On 07/19/18 11:12, [email protected] wrote:
So yes, unless you have an extremely short coax run, I highly recommend a pre-amp at the antenna.
Agreed! You can even build one of your own, if you're careful not to transmit through it.
Zach Metzinger wrote:
If you're looking for a shoestring-budget LNA for 2m, the U310 JFET preamp has been a good performer for me.
I've constructed one in a spare project box, and the gain (12dB) is right on the predicted value. I have not verified the NF, but it is claimed to be near 1.0dB. I built in in one evening, with some extra evenings diagnosing a capacitor issue. Use a multi-turn piston trimmer for the 1-10pF drain capacitor, as the output tuning is very sharp.
I've changed the layout a bit, but here's an early picture of the unit:
The air-core inductors are not difficult to wind on a 1/4" drill bit.
Not as fancy as a GaAsFET or pHEMT device, but it works just fine to hear AO-85 and AO-7 with a non-ideal satellite antenna (folded horizontal dipole) at 10 degrees above the horizon.
On the subject of rotators, don't discount the SatNOGS rotator. I've built a version 2 with a total expenditure of < $100. It will not stand up to the elements, but I have plans to mount it in the attic.
--- Zach N0ZGO