[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: Wow, good tm



>From: Jerry Pixton <jpixton@shentel.net>
>All,
**snip**
>I have been running with the SP-2000 turned on and the 10db attenuator in 
>the FT-847 on to bring the noise level back down. With that setting this 
>morning, I got bad CRC tm. But when I turned the SP-2000 off and turned off 
>the attenuator, I could copy good CRC tm. HI.  Too much gain, I guess. 
>Better Signal to Noise at lower signal levels?
>
>I am encouraged. There is still room for improvement at the antenna (helix 
>and downconverter behind the helix reflector). Have almost 0.6db loss ahead 
>of downconverter right now

Jerry,

You were probably over-driving the SP-2000 into saturation.  Look for ways
to eliminate the 0.6 dB loss as that adds directly to the system NF {i.e.
UEK NF=0.7 +  0.6, system NF = 1.1}.  Best to directly mount at the
antenna, or minimize the coax run to the converter {say 6 inches of 9913,
or less}.

Ed 

----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home