OPTICUM LTP 04H Twin LNB

Hello,

I just modified Opticum LTP04H Twin LNB serial No.19-01-0xx

Left F connector for 25MHz reference (Leo Bodnar GPSDO, 8mA drive), right F connector for IF output (no mods).

The original 25MHz crystal left on its place (bottom side), just one track to RDA3567 cut, see photo. So the external reference is now fed via the old crystal.

I soldered the 1nF in ref input because I broke the original C when opening cover. Maybe it can stay as is, I don't know what its value was.

The 49.9 ohm is not necessary, it works also without.

Regards, Marian

Hello Marian,

I just wanted to double check the cut to the RDA3567. Is it at the red line shown in my photo below?

Regards Chris G4SDG

Hi Chris,

Yes, here a zoomed image from Marian.. for LNB's with serial No.19-01-0xx

73 Peter

Thanks Peter. It’s probably my eyesight but it wasn’t clear to me in Marian’s image whether it was that track that was cut and the point of the red arrow wasn’t actually on it - seemed a bit to the right. “Measure twice - cut once” is the saying but in this case “ask twice” 😀

73 Chris

Hi Chris,

Yes I was wondering the same looking at it, the arrow is not exactly showing the exact location

But I think from the zoomed picture is more clear.. Good luck!

73 Peter

I've done the modification and it's working well so thanks for the information Marian. I seem to have gained a couple of dB S/N compared to my old modified GL-202 LNB too.

73 Chris

Quote from G4SDG

Hello Marian,

I just wanted to double check the cut to the RDA3567. Is it at the red line shown in my photo below?

Regards Chris G4SDG

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Hi,

I apologize for the late response - the question has already been answered by others.

I experienced a computer crash last week, now I'm recovering.

If you have any questions, I'm available.

Regards,

Marian

Quote from OK2XLB

Hi,

I apologize for the late response - the question has already been answered by others.

I experienced a computer crash last week, now I'm recovering.

If you have any questions, I'm available.

Regards,

Marian

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It's a good modification Marian and I'm now also using a similarly modified LNB on my 10GHz terrestrial antenna. The serial numbers of my two were a hundred or so different from yours. A friend of mine purchased a couple of Opticum LTP-04h LNBs a few days ago and discovered that internally they are yet another different board but with a Rafael Micro RT320M chip.

73 Chris G4SDG

Dear all,

I've a OPTICUM LTP 04H but I have different request for the modification. My aim is to maintain the second output, and drill a hole to take 25 MHz to the chip. Would you examine my schema to check if it's correct ? Thank you for your answer,

I leave the resistor, delete the wiring, cut the track and connect 25 MHz source to the point showed by my arrow. I will connect a small coaxial cable with gnd connected in some point were available.

73 Alex

Hi all,

I opened my Opticum LTP-04H and it looks very different from the ones you have. Maybe somebody knows if and how they can be adapted to be used with an external clock. Its chip has the markings: D8001 and A4082

Quote from hb9bla

I opened my Opticum LTP-04H and it looks very different from the ones you have..

Did you buy it recently??

It's seems to be an very old one, obviously with DRO instead of XTAL and PLL..

You can scrap it...

Edit: Just noted.. on the sticker: yours is "blue" line, the correct one is "red" line.. so it's not the same..

Thank you! I thought (hoped?) that the XTAL is below the shield I did not remove. Probably because I was convinced, I had the right product (I bought it last October at Reichelt!).
You are perfectly right. So I have to find a better one! For me, it is strange that they sell two very different products with the same number. And I find it strange that it got the best ratings from two sides But of course, when I looked closer, I saw when these "trophies" were issued: 2009 and 2011! So completely my fault. I should RTFM next time. And probably avoid Reichelt.

I bought mine a few months ago, it is apparently a different version. If I remove the XTAL, is it enough to just inject the (GPS-locked) 25 MHz signal directly on one (or the other) of its pins?

Thanks and best 73,

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Olivier / f5mzn