From the EME community, I learned that 1.2m Offset dish
would be minimum to start on 10GHz. That size was easy to incorporate into
my space. The actual start for the 3cm band project started with acquiring
the dish from a local store that used such dish which was initially used for
internet but no longer in service. I had previously purchased Icom IC9700
for my 70cm EME which also offers 2m as well as 23cm all modes operation.
Building the 10G block consisted of Kuhne MK10-5G Transverter that offers
programable IF of 28, 144 or 432 MH and 200mw TX power. The 200mw RF from
the transverter is connected to the input of the 15W SSPA with output
connected to the TX port of the WG relay. Using the feed from the original
dish setup, Incorporated (WG75) wave guide, four ports relay (Feed, RX, TX
and dummy load port). Normally closed (NC) position is the RX mode when Feed
is connected to the Wave guide26db and 0.4db NF LNA and the TX port is
bypassed to the dummy load. In TX mode, feed is connected to the TX port
while the LNA is bypassed to the dummy load. To minimize the signal loss,
between the transverter and the IC9700, I chose to use the 144 IF. One of
the biggest challenges was the frequency stability of the 10 GHz LO. To
overcome the Doppler phenomenon which requires frequency tolerance in only
few Hz. Doppler effect depends on the moon position. On 70cm is somewhere
within plus/minus 1.3 KHz while on 10GHz is Plus/Minus 30KHz, (Doppler is
actually corrected automatically by the (WSJT-X software). However, due to
known poor stability on IC9700 I had already tied up my GPSDO, providing
reference of 49.152 MHz. To satisfy both the IC9700 with 49.152 MHz and the
10MHz Reference required for the 10G transverter, I built a signal source
generator. I feed 10MHz reference from the GPSDO which is multiplied by 2.5
resulting of 25MHz reference for SI5351 which with Arduino further generates
49.152. The multiplying IC also provides buffered 10MHz which is further
distributed to three additional 10MHz reference. With this set up and
challenges I mentioned in the rotator section, I was able to complete 3hree
10GHz EME QSO’s all with European stations. Currently the whole system is
under construction to provide better tracking and TX power up to 50W.
Completion is scheduled to be done by the end of October,
See you of the moon
