Re: Es Hail 2 LNB Antidrift
as you could see from my description the Octagon LNB can be modified from a 27 MHz reference to a 26 MHz.
As it locked to the 26 MHz TCXO also locking it to the 26,03076923 MHz should be no problem.
I have not tried how much lower the reference can be but 26 MHz is no problem. I have made comparisons
of the LO spectrum before and after the modification and measured no difference. I will add those measurement
results to the description when I get back home (I am presently at my 2nd QTH).
Of course with other LNBs that might be different.
Von: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Im Auftrag von Mr VILLAIN Laurent
26,03 MHz not sure if the PLL chip will lock on it or not.
Its far from the original 27 MHz, must be tested to know.
I have tested some PLL chip, normally 25 MHz, they lock from 24,2 MHz up to 25,2 MHz, no more ...
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email@example.com de la part de Mr VILLAIN Laurent <f4aar@...>
The 27 MHz is locked on the GPS signal ( VCTCXO ) and re-injected to replace the 27 MHz crystal, only re-injected on one pin of PLL chip.
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I am presently modifying another LNB and will lock it to a GSPDO or Rubidum (both are available here).
What I do not understand in the approach from Loetlabor Jena is why they still stick to the 27 MHz reference.
I have 10 MHz to 26,03076923 MHz PLL converter built by DF9NP for me which I will use.
This moves the IF band higher and normal SAT-RX can be used and also most SDRs for narrowband.
Hello Matthias 73.
Did you check RF filter response too ?
DL3YC modification, LNB fully locked on GPS.
As you have requested here is a spectrum sweep of a unmodified dual Octagon PLL LNB. LO was 9750 Mhz.
As you can see the gain at 600 MHz drops by about 5dB (roughly).
I assume this is the frequency response of the IF chain and as the LNB has plenty of gain I don’t think it is a real problem.
It is different if the frequency response (high pass characteristic) is based on the amplifiers in front of the mixer as then total system noise figure should be impacted.
Nevertheless I changed the reference of my LNB to move the IF signals up above 1 GHz and also use a TCXO.
Here is a description of the modification I made:
The best solution for SSB is DL3YC idea.
You could see on his blog. Its the optimal one.
In all cases your 0,5 ppm TCXO's or crystals will be under the GPS signal in all cases.
Without modification of LNB, you will lost IF gain too, if not, lets share a spectrum capture.
Warm 73, no fight, just discuss. Laurent.
On Thu, Dec 27, 2018 at 7:06 PM +0900, "Matthias Bopp" <matthias.bopp@...> wrote: