New 10 GHz LNB

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radiogareth
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Joined: Wed Jan 06, 2016 9:46 am

Re: New 10 GHz LNB

Post by radiogareth » Wed Apr 24, 2019 8:40 am

Having got SDRConsole working like a charm on locking to the NB beacon, I'm finding I need both a horizontal and vertical capability at the same time for my home station. I have a four output PLL Octagon (originally bought so I could externally lock)that now de-cased looks the same as the single output mechanical dimensions wise. Before I cut the horn off the end (so it will fit a dual band patch), any reason why this won't work as just as well?
Thanks
Gareth
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g0mjw
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Re: New 10 GHz LNB

Post by g0mjw » Wed Apr 24, 2019 8:56 am

It will - but if you try to inject a reference you may find it oscillates and destroys itself, best not to open. If you do, there is advice on the Wiki on how to do it.

Mike

radiogareth
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Joined: Wed Jan 06, 2016 9:46 am

Re: New 10 GHz LNB

Post by radiogareth » Wed Apr 24, 2019 5:55 pm

Thanks Mike, I won't need the reference now so I'll go ahead and chop the horn off.
Onward :-)
Gareth

PH2M
Posts: 9
Joined: Thu Mar 07, 2019 10:56 am

Re: New 10 GHz LNB

Post by PH2M » Tue Apr 30, 2019 9:29 am

g0mjw wrote:
Sun Nov 18, 2018 2:12 pm
Wondering if this sort of thing is likely to be any use - should I get some PCBs made up? Before anyone points it out, I couldn't get the right 3D model for the 90 degree panel mount BNC/F connector and I have not even analysed it yet to see if the design makes any sense.

The idea is to inject 10/25/27 MHz and 12V DC to the LNB and get back the IF, all on one cable. At the LNB end, filter off the 10/25/27 MHz and use it to lock the PLL. I have several surplus PLL LNBs that do this already, all with 10MHz references.


BiasSch.png

bias.PNG
Hello Mike @G0MJW , I ordered one of your (designed) Bias-T - reference pcb's via the BATC shop https://batc.org.uk/shop/lnb-bias-t-and ... blank-pcb/ , and also started to order the components, could You give me the pcb's dimensions so I could look for a suitable enclosure?

73 de Frank PH2M

g0mjw
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Re: New 10 GHz LNB

Post by g0mjw » Sun Sep 29, 2019 3:30 pm

I have done a little update and added a TCXO reference and bias board to compliment the external reference board that's in the shop.
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Mike

M0JUR
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Re: New 10 GHz LNB

Post by M0JUR » Tue Jan 31, 2023 10:09 am

Intentional but brief thread necromancy: for consistency with other "blank PCBs are available from the BATC Shop" projects and to facilitate possible updates (e.g. when a part goes obsolete, as it has been the case with the BNC connectors) I have gathered the details of and compiled BoMs for both of Mike's Bias-T boards on the BATC Wiki: https://wiki.batc.org.uk/G0MJW_Bias-T_a ... ion_boards . Corrections, improvements, high-resolution / vector version of the schematics, and links on the relevant BATC Shop pages welcome!

PE5PVB
Posts: 155
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Re: New 10 GHz LNB

Post by PE5PVB » Tue Jan 31, 2023 10:19 am

Are there by any change hams using this with DATV? My experience with these kind of mods is that the MER on DVB signals are dropped by a few dB's.

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

Re: New 10 GHz LNB

Post by g0mjw » Tue Jan 31, 2023 10:53 am

M0JUR wrote:
Tue Jan 31, 2023 10:09 am
Intentional but brief thread necromancy: for consistency with other "blank PCBs are available from the BATC Shop" projects and to facilitate possible updates (e.g. when a part goes obsolete, as it has been the case with the BNC connectors) I have gathered the details of and compiled BoMs for both of Mike's Bias-T boards on the BATC Wiki: https://wiki.batc.org.uk/G0MJW_Bias-T_a ... ion_boards . Corrections, improvements, high-resolution / vector version of the schematics, and links on the relevant BATC Shop pages welcome!
That's useful. Perhaps the updates can be put in the Wiki? Parts come and go with distressing rapidity. That board was designed to allow several variants, hence the odd slotted holes.

g0mjw
Posts: 2329
Joined: Sat Sep 20, 2014 9:15 am

Re: New 10 GHz LNB

Post by g0mjw » Tue Jan 31, 2023 10:59 am

PE5PVB wrote:
Tue Jan 31, 2023 10:19 am
Are there by any change hams using this with DATV? My experience with these kind of mods is that the MER on DVB signals are dropped by a few dB's.
That's only normally the case if your reference source has poor phase noise. It affects wideband signals more than reduced bandwidth DATV or SSB. IF you look at a commercial transponder, you can measure the MER even if you can't decode the TS, it shows a significant difference. Even the Leo Bodnar reference is not all that good, especially if compared to a well designed crystal oscillator. This board was designed before the Bullseye LNB became available, and mostly with SSB in mind, strictly speaking you don't need it for DATV as long as you know your offset, but if you use a clean source, then you get a good result. Quite a bit of effort was made to try to clean up the phase noise as far as possible, hence the filtering and unusual use of a low noise voltage reference as an oscillator supply. For DATV use the Bullseye is now a better choice as it is quite stable and doesn't require an external reference and can be easily calibrated onto frequency.

Mike

PE5PVB
Posts: 155
Joined: Sun Sep 02, 2012 6:51 pm

Re: New 10 GHz LNB

Post by PE5PVB » Tue Jan 31, 2023 11:32 am

Correct, but I'm sure my reference has very little phasenoise. It's perfectly useable for SSB and FT8. But for DATV I use a LNB with the current crystal inside, because when I use an external reference I have to mich decline on DVB signal quality.

I'm not alone in this, I've heard the same results from many other amateurs. I'm just curious what can cause this decline of quality.

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