RECEPTION OF THE SUN ON 94GHz
Here are a few pictures of the system we used last summer (2007) in our experiments
for reception of the sun. It is very difficult ,and we did lots of tests before a success.
Electronics at this frequency (wavelenght of about 3mmm) uses special test
systems , waveguides (wr12) are very small and suitable equipment is difficult to find.
We succeeded with the help of our friend Phil Schnabel who owns a shop
of microwaves items in the usa Western test systems
and provided us with the gunn
local oscillator (84ghz) ,and the symetric mixer.
The receiver uses a 40 cms dish with a cassegrain reflector ,it is well polished ,
and you can see it on the photograph.
The local oscillator is a gunn diode , it is followed by an isolator for stabilisation purpose.
The mixer is symetric , lowest possible noise , no preamplifier exist at this frequency .
Its output is on 9 GHz .It is followed by a gaasfet amplifier .
This part is not refrigerated it is at local temperature.
This can also bee seen on a photograph .
The if part is made of a converter from 9GHz to 830MHz ,using a 8134 MHz M-A/Com plo
'brick' , with a diode mixer , followed by two M/A-Com amplifiers (M/A-Com AM-1383 KS-21583)
, each with a noise of 1.5dBs , and a gain of 45 dBS, then a total gain of 90 dBs .
It is followed by a classic detection (hsms 8202) and an integrator+amplifier by a AD820.
This if rig alone can receive the sun on 9GHz with a 40 cm dish.
Another picture shows that.
With that we received the sun , yes , but very small parts of dBs , and only by reflection on a glass
or on a metal sheet to protect the receiver from the heat of the sun ( the parabolic dish makes a very efficient
owen!!!) ,without this the thermal drift was very important , as this can be done only in summer when
humidity is low enought , because of the absorption of those waves by water .
This is to be continued ,and we are looking for other people interrested in this reception.