cork was in BALLYMAKEERY (N22)
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Jimme
Member
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9. November 2008 @ 15:16 |
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Originally posted by Fano:
Originally posted by alec76:
Quote:
have I got the tip (bit furthest from the grid) of the downconverter on the right way round?
it is fine for V polarization, for H u have to turn it 90 degrees
It looks Horizontal ------- .
Whats your analogue reception like from the aerial ?
Yes, It's horizontal (parallel to the ground). The analogue reception is ok. Its tolerable, but hazy. What does this indicate?
All other downconverters in the area seem to be horizontal ----- too. The tip (its just a thin piece of metal) screws onto the head of the downconverter. It can be connected to reflect inwards ) or outwards (. Does it matter which way I have it screwed on?
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yammagamm
Member
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9. November 2008 @ 15:17 |
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jimmy.. welcome to my world. i have the exact same problem as you with signal and guess what i have exact same downconverter as you and trying it with a old mesh aerial. but luckly it only takes me 2 mins to go up on roof, i have tried moving the downconverter in and out and bloody every way i even got a second downconverter same make though.i have changed cable to good quality ct100 changed all f connectors used boosters used a attenuator in case my signal 2 strong as im not far from mast. when your up on roof next time grasp the feedhorn where it goes into the downconverter with your hand and see does this give you a good signal ? i was getting 80 to 100 percent signal strength but only about 10 percent quality. i have tried just using the feedhorn/downconverter without mesh grid as that downconverter you are using has a gain of 38db, i now have the mesh grid bent in a U shape top and bottom about 10cm from feedhorn and this giving me quality reading of about 35-45 but not steady there. is your mesh grid 59cm x59cm ?
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yammagamm
Member
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9. November 2008 @ 15:33 |
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jimmy the reflector tip is right way around, this just gives a gain of about 3db. i think we have either shite downconverters or its just a positional thing how far the feedhorn is out from grid. see my posts here with problems i have been having trying to get it working look for mmds and diablo cam. and people the diablo cam and built in dvb-t tuner works instead of a "box" and as most new lcd tvs have a built in dvb-t tuner and a common interface slot this is another way.my only problem is signal quality.... jimmy i could not get my downconverter in as far as you and since you are having problems with that position ill rule that out for me...next thing ill be trying tomorow besides throwing it in the skip is to weld a longer arm on grid so to move downconverter out further from grid if i can straighten grid out enough.
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yammagamm
Member
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9. November 2008 @ 15:45 |
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o yea jimmy my serial number of downconverter ends in 601 not sure serial of other 1 as its still up on roof just incase a bad batch of converters,,and some1 said problems with these make ones.
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yammagamm
Member
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9. November 2008 @ 16:35 |
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opps.. ok should have read a few pages back about jimmies problems re signal quality , at least he has most of the channels good unlike me....any 1 know if the yagi sold at sat & cable has a adjustable gain ? as it says gain upto ?as my problem might be 2 much signal.or a crap downconverter
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318i
Newbie
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9. November 2008 @ 17:29 |
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thought i was alone with this problem.I have a dreambox 500t connected to a yagi aerial with integrated down converter and my picture breaks up very badly .the yagi is made by panorama and as was mentioned is it faulty?snr is usually 98% and agc about 52% or better and ber is zero.then for no reason snr drops down to 0% and ber shoots up driving me insane!!!is it alignement,faulty aerial,faulty downconverter or power supply.please help
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Fano
Member
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9. November 2008 @ 20:18 |
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Originally posted by 318i:
thought i was alone with this problem.I have a dreambox 500t connected to a yagi aerial with integrated down converter and my picture breaks up very badly .the yagi is made by panorama and as was mentioned is it faulty?snr is usually 98% and agc about 52% or better and ber is zero.then for no reason snr drops down to 0% and ber shoots up driving me insane!!!is it alignement,faulty aerial,faulty downconverter or power supply.please help
Its a faulty aerial M8,I've seen these symptoms on a good few of the Panorama ones.
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satguy99
Junior Member
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10. November 2008 @ 04:48 |
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Originally posted by Jimme:
Originally posted by Fano:
I've seen a few faulty downconverters (Panorama) where the snr drops like you describe every 30 secs or so for a few secs .It could be faulty.What make is it ?
The SNR does occasionally drop (by 10 or 20 percent) and then jumps back up again. My downconverter is a panorama. Here is a picture of it:
Also, here is a picture of my mesh, just in case anyone can spot anything I am doing wrong: CLICK HERE TO SEE IMAGE.
jimme, can you post a picture of the back of the aerial, the front looks wrong to me
Thanks
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Jimme
Member
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10. November 2008 @ 05:06 |
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Hi Yammagamn. Sounds like your problems are similar. Its truly frustrating not being able to identify the problem though :(
In my set-up I can rule out the following:
1. It's not my box (I have tried a eurovox-tx, thebox-t and a dreambox and none work).
2. Its not the cable quality (using RG6).
3. Don't think its the cable length. I've tried using a booster, but it didn't help.
4. It's not the height of the antenna. Its as high (if not higher) than my neighbours antennas.
5. It's not the direction. I've tweaked and fine tuned for hours on end.
6. It's not my power inserter. It works in my friends house.
The only possibilities remaining (that I can think) are:
1. The antenna might not have enough gain. If I get a 24db lance grid it might strengthen my signal. Especially as there are some trees in the distance which could be interfering.
2. My antenna is on the top of a 14 foot (or more) pole. Maybe it is shaking a bit too much. Looking at it from the ground it looks steady, but I imagine it must be waving a small bit. Maybe I could sacrifice some height in order to make it more stable.
3. Maybe it is a faulty downconverter. That would be soooo annoying. Firstly, how could I check if it is faulty? Secondly, I've spent months trying to fix this thinking it was something I was doing wrong. If it is a faulty downconverter then I have wasted so much time, energy and money because of a stupid manufactoring fault.
4. Maybe the panorama down-converters aren't built for old mesh grids and maybe we need to adjust the distance it extends out from the grid.
Originally posted by yammagamm:
next thing ill be trying tomorow besides throwing it in the skip is to weld a longer arm on grid so to move downconverter out further from grid if i can straighten grid out enough.
Sounds like a good idea - Let me know how you get on. Thanks :)
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