R: [TowerTalk] best coax/receiving

[i4jmy@iol.it]

You must really live in a terrible location for QRM and same while 
owning a great receiver if up to 10 dB extra loss with an SSB filter 
doesn't have any impact on S/N of the barely audible received signal.
Here, in a location that's far to be a real noise free one, using a 
receiver with -130 dB sensitivity (-137 with 500 Hz filter) connected 
to a 10 meter 5 element yagi, what happens adding 10 dB attenuation to 
a barely audible carrier signal (no CW to decode) is that the signal 
drop to a noise among others in the audio of the receiver. 
If a 250 Hz filter might set a top receiver sensitivity far below the 
band noise, switching to a standard SSB filter the same receiver S/N 
radio drops anyway by about 10 dB.
Since what's averagely needed to copy, in term of S/N, is roughly 7 dB 
higher in SSB mode than CW, I wouldn't want to swap my location with 
yours and I still hate to waste energy along coaxial lines.  

73,
Mauri I4JMY

> ---------- Initial message -----------
> 
> From    : owner-towertalk@contesting.com
> To      : towertalk@contesting.com
> Cc      : 
> Date    : Wed, 12 Apr 2000 20:24:27 -0600
> Subject : Re: R: [TowerTalk] best coax/receiving

> 
> With 6dB of attenuation, copy was not impaired at all.
> 
> With 12dB of attenuation, I could still hear it, but the percent
> copy went down to about 25 percent.
> 
> With 18dB attenuation, I could just about hear him, but couldn't
> copy what he was sending.
> 
> The band was a little noisier than last night. Unlike last night,
> I could hear the background noise go down a little when I went from
> 12 to 18 dB of attenuation, but the s-meter still read zero with no
> attenuation.
> 
> I conclude from this little experiment that my ability to copy
> a weak signal would not have been impaired, even if my coax cable
> loss had been 6dB for sure, and maybe even as high as 10 dB. 
> 
> It would be really interesting to have some other people in rural
> locations try this same experiment.
> 
> 
> Dave Hacha
Yuma, AZ
> K6LL@juno.com




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