Re: Es Hail 2 LNB Antidrift
Klaus Hutschenreuther <klaus.hutschenreuther@...>
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Down-Converter AMSAT P4-A
MKU LNC 10 OSCAR P4-A
· 1129 MHz ... 1140 MHz
· Low frequency drift due to TCXO
· Mountable with standard LNB peg
Es’hail-2-Up-link 2400-MHz-RADOM-Helixantenne, 22dBi für 198€
- Voraussichtlich ab Februar 2019
Von: main@SDR-Radio.groups.io [mailto:main@SDR-Radio.groups.io] Im Auftrag von Mr VILLAIN Laurent
Fully agree with you Matthias.
Obtenez Outlook pour iOS
De : firstname.lastname@example.org de la part de Matthias Bopp <matthias.bopp@...>
I understand but when already building an external reference circuit to generate the 27 MHz why not chose another reference to move the IF higher
and have higher overall gain. Also if you move the IF beyond 950 MHz you can use common DVB-S2 receivers. The effort is basically the same.
At the same time you can have an addition feature: if you chose for instance 26,03076923 MHz you get a LO frequency of 9400 MHz.
Thus you can tune your receiver easily as the last digits of your tuned frequency are the same:
for instance RF=10489,952 MHz will result in an IF=1089,952 MHz.
That might be only useful with analogue receivers as with SDRs you can typically adjust the frequency offset easily.
Anyhow, there are apparently many ways to Rome …
Have a nice day
Von: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>Im Auftrag von Mr VILLAIN Laurent
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.
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: