[Moon] SM3BYA 432 MHz

[TexasRF at aol.com]

Gudmund,
If you had a record of cold sky to ground, or cold sky to dummy load, you  
would know if the noise figure was bad. A well built station would have 5 or 6  
dB (or even more) c/s to load reading. Many stations are designed to switch 
the  receive preamp into a dummy load for transmit isolation/protection. The 
very  same load can be used for the c/s to load noise tests.
 
73,
Gerald K5GW
 
 
 
 
In a message dated 3/19/2008 2:43:39 P.M. Central Standard Time,  
sm2bya at telia.com writes:

The XYL  and I went down to our SM3 QTH last weekend with a long list of 
things to  do. The DUBUS contest was on the list too, but only towards 
the  bottom...

Anyway, in the end I managed to operate for about four hours  on Saturday 
and three hours on Sunday. Subjectively, conditions appeared  poor to 
average with lots of libration fading and below average signal  strengths 
from most stations.

Worked 21 stations: On Sat. VK3UM,  UA3PTW, OK1DFC, SV1BTR, G3LTF, OZ4MM, 
DL7APV, NC1I, SP6JLW, KL6M, RW3PX,  I1NDP, DL1YMK,K2UYH and G4RGK.
On Sun. SD3F, SM2CEW, VE6TA, K1RQG, OZ6OL  and DL9KR. Copied DJ1KJG and 
I5CTE.

Guess I should be pleased that  I did even that well - a sun noise 
measurement on Sunday yielded only 9.6  dB Sun/cold sky, which is about 
2.3-2.5 dB below what my system ought to  deliver (and normally does!). 
If this is correct, my receive performance  was in reality only like that 
of a four Yagi station, and there could have  been several two and four 
yagi stations replying to my CQs that I just  didn't copy. My apologies 
to all who wasted their time!

I simply  don't understand what the reason could be - the antenna pattern 
is normal,  the overall RX gain seems normal too and the VSWR on transmit 
is below  1.2. Admittedly, last time I had the front end down on the 
bench it  measured in at about 40 Kelvin, a bit high but nowhere close to 
what would  be needed to cause the overall system  performance to degrade 
this  badly.  Ideas anyone?

Next operation probably around the May 1 -  May 4 extended weekend / 
DUBUS CW activity. Skeds welcome!

Gudmund  SM2BYA / SM3BYA

Rig at SM3BYA:    8x 21 ele Tonna  yagis
2x 4CX250R in K2RIW PA, 800 watts  out
0.6 dB NF, transverter + Drake R-4C +  DSP59+

_______________________________________________
Moon mailing  list
Moon at moonbounce.info
http://www.moonbounce.info/mailman/listinfo/moon

Please  enter/update your standings: 
http://www.vhf-dx.net/top.html

When  you decide to remain anonymous I may consider this unpolite and remove 
you  from the list





**************Create a Home Theater Like the Pros. Watch the video on AOL 
Home.      
(http://home.aol.com/diy/home-improvement-eric-stromer?video=15?ncid=aolhom00030000000001)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.moonbounce.info/pipermail/moon/attachments/20080319/aa74c9e1/attachment.htm