BATC Forum

Hi
I successfully now have a GPS locked 27MHz from a AD9850.Does anyone know the optimum injection level at the LNB,??
I'm using an Octagon dual LNB..
Next step to order a few 27MHz crystals and make a ladder filter and then a bit of gain .
the TCXO I fitted has a min level of 0.8V pk-pk, which seems to work OK, but that is min level and the typical level is not quoted in the spec.
Thanks
Richard g8jvm

Richard,

For my Octagon LNBs, I found that an external injection level of -16dBm worked.
In general, use as little as possible but bear in mind that at other temperatures it may lose lock if the level is insufficient. I found that too high a level led to degradation in the LNB output spectrum.
Hope this helps.

73
Jen

Many thanks Jen,
thats exactly the info that was required,.The last thing I want are large signals around, its bad enough here that rotating the antennas around the noise floor is up and down like a yo yo
73 Richard