R: [TowerTalk] best coax/receiving
k6ll@juno.com
k6ll@juno.com
Wed, 12 Apr 2000 20:24:27 -0600
On Wed, 12 Apr 2000 20:16:40 +0200 "Maurizio Panicara" <i4jmy@iol.it>
writes:
> 1) Forget the S-Meter, noise, AM mode, etc etc..
> 2) Ask a friend to transmit a carrier signal on a clean spot of
> the10m band
> and receive it in SSB mode, AGC off (if possible).
> 3) Ask him to reduce power (or to do something) until it's barely
> audible
> for you.
> 4) Switch on your 3 dB attenuator.
> 5) Evaluate results.
> 6) Repost your impressions to "towertalk".
>
> 73,
> Mauri I4JMY
I just finished running this test with W7WW, who lives about 15
miles away. When a 6dB attenuator was switched in, there was absolutely
no degradation in signal to noise ratio.
I had W7WW send some slow qrp cw on 28390. The band was
pretty quiet, no LED's illuminated on the s-meter. I turned my
antenna so that I could copy just about half of what he was sending.
SSB mode on my TS-850, no agc.
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 Hachadorian, K6LL
Yuma, AZ
K6LL@juno.com
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