Adjusting the Bullseye LNB for improved frequency accuracy.

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g0mjw
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Re: Adjusting the Bullseye LNB for improved frequency accuracy.

Post by g0mjw » Fri Jul 02, 2021 9:07 pm

Easier to redo the schematic as its so few parts and plonk them on a board just for fun. Not routed. Buttons on the bottom at the moment which would fit in one of those little diecast boxes. Simple construction for beginners. Unfortunately it is missing the compulsary 4.7k resistor and flashing LED all such projects require.
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g4eml
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Re: Adjusting the Bullseye LNB for improved frequency accuracy.

Post by g4eml » Sat Jul 03, 2021 8:48 am

If you are going to mount it in a box then the USB connector of the Arduino needs to be accessible so that the remote control function is available. I doubt many people will use it connected to a PC but the feature is there so it ought to remain usable.

(And there is a flashing LED, on the Arduino)

radiogareth
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Re: Adjusting the Bullseye LNB for improved frequency accuracy.

Post by radiogareth » Sat Jul 03, 2021 8:58 am

If you are going to box it, as screening isn't a requirement, its a perfect candidate for a 3-D printed box with snap in PCB and snap fit lid.....in a bright colour Mike ;-)
Gareth

g0mjw
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Re: Adjusting the Bullseye LNB for improved frequency accuracy.

Post by g0mjw » Sat Jul 03, 2021 9:36 am

g4eml wrote:
Sat Jul 03, 2021 8:48 am
If you are going to mount it in a box then the USB connector of the Arduino needs to be accessible so that the remote control function is available. I doubt many people will use it connected to a PC but the feature is there so it ought to remain usable.

(And there is a flashing LED, on the Arduino)
I had not realised there was a remote feature - that's easily fixed by moving the Nano to the edge. It is not routed so that's easy to do. A question is would it be any use if it were? Colin's boards are fine as they are. I just like to have things in boxes. It makes them easier to store/transport.

A couple of things came up when looking at the schematc.

Firstly it has a 15V regulator. The Nano officially supports 7-12V input. I don't know if that matters in reality. The little regulator should be OK with 15V and it only takes 20mA or so.
Secondly there is no protection on the incoming supply. We don't need to worry about a short circuit on the LNB cable because of the series resistor but people have been known to confuse positive and negative. An idiot diode might be useful.

Mike

g4eml
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Joined: Thu Apr 26, 2018 9:36 am

Re: Adjusting the Bullseye LNB for improved frequency accuracy.

Post by g4eml » Sat Jul 03, 2021 10:28 am

The Arduino nano documentation is confusing, it says 7-12V in one place and 6-20V in another. 15V will be fine. The LM1117 regulator on the Arduino is rated for 15V input or 20V absolute maximum. The 15V regulator is needed to meet the bullseye serial data requirement. I agree a series diode on the power input might be worth adding.

g0mjw
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Re: Adjusting the Bullseye LNB for improved frequency accuracy.

Post by g0mjw » Sat Jul 03, 2021 11:31 am

Something like this maybe? Apologies for non-sequential parts numbering.
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It would need button caps or you could never get the PCB into the box though extended buttons could go underneath but button caps are easy to come by.

I put the LED on D13 as it might be useful as a heartbeat or similar, but it could easily go on the supply.

Mike
Last edited by g0mjw on Sat Jul 03, 2021 3:19 pm, edited 2 times in total.

g4eml
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Re: Adjusting the Bullseye LNB for improved frequency accuracy.

Post by g4eml » Sat Jul 03, 2021 2:25 pm

I have some spare PCBs and components available if anyone wants them. (Not including the Arduino, you will have to buy, program and fit that yourself.)
I was planning to sell these as kits but to be honest it is easier for me to assemble them. Producing Kits of parts is very time consuming.

Price is £10 each including postage to the UK. Assembled (excluding Arduino).

Please Private Message or email me if you are interested and we can arrange payment.

Note, these are to my prototype design and do not include the 25MHz out connection. This is not Mike's fancy new boxed design.

I only have 6 remaining available and I am not planning to get any more made. Hopefully we can arrange for the PCBs to be available through the BATC shop.

Colin G4EML

radiogareth
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Re: Adjusting the Bullseye LNB for improved frequency accuracy.

Post by radiogareth » Thu Jul 08, 2021 3:23 pm

Arrived today thanks Colin and I have now calibrated all three of the BE LNBs. One (which I have had a while, maybe 8 months) was a way off but the two more recent purchases were only a few kHz away. Great little tool, thanks :-)
Gareth

g4eml
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Joined: Thu Apr 26, 2018 9:36 am

Re: Adjusting the Bullseye LNB for improved frequency accuracy.

Post by g4eml » Thu Jul 08, 2021 4:11 pm

Thanks Gareth, that's good news. The two I have were initially about 16Khz off frequency. They both seem to be holding within 1Khz now, it will be interesting to see how much they drift over the winter.

Colin.

g1oar
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Joined: Sat Nov 20, 2010 6:54 pm

Re: Adjusting the Bullseye LNB for improved frequency accuracy.

Post by g1oar » Fri Jul 09, 2021 10:42 am

Hi Colin,
I wonder if you have 1 left, I cant PM you for some reason
Peter

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