MiniTioune/r Help Please!

[g4eml]

Dish alignment and LNB Skew are much more critical on WB. First try adjusting the skew for minimum NB signal, you should be able to null out the NB beacons almost completely. Then try tweaking the dish, a tiny movement might be all that is needed.

Colin G4EML

[Basil]

I completely agree with Colin, when I went from the NB section to the WB one I was convinced my Minitiouner was kaputt as I had a good NB signal on both RX and TX. But no, I hadn't understood how critical alignment of the dish, especially a fairly big dish, was in order to get the much lower level WB signals.

I was amazed how little movement in either axis was needed for the beacon to come, peak, then go. Hopefully it's something as simple as dish alignment, although "simple" can be a poor description of how fine an adjustment may be needed!

[GM0SCA]

Hi Gareth

I found it difficult to spot the WB beacon on SDR Console because it's so wide but I spotted a good signal on Goonhilly WB on '498.262 and can spot a definite rise in signals of approx 3dBm around that same frequency SDR Console. I can see the 'hump' and the change of colour in the waterfall.

73 Simon

[GM0SCA]

Hi Colin / Chris

I was hoping(!) that my existing dish would be OK for Rx'ing DATV; I know for sure it is inadequate for Tx and that's (yet another) project and learning curve.

I'll go and see if I can improve signal levels - thanks all for your thoughts.

73 Simon.

[Basil]

What size is the dish Simon? I quickly scanned through earlier posts but couldn't spot any mention of the dish diameter. Apologies if I missed it.

[g0mjw]

Hi Colin / Chris

I was hoping(!) that my existing dish would be OK for Rx'ing DATV; I know for sure it is inadequate for Tx and that's (yet another) project and learning curve.

I'll go and see if I can improve signal levels - thanks all for your thoughts.

73 Simon.

90cm is a bit small but should work for RX, but that assumes it is properly set up. The NB is a lot less critical. Is the LNB at the focus? Are you connected to the correct Minitiouner input? How are you powering it and are you sure the 12V is getting to the LNB.

Are you sure the dish is really a 90cm one and not a 60cm one? If it is a prime focus, that's easy to determine, but if it is an offset then the minimum dimension will matter. Especially if it is one of those offset horizontal oval ones. If it is prime focus and deep the LNB might not illuminate it very well. How about a photo?

[GM0SCA]

Dear All

I am increasingly of the opinion that the dish is the problem. I was quite confident that it would work on DATV Rx, my theory being "because SSB works fine on the NB transponder". It is 90cms wide by 66cms high; I have looked at the alignment of the dish and I think I squeezed another 2dB from it. A picture of the dish is attached - I do take the Tesco freezer bag off the POTY / LNB whilst using it!!!

For now I'll bung the MiniTiouner and the Portsdown in a cupboard - I know I need a bigger dish for Tx so I will resurrect the project then
It might make sense to have two separate systems - NB and WB.

Thanks all for your thoughts and suggestions, they are all very much appreciated and, hopefully, one day, it will all work!!

73 Simon

[radiogareth]

For reference, I have an old mesh dish 78x86 and with JUST a Bullseye LNB mounted I can get 7 MER on the beacon.
I have found that small accomodations for the POTY will seriously affect your rx signal however. It's worth finding an online dish area calculator and then comparing different dishes and vendor dimensions...all my dishes (4) were 'not as described size wize' but I get on well with a 1.05*1.05, MER 9 on an empty band.
Gareth

[DG8KD]

Hi all,

I am using a 120cm Offset for receiving and I used a normal transponder on BADR for first alignment:

Channel Frequency and Details
Channel Name BBC Arabic
Satellite Name Arabsat | Badr 4,5,6,7 | Es'hail 26.0°E
Frequency 11996 H
System MPEG-4
Symbol Rate 27500
FEC 3/4
Group Arabsat
Type Free

Benefit: No need for Minitiouner to hit the right bird, always broadcast on sat, indipedent : no outages or problems of DATV beacon.
The deviation of 0.1 degree between BADR and Es´hail-2 didn´t made a great difference, The DATV beacon is strong enough.

73
Rainer

[g0mjw]

Dear All

I am increasingly of the opinion that the dish is the problem. I was quite confident that it would work on DATV Rx, my theory being "because SSB works fine on the NB transponder". It is 90cms wide by 66cms high; I have looked at the alignment of the dish and I think I squeezed another 2dB from it. A picture of the dish is attached - I do take the Tesco freezer bag off the POTY / LNB whilst using it!!!

For now I'll bung the MiniTiouner and the Portsdown in a cupboard - I know I need a bigger dish for Tx so I will resurrect the project then
It might make sense to have two separate systems - NB and WB.

Thanks all for your thoughts and suggestions, they are all very much appreciated and, hopefully, one day, it will all work!!

73 Simon

Hi Simon,

I did wonder, picture explains all as that is actually around a 60cm dish equivalent, so really too small for DATV. You will find Iceland bags more robust for protecting the feed. Try and find a 1m or 1.2m dish, but note for an offset dish it is the shortest dimension you need to look at because of the way these dishes work.

Mike