Chicken & Egg on New Installation

Discussions about the Ryde "Set-top Box" Style Digital ATV Receiver. See https://wiki.batc.org.uk/Ryde_Receiver
EA7KIR
Posts: 86
Joined: Tue Feb 09, 2021 3:38 pm

Re: Chicken & Egg on New Installation

Post by EA7KIR » Thu Apr 14, 2022 3:00 pm

G8GKQ wrote:
Thu Apr 14, 2022 2:57 pm
I suggest that you look for the narrow band beacons first
This sounds like a great idea, but I don't have an SDR. Perhaps I should buy one.
Michael EA7KIR

g8gtz
Posts: 1732
Joined: Wed Apr 07, 2010 6:26 pm

Re: Chicken & Egg on New Installation

Post by g8gtz » Thu Apr 14, 2022 3:15 pm

What are you using for QO100 transmit?

I thought you had a Pluto? In which case you have an SDR...

Noel

EA7KIR
Posts: 86
Joined: Tue Feb 09, 2021 3:38 pm

Re: Chicken & Egg on New Installation

Post by EA7KIR » Thu Apr 14, 2022 3:23 pm

g8gtz wrote:
Thu Apr 14, 2022 3:15 pm
I thought you had a Pluto?
I have, but I haven't done anything with yet. Been too busy writing software and I want to get the receive side working first.
Michael EA7KIR

g0mjw
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Re: Chicken & Egg on New Installation

Post by g0mjw » Thu Apr 14, 2022 4:51 pm

I am worried about that entirely inadequate looking SMA patch lead and cheap N-SMA adapter. Don't put much power through those.

The offset should be 9750MHz. The Bullseye has two F-connectors. Only one is the correct one. Make sure you are using the right one which is the green one. Looks OK in the photo - unlike the LNB offset which looks incorrect.

I assume you want the cables pointing down so instead of rotating clockwise (Offset + 90 = approx 124) subtract 180 degrees and rotate it 180 - 124 = 56 anticlockwise, (or just rotate back 90 degrees from where it was in your case).

However, even if quite a way out it should still get the beacon with a 1.3m dish. I wonder how you set the focal length? I can't see from the photo.

You must, must, must, must, must allow for the focus of the POTY feed to be in the correct place once modified. Don't just clamp the LNB where it was when set up without the POTY feed. If you do that the feed will be far too far forwards and it won't work at all.

Mike

EA7KIR
Posts: 86
Joined: Tue Feb 09, 2021 3:38 pm

Re: Chicken & Egg on New Installation

Post by EA7KIR » Thu Apr 14, 2022 7:04 pm

g0mjw wrote:
Thu Apr 14, 2022 4:51 pm
I am worried about that entirely inadequate looking SMA patch lead and cheap N-SMA adapter. Don't put much power through those.
The offset should be 9750MHz. The Bullseye has two F-connectors. Only one is the correct one. Make sure you are using the right one which is the green one. Looks OK in the photo - unlike the LNB offset which looks incorrect.

I assume you want the cables pointing down so instead of rotating clockwise (Offset + 90 = approx 124) subtract 180 degrees and rotate it 180 - 124 = 56 anticlockwise, (or just rotate back 90 degrees from where it was in your case).

However, even if quite a way out it should still get the beacon with a 1.3m dish. I wonder how you set the focal length? I can't see from the photo.

You must, must, must, must, must allow for the focus of the POTY feed to be in the correct place once modified. Don't just clamp the LNB where it was when set up without the POTY feed. If you do that the feed will be far too far forwards and it won't work at all.

Mike
Hi Mike, and thank you for so much detail.

I bought the POTY ready built. It arrived with an SMA, so some kind of adapter is necessary. The 4.5m feed is M&P UltraFlex 7 with an M&P 7mm to SMA adapter - for which I'm expecting less than 2db loss. As for the SMA patch lead, I'm crossing my fingers for now. I'm told 40 watts should be enough with a 1.3m dish.


Longmynd needs the frequency in kHz. Beacon in kHz = 10491500 - 9750000. So I execute with..
./longmynd -i 192.168.1.33 7777 741500 1500

I'm expecting to launch VLC on an iMac or Apple TV with udp://satreceiver.local:7777, but I'm not sure about this. Does Longmynd emit unicast or multicast? Which endpoint does the Longmynd IP parameter refer to?

I'll play with the skew and focus tomorrow, because right now I'm exhuasted and its getting dark. Are you saying the skew in the photo is wrong? Keeping in mind the LNB is being fed with 12 volts?

Just before I packed it in for day, I "think" I saw fake_read claiming LOCKED S2 and the service and provider fields were populated. So it could be close to working. VLC didn't work, but I am aware that LOCKED doesn't always equate with decoded. The only times I use VLC is when I watch the RTMP Thursday night NET on the Apple TV.

I'll post a side elevation sometime tomorrow.
Michael EA7KIR

g0mjw
Posts: 2327
Joined: Sat Sep 20, 2014 9:15 am

Re: Chicken & Egg on New Installation

Post by g0mjw » Thu Apr 14, 2022 7:34 pm

Hi Michael,

The skew looked a little out but it might be OK, hard to tell but it won't be that critical. That SMA patch lead won't handle 40W for very long I suspect but first you need to get the RX working so let's see a side elevation. Do you know the F/D of the dish?

How did you modify the feed holder to move it backwards?

Mike

EA7KIR
Posts: 86
Joined: Tue Feb 09, 2021 3:38 pm

Re: Chicken & Egg on New Installation

Post by EA7KIR » Fri Apr 15, 2022 11:29 am

Hi Mike,

The dish is a Gibertina OP 125 L with F/D 0.66. The thought of having to make a replacement feed bracket is daunting. Buying small quantities of metal down here is challenging and I don't have the necessary tools. Do you think a different shape lens would help? Here's a few photos showing the entire thing. The large enclosure houses the server, receiver and transmitter. The smaller one houses all the tie lines coming up from my office/shack.

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Michael EA7KIR

M0SKM
Posts: 369
Joined: Sun Jul 13, 2014 3:15 pm

Re: Chicken & Egg on New Installation

Post by M0SKM » Fri Apr 15, 2022 1:04 pm

Hi,
This is the exact same dish that I and others on this forum are using. I've not had any issues with the POTY feed combined with the Bullseye LNB. As Mike said focus is critical and I achieved it with standard dish hardware.

Good luck.
Steve
Find me on D Star through GB7BP

g0mjw
Posts: 2327
Joined: Sat Sep 20, 2014 9:15 am

Re: Chicken & Egg on New Installation

Post by g0mjw » Fri Apr 15, 2022 1:17 pm

It just needs to come back a few cm, the middle of the lens needs to be about where the face of a standard LNB would be. Push back as far as you can, see if it makes it better. You may have to tweak the dish pointing a little as once in focus it will be more directional.

If the feed doesn't move back enough you don't need to cut metal. It looks like there is room but if you find the feed reflector fouls against the feed arm, then raise the height of the feed a little. I can see from the photo there is a 22mm to 40mm round adapter. If you were to make another with the hole higher up it would fix this. You will probably need to re-adjust elevation. Like this. 3D print it or make it from a bit of wood.
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I don't think the supplied lens is much good but that's all you have. Passion Radio do sell a better one designed by HB9PZK.

The SMA patch lead really isn't up to the job of handling 40W for long periods at 2.4 GHz. Please try and find a better one. That looks like RG178 / RG316, which is only rated to 3 GHz. The power rating of good quality, mil spec cable like you get from Huber Schuner is 60W at 1 GHz. There isn't a power rating given for 2.4 GHz but the attenuation is greater, 40W would be pushing it. I know it is only 6 inches long and the loss is only 0.4 dB or so, but 0.4 dB is 5% of the power and 5% of 40W is 2W which is a lot of heat in that little cable. Better would be RG142 or similar 5mm dia PTFE coax. That's what I am using, but I use only 10-20W.

Mike

g8vpg
Posts: 381
Joined: Fri Oct 11, 2013 9:35 am

Re: Chicken & Egg on New Installation

Post by g8vpg » Fri Apr 15, 2022 1:45 pm

Michael,
There are so many things that might be just not correct, sufficient to prevent reception. I suggest you remove the complete feed set up and replace it with a standard, un-modified LNB. Use this to prove and optimise the dish alignment. Once that is done, you can then try the feed set up you have, knowing that a signal is present. A dish of that size is very touchy to get correctly aligned. How did your installer align it to the correct satellite?
73 Shaun.

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