Setting up an Es'Hailsat2 reception station

[g8vpg]

Having spent much of the last two days up and down the ladder to the garage roof where my dish is located, I thought I would share a few observations about Es'hailsat2 reception and present a question for discussion.
The easiest way to line up the dish is to get a Satlink handheld receiver tuned to BBC Arabic, Badr4, 26East, 11996MHz, horizontal, 27.5ms/s, DVB-S, FEC3/4. Having optimised the dish on this, I could get no further improvement when tuned to the beacon.
It is worthwhile spending time to get the last 1% signal quality on BBC Arabic because this will help to improve your MER on the weaker through signals. This is very frustrating because with the fairly crude clamps that domestic dishes have, final tightening of the bolts often pulls it off heading. Slide the LNB up and down the clamp to get the feedhorn in the dish focus and turn the LNB slightly clockwise from vertical to optimise the skew angle.
If you have a dual output LNB, try both ports to see which is best. On my Octagon twin, one port is 1dB above the other.
Avoid the cheap satellite cable often sold at the DIY sheds today, especially for the port you are using for TV. You will know the cheap type because the centre conductor is just copper plated, not solid copper, the foil is metalised plastic and the braid very thin. Changing to Labgear branded, all copper construction cable gained me 1-2dB.
There has been much discussion about the stability of the LNB local oscillater and injecting an external reference to improve this. I have found that if you let the Octagon PLL type warm up for a short period, it is quite adequate for SSB voice reception on the narrowband transponder. A DRO type is hopeless.
Don't panic if you see the beacon MER drop drop by 3dB! Check to see what other traffic is on. When someone sends a 2ms/s signal at a similar level to the beacon, its MER will drop about 3dB.
By careful attention to all these details, I have got beacon reception up to 10dB MER on a fairly modest oval offset dish 97x87cm.
Finally, a question for discussion! Many of us have used Minitioune from its inception and have learnt that it does not like other strong signals near to where it is tuned. To what extent is a 2ms/s beacon, 10dB above the noise, preventing reception of the weaker through signals? Will we have a beacon off period to measure if this is a valid concern?
Happy watching! Shaun G8VPG.

[G8GKQ]

Hi Shaun

Thanks for that useful information. Tomorrow (Sunday 17 Feb) the team in Qatar hope to work on the beacon and reduce its output power; this should reduce the incidence of ALC-commanded transponder gain reductions. There may then be some planning for "beacon off" periods, but it depends on how much progress they make with the higher-priority elements of the installation.

I hope to try some transmissions today.

Dave, G8GKQ

[satdxer]

Hi thank you for the information and well done on the installation,

This is very frustrating because with the fairly crude clamps that domestic dishes have, final tightening of the bolts often pulls it off heading.

Its best to fabricate something it makes fine tuning so much easier, i use a large dish with a tight beam i fabricated this for it recently.

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[g8vpg]

That looks like a casting which you have adapted. Very nice. If I get a bigger dish, I might need to think of something similar. The thing is that at present, I anticipate that my dish would be fixed on 26 East and so is it worth spending hours in the workshop making something to save perhaps an hours worth of fiddly setting up? May be when all my other projects are finished!
73 Shaun.

[M0DHP]

Hi Shaun

Slide the LNB up and down the clamp to get the feedhorn in the dish focus and turn the LNB slightly clockwise from vertical to optimise the skew angle.

Newbie question - is that clockwise as seen looking into the dish from the front, or as seen looking at the satellite?

Thanks

Ray M0DHP

[g8vpg]

Ray,
Clockwise from your point of view when facing the dish. But just adjust it for a small peak when the skew is optimised. On my set up it only about 2-3% of signal quality on the Satlink, but every 1% is worth having with this.
73 Shaun.

[satdxer]

That looks like a casting which you have adapted. Very nice. If I get a bigger dish, I might need to think of something similar. The thing is that at present, I anticipate that my dish would be fixed on 26 East and so is it worth spending hours in the workshop making something to save perhaps an hours worth of fiddly setting up? May be when all my other projects are finished!
73 Shaun.

Hi Shaun yes its a casting from a old Paraclipse satellite dish its the H to H model, i am quite good at designing if you get a larger dish post a few pictures up of the fixing and i am sure i will be able to point you in the right direction if needed.

[satdxer]

Hi Shaun

Slide the LNB up and down the clamp to get the feedhorn in the dish focus and turn the LNB slightly clockwise from vertical to optimise the skew angle.

Newbie question - is that clockwise as seen looking into the dish from the front, or as seen looking at the satellite?

Thanks

Ray M0DHP

Hi Ray this should help providing i have the correct lat and longitude, on the LNB there should be a degree scale in your case this needs to be set to approximately -19.5 degree once the dish is aligned correctly try tweaking it a little.

https://www.dishpointer.eu/

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[G8XZD-TV]

Some observations from here after a week or twos worth of receive operation.
Initial set up problems were due to the skew not being 100% right (see previous post)
I've been using a zone 2 sky dish and single output pll octogan lnb and minitioune 2

Getting constant decode of beacon at about the 4/5 MER level.
I've received about a dozen different stations - interestingly irrespective of signal strength some just decode instantly
while others are stubborn and take a few minutes to work - or just wont - despite having carrier lock, SR lock and full "leds" lit.
Haven't received any SR <250 though. Have seen some very strong 66/128 - but no lock
DVBs2 seems to decode down to -3MER; 333 seems to be sweet spot.

So my thoughts. Are some streams more compliant than others? I realise not everyone uses the "standard" SRs.
Is minitioune / Express / Portsdown more fussy at certain settings?
Are other (satellite) signals (which are stronger) coming down the coax from the LNB causing any interaction?
Both TV DTT channels (55/56) are in use locally and are strong here. Despite good coax could that be getting into the system?

Finally after seeing a certain shack, XYL not going to complain about the number of wires/mess in my shack

All good (addictive) fun though. Maybe TX later this year.

73. Ian

[g8lce]

Two videos of me setting up rx:

https://youtu.be/wv1Srw6F8Bs this is 360 video and part one.

https://youtu.be/R8MSILdu2Hk This is from the screen and also has the beacon video.

They may help!!

Martin G8LCE