I wanted to show you a little project we did last weekend. We wanted to
know with how little we could get away and built an extremely simple loop
antenna for the 2.4 GHz uplink to QO-100.
It is a full wavelength loop antenna, directly soldered to a coaxial cable.
The cable is then attached to the LNB using a metal hose clamp
(a sturdy plastic zip tie might do the trick as well).
In our case, an EDUP EP-AB003 power amplifier (sold as "WiFi Booster")
powers up the signal to approx. 2.5 – 3 Watts. A "Bullseye" LNB is used
on the receiving end.
We tested this first in an offset dish with 60 cm diameter: We could
receive our signal back with approx. 25 db SNR. This isn't ideal, but I was
able to do a QSO on QO-100 with no problems.
In the next step we tested the loop antenna in front of a 180 cm dish.
Previously this 180 cm dish had a BAMAtech feed and a Opticum LNB
attach to it. So we could also do a comparision between the full
wavelength loop antenna and the BAMAtech feed.
Surprisingly, the simple loop antenna was approx. 2 dBs louder than the
BAMA feed. I believe this is because the BAMAfeed is constructed for much
smaller dishes and the loop antenna will use more of the available dish area
than the BAMA feed does.
Just wanted to throw that out there. Let me know what you think.