Please read my posting #65 in “Modification of Octagon Oslo PLL LNB for External Frequency Reference” till solution #75. Perhaps this will help.
Posts by DH2PA
What is the reason to use the filter? You want a sine wave as a reference, but why? I used the Leo Bodnar mini GPSDO with and without a filter. No difference in receiver performance.
I am using the 40 turn 13cm Helix from Wimo for uplink. The antenna is 1.2m long and not so easy to transport. You should use a cardboard roll as a protection to not bend the windings if you want to transport the antenna. 1.2m is too long for in the suitcase. I think the WiFi grid antenna is the better solution for portable activities. I use the antenna because I have no space on the mast for a reflector.
I got this answer from Leo regarding my problem:
1) update firmware to version 1.12 http://www.leobodnar.com/files/miniGPSclock-v112.zip
2) Run this configurator http://www.leobodnar.com/files…_configuration-dev112.zip
3) Type 27000000 in Setting frequency field and click "Configure output frequency" button
4) wait until you get GPS clock and click "Save current oscillator correction" - this only needs to be done once. Preferably when correction in ppb has stabilised (device has warmed up internally)
5) Select various Fvco in "DPLL setup" box and see if one of them creates nice stable output. You can play with any of the dropdown boxes but Fvco has the biggest effect. Click "Save and recalibrate PLL"
6) if this does not help, try setting BW to 7 and click "Update".
In my case by 5) and 6), no improvement was obtained
And now my test signal with the firmware 1.12 mini GPSDO (Leo B.) 27000000 Hz on LNB
and the necessary settings
DL2NED 70cm IF works perfectly
I tested last week my new original Octagon Optima OTLSO Twin Slim LNB with my signal generator to receive 10GHz narrow band from Eshail. As you can see in the Video a clear output but lot of drift after 10min warm up:
So I decided to modify the LNB by removing the cyrstal and then 27 MHz fed through a cap and 47 Ohms resistor to ground:
27MHz reference is mini GPS from Leo Bodnar. Stability is now excellent but problems with quality of the IF signal.
To exclude the generator as a source of error, I tried it with a beacon. No improvement as you can see and hear in the next video:
Changing the level of the 27MHz signal does not help. Using a BP Filter to clean up the squarewave harmonics didn`t help either.
Anyone here has an idea what the problem is and how can I solve it?
73 and thanks for reading.