MMDS Set-up Complete Beginner

try 713800 or 713900 or 714100 istead, might help, some of those satandcable downconverters arent too accurate

 

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

 

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.

 

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.

 

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.

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

 

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?

 

it is fine for V polarization, for H u have to turn it 90 degrees

 

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.

 

It looks Horizontal ------- .
Whats your analogue reception like from the aerial ?

 

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)

 

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?

 

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 ?

 

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.

 

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.

 

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

 

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.

 

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.

Sounds like a good idea - Let me know how you get on. Thanks