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AO-40 K band

Congratulations to Al Ward, W5LUA on his reception of AO-40 K band. Below is 
his note to the Microwave reflector:
AO-40 24048 MHz K Band Operation at W5LUA

At 0715 GMT on October 1, I was able to receive the 24048 MHz beacon from
AO-40. AO-40 was situated at an elevation of about 7 degrees and an azimuth
of about 265 degrees. I followed the beacon until about 0752 GMT when the
elevation of AO-40 was less than 0.5 degree. The beacon peaked at 7 dB over
the noise in a 2.4 kHz bandwidth. There was several dB of fading on the
beacon.  I am using a MACOM 2 ft dish with horizontal polarity at 65 ft
(This is my 24 GHz tropo system). Azimuth control is via an M2 rotator with
0.1 degree readout. I can elevate up to 16 degrees  with a small actuator.
Even though I was not prepared to accurately measure frequency, it appeared
to be approximately 24048.081 MHz initially and continuously decreased to
about 24048.055 MHz before setting at my QTH. My noise figure measures 3.0
dB with an Agilent Technologies HMMC-5023 LNA mounted at the antenna. My
normal sun noise with this system is 3 dB over cold sky. 

I use my normal 24192 MHz transverter with some modifications. For 24192 MHz
I use a dual conversion scheme which normally down-converts 24192 MHz down
to approximately 1994 MHz and then further down-converts to 144 MHz. The
dual conversion scheme offers greater image rejection because of the high
first IF frequency. When receiving 24048 MHz, the first IF now becomes
approximately 1850 MHz which I then pass on to a second mixer with a 1706
MHz LO which then provides the 144 MHz IF. 

While listening to the beacon and passband at 24048 MHz, I ran across JA1UK
and I had a short QSO with him. I made the assumption that the normal Mode-S
passband was also operational at this time so the JA station was probably
not aware that I was receiving him on 24048 MHz.

That's a short report from Allen Texas. 

Best DX

Al Ward
October 1, 2001

Mike, N1JEZ
AMSAT #29649
Local Area Coordinator
"A closed mouth gathers no feet."
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