BATC Forum

If you have access to two smart phones you could use them on a WhatsApp (other apps are available!) video call to remotely see your MER level.
Put one phone looking at the screen where the MER meter is and take the other to your dish while you tweak its settings.
It's also easier to do the tweaking when it has gone dark as then you can see the phone pictures easier.
A video doorbell could also be used, as well as a camera on the end of a cheap piece of coax and a monitor!

You have a very usable signal level now and will be able to decode most signals on the satellite, but as mentioned you could be a couple of db better!

73

Dave
G3ZGZ

g3zgz wrote: ↑

Sun Apr 25, 2021 8:15 pm

If you have access to two smart phones you could use them on a WhatsApp (other apps are available!) video call to remotely see your MER level.
Put one phone looking at the screen where the MER meter is and take the other to your dish while you tweak its settings.
It's also easier to do the tweaking when it has gone dark as then you can see the phone pictures easier.
A video doorbell could also be used, as well as a camera on the end of a cheap piece of coax and a monitor!

You have a very usable signal level now and will be able to decode most signals on the satellite, but as mentioned you could be a couple of db better!

73

Dave
G3ZGZ

Thanks Dave, that reminds me, I do quite a lot on the other end of the spectrum, on LF 137kHz, and was sick or running up and down stairs and across the garden to the loading coil and variometer in a wheelie bin outside. I was told of an app called Access to Go and tried it. It lets you log on to a remote PC screen from your cell phone. I could most likely use it for looking at the LNB signal, I don't why I didn't think of that before. Probably because I haven't used it in ages as I motorised the variometer and put a remote power cable in so I can fiddle with it from the shack... Thanks for jogging the old grey cells!

You could also use the ‘beep’ button on MiniTioune. That generates an audio tone that increases with MER to allow sight free alignment. You could then use just an audio link (two handhelds or two phones) to the dish.

Colin.

I am set up on QO-100 and have the NB downlink working with aias tee and 12v. I can also uplink qrp cw.

Now I am about to start construction of the Minitouner board, I just have one question for now:

To get the +18 volt (Horizontal) output from the board to drive the LNB, as set in the software, shouldn't the PSU driving the board be capable of this voltage? Or is it stepped up there somehow? i'm thinking of using an old laptop switched-mode PSU at 19v.

Or is it better to switch off the +V to the LNB from the board (with PSU-1) and use a bias tee with this laptop PSU (second PSU) ?

grateful for any advice, please

many thanks
73 de andy G0SFJ

You are correct, to use the standard minitiouner you need to increase the power supply to 18V (or turn the LNB through 90 degrees).

Alternatively there is an add on board that provides a current limited, software controlled power supply. The bare PCB is available from the BATC shop.

https://batc.org.uk/shop/rt5047-current ... version-2/

The RT5047 can generate the 18V from a 12V supply. The current limited output also prevents damage to the NIM in the event of a short circuit.

Colin

Hi Colin, I just built one of the LNB power supply boards and although it basically works the FAULT function is inoperative. I downloaded the manufacturer's data sheet and it says pin 7 (the fault pin) is not connected internally in the chip, (but it also says to use a 4.7k pull down resistor on it, for some reason...). The status of pin 7 doesn't change if, for example, I short out the LNB supply connection. Are there different versions of this RT5047 chip? Thanks. Chris, 2E0ILY.

Yes, there are different versions of the chip. Some do not have the fault function. Some that should not have it appear to have it. Rather confusing.

Mike

These were the versions of RT5047 I found a few months ago.

Brian

viewtopic.php?f=136&t=7275&start=10#p26865

Ahh, yes, it looks a bit of a minefield, the type A are still in stock and available in small quantities at Farnell, so I have just ordered some. Of course it would be a chip with a heat sink back plane. I think I will try and sever the legs then apply heat from the back through the vias. Now the plastic connectors are on, and given the close proximity of tiny components, hot air from the top, like I used to fit them initially, is probably a no no. How is the shop fixed for a third board (I am awaiting one I ordered the other day, to do for a good friend who has a medical issue meaning SMD is extremely hard for him), I fear the worst for this one given my lack of experience?

Thanks everyone.

I have a question for G4KLB

i have the same setup as you 1.2m dish and a bulls eye lnb at the moment the skew is set to -19deg and ive been trying to receive the beacon on 1049150 do i also have to rotate the lnb 90deg and feed it with 18v, also which way do i turn it to -109 or +81.
Im not very familiar with satellite systems but i thought you either applied 18v or turned the lnb 90deg to get horizontal but not both would you mind explaining it a bit.
I managed to get all the dish setup with a standard lnb and fed into a freesat box and was able to get the tv perfectly, i then changed the lnb to the bullseye and ive spent about 3 days getting nowhere with the qo100 setup, thank you for any help you can give me.

Nigel