[amsat-bb] Cables loss

[Zach Metzinger]

On 07/19/18 11:12, jim at k6ccc.org 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.
> 
> http://www.ham-radio.com/n6ca/50MHz/50appnotes/U310.html
> 
> 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:
> 
> http://www.n0zgo.net/lna/
> 
> 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